COMPREHENSIVE COVERAGE ON HYDROGEN, HYDROGEN PRODUCTION, HYDROGEN FUEL CELL AND HYDROGEN I.C. ENGINE ELECTRIC VEHICLES
vijay tharad
Director Operations at Corporate Professional Academy for Technical Training & Career Development
Hydrogen is a gas that is colorless, odorless, and tasteless. It enjoys its reputation as the simplest and most abundant chemical element in the universe. Hydrogen consists of tiny particles, protons, and electrons. Hydrogen is the simplest and most abundant element on earth. Hydrogen combines readily with other chemical elements, and it is always found as part of another substance, such as water, hydrocarbon, or alcohol. Hydrogen is also found in natural biomass, which includes plants and animals. For this reason, it is considered as an?energy carrier?and not as an energy source.?
Hydrogen is becoming increasingly important as a promising clean energy carrier – especially with a view to a more climate-friendly future.
It is extremely responsive and can combine with other elements to form compounds such as water. It acts as a powerful fuel and can be used to generate electricity, operate vehicles, and generate heat. As a clean energy carrier, hydrogen has the potential to reduce environmental impact and contribute to a sustainable energy supply.
There are four main sources for the commercial production of hydrogen:?
1.Natural Gas ???48%
2.Oil ??????????????????30%
3.?Coal ???????????????18%
4. Electrolysis ???????4%
Fossil fuels are the dominant source of?industrial hydrogen. Hydrogen is a chemical widely used in various applications including ammonia production, oil refining and energy. The most common methods for producing hydrogen on an industrial scale are: Steam reforming, oil reforming, coal gasification, water electrolysis. Hydrogen can be produced using diverse, domestic resources, including nuclear, natural gas and coal, biomass, and other renewable sources. The latter include solar, wind, hydroelectric, or geothermal energy. This diversity of domestic energy sources makes hydrogen a promising energy carrier and important for energy security. It is desirable that hydrogen be produced using a variety of resources and process technologies or pathways. The production of hydrogen can be achieved via various process technologies, including thermal (natural gas reforming, renewable liquid and biooil processing, biomass, and coal gasification), electrolytic (water splitting using a variety of energy resources), and photolytic (splitting of water using sunlight through biological and electrochemical materials).
The annual production of hydrogen is estimated to be about 55 million tons with its consumption increasing by approximately 6% per year. Hydrogen can be produced in many ways from a broad spectrum of initial raw materials. Nowadays, hydrogen is mainly produced by the steam reforming of natural gas, a process which leads to massive emissions of greenhouse gases . Close to 50% of the global demand for hydrogen is currently generated via steam reforming of natural gas, about 30% from oil/naphtha reforming from refinery/chemical industrial off-gases, 18% from coal gasification, 3.9% from water electrolysis, and 0.1% from other sources .?Electrolytic and plasma processes demonstrate a high efficiency for hydrogen production, but unfortunately they are considered as energy intensive processes .
The fundamental question lies in the development of alternative technologies for hydrogen production to those based on fossil fuels, especially for its utilization as a fuel in the transportation sector. This problem can be faced by the utilization of alternative renewable resources and related methods of production, such as the gasification or pyrolysis of biomass, electrolytic, photolytic, and thermal cracking of water. 95% of hydrogen is produced by?steam reforming of natural gas?and other light hydrocarbons, partial oxidation of heavier hydrocarbons, and?coal gasification.
Hydrogen production through technological use
Following are some of the technologies for Hydrogen production?
Steam reforming of natural gas:?
This is currently the most widely used technology for hydrogen production. In this process, natural gas, which consists mainly of methane, is heated with water vapor in the presence of a catalyst. Figuratively, steam reforming can be thought of as the "breaking up" of natural gas.
Steam methane reforming (SMR) produces hydrogen from natural gas, mostly methane (CH4), and water. It is the cheapest source of industrial hydrogen, being the source of nearly 50% of the world's hydrogen.?The process consists of heating the gas to 700–1,100?°C (1,300–2,000?°F) in the presence of steam over a?nickel catalyst. The resulting?endothermic reaction?forms carbon monoxide and molecular hydrogen (H2).?
