Part 1
This article examines in more detail the principle of operation of fuel cells, their design, classification, advantages and disadvantages, scope of application, efficiency, history of creation and modern prospects for use. In the second part of the article, which will be published in the next issue of the ABOK magazine, provides examples of facilities where heat and power supply (or only power supply) were used various types fuel cells.
Introduction
Fuel cells are a very efficient, reliable, durable and environmentally friendly way to generate energy.
Initially used only in the space industry, fuel cells are now increasingly used in a variety of areas - as stationary power plants, autonomous sources of heat and power supply to buildings, engines vehicles, power supplies for laptops and mobile phones. Some of these devices are laboratory prototypes, some are undergoing pre-production testing or are used for demonstration purposes, but many models are mass-produced and used in commercial projects.
A fuel cell (electrochemical generator) is a device that directly converts the chemical energy of fuel (hydrogen) into electrical energy through an electrochemical reaction, in contrast to traditional technologies that use the combustion of solid, liquid and gaseous fuels. Direct electrochemical conversion of fuel is very effective and attractive from an environmental point of view, since the operation process produces a minimal amount of pollutants and there is no strong noise or vibration.
From a practical point of view, a fuel cell resembles a conventional voltaic battery. The difference is that the battery is initially charged, i.e. filled with “fuel”. During operation, “fuel” is consumed and the battery is discharged. Unlike a battery, a fuel cell for production electrical energy uses fuel supplied from an external source (Fig. 1).
To produce electrical energy, not only pure hydrogen can be used, but also other hydrogen-containing raw materials, for example, natural gas, ammonia, methanol or gasoline. Ordinary air is used as a source of oxygen, also necessary for the reaction.
When using pure hydrogen as a fuel, the reaction products, in addition to electrical energy, are heat and water (or water vapor), i.e., gases that cause air pollution or cause the greenhouse effect are not emitted into the atmosphere. If a hydrogen-containing feedstock such as natural gas is used as a fuel, other gases such as carbon and nitrogen oxides will be a by-product of the reaction, but the amount will be significantly lower than if the same amount is burned natural gas.
The process of chemically converting fuel to produce hydrogen is called reforming, and the corresponding device is called a reformer.
Advantages and disadvantages of fuel cells
Fuel cells are more energy efficient than internal combustion engines because there is no thermodynamic energy efficiency limitation for fuel cells. The efficiency of fuel cells is 50%, while the efficiency of internal combustion engines is 12-15%, and the efficiency of steam turbine power plants does not exceed 40%. By using heat and water, the efficiency of fuel cells is further increased.
Unlike, for example, internal combustion engines, the efficiency of fuel cells remains very high even when they are not operating at full power. In addition, the power of fuel cells can be increased by simply adding individual units, while the efficiency does not change, i.e. large installations are just as efficient as small ones. These circumstances make it possible to very flexibly select the composition of equipment in accordance with the wishes of the customer and ultimately lead to a reduction in equipment costs.
An important advantage of fuel cells is their environmental friendliness. Fuel cell emissions are so low that in some areas of the United States, their operation does not require special approval from government air quality regulators.
Fuel cells can be placed directly in a building, reducing losses during energy transportation, and the heat generated as a result of the reaction can be used to supply heat or hot water to the building. Autonomous sources of heat and electricity can be very beneficial in remote areas and in regions characterized by a shortage of electricity and its high cost, but at the same time there are reserves of hydrogen-containing raw materials (oil, natural gas).
The advantages of fuel cells are also the availability of fuel, reliability (there are no moving parts in a fuel cell), durability and ease of operation.
One of the main disadvantages of fuel cells today is their relatively high cost, but this disadvantage can soon be overcome - more and more companies are producing commercial samples of fuel cells, they are constantly being improved, and their cost is decreasing.
The most effective way is to use pure hydrogen as a fuel, but this will require the creation of a special infrastructure for its production and transportation. Currently, all commercial designs use natural gas and similar fuels. Motor vehicles can use regular gasoline, which will allow maintaining the existing developed network of gas stations. However, the use of such fuel leads to harmful emissions into the atmosphere (albeit very low) and complicates (and therefore increases the cost of) the fuel cell. In the future, the possibility of using environmentally friendly renewable energy sources (for example, solar or wind energy) to decompose water into hydrogen and oxygen using electrolysis, and then converting the resulting fuel in a fuel cell, is being considered. Such combined plants, operating in a closed cycle, can represent a completely environmentally friendly, reliable, durable and efficient source of energy.
Another feature of fuel cells is that they are most efficient when using both electrical and thermal energy simultaneously. However, not every facility has the opportunity to use thermal energy. If fuel cells are used only to generate electrical energy, their efficiency decreases, although it exceeds the efficiency of “traditional” installations.
History and modern use of fuel cells
The principle of operation of fuel cells was discovered in 1839. The English scientist William Robert Grove (1811-1896) discovered that the process of electrolysis - the decomposition of water into hydrogen and oxygen through electric current - is reversible, i.e. hydrogen and oxygen can be combined into water molecules without combustion, but with the release of heat and electric current. Grove called the device in which such a reaction was possible a “gas battery,” which was the first fuel cell.
The active development of technologies for the use of fuel cells began after the Second World War, and it is associated with the aerospace industry. At this time, a search was underway for an effective and reliable, but at the same time quite compact, source of energy. In the 1960s, NASA (National Aeronautics and Space Administration, NASA) specialists chose fuel cells as the energy source for the spacecraft of the Apollo (manned flights to the Moon), Apollo-Soyuz, Gemini and Skylab programs. . The Apollo spacecraft used three 1.5 kW (2.2 kW peak) plants using cryogenic hydrogen and oxygen to produce electricity, heat and water. The mass of each installation was 113 kg. These three cells operated in parallel, but the energy generated by one unit was sufficient for a safe return. Over the course of 18 flights, the fuel cells operated for a total of 10,000 hours without any failures. Currently, fuel cells are used in the Space Shuttle, which uses three 12 W units to generate all the electrical energy on board the spacecraft (Fig. 2). The water obtained as a result of the electrochemical reaction is used as drinking water and also for cooling equipment.
In our country, work was also carried out on the creation of fuel cells for use in astronautics. For example, fuel cells were used to power the Soviet Buran reusable spacecraft.
Development of methods for the commercial use of fuel cells began in the mid-1960s. These developments were partially funded by government organizations.
Currently, the development of technologies for the use of fuel cells is proceeding in several directions. This is the creation of stationary power plants on fuel cells (both for centralized and decentralized energy supply), power plants for vehicles (samples of cars and buses on fuel cells have been created, including in our country) (Fig. 3), and also power supplies of various mobile devices(laptop computers, mobile phones etc.) (Fig. 4).
Examples of the use of fuel cells in various fields are given in Table. 1.
One of the first commercial fuel cell models designed for autonomous heat and power supply to buildings was the PC25 Model A, manufactured by ONSI Corporation (now United Technologies, Inc.). This fuel cell with a nominal power of 200 kW is a type of cell with an electrolyte based on phosphoric acid (Phosphoric Acid Fuel Cells, PAFC). The number “25” in the model name means the serial number of the design. Most previous models were experimental or test units, such as the 12.5 kW "PC11" model introduced in the 1970s. The new models increased the power extracted from an individual fuel cell, and also reduced the cost per kilowatt of energy produced. Currently, one of the most efficient commercial models is the PC25 Model C fuel cell. Like Model A, this is a fully automatic PAFC fuel cell with a power of 200 kW, designed for installation directly on the serviced site as an autonomous source of heat and power supply. Such a fuel cell can be installed outside a building. Externally, it is a parallelepiped 5.5 m long, 3 m wide and high, weighing 18,140 kg. The difference from previous models is an improved reformer and a higher current density.
| Table 1 Field of application of fuel cells |
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In some types of fuel cells, the chemical process can be reversed: by applying a potential difference to the electrodes, water can be broken down into hydrogen and oxygen, which collect on the porous electrodes. When a load is connected, such a regenerative fuel cell will begin to generate electrical energy.
A promising direction for the use of fuel cells is their use in conjunction with renewable energy sources, for example, photovoltaic panels or wind power plants. This technology allows us to completely avoid air pollution. A similar system is planned to be created, for example, at the Adam Joseph Lewis Training Center in Oberlin (see ABOK, 2002, No. 5, p. 10). Currently, solar panels are used as one of the energy sources in this building. Together with NASA specialists, a project has been developed for using photovoltaic panels to produce hydrogen and oxygen from water by electrolysis. The hydrogen is then used in fuel cells to produce electrical energy and hot water. This will allow the building to maintain the functionality of all systems during cloudy days and at night.
Operating principle of fuel cells
Let's consider the principle of operation of a fuel cell using the example of a simple element with a proton exchange membrane (Proton Exchange Membrane, PEM). Such a cell consists of a polymer membrane placed between an anode (positive electrode) and a cathode (negative electrode) along with anode and cathode catalysts. The polymer membrane is used as an electrolyte. The diagram of the PEM element is shown in Fig. 5.
A proton exchange membrane (PEM) is a thin (about 2-7 sheets of paper thick) solid organic compound. This membrane functions as an electrolyte: it separates a substance into positively and negatively charged ions in the presence of water.
An oxidation process occurs at the anode, and a reduction process occurs at the cathode. The anode and cathode in a PEM cell are made of a porous material, which is a mixture of carbon and platinum particles. Platinum acts as a catalyst that promotes the dissociation reaction. The anode and cathode are made porous for the free passage of hydrogen and oxygen through them, respectively.
The anode and cathode are placed between two metal plates, which supply hydrogen and oxygen to the anode and cathode, and remove heat and water, as well as electrical energy.
Hydrogen molecules pass through channels in the plate to the anode, where the molecules are decomposed into individual atoms (Fig. 6).
