A DETAILED OVERVIEW OF HYDROGEN AND HYDROGEN FUEL CELL TECHNOLOGY FOR MOBILITY AND STATIONARY APPLICATIONS
vijay tharad
Director Operations at Corporate Professional Academy for Technical Training & Career Development
Overview
Hydrogen fuel cells are emerging as a high-potential technology that offers significant energy efficiency and decarbonisation benefits to a range of industries—including automotive and heavy transport.
Today, hydrogen fuel cell technology is being used for a variety of applications, including to:
Hydrogen fuel cell is an Electrochemical cell which produce electrical energy through a chemical reaction called Redox Reaction. In some reaction electrical energy is used to complete the chemical reaction so based on this observation it was thought that reverse of this is also possible that is generating electrical energy through chemical reactions.
Before diving deep into the fuel cell working it is important to know that what Redox reaction is and how it generates electrical energy
Fuel cell History
It is said that in 1838 edition of The London and Edinburgh Philosophical Magazine and Journal of Science, Welsh physicist and barrister Sir William Grove wrote about the development of his first fuel cells. He used a combination of sheet iron, copper and porcelain plates, and a solution of sulphate of copper and dilute acid.
same publication written in December 1838 but published in June 1839, German physicist Christian Friedrich Sch?nbein discussed the first crude fuel cell that he had invented.
His letter discussed current generated from hydrogen and oxygen dissolved in water. Grove later sketched his design, in 1842, in the same journal. The fuel cell he made used similar materials to today’s phosphoric acid fuel cell. In 1932, Francis Thomas Bacon invented a fuel cell which derived power from hydrogen and oxygen.
Redox Reaction
Redox word is the combination of reduction and oxidation. Reduction is the state of gaining electrons of a chemical substance often referred to as reducing agent and Oxidation is the state of loosing electrons of a chemical substance often referred to as oxidizing agent undergoing chemical reaction.
so in summary here it goes like this – one substance is said to be oxidized (loosing electron) undergoes oxidation and other substance is said to be reduced (gaining electron) undergoes reduction.
lets understand with the help of an example:
Zn (s) + CuSO4?(aq) → ZnSO4?(aq) + Cu (s)
The oxidation half-reaction can be written as: Zn → Zn2+?+ 2e–
The reduction half-reaction can be written as: Cu2+?+?2e–?→ Cu
2Fe2+?+ H2O2?+ 2H+?→ 2Fe3+?+ 2H2O
Oxidation half-reaction:?Fe2+?→ Fe3+?+ e–
Reduction half-reaction:?H2O2?+ 2e–?→ 2 OH–
Half Reaction
Half Reaction is either the reduction or oxidation component of the complete redox reaction. Half reactions are often used as a method of balancing Redox reactions. lets understand this with example. The reaction between magnesium metal and oxygen, for example, involves the oxidation of magnesium.
as seen in the above example zinc and copper sulphate following are the half reaction
Zn → Zn2+?+ 2e– and Cu2+?+?2e–?→ Cu in these reactions one reactant zinc is loosing electron and thus oxidizing on the other hand copper is gaining electron and thus reducing. In actual condition both these reactions occur simultaneously.
Types of Redox Reaction
The different types of redox reactions are:
Decomposition Reaction
This kind of reaction involves the breakdown of a compound into different compounds. Examples of these types of reactions are:
2NaH → 2Na + H2
2H2O → 2H2?+ O2
Na2CO3 → Na2O + CO2
Combination Reaction
These reactions are the opposite of decomposition reaction and hence involve the combination of two compounds to form a single compound in the form of A + B → AB.?For example:
H2 + Cl2 → 2HClC+O2→CO2
4Fe+ 3O2→2Fe2O3
Displacement Reaction
an atom or an ion in a compound is replaced by an atom or an ion of another element. It can be represented in the form of X + YZ → XZ + Y. Further displacement reaction can be categorized into
Metal displacement Reaction and Non-metal displacement Reaction
Disproportionation Reactions
a single reactant is oxidized and reduced is known as Disproportionation reactions.
For example: P4 + 3NaOH + 3H2O → 3NaH2PO2 + PH3
How Fuel Cells Work
Fuel cells work like batteries, but they do not run down or need recharging. They produce electricity and heat as long as fuel is supplied. A fuel cell consists of two electrodes—a negative electrode (or anode) and a positive electrode (or cathode)—sandwiched around an electrolyte. A fuel, such as hydrogen, is fed to the anode, and air is fed to the cathode. In a polymer electrolyte membrane fuel cell, a catalyst separates hydrogen atoms into protons and electrons, which take different paths to the cathode. The electrons go through an external circuit, creating a flow of electricity. The protons migrate through the electrolyte to the cathode, where they reunite with oxygen and the electrons to produce water and heat
Design Considerations
There are many factors that needs to be consider before designing the fuel cell however 7 of them are mentioned below.
1. Electrolyte, which is the deciding factor for the type of fuel cell, and can be made from substances like potassium hydroxide, salt carbonates, and phosphoric acid.
2. Fuel used, The most common fuel is hydrogen and thus named as hydrogen fuel cell
3. Anode catalyst, usually fine platinum powder, breaks down the fuel into electrons and ions.
4. Cathode catalyst, often nickel, converts ions into waste chemicals, with water being the most common type of waste
5. Gas diffusion layers that are designed to resist oxidization.
6. Voltage produced, how much voltage is needed is the main deciding factor before design the cell typically each cell can produce up to 1V and is however not limited to it and varies from application to application.
7. Ohmic loss or voltage drop is the main concern involved in designing the fuel cel
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Superior Features of Fuel Cell
Because fuel cells generate electricity through an electrochemical reaction, they are a clean source of power. In fact, fuel cells that use pure hydrogen are carbon-free. Some other key advantages of fuel cells include the following:
Types of Fuel Cells
Although the basic operations of all fuel cells are the same, special varieties have been developed to take advantage of different electrolytes and serve different application needs. The fuel and the charged species migrating through the electrolyte may be different, but the principle is the same. An oxidation occurs at the anode, while a reduction occurs at the cathode. The two reactions are connected by a charged species that migrates through the electrolyte and electrons that flow through the external circuit.
POLYMER ELECTROLYTE MEMBRANE FUEL CELLS
Polymer electrolyte membrane (PEM) fuel cells, also called proton exchange membrane fuel cells, use a proton-conducting polymer membrane as the electrolyte. Hydrogen is typically used as the fuel. These cells operate at relatively low temperatures and can quickly vary their output to meet shifting power demands. PEM fuel cells are the best candidates for powering automobiles. They can also be used for stationary power production. However, due to their low operating temperature, they cannot directly use hydrocarbon fuels, such as natural gas, liquefied natural gas, or ethanol. These fuels must be converted to hydrogen in a fuel reformer to be able to be used by a PEM fuel cell.
DIRECT-METHANOL FUEL CELLS
The direct-methanol fuel cell (DMFC) is similar to the PEM cell in that it uses a proton conducting polymer membrane as an electrolyte. However, DMFCs use methanol directly on the anode, which eliminates the need for a fuel reformer. DMFCs are of interest for powering portable electronic devices, such as laptop computers and battery rechargers. Methanol provides a higher energy density than hydrogen, which makes it an attractive fuel for portable devices.