In the?water-gas shift reaction, the carbon monoxide reacts with steam to obtain further quantities of H2. The WGSR also requires a catalyst, typically over iron oxide ?or other?oxides.. The byproduct is CO2.?Depending on the quality of the?feedstock?(natural gas,?naphtha etc.), one ton of hydrogen produced will also produce 9 to 12 tons of CO2, a greenhouse gas that may be?captured.
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For this process, high temperature steam (H2O) reacts with methane (CH4) in an endothermic reaction to yield?syngas.
CH4?+ H2O → CO + 3 H2
In a second stage, additional hydrogen is generated through the lower-temperature,?exothermic, water-gas shift reaction, performed at about 360?°C (680?°F):
CO + H2O → CO2?+ H2
Essentially, the?oxygen?(O) atom is stripped from the additional water (steam) to oxidize CO to CO2. This oxidation also provides energy to maintain the reaction. Additional heat required to drive the process is generally supplied by burning some portion of the methane. In this process, the methane in the natural gas reacts with the water vapor, producing hydrogen (H2) and carbon monoxide (CO). The hydrogen obtained is purified and can then be used as fuel in vehicles, to generate electricity in fuel cells or in various industrial applications. This process is inexpensive, but it also has disadvantages. Carbon dioxide is released as a by-product, which has an impact on the environment.?
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ELECROLYSIS OF WATER
In electrolysis, water is split into hydrogen and oxygen with the help of an electric current.?Equipment called electrolyzers carry out the electrolysis process to do this.
Water electrolysis is using electricity to split water into hydrogen and oxygen. As of 2020, less than 0.1% of hydrogen production comes from water electrolysis. Electrolysis of water?is 70–80% efficient. while?steam reforming?of natural gas has a?thermal efficiency?between 70 and 85%.?The electrical efficiency of electrolysis is expected to reach 82–86%?before 2030, while also maintaining durability as progress in this area continues apace.?
Water electrolysis can operate at 50–80?°C (120–180?°F), while steam methane reforming requires temperatures at 700–1,100?°C (1,300–2,000?°F).?The difference between the two methods is the primary energy used; either electricity (for electrolysis) or natural gas (for steam methane reforming). Due to their use of water, a readily available resource, electrolysis and similar water-splitting methods have attracted the interest of the scientific community. With the objective of reducing the cost of hydrogen production, renewable sources of energy have been targeted to allow electrolysis.?
There are three main types of electrolytic cells,
2. Polymer electrolyte?memberance cells?(PEM)?
3. Alkaline electrolysis cells?(AECs).?
Traditionally, alkaline electrolysers are cheaper in terms of investment (they generally use nickel catalysts), but less-efficient; PEM electrolysers, conversely, are more expensive (they generally use expensive?platinum group?metal catalysts) but are more efficient and can operate at higher?current densities, and can therefore be possibly cheaper if the hydrogen production is large enough.
PEM ELECTROLYSIS
PEM electrolysis, also known as proton exchange membrane electrolysis, splits water into hydrogen and oxygen using a polymer membrane and electric current.?PEM electrolysis cells typically operate below 100?°C (212?°F).?These cells have the advantage of being comparatively simple and can be designed to accept widely varying?voltage?inputs, which makes them ideal for use with renewable sources of energy such as?photovoltaic solar panels.?AECs optimally operate at high concentrations of electrolyte (KOH or potassium carbonate) and at high temperatures, often near 200?°C (392?°F).
Advantages:
· Fast start-up and quick adaptation to variable loads
· High efficiency in partial load operation
· Low operating temperature (50-80°C), reducing the use of expensive materials
· Compact size and easy integration into existing systems
· High level of technological maturity
Disadvantages:
Sensitive to impurities in the water, therefore requires pre-treatment of the water
Limited service life of the PEM fuel cell (approx. 10,000 operating hours)
Higher costs compared to alkaline electrolysis
ALKALINE ELECTROLYSIS
In alkaline electrolysis, water is split into its constituents hydrogen and oxygen using an alkaline electrolyte, typically an aqueous solution of potassium hydroxide.