Figure 5. () Schematic of a fuel cell with a proton exchange membrane (PEM cell) |
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Figure 6. () Hydrogen molecules pass through channels in the plate to the anode, where the molecules decompose into individual atoms |
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Figure 7. () As a result of chemisorption in the presence of a catalyst, hydrogen atoms are converted into protons |
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Figure 8. () Positively charged hydrogen ions diffuse through the membrane to the cathode, and a flow of electrons is directed to the cathode through an external electrical circuit to which the load is connected |
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Figure 9. () Oxygen supplied to the cathode, in the presence of a catalyst, enters into a chemical reaction with hydrogen ions from the proton exchange membrane and electrons from the external electrical circuit. As a result chemical reaction water is formed |
Then, as a result of chemisorption in the presence of a catalyst, hydrogen atoms, each giving up one electron e –, are converted into positively charged hydrogen ions H +, i.e. protons (Fig. 7).
Positively charged hydrogen ions (protons) diffuse through the membrane to the cathode, and the flow of electrons is directed to the cathode through an external electrical circuit to which the load (consumer of electrical energy) is connected (Fig. 8).
Oxygen supplied to the cathode, in the presence of a catalyst, enters into a chemical reaction with hydrogen ions (protons) from the proton exchange membrane and electrons from the external electrical circuit (Fig. 9). As a result of a chemical reaction, water is formed.
The chemical reaction in other types of fuel cells (for example, with an acid electrolyte, which uses a solution of orthophosphoric acid H 3 PO 4) is absolutely identical to the chemical reaction in a fuel cell with a proton exchange membrane.
In any fuel cell, some of the energy from a chemical reaction is released as heat.
The flow of electrons in an external circuit is a direct current that is used to do work. Opening the external circuit or stopping the movement of hydrogen ions stops the chemical reaction.
The amount of electrical energy produced by a fuel cell depends on the type of fuel cell, geometric dimensions, temperature, gas pressure. A separate fuel cell provides an EMF of less than 1.16 V. The size of fuel cells can be increased, but in practice several elements connected into batteries are used (Fig. 10).
Fuel cell design
Let's look at the design of a fuel cell using the PC25 Model C as an example. The fuel cell diagram is shown in Fig. 11.
The PC25 Model C fuel cell consists of three main parts: the fuel processor, the actual power generation section and the voltage converter.
The main part of the fuel cell - the power generation section - is a battery made up of 256 individual fuel cells. The fuel cell electrodes contain a platinum catalyst. Through these cells a constant electric current 1,400 amps at 155 volts. The battery dimensions are approximately 2.9 m in length and 0.9 m in width and height.
Since the electrochemical process occurs at a temperature of 177 °C, it is necessary to heat the battery at the time of start-up and remove heat from it during operation. To achieve this, the fuel cell includes a separate water circuit, and the battery is equipped with special cooling plates.
The fuel processor converts natural gas into hydrogen needed for an electrochemical reaction. This process is called reforming. The main element of the fuel processor is the reformer. In the reformer, natural gas (or other hydrogen-containing fuel) reacts with water vapor at high temperature (900 °C) and high pressure in the presence of a nickel catalyst. In this case, the following chemical reactions occur:
CH 4 (methane) + H 2 O 3H 2 + CO
(the reaction is endothermic, with heat absorption);
CO + H 2 O H 2 + CO 2
(the reaction is exothermic, releasing heat).
The overall reaction is expressed by the equation:
CH 4 (methane) + 2H 2 O 4H 2 + CO 2
(the reaction is endothermic, with heat absorption).
To provide the high temperature required to convert natural gas, a portion of the spent fuel from the fuel cell stack is directed to a burner, which maintains the required reformer temperature.
The steam required for reforming is generated from condensate generated during operation of the fuel cell. This uses the heat removed from the battery of fuel cells (Fig. 12).
The fuel cell stack produces an intermittent direct current that is low voltage and high current. A voltage converter is used to convert it to industry standard AC current. In addition, the voltage converter unit includes various control devices and safety interlock circuits that allow the fuel cell to be turned off in the event of various failures.
In such a fuel cell, approximately 40% of the fuel energy can be converted into electrical energy. Approximately the same amount, about 40% of the fuel energy, can be converted into thermal energy, which is then used as a heat source for heating, hot water supply and similar purposes. Thus, the total efficiency of such an installation can reach 80%.
An important advantage of such a source of heat and electricity supply is the possibility of its automatic operation. For maintenance, the owners of the facility where the fuel cell is installed do not need to maintain specially trained personnel - periodic maintenance can be carried out by employees of the operating organization.
Types of fuel cells
Currently, several types of fuel cells are known, differing in the composition of the electrolyte used. The following four types are most widespread (Table 2):
1. Fuel cells with a proton exchange membrane (Proton Exchange Membrane Fuel Cells, PEMFC).
2. Fuel cells based on orthophosphoric acid (Phosphoric Acid Fuel Cells, PAFC).
3. Fuel cells based on molten carbonate (Molten Carbonate Fuel Cells, MCFC).
4. Solid Oxide Fuel Cells (SOFC). Currently, the largest fleet of fuel cells is based on PAFC technology.
One of the key characteristics of different types of fuel cells is operating temperature. In many ways, it is the temperature that determines the area of application of fuel cells. For example, high temperatures are critical for laptops, so proton exchange membrane fuel cells with low operating temperatures are being developed for this market segment.
For autonomous power supply of buildings, fuel cells of high installed power are required, and at the same time there is the possibility of using thermal energy, so other types of fuel cells can be used for these purposes.
Proton exchange membrane fuel cells (PEMFC)
These fuel cells operate at relatively low operating temperatures (60-160 °C). They are characterized by high power density, allow you to quickly adjust the output power, and can be quickly turned on. The disadvantage of this type of element is the high requirements for fuel quality, since contaminated fuel can damage the membrane. The rated power of this type of fuel cells is 1-100 kW.
Proton exchange membrane fuel cells were originally developed by General Electric in the 1960s for NASA. This type of fuel cell uses a solid-state polymer electrolyte called a Proton Exchange Membrane (PEM). Protons can move through the proton exchange membrane, but electrons cannot pass through it, resulting in a potential difference between the cathode and anode. Because of their simplicity and reliability, such fuel cells were used as a power source on the manned Gemini spacecraft.
This type of fuel cell is used as a power source for a wide range of different devices, including prototypes and prototypes, from mobile phones to buses and stationary systems nutrition. The low operating temperature allows such cells to be used to power various types of complex electronic devices. Their use is less effective as a source of heat and electricity supply to public and industrial buildings, where large volumes of thermal energy are required. At the same time, such elements are promising as an autonomous source of power supply for small residential buildings such as cottages built in regions with a hot climate.
| Table 2 Types of fuel cells |
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Phosphoric Acid Fuel Cells (PAFC)
Tests of fuel cells of this type were carried out already in the early 1970s. Operating temperature range - 150-200 °C. The main area of application is autonomous sources of heat and electricity supply of medium power (about 200 kW).
These fuel cells use a phosphoric acid solution as the electrolyte. The electrodes are made of paper coated with carbon in which a platinum catalyst is dispersed.
The electrical efficiency of PAFC fuel cells is 37-42%. However, since these fuel cells operate at a fairly high temperature, it is possible to use the steam generated as a result of operation. In this case, the overall efficiency can reach 80%.
To produce energy, hydrogen-containing feedstock must be converted into pure hydrogen through a reforming process. For example, if gasoline is used as fuel, it is necessary to remove sulfur-containing compounds, since sulfur can damage the platinum catalyst.
PAFC fuel cells were the first commercial fuel cells whose use became feasible with economic point vision. The most common model was the 200 kW PC25 fuel cell manufactured by ONSI Corporation (now United Technologies, Inc.) (Fig. 13). For example, these elements are used as a source of thermal and electrical energy in a police station in Central Park New York or as an additional source of energy for the Conde Nast Building & Four Times Square. The largest installation of this type is being tested as an 11 MW power plant located in Japan.
Phosphoric acid fuel cells are also used as an energy source in vehicles. For example, in 1994, H-Power Corp., Georgetown University and the US Department of Energy equipped a bus with a 50 kW power plant.
Molten Carbonate Fuel Cells (MCFC)
Fuel cells of this type operate at very high temperatures - 600-700 °C. These operating temperatures allow the fuel to be used directly in the cell itself, without the use of a separate reformer. This process was called “internal reform”. It makes it possible to significantly simplify the design of the fuel cell.
Fuel cells based on molten carbonate require a significant start-up time and do not allow for prompt adjustment of output power, so their main area of application is large stationary sources of thermal and electrical energy. However, they are characterized by high fuel conversion efficiency - 60% electrical efficiency and up to 85% overall efficiency.
In this type of fuel cell, the electrolyte consists of potassium carbonate and lithium carbonate salts heated to approximately 650 °C. Under these conditions, the salts are in a molten state, forming an electrolyte. At the anode, hydrogen reacts with CO 3 ions, forming water, carbon dioxide and releasing electrons, which are sent to the external circuit, and at the cathode, oxygen interacts with carbon dioxide and electrons from the external circuit, again forming CO 3 ions.
Laboratory samples of fuel cells of this type were created in the late 1950s by Dutch scientists G. H. J. Broers and J. A. A. Ketelaar. In the 1960s, engineer Francis T. Bacon, a descendant of the famous English writer and scientist of the 17th century, worked with these cells, which is why MCFC fuel cells are sometimes called Bacon cells. In the NASA Apollo, Apollo-Soyuz and Scylab programs, these fuel cells were used as a source of energy supply (Fig. 14). During these same years, the US military department tested several samples of MCFC fuel cells produced by Texas Instruments, which used military grade gasoline as fuel. In the mid-1970s, the US Department of Energy began research to create a stationary fuel cell based on molten carbonate, suitable for practical application. In the 1990s, a number of commercial installations with rated power up to 250 kW were introduced, for example at the US Naval Air Station Miramar in California. In 1996, FuelCell Energy, Inc. launched a pre-production 2 MW plant in Santa Clara, California.