ALKALINE FUEL CELLS
Alkaline fuel cells use an alkaline electrolyte such as potassium hydroxide or an alkaline membrane that conducts hydroxide ions rather than protons. Originally used by the National Aeronautics and Space Administration (NASA) on space missions, alkaline fuel cells are now finding new applications, such as in portable power.
PHOSPHORIC ACID FUEL CELLS
Phosphoric acid fuel cells use a phosphoric acid electrolyte that conducts protons held inside a porous matrix, and operate at about 200°C. They are typically used in modules of 400 kW or greater and are being used for stationary power production in hotels, hospitals, grocery stores, and office buildings, where waste heat can also be used. Phosphoric acid can also be immobilized in polymer membranes, and fuel cells using these membranes are of interest for a variety of stationary power applications.
MOLTEN CARBONATE FUEL CELLS
Molten carbonate fuel cells use a molten carbonate salt immobilized in a porous matrix that conducts carbonate ions as their electrolyte. They are already being used in a variety of medium-to-large-scale stationary applications, where their high efficiency produces net energy savings. Their high-temperature operation (approximately 600°C) enables them to internally reform fuels such as natural gas and biogas.
SOLID OXIDE FUEL CELLS
Solid oxide fuel cells use a thin layer of ceramic as a solid electrolyte that conducts oxide ions. They are being developed for use in a variety of stationary power applications, as well as in auxiliary power devices for heavy-duty trucks. Operating at 700°C–1,000°C with zirconia-based electrolytes, and as low as 500°C with ceria-based electrolytes, these fuel cells can internally reform natural gas and biogas, and can be combined with a gas turbine to produce electrical efficiencies as high as 75%.
COMBINED HEAT AND POWER FUEL CELLS
In addition to electricity, fuel cells produce heat. This heat can be used to fulfill heating needs, including hot water and space heating. Combined heat and power fuel cells are of interest for powering houses and buildings, where total efficiency as high as 90% is achievable. This high-efficiency operation saves money, saves energy, and reduces greenhouse gas emissions.
REGENERATIVE OR REVERSIBLE FUEL CELLS
This special class of fuel cells produces electricity from hydrogen and oxygen, but can be reversed and powered with electricity to produce hydrogen and oxygen. This emerging technology could provide storage of excess energy produced by intermittent renewable energy sources, such as wind and solar power stations, releasing this energy during times of low power production.
Fuel cell Efficiency
Fuel cell efficiency is based on the ratio of the energy produced at the output to the energy given in the input side. According to the U.S. Department of Energy, fuel cells are generally between 40 and 60% energy efficient. In actual vehicle the fuel cell efficiency from fuel to wheel is more than 45% and average values of about 36% when a driving cycle like the NEDC.
Fuel cell vehicles running on compressed hydrogen may have a power-plant-to-wheel efficiency of 22% if the hydrogen is stored as high-pressure gas, and 17% if it is stored as liquid hydrogen.
PARTS OF A FUEL CELL:
Polymer electrolyte membrane (PEM) fuel cells are the current focus of research for fuel cell vehicle applications. PEM fuel cells are made from several layers of different materials. The main parts of a PEM fuel cell are described below.
The heart of a PEM fuel cell is the membrane electrode assembly (MEA), which includes the membrane, the catalyst layers and gas diffusion layers (GDLs).
Hardware components used to incorporate an MEA into a fuel cell include gaskets, which provide a seal around the MEA to prevent leakage of gases, and bipolar plates, which are used to assemble individual PEM fuel cells into a fuel cell stack and provide channels for the gaseous fuel and air.
Membrane Electrode Assembly
The membrane, catalyst layers (anode and cathode), and diffusion media together form the membrane electrode assembly (MEA) of a PEM fuel cell.
Polymer Electrolyte Membrane
The polymer electrolyte membrane, or PEM (also called a proton exchange membrane)—a specially treated material that looks something like ordinary kitchen plastic wrap—conducts only positively charged ions and blocks the electrons. The PEM is the key to the fuel cell technology; it must permit only the necessary ions to pass between the anode and cathode. Other substances passing through the electrolyte would disrupt the chemical reaction. For transportation applications, the membrane is very thin—in some cases under 20 microns.
Catalyst Layers
A layer of catalyst is added on both sides of the membrane—the anode layer on one side and the cathode layer on the other. Conventional catalyst layers include nanometer-sized particles of platinum dispersed on a high-surface-area carbon support. This supported platinum catalyst is mixed with an ion-conducting polymer (ionomer) and sandwiched between the membrane and the GDLs. On the anode side, the platinum catalyst enables hydrogen molecules to be split into protons and electrons. On the cathode side, the platinum catalyst enables oxygen reduction by reacting with the protons generated by the anode, producing water. The ionomer mixed into the catalyst layers allows the protons to travel through these layers.
Gas Diffusion Layers
The GDLs sit outside the catalyst layers and facilitate transport of reactants into the catalyst layer, as well as removal of product water. Each GDL is typically composed of a sheet of carbon paper in which the carbon fibers are partially coated with polytetrafluoroethylene (PTFE). Gases diffuse rapidly through the pores in the GDL. These pores are kept open by the hydrophobic PTFE, which prevents excessive water buildup. In many cases, the inner surface of the GDL is coated with a thin layer of high-surface-area carbon mixed with PTFE, called the microporous layer. The microporous layer can help adjust the balance between water retention (needed to maintain membrane conductivity) and water release (needed to keep the pores open so hydrogen and oxygen can diffuse into the electrodes).
Hardware
The MEA is the part of the fuel cell where power is produced, but hardware components are required to enable effective MEA operation.
Bipolar Plates
Each individual MEA produces less than 1 V under typical operating conditions, but most applications require higher voltages. Therefore, multiple MEAs are usually connected in series by stacking them on top of each other to provide a usable output voltage. Each cell in the stack is sandwiched between two bipolar plates to separate it from neighboring cells. These plates, which may be made of metal, carbon, or composites, provide electrical conduction between cells, as well as providing physical strength to the stack. The surfaces of the plates typically contain a “flow field,” which is a set of channels machined or stamped into the plate to allow gases to flow over the MEA. Additional channels inside each plate may be used to circulate a liquid coolant.
Gaskets
Each MEA in a fuel cell stack is sandwiched between two bipolar plates, but gaskets must be added around the edges of the MEA to make a gas-tight seal. These gaskets are usually made of a rubbery polymer.
FUEL CELL SYSTEMS:
The design of fuel cell systems is complex and can vary significantly depending upon fuel cell type and application. However, several basic components are found in many fuel cell systems:
Fuel Cell Stack
The fuel cell stack is the heart of a fuel cell power system. It generates electricity in the form of direct current (DC) from electrochemical reactions that take place in the fuel cell. A single fuel cell produces less than 1 V, which is insufficient for most applications. Therefore, individual fuel cells are typically combined in series into a fuel cell stack. A typical fuel cell stack may consist of hundreds of fuel cells. The amount of power produced by a fuel cell depends upon several factors, such as fuel cell type, cell size, the temperature at which it operates, and the pressure of the gases supplied to the cell.