Advantages:
· Lower costs compared to PEM electrolysis
· Robust against contaminants in the water
· Long service life of the electrolytic cell (approx. 40,000-80,000 operating hours)
· Highest level of technological maturity
Disadvantages:
· Slower reaction rate compared to PEM electrolysis
· Higher operating temperatures (70-100°C) lead to higher energy consumption
· More difficult integration into existing systems due to different operating parameters
SOLID OXIDE ELECTROLYSIS CELL
SOEC stands for Solid Oxide Electrolysis Cell and refers to a high-temperature electrolytic cell that converts water into hydrogen and oxygen at high temperatures and with solid oxides as the electrolyte.?SOECs operate at high temperatures, typically around 800?°C (1,500?°F). At these high temperatures, a significant amount of the energy required can be provided as thermal energy (heat), and as such is termed?high temperature electrolysis. The heat energy can be provided from a number of different sources, including waste industrial heat,?nuclear power stations?or concentrated?solar thermal plants. This has the potential to reduce the overall cost of the hydrogen produced by reducing the amount of electrical energy required for electrolysis.?
Advantages:
· High efficiency and heat recovery due to high operating temperatures (800-1000°C)
· Flexibility in the use of different fuels (e.g. steam, CO2)
Disadvantages:
· High operating temperatures require expensive materials and special thermal insulation
· Slow start and adaptation to variable loads
· Larger dimensions and complex system integration
· Little operating experience on a large scale
AEM ELECTROLYSIS (ANION EXCHANGE MEMBRANE)
AEM stands for Anion Exchange Membrane and refers to an electrolyzer technology that uses a special membrane that allows permeability to negatively charged ions and splits water into hydrogen and oxygen using electric current.
Advantages:
· Lower costs compared to PEM electrolysis
· Robust against contaminants in the water
· Operation at lower temperatures (approx. 60-80°C)
Disadvantages:
· Limited development and commercialization compared to PEM and alkaline electrolysis
· Potential challenges to membrane long-term stability
· No large-scale installations available. Low level of technological maturity.
?Solar hydrogen production:?
In this method, solar energy is used instead of electrical energy to carry out the electrolysis process. This can be done either by direct sunlight or by concentrating solar radiation with the help of solar mirrors or collectors. This new technology could be used in countries where sufficient sun is available and make it possible to produce hydrogen particularly cost-effectively.?
Thermochemical Hydrogen Production (Biological Hydrogen Production):?
Some microorganisms, such as certain bacteria or algae, can produce hydrogen through fermentation or photosynthesis. This method is still under development, but has potential as a sustainable and environmentally friendly hydrogen source. However, the disadvantage of this type of production is the finite resources.
Biohydrogen routes for Hydrogen production
Biomass and waste streams can in principle be converted into?biohydrogen?with biomass?gasification, steam reforming, or biological conversion like biocatalysed electrolysis?or fermentative hydrogen production.
Among hydrogen production methods biological routes are potentially less energy intensive. In addition, a wide variety of waste and low-value materials such as agricultural biomass as renewable sources can be utilized to produce hydrogen via biochemical pathways. Nevertheless, at present hydrogen is produced mainly from fossil fuels, in particular, natural gas which are non-renewable sources. Hydrogen is not only the cleanest fuel but also widely used in a number of industries, especially fertilizer, petrochemical and food ones
Biochemical routes to hydrogen are classified as dark and photo fermentation processes. In dark fermentation, carbohydrates are converted to hydrogen by fermentative microorganisms including strict anaerobe and facultative anaerobic bacteria. A theoretical maximum of 4?mol H2/mol glucose can be produced.]?Sugars are convertable to volatile fatty acids (VFAs) and alcohols as by-products during this process. Photo fermentative bacteria are able to generate hydrogen from VFAs. Hence, metabolites formed in dark fermentation can be used as feedstock in photo fermentation to enhance the overall yield of hydrogen.
Hydrogen USES
Hydrogen is used for the conversion of heavy petroleum fractions into lighter ones via?hydrocracking.
It is also used in other processes including the?aromatization?process,?hydrodesulfurization?and the production of?ammonia?via the?Haber process. the primary industrial method for the production of synthetic nitrogen fertilizer for growing 47 percent of food worldwide.
Hydrogen is used in?fuel cells?for local electricity generation or potentially as a transportation fuel.
Hydrogen is produced as a?by-product?of?industrial chlorine production by electrolysis. Although requiring expensive technologies, hydrogen can be cooled, compressed and purified for use in other processes on site or sold to a customer via pipeline, cylinders or trucks.