Solid-state oxide fuel cells (SOFC)
Solid-state oxide fuel cells are simple in design and operate at very high temperatures - 700-1,000 °C. Such high temperatures allow the use of relatively “dirty”, unrefined fuel. The same features as those of fuel cells based on molten carbonate determine a similar field of application - large stationary sources of thermal and electrical energy.
Solid oxide fuel cells are structurally different from fuel cells based on PAFC and MCFC technologies. The anode, cathode and electrolyte are made of special grades of ceramics. The most commonly used electrolyte is a mixture of zirconium oxide and calcium oxide, but other oxides can also be used. The electrolyte forms a crystal lattice coated on both sides with porous electrode material. Structurally, such elements are made in the form of tubes or flat circuit boards, which makes it possible to use technologies widely used in the electronics industry in their production. As a result, solid-state oxide fuel cells can operate at very high temperatures, making them advantageous for producing both electrical and thermal energy.
At high operating temperatures, oxygen ions are formed at the cathode, which migrate through the crystal lattice to the anode, where they interact with hydrogen ions, forming water and releasing free electrons. In this case, hydrogen is separated from natural gas directly in the cell, i.e. there is no need for a separate reformer.
The theoretical foundations for the creation of solid-state oxide fuel cells were laid back in the late 1930s, when Swiss scientists Emil Bauer and H. Preis experimented with zirconium, yttrium, cerium, lanthanum and tungsten, using them as electrolytes.
The first prototypes of such fuel cells were created in the late 1950s by a number of American and Dutch companies. Most of these companies soon abandoned further research due to technological difficulties, but one of them, Westinghouse Electric Corp. (now Siemens Westinghouse Power Corporation), continued work. The company is currently accepting pre-orders for a commercial model of a tubular solid-state oxide fuel cell, expected to be available this year (Figure 15). The market segment of such elements is stationary installations for the production of thermal and electrical energy with a capacity of 250 kW to 5 MW.
SOFC fuel cells have demonstrated very high reliability. For example, a prototype fuel cell manufactured by Siemens Westinghouse has achieved 16,600 hours of operation and continues to operate, making it the longest continuous fuel cell life in the world.
The high-temperature, high-pressure operating mode of SOFC fuel cells allows for the creation of hybrid plants in which fuel cell emissions drive gas turbines used to generate electrical power. The first such hybrid installation is operating in Irvine, California. The rated power of this installation is 220 kW, of which 200 kW from the fuel cell and 20 kW from the microturbine generator.
A fuel cell is a device that efficiently produces heat and direct current through an electrochemical reaction and uses a hydrogen-rich fuel. Its operating principle is similar to that of a battery. Structurally, the fuel cell is represented by an electrolyte. What's so special about it? Unlike batteries, hydrogen fuel cells do not store electrical energy, do not require electricity to recharge, and do not discharge. The cells continue to produce electricity as long as they have a supply of air and fuel.
Peculiarities
The difference between fuel cells and other electricity generators is that they do not burn fuel during operation. Due to this feature, they do not require rotors high pressure, do not emit loud noise or vibrations. Electricity in fuel cells is generated through a silent electrochemical reaction. The chemical energy of the fuel in such devices is converted directly into water, heat and electricity.
Fuel cells are highly efficient and do not produce large quantity greenhouse gases. The emission product during cell operation is a small amount of water in the form of steam and carbon dioxide, which is not released if pure hydrogen is used as fuel.
History of appearance
In the 1950s and 1960s, NASA's emerging need for energy sources for long-term space missions provoked one of the most critical challenges for fuel cells that existed at that time. Alkaline cells use oxygen and hydrogen as fuel, which are converted through an electrochemical reaction into byproducts useful during space flight - electricity, water and heat.
Fuel cells were first discovered at the beginning of the 19th century - in 1838. At the same time, the first information about their effectiveness appeared.
Work on fuel cells using alkaline electrolytes began in the late 1930s. Cells with nickel-plated electrodes under high pressure were not invented until 1939. During World War II, fuel cells consisting of alkaline cells with a diameter of about 25 centimeters were developed for British submarines.
Interest in them increased in the 1950-80s, characterized by a shortage of petroleum fuel. Countries around the world have begun to address air pollution and environment, striving to develop environmentally friendly fuel cell production technology is currently undergoing active development.
Operating principle
Heat and electricity are generated by fuel cells as a result of an electrochemical reaction involving a cathode, anode and an electrolyte.
The cathode and anode are separated by a proton-conducting electrolyte. After oxygen enters the cathode and hydrogen enters the anode, a chemical reaction is started, resulting in heat, current and water.
Dissociates on the anode catalyst, which leads to the loss of electrons. Hydrogen ions enter the cathode through the electrolyte, and at the same time electrons pass through the outer electrical network and create direct current, which is used to power equipment. An oxygen molecule on the cathode catalyst combines with an electron and an incoming proton, ultimately forming water, which is the only product of the reaction.
Types
The choice of a specific type of fuel cell depends on its application. All fuel cells are divided into two main categories - high temperature and low temperature. The latter use pure hydrogen as fuel. Such devices typically require processing of primary fuel into pure hydrogen. The process is carried out using special equipment.
High temperature fuel cells do not need this as they convert the fuel at elevated temperatures, which eliminates the need to create a hydrogen infrastructure.
The operating principle of hydrogen fuel cells is based on the conversion of chemical energy into electrical energy without ineffective combustion processes and the transformation of thermal energy into mechanical energy.
General concepts
Hydrogen fuel cells are electrochemical devices that produce electricity through highly efficient "cold" combustion of fuel. There are several types of such devices. The most promising technology is considered to be hydrogen-air fuel cells equipped with a proton exchange membrane PEMFC.
The proton-conducting polymer membrane is designed to separate two electrodes - the cathode and the anode. Each of them is represented by a carbon matrix with a catalyst deposited on it. dissociates on the anode catalyst, donating electrons. Cations are conducted to the cathode through the membrane, but electrons are transferred to the external circuit because the membrane is not designed to transfer electrons.
An oxygen molecule on the cathode catalyst combines with an electron from the electrical circuit and an incoming proton, ultimately forming water, which is the only product of the reaction.
Hydrogen fuel cells are used to manufacture membrane-electrode units, which act as the main generating elements of the energy system.
Advantages of Hydrogen Fuel Cells
Among them are:
- Increased specific heat.
- Wide operating temperature range.
- No vibration, noise or heat stain.
- Cold start reliability.
- No self-discharge, which ensures long-term energy storage.
- Unlimited autonomy thanks to the ability to adjust energy intensity by changing the number of fuel cartridges.
- Providing virtually any energy intensity by changing the hydrogen storage capacity.
- Long service life.
- Quiet and environmentally friendly operation.
- High level of energy intensity.
- Tolerance to foreign impurities in hydrogen.
Scope of application
Thanks to high efficiency Hydrogen fuel cells are used in various fields:
- Portable chargers.
- Power supply systems for UAVs.
- Uninterruptible power supplies.
- Other devices and equipment.
Prospects for hydrogen energy
The widespread use of hydrogen peroxide fuel cells will be possible only after the creation effective way obtaining hydrogen. New ideas are required to bring the technology into active use, with high hopes placed on the concept of biofuel cells and nanotechnology. Some companies have relatively recently released effective catalysts based on various metals, at the same time information has emerged about the creation of fuel cells without membranes, which has significantly reduced the cost of production and simplified the design similar devices. The advantages and characteristics of hydrogen fuel cells do not outweigh their main disadvantage - high cost, especially in comparison with hydrocarbon devices. The creation of one hydrogen power plant requires a minimum of 500 thousand dollars.
How to assemble a hydrogen fuel cell?
You can create a low-power fuel cell yourself in a regular home or school laboratory. The materials used are an old gas mask, pieces of plexiglass, an aqueous solution of ethyl alcohol and alkali.
The body of a hydrogen fuel cell is created with your own hands from plexiglass with a thickness of at least five millimeters. The partitions between the compartments can be thinner - about 3 millimeters. Plexiglas is glued together special glue, made from chloroform or dichloroethane and plexiglass shavings. All work is carried out only with the hood running.
IN outer wall In the housing, a hole with a diameter of 5-6 centimeters is drilled into which a rubber stopper and a glass drain tube are inserted. Activated carbon from the gas mask is poured into the second and fourth compartments of the fuel cell housing - it will be used as an electrode.
Fuel will circulate in the first chamber, while the fifth is filled with air, from which oxygen will be supplied. The electrolyte, poured between the electrodes, is impregnated with a solution of paraffin and gasoline to prevent it from entering the air chamber. Copper plates with wires soldered to them are placed on the layer of coal, through which the current will be drained.
The assembled hydrogen fuel cell is charged with vodka diluted with water in a 1:1 ratio. Caustic potassium is carefully added to the resulting mixture: 70 grams of potassium dissolve in 200 grams of water.
Before testing a hydrogen fuel cell, fuel is poured into the first chamber and electrolyte into the third. The voltmeter readings connected to the electrodes should vary from 0.7 to 0.9 volts. To ensure continuous operation of the element, spent fuel must be removed, and new fuel must be poured through a rubber tube. By squeezing the tube, the fuel supply rate is adjusted. Such hydrogen fuel cells, assembled at home, have little power.
Fuel cell is an electrochemical device similar to a galvanic cell, but differs from it in that the substances for the electrochemical reaction are supplied to it from the outside - in contrast to the limited amount of energy stored in galvanic cell or battery.