Fuel Processor
The fuel processor converts fuel into a form usable by the fuel cell. Depending on the fuel and type of fuel cell, the fuel processor can be a simple sorbent bed to remove impurities, or a combination of multiple reactors and sorbents.
If the system is powered by a hydrogen-rich, conventional fuel, such as methanol, gasoline, diesel, or gasified coal, a reformer is typically used to convert hydrocarbons into a gas mixture of hydrogen and carbon compounds called "reformate." In many cases, the reformate is then sent to a set of reactors to convert carbon monoxide to carbon dioxide and remove any trace amounts of carbon monoxide remaining and a sorbent bed to remove other impurities, such as sulfur compounds, before it is sent to the fuel cell stack. This process prevents impurities in the gas from binding with the fuel cell catalysts. This binding process is also called "poisoning" because it reduces the efficiency and life expectancy of the fuel cell.
Some fuel cells, such as molten carbonate and solid oxide fuel cells, operate at temperatures high enough that the fuel can be reformed in the fuel cell itself. This process is called internal reforming. Fuel cells that use internal reforming still need traps to remove impurities from the unreformed fuel before it reaches the fuel cell. Both internal and external reforming release carbon dioxide, but due to the fuel cells’ high efficiency, less carbon dioxide is emitted than by internal-combustion engines, such as those used in gasoline-powered vehicles.
Power Conditioners
Power conditioning includes controlling current (amperes), voltage, frequency, and other characteristics of the electrical current to meet the needs of the application. Fuel cells produce electricity in the form of direct current (DC). In a DC circuit, electrons flow in only one direction. The electricity in your home and workplace is in the form of alternating current (AC), which flows in both directions on alternating cycles. If the fuel cell is used to power equipment that uses AC, the direct current will have to be converted to alternating current.
Both AC and DC power must be conditioned. Current inverters and conditioners adapt the electrical current from the fuel cell to suit the electrical needs of the application, whether it is a simple electrical motor or a complex utility power grid. Conversion and conditioning reduce system efficiency only slightly, around 2%–6%.
Air Compressors
Fuel cell performance improves as the pressure of the reactant gases increases; therefore many fuel cell systems include an air compressor, which raises the pressure of the inlet air to 2–4 times the ambient atmospheric pressure. For transportation applications, air compressors should have an efficiency of at least 75%. In some cases, an expander is also included to recover power from the high pressure exhaust gases. Expander efficiency should be at least 80%.
Humidifiers
The polymer electrolyte membrane at the heart of a PEM fuel cell does not work well when dry, so many fuel cell systems include a humidifier for the inlet air. Humidifiers usually consist of a thin membrane, which may be made of the same material as the PEM. By flowing dry inlet air on one side of the humidifier and wet exhaust air on the other side, the water produced by the fuel cell may be recycled to keep the PEM well hydrated
Application
Fuel cells are alternative of electric battery hence they have applications wherever the battery can be used, specifically where there is a power requirement. It can be used either for industrial application, domestic purpose, commercial purpose, remote locations where power is required such as in island, space craft, aircraft, ships, rockets etc.
A fuel cell system running on hydrogen can be compact and lightweight, and have no major moving parts. Because fuel cells have no moving parts and do not involve combustion, in ideal conditions they can achieve up to 99.9999% reliability. This equates to less than one minute of downtime in a six-year period.
There are many different types of stationary fuel cells so efficiencies vary, but most are between 40% and 60% energy efficient. However, when the fuel cell’s waste heat is used to heat a building in a cogeneration system this efficiency can increase to 85%.
Fuel cell can also be used in a cogeneration that is Combined heat and power (CHP) fuel cell systems. The system generates constant electric power, and at the same time produces hot air and water from the waste heat.
As the result CHP systems have the potential to save primary energy as they can make use of waste heat which is generally rejected by thermal energy conversion systems. A typical capacity range of home fuel cell is 1–3?kWel, 4–8?kWth. CHP systems linked to absorption chillers use their waste heat for refrigeration.
The waste heat from fuel cells can be diverted during the summer directly into the ground providing further cooling while the waste heat during winter can be pumped directly into the building. The University of Minnesota owns the patent rights to this type of system.
Hydrogen can be used in fuel cells to generate power using a chemical reaction rather than combustion, producing only water and heat as byproducts. It can be used in cars, in houses, for portable power, and in many more applications.
Major application for fuel cell is seen in Automotive industry in the form Fuel cell electric vehicle (FCEV).
Hydrogen
Hydrogen does not exist in convenient reservoirs or deposits like?fossil fuels or helium.?It is produced from feedstocks such as natural gas and biomass or electrolyzed from water.?A suggested benefit of large-scale deployment of hydrogen vehicles is that it could lead to decreased emissions of greenhouse gases and ozone precursors.?However, as of 2014, 95% of hydrogen is made from methane. It can be produced by thermochemical or pyrolitic means using renewable feedstocks, but that is an expensive process.
Renewable electricity can however be used to power the conversion of water into hydrogen: Integrated wind-to-hydrogen (power to gas) plants, using?electrolysis of water, are exploring technologies to deliver costs low enough, and quantities great enough, to compete with traditional energy sources.?The challenges facing the use of hydrogen in vehicles include its storage on board the vehicle.
Hydrogen Production
The molecular hydrogen needed as an onboard fuel for hydrogen vehicles can be obtained through many thermochemical methods utilizing?natural gas, coal?(by a process known as coal gasification),?liquefied petroleum gas, biomass gas, (biomass gasification), by a process called?thermolysis, or as a microbial waste product called?biohydrogen?or?Biological hydrogen production. 95% of hydrogen is produced using natural gas?Hydrogen can be produced from water by?electrolysis?at working efficiencies of 65–70%.?Hydrogen can be made by chemical reduction using chemical hydrides or aluminum.?Current technologies for manufacturing hydrogen use energy in various forms, totaling between 25 and 50 percent of the?higher heating value?of the hydrogen fuel, used to produce, compress or liquefy, and transmit the hydrogen by pipeline or truck.
Environmental consequences of the production of hydrogen from fossil energy resources include the emission of?greenhouse gas, a consequence that would also result from the on-board reforming of methanol into hydrogen.?Hydrogen production using?renewable?resources would not create such emissions, but the scale of renewable energy production would need to be expanded to be used in producing hydrogen for a significant part of transportation needs.?In a few countries, renewable sources are being used more widely to produce energy and hydrogen. For example,?Iceland?is using?geothermal power?to produce hydrogen,?and?Denmark?is using?wind.
Hydrogen Safety and Supply
Hydrogen fuel is hazardous because of the low?ignition energy Autoignition temperature and high combustion energy of hydrogen, and because it tends to leak easily from tanks.?Explosions at hydrogen filling stations have been reported.?Hydrogen fuelling stations generally receive deliveries of hydrogen by truck from hydrogen suppliers. An interruption at a hydrogen supply facility can shut down multiple hydrogen fuelling stations.
Regulations limiting greenhouse gas emissions (GHGs) from motor vehicles are tightening around the world. With this, both hydrogen engines and hydrogen fuel cells are receiving an increasing interest.?
Given medium and heavy-duty trucks are a major source of CO2 emissions, the transportation sector’s journey to destination zero features both technologies.