Rice. 1. Some fuel cells
Fuel cells convert the chemical energy of fuel into electricity, bypassing ineffective combustion processes that occur with large losses. They convert hydrogen and oxygen into electricity through a chemical reaction. As a result of this process, water is formed and a large amount of heat is released. A fuel cell is very similar to a battery that can be charged and then use the stored electrical energy. The inventor of the fuel cell is considered to be William R. Grove, who invented it back in 1839. This fuel cell used a sulfuric acid solution as an electrolyte and hydrogen as a fuel, which was combined with oxygen in an oxidizing agent. Until recently, fuel cells were used only in laboratories and on spacecraft.
Rice. 2.
Unlike other power generators, such as internal combustion engines or turbines powered by gas, coal, fuel oil, etc., fuel cells do not burn fuel. This means no noisy high-pressure rotors, no loud exhaust noise, no vibrations. Fuel cells produce electricity through a silent electrochemical reaction. Another feature of fuel cells is that they convert the chemical energy of the fuel directly into electricity, heat and water.
Fuel cells are highly efficient and do not produce large amounts of greenhouse gases such as carbon dioxide, methane and nitrous oxide. The only emissions from fuel cells are water in the form of steam and a small amount of carbon dioxide, which is not released at all if pure hydrogen is used as fuel. Fuel cells are assembled into assemblies and then into individual functional modules.
Fuel cells have no moving parts (at least not within the cell itself) and therefore do not obey Carnot's law. That is, they will have greater than 50% efficiency and are especially effective at low loads. Thus, fuel cell cars can become (and have already proven to be) more fuel efficient than conventional cars in real-world driving conditions.
The fuel cell provides the generation of direct voltage electric current, which can be used to drive an electric motor, lighting system devices, and other electrical systems in the car.
There are several types of fuel cells, differing in the chemical processes used. Fuel cells are usually classified by the type of electrolyte they use.
Some types of fuel cells are promising for use in power plants, while others are promising for portable devices or to drive cars.
1. Alkaline fuel cells (ALFC)
Alkaline fuel cell- This is one of the very first elements developed. Alkaline fuel cells (AFC) are one of the most studied technologies, used since the mid-60s of the twentieth century by NASA in the Apollo and Space Shuttle programs. On board these spacecraft, fuel cells produce electrical energy and potable water.
Rice. 3.
Alkaline fuel cells are one of the most efficient cells used to generate electricity, with power generation efficiency reaching up to 70%.
Alkaline fuel cells use an electrolyte, an aqueous solution of potassium hydroxide, contained in a porous, stabilized matrix. The potassium hydroxide concentration may vary depending on the operating temperature of the fuel cell, which ranges from 65°C to 220°C. The charge carrier in SHTE is the hydroxyl ion (OH-), moving from the cathode to the anode, where it reacts with hydrogen, producing water and electrons. The water produced at the anode moves back to the cathode, again generating hydroxyl ions there. As a result of this series of reactions taking place in the fuel cell, electricity and, as a by-product, heat are produced:
Reaction at the anode: 2H2 + 4OH- => 4H2O + 4e
Reaction at the cathode: O2 + 2H2O + 4e- => 4OH
General reaction of the system: 2H2 + O2 => 2H2O
The advantage of SHTE is that these fuel cells are the cheapest to produce, since the catalyst needed on the electrodes can be any of the substances that are cheaper than those used as catalysts for other fuel cells. In addition, SHTEs operate at relatively low temperatures and are among the most efficient.
One of characteristic features SHTE – high sensitivity to CO2, which may be contained in fuel or air. CO2 reacts with the electrolyte, quickly poisons it, and greatly reduces the efficiency of the fuel cell. Therefore, the use of SHTE is limited to enclosed spaces, such as space and underwater vehicles; they operate on pure hydrogen and oxygen.
2. Molten carbonate fuel cells (MCFC)
Fuel cells with molten carbonate electrolyte are high temperature fuel cells. The high operating temperature allows the direct use of natural gas without a fuel processor and low calorific value fuel gas from industrial processes and other sources. This process was developed in the mid-60s of the twentieth century. Since then, production technology, performance and reliability have been improved.
Rice. 4.
The operation of RCFC differs from other fuel cells. These cells use an electrolyte made from a mixture of molten carbonate salts. Currently, two types of mixtures are used: lithium carbonate and potassium carbonate or lithium carbonate and sodium carbonate. To melt carbonate salts and achieve a high degree of ion mobility in the electrolyte, fuel cells with molten carbonate electrolyte operate at high temperatures (650°C). Efficiency varies between 60-80%.
When heated to a temperature of 650°C, the salts become a conductor for carbonate ions (CO32-). These ions pass from the cathode to the anode, where they combine with hydrogen to form water, carbon dioxide and free electrons. These electrons are sent through an external electrical circuit back to the cathode, generating electric current and heat as a by-product.
Reaction at the anode: CO32- + H2 => H2O + CO2 + 2e
Reaction at the cathode: CO2 + 1/2O2 + 2e- => CO32-
General reaction of the element: H2(g) + 1/2O2(g) + CO2(cathode) => H2O(g) + CO2(anode)
The high operating temperatures of molten carbonate electrolyte fuel cells have certain advantages. The advantage is the ability to use standard materials (stainless steel sheets and nickel catalyst on the electrodes). The waste heat can be used to produce high pressure steam. High reaction temperatures in the electrolyte also have their advantages. The use of high temperatures requires a long time to achieve optimal operating conditions, and the system responds more slowly to changes in energy consumption. These characteristics allow the use of fuel cell installations with molten carbonate electrolyte under constant power conditions. High temperatures prevent damage to the fuel cell by carbon monoxide, “poisoning,” etc.
Fuel cells with molten carbonate electrolyte are suitable for use in large stationary installations. Thermal power plants with an electrical output power of 2.8 MW are commercially produced. Installations with output power up to 100 MW are being developed.
3. Phosphoric acid fuel cells (PAFC)
Fuel cells based on phosphoric (orthophosphoric) acid became the first fuel cells for commercial use. This process was developed in the mid-60s of the twentieth century, tests have been carried out since the 70s of the twentieth century. The result was increased stability and performance and reduced cost.
Rice. 5.
Phosphoric (orthophosphoric) acid fuel cells use an electrolyte based on orthophosphoric acid (H3PO4) at concentrations up to 100%. The ionic conductivity of orthophosphoric acid is low at low temperatures Therefore, these fuel cells are used at temperatures up to 150-220 °C.
The charge carrier in fuel cells of this type is hydrogen (H+, proton). A similar process occurs in proton exchange membrane fuel cells (PEMFCs), in which hydrogen supplied to the anode is split into protons and electrons. Protons travel through the electrolyte and combine with oxygen from the air at the cathode to form water. The electrons are sent through an external electrical circuit, thereby generating an electric current. Below are reactions that generate electric current and heat.
Reaction at the anode: 2H2 => 4H+ + 4e
Reaction at the cathode: O2(g) + 4H+ + 4e- => 2H2O
General reaction of the element: 2H2 + O2 => 2H2O
The efficiency of fuel cells based on phosphoric (orthophosphoric) acid is more than 40% when generating electrical energy. With combined production of heat and electricity, the overall efficiency is about 85%. In addition, given operating temperatures, waste heat can be used to heat water and generate atmospheric pressure steam.
The high performance of thermal power plants using fuel cells based on phosphoric (orthophosphoric) acid in the combined production of thermal and electrical energy is one of the advantages of this type of fuel cells. The units use carbon monoxide with a concentration of about 1.5%, which significantly expands the choice of fuel. Simple design, low degree of electrolyte volatility and increased stability are also advantages of such fuel cells.
Thermal power plants with electrical output power of up to 400 kW are commercially produced. Installations with a capacity of 11 MW have passed appropriate tests. Installations with output power up to 100 MW are being developed.
4. Proton exchange membrane fuel cells (PEMFC)
Proton exchange membrane fuel cells are considered the most the best type fuel cells to generate power for vehicles, which can replace gasoline and diesel internal combustion engines. These fuel cells were first used by NASA for the Gemini program. Installations based on MOPFC with power from 1 W to 2 kW have been developed and demonstrated.
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The electrolyte in these fuel cells is a solid polymer membrane (a thin film of plastic). When saturated with water, this polymer allows protons to pass through but does not conduct electrons.
The fuel is hydrogen, and the charge carrier is a hydrogen ion (proton). At the anode, the hydrogen molecule is split into a hydrogen ion (proton) and electrons. Hydrogen ions pass through the electrolyte to the cathode, and electrons move around the outer circle and produce electrical energy. Oxygen, which is taken from the air, is supplied to the cathode and combines with electrons and hydrogen ions to form water. The following reactions occur at the electrodes: Reaction at the anode: 2H2 + 4OH- => 4H2O + 4eReaction at the cathode: O2 + 2H2O + 4e- => 4OH Overall cell reaction: 2H2 + O2 => 2H2O Compared to other types of fuel cells, fuel cells with a proton exchange membrane produce more energy for a given volume or weight of the fuel cell. This feature allows them to be compact and lightweight. In addition, the operating temperature is less than 100°C, which allows you to quickly start operation. These characteristics, as well as the ability to quickly change energy output, are just a few that make these fuel cells a prime candidate for use in vehicles.
Another advantage is that the electrolyte is a solid and not liquid substance. It is easier to retain gases at the cathode and anode using a solid electrolyte, so such fuel cells are cheaper to produce. With a solid electrolyte, there are no orientation issues and fewer corrosion problems, increasing the longevity of the cell and its components.
Rice. 7.
5. Solid oxide fuel cells (SOFC)
Solid oxide fuel cells are the highest operating temperature fuel cells. Operating temperature can vary from 600°C to 1000°C, allowing the use of different types of fuel without special pre-treatment. To handle such high temperatures, the electrolyte used is a thin solid metal oxide on a ceramic base, often an alloy of yttrium and zirconium, which is a conductor of oxygen ions (O2-). The technology of using solid oxide fuel cells has been developing since the late 50s of the twentieth century and has two configurations: planar and tubular.
The solid electrolyte provides a sealed transition of gas from one electrode to another, while liquid electrolytes are located in a porous substrate. The charge carrier in fuel cells of this type is the oxygen ion (O2-). At the cathode, oxygen molecules from the air are separated into an oxygen ion and four electrons. Oxygen ions pass through the electrolyte and combine with hydrogen, creating four free electrons. The electrons are sent through an external electrical circuit, generating electric current and waste heat.
Rice. 8.
Reaction at the anode: 2H2 + 2O2- => 2H2O + 4e
Reaction at the cathode: O2 + 4e- => 2O2-
General reaction of the element: 2H2 + O2 => 2H2O
The efficiency of electrical energy production is the highest of all fuel cells - about 60%. In addition, high operating temperatures allow for the combined production of thermal and electrical energy to generate high-pressure steam. Combining a high-temperature fuel cell with a turbine makes it possible to create a hybrid fuel cell to increase the efficiency of generating electrical energy by up to 70%.
Solid oxide fuel cells operate at very high temperatures (600°C-1000°C), resulting in significant time required to reach optimal operating conditions and the system being slower to respond to changes in energy consumption. At such high operating temperatures, no converter is required to recover hydrogen from the fuel, allowing the thermal power plant to operate with relatively impure fuels resulting from gasification of coal or waste gases, etc. This fuel cell is also excellent for use with high power, including industrial and large central power plants. Modules with an electrical output power of 100 kW are commercially produced.
6. Direct methanol oxidation fuel cells (DOMFC)
Direct methanol oxidation fuel cells They are successfully used in the field of powering mobile phones, laptops, as well as to create portable power sources, which is what the future use of such elements is aimed at.
The design of fuel cells with direct oxidation of methanol is similar to the design of fuel cells with a proton exchange membrane (MEPFC), i.e. A polymer is used as an electrolyte, and a hydrogen ion (proton) is used as a charge carrier. But liquid methanol (CH3OH) oxidizes in the presence of water at the anode, releasing CO2, hydrogen ions and electrons, which are sent through an external electrical circuit, thereby generating an electric current. Hydrogen ions pass through the electrolyte and react with oxygen from the air and electrons from the external circuit to form water at the anode.
Reaction at the anode: CH3OH + H2O => CO2 + 6H+ + 6eReaction at the cathode: 3/2O2 + 6H+ + 6e- => 3H2O General reaction of the element: CH3OH + 3/2O2 => CO2 + 2H2O The development of such fuel cells has been carried out since the beginning of the 90s s of the twentieth century and their specific power and efficiency were increased to 40%.
These elements were tested in the temperature range of 50-120°C. Because of their low operating temperatures and the absence of the need for a converter, such fuel cells are a prime candidate for use in mobile phones and other consumer products, as well as in car engines. Their advantage is also their small size.
7. Polymer electrolyte fuel cells (PEFC)
In the case of polymer electrolyte fuel cells, the polymer membrane consists of polymer fibers with water regions in which conduction water ions H2O+ (proton, red) attaches to a water molecule. Water molecules pose a problem due to slow ion exchange. Therefore, a high concentration of water is required both in the fuel and at the outlet electrodes, which limits the operating temperature to 100°C.
8. Solid acid fuel cells (SFC)
In solid acid fuel cells, the electrolyte (CsHSO4) does not contain water. The operating temperature is therefore 100-300°C. The rotation of the SO42 oxyanions allows the protons (red) to move as shown in the figure. Typically, a solid acid fuel cell is a sandwich in which a very thin layer of solid acid compound is sandwiched between two electrodes that are tightly pressed together to ensure good contact. When heated, the organic component evaporates, exiting through the pores in the electrodes, maintaining the ability of multiple contacts between the fuel (or oxygen at the other end of the element), the electrolyte and the electrodes.
Rice. 9.
9. Comparison of the most important characteristics of fuel cells
Fuel cell type | Operating temperature | Power generation efficiency | Fuel type | Scope of application |
Medium and large installations |
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Pure hydrogen | installations |
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Pure hydrogen | Small installations |
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Most hydrocarbon fuels | Small, medium and large installations |
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Portable installations |
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Pure hydrogen | Space researched |
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Pure hydrogen | Small installations |
Rice. 10.
10. Use of fuel cells in cars
Rice. 11.
Rice. 12.
Entrepreneur Danila Shaposhnikov says he undertook to bring the product to market from the laboratory. The startup AT Energy makes hydrogen fuel cells that will allow drones to fly many times longer than they can now.
Entrepreneur Danila Shaposhnikov is helping scientists Yuri Dobrovolsky and Sergei Nefedkin commercialize their invention - compact hydrogen fuel cells that can operate for several hours without fear of frost and moisture. The company they created, AT Energy, has already raised about 100 million rubles. investments and is preparing to conquer the global unmanned aerial market aircraft volume of $7 billion, which so far mainly uses lithium-ion batteries.
From laboratory to market
The business was started by Shaposhnikov’s acquaintance with two doctors of science in the field of energy and electrochemistry - Dobrovolsky from the Institute of Problems of Chemical Physics of the Russian Academy of Sciences in Chernogolovka and Nefedkin, who heads the Center for Hydrogen Energy at the Moscow Energy Institute. The professors had an idea how to make low-temperature fuel cells, but they didn't understand how to bring their invention to market. “I acted as an entrepreneur-investor who took the risk of bringing a product to the market from the laboratory,” recalls Shaposhnikov in an interview with RBC.
In August 2012, Shaposhnikov, Dobrovolsky and Nefedkin registered the AT Energy company (AT Energy LLC) and began preparing prototypes. The company submitted an application and became a resident of Skolkovo. Throughout 2013, at the institute’s rented base in Chernogolovka, the founders of AT Energy worked to radically increase the service life of fuel cell-based batteries. “Chernogolovka is a science city, it’s quite easy to find and attract laboratory assistants, engineers and electrochemists there,” says Shaposhnikov. Then AT Energy moved to the Chernogolovsky technology park. There the first product appeared - a fuel cell for drones.
The “heart” of the fuel cell developed by AT Energy is a membrane-electrode unit in which an electrochemical reaction occurs: air with oxygen is supplied on one side, compressed hydrogen gas is supplied on the other, and energy is generated as a result of the chemical reaction of hydrogen oxidation.
For a real product, AT Energy was able to receive two Skolkovo grants (in the amount of almost 47 million rubles), and also attract about $1 million in investments. The project was believed in by the North Energy Ventures fund (received 13.8% of AT Energy, its partner is Shaposhnikov himself), the Phystech Ventures venture fund (13.8%), founded by graduates of the Moscow Institute of Physics and Technology, and the developer Morton (10% ); Shaposhnikov and Dobrovolsky now directly own 26.7% of AT Energy, and Nefedkin - 9% (all according to the Unified State Register of Legal Entities).
AT Energy in numbers
About 1 00 million rub.— total amount of attracted investments
3-30 kg- a lot of drones for which AT Energy makes power systems
$7 billion per year - the volume of the global drone market in 2015
$90 million- volume Russian market military drones in 2014
$5 million— volume of the Russian civilian drone market in 2014
$2.6 billion— volume of the global fuel cell market in 2014
Source: company data, Business Insider, Markets & Markets
Flies longer, even longer
Today, almost 80% of the world's drones use electric motors, which are powered by lithium-ion or lithium-polymer batteries. “The biggest problem with batteries is that they have energy capacity limitations due to their size. If you want twice as much energy, install another battery, and another, etc. And in drones, the most important parameter is its mass,” explains Shaposhnikov.
The weight of the drone determines its payload - the number of devices that can be hung on it (for example, cameras, thermal imagers, scanning devices, etc.), as well as the flight time. Today, drones generally fly for half an hour to an hour and a half. “It’s not interesting for half an hour,” says Shaposhnikov. “It turns out that as soon as you lift it into the air, it’s time to change the battery.” In addition, lithium-ion batteries behave capriciously when negative temperatures. Shaposhnikov claims that the fuel cells developed by AT Energy allow drones to fly up to five times longer: from two and a half to four hours, and are not afraid of frost (down to minus 20 degrees).
AT Energy purchases consumables and components for its batteries both in Russia and abroad. “For scientific developments, small series are implied, so we cannot yet give potential Russian manufacturers the components we need have a planning horizon so that they can localize their production,” explains Shaposhnikov.
In 2014, AT Energy completed its first contracts: it supplied 20 battery systems based on its fuel cells to the military (Shaposhnikov does not name the customer). They were also equipped with drones from the AFM-Servers company, which used them when filming the Olympics in Sochi. “One of the company’s goals was to test our systems on drones, and we didn’t care whether they paid us for it or not,” recalls Shaposhnikov. To date, AT Energy has signed a number of contracts and pre-contracts, the potential revenue for which, according to Shaposhnikov, is 100 million rubles. (mainly with government agencies).
Shaposhnikov does not disclose the financial results of AT Energy. According to Kontur.Focus, in 2014 the company had revenue of 12.4 million rubles. and a net loss of 1.2 million rubles. The cost of fuel cells with a power of up to 0.5 kW produced by AT Energy, according to Shaposhnikov, ranges from $10-25 thousand, depending on the type of drone, the tasks it faces, flight duration and other parameters.
The devaluation of the ruble, according to Shaposhnikov, will make it easier for the company to enter the world market. “We set ourselves the goal of establishing relationships with Western players in 2016, and in 2017 making the first products for the main types of foreign drones,” he says.