As more truck makers join the ranks of auto companies developing CO2-free or CO2-neutral alternative to gasoline and diesel vehicles, let’s look at the similarities and differences between hydrogen engines and fuel cells.
HYDROGEN ENGINES AND FUEL CELLS: SIMILARITIES AND DIFFERENCES IN HOW THEY WORK?
Both hydrogen internal combustion engines and hydrogen fuel cells can power vehicles using hydrogen, a zero-carbon fuel.
Hydrogen engines burn hydrogen in an internal combustion engine, in just the same way gasoline is used in an engine. Hydrogen internal combustion engines (Hydrogen ICE) are nearly identical to traditional spark-ignition engines.
Fuel cell hydrogen vehicles (FCEVs) generate electricity from hydrogen in a device known as a fuel cell, and use that electricity in an electric motor much like an electric vehicle.?
HYDROGEN ENGINES AND FUEL CELLS: COMPLEMENTARY USE-CASES
Hydrogen engines and hydrogen fuel cells offer complementary use cases.?
Internal combustion engines tend to be most efficient under high load—which is to say, when they work harder. FCEVs, in contrast, are most efficient at lower loads.
So, for heavy trucks that tend to spend most of their time hauling the biggest load they can pull, internal combustion engines are usually the ideal and efficient choice. On the other hand, vehicles that frequently operate without any load—tow trucks or concrete mixer trucks, for example, may be more efficient with a fuel cell. Fuel cell electric vehicles can also capture energy through regenerative braking in very transient duty cycles, improving their overall efficiency. ?
Hydrogen engines can also operate as standalone powertrain solutions and handle transient response demand without the need for a battery pack. Fuel cells combined with battery packs can also accomplish the same.
HYDROGEN ENGINES AND FUEL CELLS: SIMILARITIES IN EMISSIONS
Hydrogen engines and hydrogen fuel cells also have similar emissions profiles.
FCEVs, actually, produce no emissions at all besides water vapor. This is a very attractive feature for vehicles operating in closed spaces or spaces with limited ventilation.?
Hydrogen engines release near zero, trace amounts of CO2 (from ambient air and lubrication oil), but can produce nitrogen oxides, or NOx. As a result, they are not ideal for indoor use and require exhaust aftertreatments to reduce NOx emissions.
HYDROGEN ENGINES AND FUEL CELLS: HYDROGEN FUEL CONSIDERATIONS
Yes, both hydrogen engines and fuel cells use hydrogen fuel; but there is more to this story.
Hydrogen engines often are able to operate with lower grade hydrogen. This becomes handy for specific use cases. For example, you might have a site where hydrogen can be produced on site using steam methane reforming and carbon capture and storing (CCS). This hydrogen then can be used in hydrogen engines without the need for purification.?
The hydrogen engine’s robustness to impurities is also handy for a transportation industry where the transition to high quality green hydrogen will take time.
Hydrogen-powered engines
There are two technologies: hydrogen fuel cell electric vehicles (FCEVs) and hydrogen internal combustion engines (H2ICE). FCEVs generate electricity from hydrogen in a device known as a fuel cell that is used to power the electric motor, whereas H2ICE burn hydrogen in an internal combustion engine.
While most discussions around hydrogen are centered on efficiency gains achievable using fuel cells, there has been a renewed interest in H2ICE lately. Powertrain development companies are developing H2ICE for heavy-duty applications, with a focus on increasing the efficiency potential of multiport and directly injected hydrogen concepts, utilizing the existing powertrain architecture. For instance, a multinational engine manufacturing and fuel technology company recently developed a H2ICE engine for heavy-duty trucks across the 10 to 26 ton GVW (gross vehicle weight) range. A major construction equipment?manufacturer has invested 100 million pounds to produce super-efficient hydrogen engines, rolling out its 50th H2ICE in January 2023.?
Most of these OEMs are modifying their existing conventional spark-ignition engines to develop H2ICEs. This is because a four-stroke H2ICE operates on the same cycle as a regular natural gas engine and shares most of the components. H2ICE, however, requires minimum changes to the fuel injection and ignition systems, along with different controls, to handle high pressure hydrogen fuel and the corresponding light changes to the cylinder head.
With higher part-sharing and a known technical arena, R&D costs required to develop H2ICE from a base spark-ignition engine are much lower than the cost of FCEV development. Also, with these engines being manufactured in the same production facilities and following the same manufacturing processes as conventional fossil-fuel ICE, with limited changes, economies of scale could be achieved faster. Moreover, the existing and established ICE supply chain can be leveraged efficiently.
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An area where additional investment would be needed is that H2ICE requires a storage tank similar to FCEVs. In comparison to H2ICE, fuel cell technology is very cost-intensive. Operationally, it requires pure hydrogen and a high specification compressor to supply compressed air. Intricate designs of critical components such as bipolar plates, membranes, etc., add to the cost. Also, new development and testing methods are required to validate the technology.
HYDROGEN ENGINES AND FUEL CELLS: VARYING MATURITY LEVELS
Finally, hydrogen engines and hydrogen fuel cell technologies have different levels of maturity.?
Internal combustion engines have been universally used for decades and are supported by extensive service networks. Rugged engines that can operate in dusty environments or that can be subjected to heavy vibrations are available in all sizes and configurations.
From the perspective of vehicle manufacturers and fleet operators, the switch to hydrogen engine drivetrains involves familiar parts and technology. Risk-averse end-users will find comfort in the tried-and-tested, reliable nature of internal combustion engines.
So it is not really the case that FCEVs and hydrogen ICEs are competing with one another. On the contrary, the development of one supports that of the other, since both drive the development of a common hydrogen production, transportation, and distribution infrastructure. Both also involve the same vehicle storage tanks. They are complementary technologies that are part of reducing vehicle and transportation emissions towards destination zero, now.
Hydrogen Fuel Cell Electric Vehicle (FCEV)what are important character
Fuel Cell is now seen as an alternative to Battery electric vehicle (BEVs) as the market of BEVs is quite saturated and there is a concern about Lithium availability as it is very much evident that lithium is not going to last for unlimited time as compared to coal.
That’s why mobility engineers and Physicist are now trying to find an alternative source of electric vehicle fuel. Which is the hydrogen considered as an alternate solution to lithium.
Fuel Cell Electric vehicle – Operating principle
In fuel cell technology, a process known as reverse electrolysis takes place, in which hydrogen reacts with oxygen in the fuel cell. The hydrogen comes from one or more tanks built into the FCEV, while the oxygen comes from the ambient air.
In the fuel cell of an FCEV, hydrogen and oxygen generate electrical energy. This energy is directed into the electric motor and/or the battery, as needed.
The only results of this reaction are electrical energy, heat and water, which is emitted through the exhaust as water vapor. So hydrogen-powered cars are locally emission-free – more about that in a minute.
The electricity generated in the fuel cell of a hydrogen engine can take two routes, depending on the demands of the specific driving situation.
It either flows to the electric motor and powers the FCEV directly or it charges a battery, which stores the energy until it’s needed for the engine.
This battery, known as a Peak Power Battery, is significantly smaller and therefore lighter than the battery of a fully electric car, as it’s being constantly recharged by the fuel cell.?