INVESTOR
“AT Energy managed to create a fuel cell with unique characteristics”
Oleg Pertsovsky, Director for Operations of the Energy Efficient Technologies Cluster of the Skolkovo Foundation
“They were able to make a device that works at subzero temperatures, while being quite compact and inexpensive. For science-intensive projects, four years is a short period of time, so they are moving at a normal pace, in our opinion. Drones are one of the obvious and most promising areas for the use of fuel cells. By replacing the power source, the drone will be able to increase its flight time several times with the same mass-dimensional characteristics. There is also a market for autonomous power supply, for example for cellular networks, where there is a great need for low-power power supplies in remote areas where electrical networks are not connected.”
“Creating a competitive product and entering this market has significant investment risks”
Sergey Filimonov, head of the corporate venture fund GS Venture (as part of the GS Group)
“The high-capacity fuel cell market is much broader and more complex than the drone industry. But fuel cells will have to compete with a number of existing energy sources, both in terms of efficiency and cost. Creating a competitive product and entering this market have significant investment risks. For GS Venture, the areas of UAVs and fuel cells are quite interesting, but the fund is not ready to invest in a startup just because this company operates in a developing area and is aimed at an actively growing market.
CLIENTS
"This best technology on the market, but too expensive"
Oleg Panfilenok, founder and CEO of Copter Express
“AT Energy has very strong technology. The combination of a “fuel cell plus a hydrogen cylinder” makes it possible to achieve reliable energy intensity, significantly higher than in lithium-polymer or lithium-ion batteries. We have already designed a mapping drone, about 1 meter in diameter, to fly over a large area - if you put hydrogen fuel cells on it, it will fly for up to four hours. It would be convenient and efficient; you wouldn’t have to sit down the device several times to recharge.
At the moment this is definitely the best technology on the market, but there is one problem: it is too expensive for us. One battery from AT Energy can cost about 500 thousand rubles. - an order of magnitude higher than a lithium polymer battery. Yes, it is one and a half times cheaper than foreign analogues, but we need ten. We are not military personnel who have budgets, we are a commercial company and are not ready to pay big money. For the military, the characteristics of a drone are more important than its cost, but for commerce, on the contrary, it’s better if it’s worse, but cheaper.”
“The flight time of a drone is the most important factor for many missions.”
Maxim Shinkevich, CEO of the Unmanned Systems group of companies
“We are very familiar with AT Energy and have signed a cooperation agreement with them. We have recently completed the development of a new larger multicopter with a payload of up to 2 kg, which will be equipped with fuel cells from AT Energy and will fly on them from 2.5 to 4 hours. On lithium batteries such a drone would fly for only 30 minutes. This drone can be used for both civilian and military purposes - it is a video surveillance system for searching and rescuing people, we are already ready to launch it into series. We already have the first civilian customer for it, and as soon as we show it in action, other contracts will appear.
One of the main problems in the mass use of fuel cells is the lack of a network of stations for charging them. They are more expensive than batteries (as a result, the cost of a drone using them increases by 15%), but in return you get more than double the flight duration. Drone flight time is the most important factor for many applications.”
Natalia Suvorova
Advantages of fuel cells/cells
A fuel cell/cell is a device that efficiently produces direct current and heat from hydrogen-rich fuel through an electrochemical reaction.
A fuel cell is similar to a battery in that it produces direct current through a chemical reaction. The fuel cell includes an anode, a cathode and an electrolyte. However, unlike batteries, fuel cells cannot store electrical energy and do not discharge or require electricity to recharge. Fuel cells/cells can continuously produce electricity as long as they have a supply of fuel and air.
Unlike other power generators, such as internal combustion engines or turbines powered by gas, coal, fuel oil, etc., fuel cells/cells do not burn fuel. This means no noisy high pressure rotors, no loud exhaust noise, no vibration. Fuel cells/cells produce electricity through a silent electrochemical reaction. Another feature of fuel cells/cells is that they convert the chemical energy of the fuel directly into electricity, heat and water.
Fuel cells are highly efficient and do not produce large amounts of greenhouse gases such as carbon dioxide, methane and nitrous oxide. The only emission products during operation are water in the form of steam and a small amount of carbon dioxide, which is not released at all if pure hydrogen is used as fuel. Fuel elements/cells are assembled into assemblies and then into individual functional modules.
History of development of fuel cells/cells
In the 1950s and 1960s, one of the most pressing challenges for fuel cells arose from the National Aeronautics and Space Administration's (NASA) need for energy sources for long-duration space missions. NASA's alkaline fuel cell uses hydrogen and oxygen as fuel, combining the two chemical element in an electrochemical reaction. The output is three useful byproducts of the reaction in spaceflight - electricity to power the spacecraft, water for drinking and cooling systems, and heat to warm the astronauts.
The discovery of fuel cells dates back to the beginning of the 19th century. The first evidence of the effect of fuel cells was obtained in 1838.
In the late 1930s, work began on fuel cells with an alkaline electrolyte and by 1939 a cell using high-pressure nickel-plated electrodes was built. During the Second World War, fuel cells/cells were developed for British Navy submarines and in 1958 a fuel assembly consisting of alkaline fuel cells/cells with a diameter of just over 25 cm was introduced.
Interest increased in the 1950s and 1960s, and also in the 1980s, when the industrial world experienced a shortage of petroleum fuels. During the same period, world countries also became concerned about the problem of air pollution and considered ways to environmentally net receipt electricity. Fuel cell technology is currently undergoing rapid development.
Operating principle of fuel cells/cells
Fuel cells/cells produce electricity and heat due to an electrochemical reaction taking place using an electrolyte, a cathode and an anode.
The anode and cathode are separated by an electrolyte that conducts protons. After hydrogen flows to the anode and oxygen to the cathode, a chemical reaction begins, as a result of which electric current, heat and water are generated.
At the anode catalyst, molecular hydrogen dissociates and loses electrons. Hydrogen ions (protons) are conducted through the electrolyte to the cathode, while electrons are passed through the electrolyte and travel through an external electrical circuit, creating a direct current that can be used to power equipment. At the cathode catalyst, an oxygen molecule combines with an electron (which is supplied from external communications) and an incoming proton, and forms water, which is the only reaction product (in the form of vapor and/or liquid).
Below is the corresponding reaction:
Reaction at the anode: 2H 2 => 4H+ + 4e -
Reaction at the cathode: O 2 + 4H+ + 4e - => 2H 2 O
General reaction of the element: 2H 2 + O 2 => 2H 2 O
Types and variety of fuel elements/cells
Just as there are different types of internal combustion engines, there are different types of fuel cells - choosing the right type of fuel cell depends on its application.
Fuel cells are divided into high temperature and low temperature. Low temperature fuel cells require relatively pure hydrogen as fuel. This often means that fuel processing is required to convert the primary fuel (such as natural gas) into pure hydrogen. This process consumes additional energy and requires special equipment. High temperature fuel cells do not need this additional procedure as they can "internally convert" the fuel at elevated temperatures, meaning there is no need to invest in hydrogen infrastructure.
Molten Carbonate Fuel Cells/Cells (MCFC)
Molten carbonate electrolyte fuel cells are high temperature fuel cells. The high operating temperature allows the direct use of natural gas without a fuel processor and low calorific value fuel gas from industrial processes and other sources.
The operation of RCFC differs from other fuel cells. These cells use an electrolyte made from a mixture of molten carbonate salts. Currently, two types of mixtures are used: lithium carbonate and potassium carbonate or lithium carbonate and sodium carbonate. To melt carbonate salts and achieve a high degree of ion mobility in the electrolyte, fuel cells with molten carbonate electrolyte operate at high temperatures (650°C). Efficiency varies between 60-80%.
When heated to a temperature of 650°C, the salts become a conductor for carbonate ions (CO 3 2-). These ions pass from the cathode to the anode, where they combine with hydrogen to form water, carbon dioxide and free electrons. These electrons are sent through an external electrical circuit back to the cathode, generating electric current and heat as a by-product.
Reaction at the anode: CO 3 2- + H 2 => H 2 O + CO 2 + 2e -
Reaction at the cathode: CO 2 + 1/2O 2 + 2e - => CO 3 2-
General reaction of the element: H 2 (g) + 1/2O 2 (g) + CO 2 (cathode) => H 2 O (g) + CO 2 (anode)
The high operating temperatures of molten carbonate electrolyte fuel cells have certain advantages. At high temperatures, natural gas is internally reformed, eliminating the need for a fuel processor. In addition, advantages include the ability to use standard construction materials such as stainless steel sheets and nickel catalyst on the electrodes. The waste heat can be used to generate high pressure steam for a variety of industrial and commercial purposes.
High reaction temperatures in the electrolyte also have their advantages. The use of high temperatures requires significant time to achieve optimal operating conditions, and the system responds more slowly to changes in energy consumption. These characteristics allow the use of fuel cell installations with molten carbonate electrolyte under constant power conditions. High temperatures prevent carbon monoxide from damaging the fuel cell.
Fuel cells with molten carbonate electrolyte are suitable for use in large stationary installations. Thermal power plants with an electrical output power of 3.0 MW are commercially produced. Installations with output power up to 110 MW are being developed.
Phosphoric acid fuel cells/cells (PAFC)
Phosphoric (orthophosphoric) acid fuel cells were the first fuel cells for commercial use.
Phosphoric (orthophosphoric) acid fuel cells use an electrolyte based on orthophosphoric acid (H 3 PO 4) with a concentration of up to 100%. The ionic conductivity of phosphoric acid is low at low temperatures, for this reason these fuel cells are used at temperatures up to 150–220°C.
The charge carrier in fuel cells of this type is hydrogen (H+, proton). A similar process occurs in proton exchange membrane fuel cells, in which hydrogen supplied to the anode is split into protons and electrons. Protons travel through the electrolyte and combine with oxygen from the air at the cathode to form water. The electrons are sent through an external electrical circuit, thereby generating an electric current. Below are reactions that generate electric current and heat.
Reaction at the anode: 2H 2 => 4H + + 4e -
Reaction at the cathode: O 2 (g) + 4H + + 4e - => 2 H 2 O
General reaction of the element: 2H 2 + O 2 => 2H 2 O
The efficiency of fuel cells based on phosphoric (orthophosphoric) acid is more than 40% when generating electrical energy. With combined production of heat and electricity, the overall efficiency is about 85%. In addition, given operating temperatures, waste heat can be used to heat water and generate atmospheric pressure steam.
The high performance of thermal power plants using fuel cells based on phosphoric (orthophosphoric) acid in the combined production of thermal and electrical energy is one of the advantages of this type of fuel cells. The units use carbon monoxide with a concentration of about 1.5%, which significantly expands the choice of fuel. In addition, CO 2 does not affect the electrolyte and the operation of the fuel cell; this type of cell works with reformed natural fuel. Simple design, low degree of electrolyte volatility and increased stability are also advantages of this type of fuel cell.
Thermal power plants with electrical output power of up to 500 kW are commercially produced. The 11 MW installations have passed the appropriate tests. Installations with output power up to 100 MW are being developed.
Solid oxide fuel cells/cells (SOFC)
Solid oxide fuel cells are the highest operating temperature fuel cells. The operating temperature can vary from 600°C to 1000°C, allowing the use of different types of fuel without special pre-treatment. To handle such high temperatures, the electrolyte used is a thin solid metal oxide on a ceramic base, often an alloy of yttrium and zirconium, which is a conductor of oxygen ions (O2-).
The solid electrolyte provides a sealed transition of gas from one electrode to another, while liquid electrolytes are located in a porous substrate. The charge carrier in fuel cells of this type is the oxygen ion (O 2-). At the cathode, oxygen molecules from the air are separated into an oxygen ion and four electrons. Oxygen ions pass through the electrolyte and combine with hydrogen, creating four free electrons. The electrons are sent through an external electrical circuit, generating electric current and waste heat.
Reaction at the anode: 2H 2 + 2O 2- => 2H 2 O + 4e -
Reaction at the cathode: O 2 + 4e - => 2O 2-
General reaction of the element: 2H 2 + O 2 => 2H 2 O
The efficiency of the produced electrical energy is the highest of all fuel cells - about 60-70%. High operating temperatures allow combined production of thermal and electrical energy to generate high pressure steam. Combining a high-temperature fuel cell with a turbine makes it possible to create a hybrid fuel cell to increase the efficiency of generating electrical energy by up to 75%.
Solid oxide fuel cells operate at very high temperatures (600°C–1000°C), resulting in significant time to reach optimal operating conditions and a slower system response to changes in energy consumption. At such high operating temperatures, no converter is required to recover hydrogen from the fuel, allowing the thermal power plant to operate with relatively impure fuels resulting from gasification of coal or waste gases, etc. The fuel cell is also excellent for high power applications, including industrial and large central power plants. Modules with an electrical output power of 100 kW are commercially produced.
Direct Methanol Oxidation Fuel Cells/Cells (DOMFC)
The technology of using fuel cells with direct methanol oxidation is undergoing a period of active development. It has successfully proven itself in the field of powering mobile phones, laptops, as well as for creating portable power sources. This is what the future use of these elements is aimed at.
The design of fuel cells with direct oxidation of methanol is similar to fuel cells with a proton exchange membrane (MEPFC), i.e. A polymer is used as an electrolyte, and a hydrogen ion (proton) is used as a charge carrier. However, liquid methanol (CH 3 OH) oxidizes in the presence of water at the anode, releasing CO 2, hydrogen ions and electrons, which are sent through an external electrical circuit, thereby generating an electric current. Hydrogen ions pass through the electrolyte and react with oxygen from the air and electrons from the external circuit to form water at the anode.
Reaction at the anode: CH 3 OH + H 2 O => CO 2 + 6H + + 6e -
Reaction at the cathode: 3/2O 2 + 6 H + + 6e - => 3H 2 O
General reaction of the element: CH 3 OH + 3/2O 2 => CO 2 + 2H 2 O
The advantage of this type of fuel cells is their small dimensions, due to the use liquid fuel, and no need to use a converter.
Alkaline fuel cells/cells (ALFC)
Alkaline fuel cells are one of the most efficient cells used to generate electricity, with power generation efficiency reaching up to 70%.
Alkaline fuel cells use an electrolyte, an aqueous solution of potassium hydroxide, contained in a porous, stabilized matrix. The potassium hydroxide concentration may vary depending on the operating temperature of the fuel cell, which ranges from 65°C to 220°C. The charge carrier in SHTE is the hydroxyl ion (OH -), moving from the cathode to the anode, where it reacts with hydrogen, producing water and electrons. The water produced at the anode moves back to the cathode, again generating hydroxyl ions there. As a result of this series of reactions taking place in the fuel cell, electricity and, as a by-product, heat are produced:
Reaction at the anode: 2H 2 + 4OH - => 4H 2 O + 4e -
Reaction at the cathode: O 2 + 2H 2 O + 4e - => 4 OH -
General reaction of the system: 2H 2 + O 2 => 2H 2 O
The advantage of SHTE is that these fuel cells are the cheapest to produce, since the catalyst needed on the electrodes can be any of the substances that are cheaper than those used as catalysts for other fuel cells. SFCs operate at relatively low temperatures and are among the most efficient fuel cells - such characteristics can consequently contribute to faster power generation and high fuel efficiency.
One of the characteristic features of SHTE is its high sensitivity to CO 2, which may be contained in fuel or air. CO 2 reacts with the electrolyte, quickly poisons it, and greatly reduces the efficiency of the fuel cell. Therefore, the use of SHTE is limited to enclosed spaces such as spacecraft and underwater vehicles; they must run on pure hydrogen and oxygen. Moreover, molecules such as CO, H 2 O and CH4, which are safe for other fuel cells, and even act as fuel for some of them, are harmful to SHFC.
Polymer Electrolyte Fuel Cells (PEFC)
In the case of polymer electrolyte fuel cells, the polymer membrane consists of polymer fibers with water regions in which there is conduction of water ions H2O+ (proton, red) attaches to a water molecule). Water molecules pose a problem due to slow ion exchange. Therefore, a high concentration of water is required both in the fuel and at the outlet electrodes, limiting the operating temperature to 100°C.
Solid acid fuel cells/cells (SFC)
In solid acid fuel cells, the electrolyte (CsHSO 4) does not contain water. The operating temperature is therefore 100-300°C. The rotation of the oxy anions SO 4 2- allows the protons (red) to move as shown in the figure. Typically, a solid acid fuel cell is a sandwich in which a very thin layer of solid acid compound is sandwiched between two electrodes that are tightly pressed together to ensure good contact. When heated, the organic component evaporates, exiting through the pores in the electrodes, maintaining the ability of multiple contacts between the fuel (or oxygen at the other end of the element), the electrolyte and the electrodes.
Various fuel cell modules. Fuel cell battery
- Fuel cell battery
- Other equipment operating at high temperatures (integrated steam generator, combustion chamber, heat balance changer)
- Heat resistant insulation
Fuel cell module
Comparative analysis of types and varieties of fuel cells
Innovative energy-efficient municipal heat and power plants are typically built on solid oxide fuel cells (SOFC), polymer electrolyte fuel cells (PEFC), phosphoric acid fuel cells (PAFC), proton exchange membrane fuel cells (PEMFC) and alkaline fuel cells (ALFC). . Typically have the following characteristics:
The most suitable should be considered solid oxide fuel cells (SOFC), which:
- operate at higher temperatures, reducing the need for expensive precious metals (such as platinum)
- can work for various types hydrocarbon fuels, mainly natural gas
- have a longer start-up time and are therefore better suited for long-term action
- demonstrate high power generation efficiency (up to 70%)
- Due to the high operating temperatures, the units can be combined with heat transfer systems, bringing the overall system efficiency up to 85%
- have practically zero level emissions, operate silently and have low operating requirements compared to existing power generation technologies
| Fuel cell type | Operating temperature | Power generation efficiency | Fuel type | Scope of application |
|---|---|---|---|---|
| RKTE | 550–700°C | 50-70% | Medium and large installations | |
| FCTE | 100–220°C | 35-40% | Pure hydrogen | Large installations |
| MOPTE | 30-100°C | 35-50% | Pure hydrogen | Small installations |
| SOFC | 450–1000°C | 45-70% | Most hydrocarbon fuels | Small, medium and large installations |
| PEMFC | 20-90°C | 20-30% | Methanol | Portable |
| SHTE | 50–200°C | 40-70% | Pure hydrogen | Space research |
| PETE | 30-100°C | 35-50% | Pure hydrogen | Small installations |
Since small thermal power plants can be connected to a conventional gas supply network, fuel cells do not require a separate hydrogen supply system. When using small thermal power plants based on solid oxide fuel cells, the heat generated can be integrated into heat exchangers to heat water and ventilation air, increasing the overall efficiency of the system. This innovative technology in the best possible way suitable for efficient electricity generation without the need for expensive infrastructure and complex instrument integration.
Application of fuel cells/cells
Application of fuel cells/cells in telecommunication systems
Due to the rapid proliferation of wireless communication systems throughout the world, as well as the increasing socio-economic benefits of mobile phone technology, the need for reliable and cost-effective power backup has become critical. Electricity grid losses throughout the year due to bad weather conditions, natural disasters or limited grid capacity pose an ongoing challenge for grid operators.