Like other e-cars, hydrogen vehicles can also recover or “recuperate” braking energy. The electric motor converts the car’s kinetic energy back into electrical energy and feeds it into the back-up battery.
Hydrogen Fuel cell – Pros and Cons
The pros and cons of a particular propulsion technology can be seen from two main perspectives: that of the user, and that of the environment. If any technology is to succeed as an alternative to the combustion engine, it must be user-friendly and significantly reduce the emission of pollutants.
Advantages for users
The propulsion in hydrogen fuel cell cars is purely electrical. When you drive one, it feels similar to driving a regular electric car. What does that mean? Virtually no engine?noise and a lively start, because electric motors provide full torque even at low speeds.
Another advantage is the quick?charging?time. Depending on the charging station and battery capacity, fully electric vehicles currently require between 30 minutes and several hours for a full charge. The hydrogen tanks of fuel cell cars, on the other hand, are full and ready to go again in less than five minutes. For users, this brings vehicle availability and flexibility into line with those of a conventional car.
For the time being, hydrogen cars still have a longer?range?than purely electric cars. A full hydrogen tank will last around 300 miles (approx. 480 kilometers). Battery-powered cars can match this with very large batteries – which in turn will lead to an increase in both vehicle weight and charging times.
The range of fuel cell vehicles is not dependent on the outside temperature. In other words, it does not deteriorate in cold weather.
Disadvantages for users
Currently, the biggest shortcoming of hydrogen fuel cell cars is the sparsity of options for refueling. A hydrogen engine is refueled at special fuel pumps, which in the future will probably find their way into ordinary service stations.
As things stand, however, there are still very few refueling stations for hydrogen-powered cars. At the end of 2019 there are only around 40 in the U.S., as compared to approx. 80 in Germany.
hydrogen producers and filling station operators in the?Clean Energy Partnership initiative, which plans to expand the hydrogen fueling station network to 130 stations by 2022.
That would allow the operation of about 60,000 hydrogen cars on Germany’s roads. The next target, with a corresponding increase in fuel cell vehicles, will be 400 stations by 2025.
Environmentally friendly and Sustainable Technology
Alternative propulsion systems are designed to reduce the emission of pollutants, in particular climate-harming CO2, but also other noxious gases such as nitrous oxide.
The exhaust gas from a hydrogen engine consist of pure water vapor. Hydrogen fuel cell technology is therefore locally emission-free. This means it keeps the air clean in cities, but does it protect the climate at the same time.
That depends on the conditions under which the hydrogen for the fuel cell vehicles was produced. Hydrogen production requires electrical energy.
This electrical energy is used to break water down into its constituent elements, hydrogen and oxygen, via the process of electrolysis. If the electricity used comes from renewable energy sources, the hydrogen production has a neutral?carbon?footprint. If,
on the other hand, fossil fuels are used, this will ultimately have a knock-on effect on the carbon footprint of the fuel cell cars using the hydrogen. How strong that effect is depends on the energy mix used. In this respect, hydrogen fuel cell cars are no different from other electric vehicles.
However, one disadvantage of producing hydrogen is the losses during electrolysis. The?overall?efficiency in the “power to vehicle drive” energy chain is therefore only half the level of a BEV.
However, hydrogen can be produced at times when there is an oversupply?of electricity from renewable energy sources when the wind or solar energy currently produced is not otherwise used. The potential for this is huge.
Hydrogen is also a by-product of many industrial processes, where all too often it is treated as waste with no further use. The fuel cell battery offers a way to?upcycle?this hydrogen, although it must be cleaned first.
Risk Involved
What happens when hydrogen reacts with oxygen in an uncontrolled reaction? What you get is an explosive reaction known as an oxy-hydrogen gas reaction. Hydrogen is flammable, as this shows, but an uncontrolled reaction of hydrogen and oxygen in the operation of an FCEV is virtually impossible.
This is because, in hydrogen fuel cell cars, the hydrogen is stored in liquid form in thick-walled tanks that are particularly?safe.
As Rücker emphasizes, numerous crash tests have confirmed the safety of how hydrogen cars are designed: the tanks came out of the tests undamaged and no hydrogen leaked.
We should also not forget that hydrogen technology is not new, but is tried and tested in a range of fields. By way of example,
Refineries today use large quantities of hydrogen as a process gas in the processing of crude oil. Pipelines and hydrogen storage have also been in operation for decades.
Technical details of the Powertrain for the BMW i Hydrogen NEXT
“The fuel cell system for the powertrain for the BMW i Hydrogen NEXT generates up to 125 kW (170 hp) of electric power from the chemical reaction between hydrogen and oxygen from the ambient air,” explains Jürgen Guldner, Vice President of Hydrogen Fuel Cell Technology and Vehicle Projects at the BMW Group.
This means the vehicle emits nothing but water vapour. The electric converter located underneath the fuel cell adapts the voltage level to that of both the electric powertrain and the peak power battery, which is fed by brake energy as well as the energy from the fuel cell.
The vehicle also accommodates a pair of 700 bar tanks that can together hold six kilograms of hydrogen. “This guarantees a long range regardless of the weather conditions,” notes Guldner. “And refuelling only takes three to four minutes.” The fifth-generation eDrive unit set to make its debut in the BMW iX3 is also fully integrated into the BMW i Hydrogen NEXT.
The peak power battery positioned above the electric motor injects an extra dose of dynamics when overtaking or accelerating. The total system output of 275 kW (374 hp) fuels the typical driving dynamics for which BMW is renowned.
This hydrogen fuel cell electric powertrain will be piloted in a small series based on the current BMW X5 that the BMW Group plans to present in 2022. A customer offer powered by hydrogen fuel cell technology will be brought to market at the earliest in the second half of this decade by the BMW Group, depending on the global market conditions and requirements.
Hydrogen storage pressure and Temperature
Hydrogen can be stored in both states solid and liquid. storing in gas requires a tank pressure of 320–750 bar or 5,000–10,000 psi. temperature requirement for the hydrogen storage is cryogenic as the boiling point of Hydrogen is -252degC at 1 atmospheric pressure.
Typical energy density during storage is 1.0kwh/kg to 1.7kwh/kg however energy density totally depends on the system and application requirement and is not universal.
finally we reached to the end of our discussion, lets have a quick look what we covered so far – we looked on the history of fuel cell, than we covered equations involved in the hydrogen fuel cells, than we deep dived into the topic of fuel cell based on the hydrogen where we covered topics like application, powertrain, applications, pros and cons etc. we also looked into the design consideration of fuel cell and storage standards of hydrogen.
1. Hydrogen is the simplest and most abundant element in the universe, but it rarely exists as a gas on Earth—it must be separated from other elements. Hydrogen can be produced from diverse, domestic resources, including fossil fuels, nuclear energy, biomass, and other renewable energy sources such as solar, wind, and geothermal, using a wide range of processes. One of these processes is called electrolysis, which splits water into hydrogen and oxygen using electricity from multiple energy resources. ?
2.? More than 10 million metric tons of hydrogen are produced annually in the United States. Most of the hydrogen produced in the United States comes from a process called steam methane reforming. Two of the largest users for this hydrogen are the petroleum refining and fertilizer production industries. There are currently 1,600 miles of hydrogen pipeline in the United States and there are large hydrogen production facilities in almost every state.
3.? Hydrogen can connect various sectors of the economy. For example, producing hydrogen when generation exceeds load on the grid can reduce curtailment of renewables and optimize existing base load plants, such as nuclear. The hydrogen can be stored, distributed, and used as a feedstock for transportation (trucks, rail, marine, etc.), stationary power, process or building heat, and industrial and manufacturing sectors (such as steel manufacturing), creating an additional revenue stream and increased economic value. ?DOE’s H2@Scale initiative is tapping into hydrogen’s potential to unlock these opportunities.
4.? Fuel cells generate electricity through an electrochemical reaction and can use different fuels. When using hydrogen as the fuel, they emit only water and heat. As long as there is a constant source of fuel and oxygen, fuel cells will continue to generate power.
5.? Fuel cells can be grid independent. Over 300,000 stationary fuel cell systems exist worldwide. Over 500 MWs of fuel cell power serves more than 40 states in the United States. These systems provide non-stop power for critical load functions such as data centers, telecommunications towers, hospitals, emergency response systems, and even military applications for national defense.
6.? There are more than 35,000 hydrogen fuel cell forklifts in use across the United States and over 20 million hydrogen refuelings have supported their operation. Fuel cell forklifts are in use now in warehouses, stores, and manufacturing facilities throughout the United States. Hydrogen-powered forklifts offer refueling in minutes, increased performance, and zero emissions for use within warehouses and buildings.
7.? More than 60 hydrogen fuel cell buses are providing transit service in the United States. These buses are already running in various states including California, Massachusetts, Michigan, and Ohio. One of these fuel cell buses has surpassed 32,000 hours of drive time and twelve buses have exceeded 20,000 hours without major repairs or replacement of the fuel cell stack. This is comparable to the life expectancy of a diesel engine in a transit bus.
8.? More than 45 hydrogen stations support the more than 8,800 fuel cell cars that are on the road in the United States. Of these, 42 are retail stations located in California where customers can drive up, fuel, and pay just like at a gasoline station. Other states with hydrogen stations include Connecticut, Hawaii, Massachusetts, and South Carolina.
9.??There is increasing interest in hydrogen and fuel cells from the rail, truck, and maritime sectors.?This is shown through the rollout of the first hydrogen fuel cell train and hydrogen-powered boat. In addition, fuel cell delivery and parcel trucks are starting to deliver in California and New York, the world’s first fuel cell for marine ports was installed in Hawaii, and a heavy-duty fuel cell drayage truck demonstration is underway at the Port of Long Beach.
10.? Fuel cell cost has decreased by 60% since 2006. Many of these cost reductions have come from DOE-funded research and development of catalysts and durable membrane electrode assemblies, as well as increased electrode performance. Fuel cell durability has also increased by a factor of 4 since 2006, and is now equivalent to 120,000 miles.
You've likely heard a lot about electric vehicles lately, as well as news about legislation to reduce carbon emissions from vehicles. But there's another kind of zero-emission vehicle, one that emits only water vapor as it carries you down the road. That's the hydrogen fuel-cell vehicle, related to an EV but with specific differences that make hydrogen cars different and much rarer.
To date, about 2.5 million EVs have been sold in the U.S. By contrast, as of mid-2022, 15,000 or fewer hydrogen-powered vehicles can be found on U.S. roads. All of them will be in California, the sole state with a network of retail hydrogen fueling stations to make the cars usable.
Hydrogen Cars Currently Available
Since 2015, three hydrogen -powered cars have been offered for sale from three different car companies: the Honda Clarity Fuel Cell, the Hyundai Nexo SUV, and the Toyota Mirai. But Honda has now stopped production of all models of the Clarity, and Hyundai has sold fewer than 1500 Nexo SUVs thus far.
Toyota, the company most devoted to hydrogen power as an alternative to battery-electric vehicles, has sold roughly 10,700 Mirai sedans across two generations in the U.S.—though in some periods it resorted to substantial discounting to move them. (Honda does not break out sales of its Clarity Fuel Cell model from the plug-in-hybrid and battery-electric Clarity versions.)
What is a Hydrogen Car?
A hydrogen fuel-cell vehicle (HFCV for short) uses the same kind of electric motor to turn the wheels that a battery-electric car does. But it's powered not by a large, heavy battery but by a fuel-cell stack in which pure hydrogen (H2) passes through a membrane to combine with oxygen (O2) from the air, producing the electricity that turns the wheels plus water vapor. What this means is that a fuel-cell vehicle is technically a series hybrid, which is why they are sometimes classified as fuel-cell hybrid electric vehicles (FCHEV).
To scientists, hydrogen isn't actually a fuel but an energy carrier. Ignore that distinction, though, because HFCV drivers refill their vehicles' carbon-fiber high-pressure tanks at "hydrogen fueling stations" very similar in concept to the old reliable gas station, with a similar five-minute refueling time.
You may hear that hydrogen is the most common element in the universe. At the atomic level, that's true—but hydrogen is never found in its pure state. It's always combined with other elements. Its strong propensity to bind with anything in sight makes it a good energy carrier. Creating pure hydrogen for vehicles requires using a great deal of energy to "crack" a compound like natural gas (CH4) into pure H2, with CO2 as a byproduct. (Most hydrogen today is derived from fossil fuels like natural gas.) Run through a fuel cell, the hydrogen immediately gives back that energy, in the form of electricity, as soon as it combines with oxygen. Out of the exhaust pipe comes only water vapor (H2O).
Behind the Wheel
In practice, the driver of an HFCV will find the experience almost identical to driving a battery-electric vehicle, though perhaps not one of the faster ones. There's no transmission, and the car includes regenerative braking to recapture wasted energy as it slows down.
The challenge for automotive engineers is that hydrogen fuel cells are happiest at a steady power output. That’s what makes them suitable for backup power use, for instance. But the power demands in the average car vary by an order of magnitude, from something like 15 kilowatts (20 horsepower) to keep a vehicle at a steady highway speed on a flat road to perhaps 10 or 20 times that amount for maximum acceleration to 60 mph or higher.
The fuel cell in the Toyota Mirai, the best-selling hydrogen car in the U.S., is rated at 90 kW (120 horsepower). But that's not enough to accelerate onto a fast-moving highway, so Toyota (as do other HFCV makers) adds in a high-voltage low-capacity battery, very similar to those used in gasoline-electric hybrid vehicles. It's there to supply supplemental power for short periods of intense acceleration, and it's recharged from either excess fuel-cell output when the car is cruising at a steady speed or via regenerative braking when the car slows. The three hydrogen cars sold in recent years all have EPA-rated ranges of 300 miles or more, though, like EVs, that range falls substantially at higher speeds.
Are Hydrogen Cars Safe?
HFCVs are widely considered as safe as any other car; since the high-pressure tanks are designed to survive even the highest-speed crashes without leaking or breaching. While hydrogen skeptics routinely cite the Hindenburg explosion of 1937, the hydrogen tanks and their hardware would likely survive even if the rest of the car were destroyed in a crash. No injuries or deaths specific to the hydrogen components have been recorded in the relatively small number of HFCVs sold to date.