Traditional telecom power backup solutions include batteries (valve-regulated lead-acid battery cell) for short-term backup power and diesel and propane generators for longer-term backup power. Batteries are a relatively cheap source of backup power for 1 - 2 hours. However, batteries are not suitable for longer-term backup power because they are expensive to maintain, become unreliable after long periods of use, are sensitive to temperatures, and are hazardous to the environment after disposal. Diesel and propane generators can provide long-term power backup. However, generators can be unreliable, require extensive maintenance, and emit high levels of pollutants and greenhouse gases.
To overcome the limitations of traditional power backup solutions, innovative green fuel cell technology has been developed. Fuel cells are reliable, quiet, contain fewer moving parts than a generator, have a wider operating temperature range than a battery: from -40°C to +50°C and, as a result, provide extremely high levels of energy savings. In addition, the lifetime costs of such an installation are lower than the costs of a generator. Lower fuel cell costs result from just one maintenance visit per year and significantly higher plant productivity. At the end of the day, the fuel cell is a green technology solution with minimal environmental impact.
Fuel cell installations provide backup power for critical communications network infrastructures for wireless, permanent and broadband communications in the telecommunications system, ranging from 250 W to 15 kW, they offer many unrivaled innovative features:
- RELIABILITY– few moving parts and no discharge in standby mode
- ENERGY SAVING
- SILENCE– low noise level
- SUSTAINABILITY– operating range from -40°C to +50°C
- ADAPTABILITY– installation outdoors and indoors (container/protective container)
- HIGH POWER– up to 15 kW
- LOW MAINTENANCE REQUIREMENT– minimal annual maintenance
- ECONOMICAL- attractive total cost of ownership
- GREEN ENERGY– low emissions with minimal impact on the environment
The system senses the DC bus voltage at all times and smoothly accepts critical loads if the DC bus voltage drops below a user-defined set point. The system runs on hydrogen, which is supplied to the fuel cell stack in one of two ways - either from an industrial hydrogen source or from a liquid fuel of methanol and water, using an integrated reforming system.
Electricity is produced by the fuel cell stack in the form of direct current. The DC power is transferred to a converter, which converts the unregulated DC power coming from the fuel cell stack into high quality regulated DC power for the required loads. Fuel cell installations can provide backup power for many days as the duration is limited only by the amount of hydrogen or methanol/water fuel available.
Fuel cells offer superior energy savings, improved system reliability, more predictable performance in a wide range of climates, and reliable operational durability compared to industry standard valve-regulated lead-acid cell battery packs. Lifetime costs are also lower due to significantly lower maintenance and replacement requirements. Fuel cells offer environmental benefits to the end user as disposal costs and liability risks associated with lead-acid cells are a growing concern.
For performance characteristics electric batteries may be adversely affected by a wide range of factors such as charge level, temperature, cycles, service life and other variables. The energy provided will vary depending on these factors and is not easy to predict. Performance characteristics Proton exchange membrane fuel cells (PEMFCs) are relatively unaffected by these factors and can provide critical power as long as fuel is available. Increased predictability is an important benefit when moving to fuel cells for mission-critical backup power applications.
Fuel cells generate power only when fuel is supplied, similar to a gas turbine generator, but have no moving parts in the generation area. Therefore, unlike a generator, they are not subject to rapid wear and do not require constant maintenance and lubrication.
The fuel used to drive the extended duration fuel converter is a fuel mixture of methanol and water. Methanol is a widely available, commercially produced fuel that currently has many uses, including windshield washer, plastic bottles, engine additives, emulsion paints. Methanol is easily transported, can be mixed with water, has good biodegradability and does not contain sulfur. It has a low freezing point (-71°C) and does not decompose during long-term storage.
Application of fuel cells/cells in communication networks
Secure communications networks require reliable backup power solutions that can operate for hours or days in emergency situations if the power grid is no longer available.
With few moving parts and no standby power loss, innovative fuel cell technology offers an attractive solution to current backup power systems.
The most compelling argument for using fuel cell technology in communications networks is the increased overall reliability and safety. During events such as power outages, earthquakes, storms and hurricanes, it is important that systems continue to operate and are provided with reliable backup power over an extended period of time, regardless of temperature or the age of the backup power system.
The line of fuel cell-based power devices are ideal for supporting classified communications networks. Thanks to their energy-saving design principles, they provide environmentally friendly, reliable backup power with extended duration (up to several days) for use in the power range from 250 W to 15 kW.
Application of fuel cells/cells in data networks
Reliable power supply for data networks, such as high-speed data networks and fiber optic backbones, is of key importance throughout the world. The information transmitted over such networks contains critical data for institutions such as banks, airlines or medical centers. A power outage in such networks not only poses a danger to the transmitted information, but also, as a rule, leads to significant financial losses. Reliable, innovative fuel cell installations that provide backup power supply provide the reliability needed to ensure uninterrupted power supply.
Fuel cell units, powered by a liquid fuel mixture of methanol and water, provide reliable backup power with extended duration, up to several days. In addition, these units have significantly reduced maintenance requirements compared to generators and batteries, requiring only one maintenance visit per year.
Typical application site characteristics for using fuel cell installations in data networks:
- Applications with power consumption quantities from 100 W to 15 kW
- Applications with battery life requirements > 4 hours
- Repeaters in fiber optic systems (hierarchy of synchronous digital systems, high-speed Internet, voice communication over IP protocol...)
- Network nodes for high-speed data transmission
- WiMAX transmission nodes
Fuel cell power backup installations offer numerous benefits for critical data network infrastructures compared to traditional battery or diesel generators, allowing for increased on-site use:
- Liquid fuel technology solves the problem of hydrogen placement and provides virtually unlimited backup power.
- Thanks to their quiet operation, low weight, resistance to temperature changes and virtually vibration-free operation, fuel cells can be installed outside buildings, in industrial buildings/containers or on rooftops.
- Preparations for the use of the system on site are quick and economical, and operating costs are low.
- The fuel is biodegradable and provides an environmentally friendly solution for urban environments.
Application of fuel cells/cells in security systems
The most carefully designed building security and communications systems are only as reliable as the power supply that supports them. While most systems include some type of backup uninterruptible power system for short-term power losses, they do not accommodate the longer-term power outages that can occur after natural disasters or terrorist attacks. This could get critical important issue for many corporate and government agencies.
Vital systems such as monitoring and access control systems using CCTV (ID card readers, door lock devices, biometric identification technology, etc.), automatic fire alarm and fire suppression systems, elevator control systems and telecommunications networks are at risk in the absence of a reliable, alternative, long-lasting power supply.
Diesel generators make a lot of noise, are difficult to place, and have well-known problems with their reliability and technical maintenance. In contrast, a fuel cell installation that provides backup power is quiet, reliable, produces zero or very low emissions, and can be easily installed on a rooftop or outside a building. It does not discharge or lose power in standby mode. It ensures the continued operation of critical systems, even after the facility ceases operations and the building is vacated.
Innovative fuel cell installations protect expensive investments in critical applications. They provide environmentally friendly, reliable backup power with extended duration (up to many days) for use in the power range from 250 W to 15 kW, combined with numerous unrivaled features and, especially, high level energy saving.
Fuel cell power backup installations offer numerous advantages for use in mission-critical applications such as security and building control systems over traditional battery-powered or diesel-powered generators. Liquid fuel technology solves the problem of hydrogen placement and provides virtually unlimited backup power.
Application of fuel cells/cells in municipal heating and power generation
Solid oxide fuel cells (SOFCs) are used to build reliable, energy-efficient, and energy-efficient fuel cells. harmful emissions thermal power plants for generating electricity and heat from widely available natural gas and renewable fuel sources. These innovative installations are used in a variety of markets, from home power generation to remote power supply, as well as auxiliary power supplies.
Application of fuel cells/cells in distribution networks
Small thermal power plants are designed to operate in a distributed energy generation network consisting of a large number of small generator sets instead of one centralized power plant.
The figure below shows the loss in efficiency of electricity generation when it is generated at a thermal power plant and transmitted to homes through traditional power transmission networks used in at the moment. Efficiency losses in centralized generation include losses from the power plant, low-voltage and high-voltage transmission, and distribution losses.
The figure shows the results of the integration of small thermal power plants: electricity is generated with generation efficiency of up to 60% at the point of use. In addition, a household can use the heat generated by the fuel cells to heat water and space, which increases the overall efficiency of fuel energy processing and increases energy savings.
Use of fuel cells to protect the environment - utilization of associated petroleum gas
One of most important tasks in the oil industry is the utilization of associated petroleum gas. Existing methods Utilization of associated petroleum gas has a lot of disadvantages, the main one being that they are not economically viable. Associated petroleum gas is burned, which causes enormous harm to the environment and human health.
Innovative thermal power plants using fuel cells using associated petroleum gas as fuel open the way to radical and economic profitable solution problems related to associated petroleum gas utilization.
- One of the main advantages of fuel cell installations is that they can operate reliably and stably on associated petroleum gas of variable composition. Due to the flameless chemical reaction underlying the operation of the fuel cell, a decrease in the percentage of, for example, methane only causes a corresponding decrease in power output.
- Flexibility in relation to the electrical load of consumers, drop, load surge.
- For installation and connection of thermal power plants on fuel cells, their implementation does not require capital expenditures, because The units can be easily installed on unprepared sites near fields, are easy to use, reliable and efficient.
- High automation and modern remote control do not require permanent presence of personnel at the installation.
- Simplicity and technical perfection of the design: the absence of moving parts, friction, and lubrication systems provides significant economic benefits from the operation of fuel cell installations.
- Water consumption: none at ambient temperatures up to +30 °C and negligible at higher temperatures.
- Water outlet: none.
- In addition, thermal power plants using fuel cells do not make noise, do not vibrate, do not produce harmful emissions into the atmosphere