Pros and Cons of Hydrogen Fuel-Cell Vehicles
HFCVs have some of the same positive features as battery-electric cars: they’re smooth, quiet, and peaceful to drive—and they emit no carbon dioxide or other harmful exhaust out their tailpipes, just water vapor. They also lack the charging time problem that EVs have; it takes just five minutes or so to refuel them for another 300- to 400-mile stint.
There are a few disadvantages, however, the most challenging being the availability of hydrogen fuel. While plans a decade ago called for California to have 100 hydrogen stations by now, in reality, the number is about 60.
Most problematic, not all those stations are online and available for fueling at all times. You can count the total number of "H70" green dots in the real-time Station Status report maintained by the California Fuel Cell Partnership to see how many are live at any given moment. Many hydrogen drivers rely on that app to map their fueling stops before they venture out.
Hydrogen Fueling Stations
Fueling a hydrogen car comes naturally over time, but aligning the heavy nozzle and sealing it properly so the car and pump can communicate electronically can require some practice. Today's stations can often only fuel two to five vehicles before they go offline for up to half an hour to repressurize.
As HFCV drivers in the San Francisco Bay Area discovered in June 2019, the infrastructure for supplying hydrogen to retail outlets is very thin. An explosion cut off supply to nine of the area’s 11 hydrogen stations, requiring diesel trucks to transport tanks of compressed hydrogen hundreds of miles from Southern California overnight.
Drivers who depended on their hydrogen vehicles to get them to work had to set alarms for the wee hours, in hopes of reaching a fueling station in time to get some of the limited hydrogen fuel. Toyota ended up refunding several months of lease payments to Mirai drivers across the state who couldn’t reliably use their cars.
The main contrast, and biggest disadvantage, of hydrogen cars compared to EVs is that they're similar to gasoline cars in that they can’t be “refueled” or recharged at home overnight. But unlike gasoline cars, for which there’s a well-developed set of more than 100,000 fuel stations nationwide, hydrogen drivers are utterly dependent on both a reliable supply of the gas itself and an available—and properly operating—high-pressure fueling station.
Cost of Hydrogen Fuel
With hydrogen fuel a specialized commodity for the general public, the small network of retail stations naturally charges high prices. To quote the California Hydrogen Business Council, “Currently, a kilogram of hydrogen costs between $10 and $17 at California hydrogen stations, which equals about $5 to $8.50 per gallon of gasoline” to cover the same distance. (A Toyota Mirai hydrogen car holds about five gallons of hydrogen.)
To offset this disadvantage, Honda, Hyundai, and Toyota have all offered their lessees and buyers free hydrogen fuel for various periods. Each manufacturer has a slightly different offer: A Toyota Mirai comes with up to $15,000 of complimentary hydrogen, while a Hyundai Nexo includes the same $15,000 over a three-year lease or up to six years of ownership.
After those offers expire, however, the driver is on their own. And if hydrogen can be compared to gasoline at $5 to $8.50 a gallon, note that charging an EV overnight usually equates to gasoline at just $1 to $2 a gallon.
Servicing a Hydrogen Car
Like electric cars, hydrogen vehicles require dealership service centers to exercise some special precautions. HFCVs have the same high-voltage battery packs as a hybrid, plug-in hybrid, or electric car, but they also have one or more armored, carbon-fiber tanks to hold pure hydrogen under extremely high pressure: 10,000 pounds per square inch (psi), or 700 bar in metric.
Normal service for a hydrogen car that doesn’t involve the hydrogen tanks, the fuel-cell stack, or the plumbing that connects them is just like any other vehicle. But if any of those components have to be handled, the state of California has a set of rules to ensure any escaping hydrogen doesn’t run the risk of an explosion.
Those include largely draining the hydrogen tanks of their fuel in specific types of outdoor areas away from buildings. Then the rest of the system is purged of all remaining hydrogen by flushing components with various gases, a process that takes between 30 and 180 minutes.
The Future of Hydrogen Cars
If you’re in California, and you’re interested in a zero-emission vehicle powered by an electric motor, a hydrogen vehicle may be worth considering. But at the moment, it’s something of a risk. Creating a brand-new fueling network from scratch has proven to be far more problematic—both expensive and unreliable—than automakers envisioned, and the fuel is pricier for drivers than gasoline.
Lacking that hydrogen fuel, delivered at 10,000 psi, an HFCV is no more than a large, pricey doorstop. If we had to guess, we’d suggest the future for passenger cars is more likely to be electric.
Benefits and FUEL CELL
Advantages: More detailed information is available in the applications section, which offers information specific to each industry.
Hydrogen fuel cell technology offers numerous advantages over other power sources :
Renewable and Promptly Available
Hydrogen is the most abundant ingredient in the Universe and, despite the challenges related to its removal from water, is a uniquely renewable and plentiful source of energy, ideal for our future zero-carbon requirements for combined power and heat supplies.
More Robust and Energy Efficient Compared to Fossil Fuels
Hydrogen fuel cell technology gives a high-density energy source with excellent energy efficiency. Hydrogen has the leading energy content of any standard fuel by weight. High-pressure liquid and gaseous hydrogen have almost three times the gravimetric energy density of LNG and diesel and a comparable volumetric energy density to natural gas.
Hydrogen is a Reliable and Adjustable Energy Source to Assist Zero-Carbon Energy Strategies
Hydrogen fuel cells produce an intrinsically clean energy source, with no unfavorable environmental influence during running as the by-products are solely water and heat. Unlike hydropower or biofuel, hydrogen doesn’t need large fields to generate electricity. NASA has been working on applying hydrogen as a resource with the water created as a byproduct of drinking water for astronauts.
This proves that hydrogen fuel cells are a non-toxic fuel source and hence preferred to natural gas, coal, and nuclear power, which are all potentially hazardous or hard to obtain. Production, storage, and hydrogen use will play an essential role in stimulating further advancement of renewable energy by adjusting their alternate supply modalities with the challenging end-user requirements, avoiding the demand for notable early investment to enhance grid infrastructure.
Highly Efficient than Other Sources of Energy
Hydrogen fuel cells are a very effective way of energy production compared to other sources of energy, such as many green energy solutions. This fuel efficiency provides a higher production rate per kg of fuel. For instance, a traditional combustion-based power plant produces electricity at 33-35% efficiency, while a hydrogen fuel cell can generate electricity with an efficiency of up to 65%.
Diminishes Carbon Traces
With nearly no emissions, hydrogen fuel cells do not discharge greenhouse gases, which suggests they do not have a carbon track while in operation.
Virtually Zero Emissions
Hydrogen fuel cells do not produce greenhouse gas emissions as fossil fuel sources, thus diminishing pollution and promoting air quality.
Very Small Noise Pollution
Hydrogen fuel cells do not create noise pollution like other renewable energy sources, such as wind power. This also indicates that, much like electric cars, hydrogen-powered vehicles are much quieter than those that use traditional internal combustion engines.
Quick Charging Times
The charge time for power units of a hydrogen fuel cell is exceptionally speedy, comparable to that for traditional internal combustion engine (ICE) vehicles, and notably faster than battery-powered electric vehicles. Electric vehicles need between 30 minutes and several hours to charge; hydrogen fuel cells can be recharged below five minutes. This fast-charging time suggests that hydrogen-powered vehicles afford the same flexibility as standard cars.
Perfect for Application in Remote Areas
Local limitations allow hydrogen availability through local production and storage to be an alternative to diesel-based power and heating in distant areas. This will diminish the necessity to transport fuels and improve the life quality of those living in remote areas by offering non-polluting energy obtained from a readily available natural resource.
Extended Usage Times
Hydrogen fuel cells allow higher efficiencies regarding usage times. A hydrogen vehicle has an identical range as those that use fossil fuels (around 500 Kilometers). This is preferred to that currently proposed by electric vehicles (EVs), which are frequently being improved with fuel cell power units as range extenders. Hydrogen fuel cells are also not significantly affected by the outside temperature and do not decline in cold weather, unlike EVs. This benefit is extended further when coupled with the quick charging times.
Low Visual Pollution
Some low-carbon energy sources, including biofuel power plants and wind energy, can provide some poor visual scenes; however, hydrogen fuel cells do not have the equivalent space requirements, meaning less visual pollution.
The Versatility of Adoption
As the technology progress, hydrogen fuel cells will be able to afford energy for a range of stationery and portable applications. Hydrogen-powered vehicles are merely one example, but they could also be employed in more miniature applications such as domestic and larger-scale heating systems. Like ICE power plants, the roles of energy storage capacity (i.e. the fuel tank) and engine size are decoupled. In contrast, battery-based power (i.e. power mounts linearly with mass) offers excellent design versatility.
The Democratization of Power Supply
Hydrogen fuel cells can diminish the dependency of a nation on fossil fuels, which will help democratize energy and power supplies worldwide. This increased independence will establish an interest in various countries that are currently reliant on fossil fuel stocks. Of course, this will also withdraw the problem of rising fossil fuel prices as supplies decrease.
Disadvantages of Hydrogen Fuel Cells?
For all the many advantages of hydrogen fuel cells, there are still a few disadvantages and challenges to address:
1.?Hydrogen Extraction
Despite being the most abundant element in the Universe, hydrogen does not exist on its own so needs to be extracted from water via electrolysis or separated from carbon fossil fuels. Both of these processes require a significant amount of energy to achieve. This energy can be more than that gained from the hydrogen itself as well as being expensive. In addition, this extraction typically requires the use of fossil fuels, which in the absence of CCS undermines the green credentials of hydrogen.
2.?Investment is Required
Hydrogen fuel cells need investment to be developed to the point where they become a genuinely viable energy source. This will also require the political will to invest the time and money into development in order to improve and mature the technology. Put simply, the global challenge for development of widespread and sustainable hydrogen energy is how best to incrementally build the ‘supply and demand’ chain in the most cost-effective manner.
3.?Cost of Raw Materials
Precious metals such as platinum and iridium are typically required as catalysts in fuel cells and some? types of water electrolyser, which means that the initial cost of fuel cells (and electrolysers) can be high. This high cost has deterred some from investing in hydrogen fuel cell technology. Such costs need to be reduced in order to make hydrogen fuel cells a feasible fuel source for all.
4.?Regulatory Issues
There are also barriers around regulatory issues concerning the framework that defines commercial deployment models. Without clear regulatory frameworks to allow commercial projects to understand their cost and revenue basis, commercial projects can struggle to reach a financial investment decision (FID).
5.?Overall Cost
The cost for a unit of power from hydrogen fuel cells is currently greater than other energy sources, including solar panels. This may change as technology advances, but currently this cost is a barrier to widespread use of hydrogen even though it is more efficient once produced. This expense also impacts costs further down the line, such as with the price of hydrogen operated vehicles, making widespread adoption unlikely at the moment.
6.?Hydrogen Storage
Storage and transportation of hydrogen is more complex than that required for? fossil fuels. This implies additional costs to consider for hydrogen fuel cells as a source of energy.
7.?Infrastructure
Because fossil fuels have been used for decades, the infrastructure for this power supply already exists. Large scale adoption of hydrogen fuel cell technology for automotive applications will require new refueling infrastructure to support it, although for long-range applications such as those for HGVs and delivery truck is it likely the start-to-end refueling will be used.
8.?Highly Flammable
Hydrogen is a highly flammable fuel source, which brings understandable safety concerns. Hydrogen gas burns in air at concentrations ranging from 4 to 75%.
HYDROGEN IN AVIATION INDUSTRY
Putting hydrogen combustion technology to the test
Hydrogen combustion has already been used to fuel aircraft. In fact, in 1988, the world’s first experimental commercial aircraft operating on liquid hydrogen (and later, liquefied natural gas) took to the skies: the?Tupolev Tu-155. It flew approximately 100 test flights and was then placed into storage.
Now, more than 30 years later, the aviation industry is once again turning its attention to hydrogen combustion in commercial aircraft. Indeed, Airbus’?ZEROe?concept aircraft could run on hydrogen combustion. To explore the possibilities and limitations of this technology for commercial aircraft, Airbus will team up with a variety of partners across industries.?
“The only way to determine which hydrogen technology is best-placed to fuel our ZEROe concept aircraft is to test, test, test,” says Matthieu Thomas, ZEROe Aircraft Lead Architect. “We look forward to sharing more details about an exciting cross-industry partnership on hydrogen combustion.”??
?But for hydrogen combustion to work, liquid hydrogen must be stored safely and securely on board aircraft. Due to hydrogen’s unique properties, this can be tricky. For example, tanks need to be insulated to avoid evaporation if heat is carried over into the stored content by factors such as conduction. This is why the Airbus Defence and Space’s Engineering Division has stepped in to help. The team will provide support for the development and industrialisation of cryogenic tanks for liquid hydrogen storage in a three-year project collaboration with the ZEROe programme team.?
“The space industry has been using pressure vessels for the storage of liquid propellant to fuel space exploration for decades,” explains Renato Bellarosa, Head of Propulsion Products and Tanks at Airbus Defence and Space. “So we have a lot of expertise in damage tolerance, in advanced manufacturing technologies and in vessel pressure testing, all of which is key to supporting the development of liquid hydrogen storage tanks for future aircraft propulsion systems. It’s cross-industry collaboration like this that will bring us closer to putting a hydrogen-powered aircraft into the skies over the next decade.”
Conclusion / Summary
The advantages of hydrogen fuel cells as one of the best renewable energy sources are evident, however there are still a number of challenges to overcome to realise the full? potential of hydrogen as a key enabler for a future decarbonised energy system.
On the positive side, hydrogen fuel cells could offer a fully renewable and clean power source for stationary and mobile applications in the near future.? To achieve this there is the need to scale up decarbonised hydrogen production and fuel cell manufacture, and develop the required regulatory framework to clearly define commercial deployment models.? Further technological advances to lower the associated costs of extraction, storage and transportation are envisaged, along with further investment in the infrastructure to support it.
Hydrogen could become the best solution for the future of our energy requirements but this will require political will and investment to achieve. However, as fossil fuels run out hydrogen could be a key solution for our global energy needs.
Centre Head, Vehicle Inspection & Certification center (I & C center)
1 年Thanks for sharing
Director Operations at Corporate Professional Academy for Technical Training & Career Development
1 年v.k. gupta