Sustainability of Hydrogen production:.
It should be noted that not all hydrogen production processes are equally sustainable or environmentally friendly. The sustainability of hydrogen production depends on the energy source used and the CO2 emissions during the production process. In order to make the most of the benefits of hydrogen as a clean energy source, it is of great importance to use renewable energy sources for the production of hydrogen. The use of renewable energies such as solar energy, wind energy or hydropower can significantly reduce CO2 emissions in hydrogen production, making it more sustainable and sustainable. Environmentally friendly hydrogen is produced. This is an important step towards achieving a low-carbon future and tackling climate change.
Electrolysis is the process that is most promising. The electrolysis process enables the environmentally friendly production of hydrogen, especially if the electricity used for it comes from renewable energy sources. These technologies play an important role in enabling
?Hydrogen vehicles include hydrogen-fueled space rockets, as well as ships and aircraft.? less commonly, by burning hydrogen in an internal combustion engine.·
The chemical energy of hydrogen is converted to mechanical energy through a REDOX (reduction/oxidation) reaction between hydrogen and oxygen within a specially developed fuel cell., The second option less commonly by burning hydrogen in an internal combustion engine.
As hydrogen is not found in reservoirs or natural deposits, as with fossil fuels, it needs to be produced from natural gas or biomass, or electrolysed from water. 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).
One? benefit of hydrogen power is the decrease in greenhouse gas emissions, particularly when the gas is produced using renewable electricity to convert water into hydrogen.
So, in order to obtain the quantity of?hydrogen?needed to power a?vehicle, it is necessary to store a considerable amount in large tanks at high pressure. The?hydrogen?fuel cell electric?vehicle?is, for Renault Group, an electric?vehicle?that combines a lithium-ion battery and a?hydrogen?fuel cell under one hood.
How Do Hydrogen Fuel Cells Work?
A hydrogen fuel cell converts potential chemical energy into electrical energy using a proton exchange membrane (PEM) that uses hydrogen gas (H2) and oxygen (O2). However, since oxygen is readily available in the atmosphere, the fuel cell only needs to be supplied with the hydrogen required to power the vehicle.
Hydrogen fuel cells are made up of a negatively charged cathode and a positively charged anode which are put in contact with an electrolyte. The electrolyte is the proton exchange membrane, a specially treated material. Hydrogen gas enters the fuel cell on the anode side and is forced through the catalyst by pressure. The PEM only conducts positively charged ions, while blocking the electrons. The anode conducts the electrons, which have been freed from the hydrogen molecules, through an external circuit. These electrons provide the power to drive the electric motor, light bulbs, and so forth.
Meanwhile, oxygen is forced through the catalyst from the cathode side, where the negative charge of the atoms attracts the hydrogen atoms that have been pushed through the external circuit, before the hydrogen ions and the oxygen recombines to form water.
The following hydrogen fuel cell equation shows the process:
O2 + 4H+ + 4e– → 2H2O
2H2 → 4H+ + 4e–
2H2 + O2 → 2H2O (net reaction)
Hydrogen fuel cells vary and use different materials for the catalyst, mainly platinum nanoparticles. These nanoparticles face the PEM and the catalyst is rough and porous so as to expose the maximum surface area to the hydrogen or oxygen.
The fuel cells are placed together in stacks. The stacks are embedded in a module including fuel, water and air management, and coolant control hardware and software.Y
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Hydrogen Fuel Cells Advantages and Disadvantages
Hydrogen fuel cells offer both advantages and disadvantages compared to traditional engines. Fuel cells are not only more reliable due to a lack of moving parts, but they are more efficient too. This greater efficiency is because the chemical potential energy is converted directly into electrical energy rather than having to first be converted into heat and then again for the mechanical work – which is known as the ‘thermal bottleneck.’ Exhaust or tailpipe emissions from hydrogen fuel cell electric vehicles (FCEV) are also cleaner than from traditional internal combustion engines, as they emit just water and some heat, rather than the plethora of greenhouse gases associated with traditional combustion engines.
However, there are a number of challenges with hydrogen fuel cells, including being expensive to produce. This is primarily due to the expense of the rare substances, such as platinum, required for the catalyst. The earliest fuel cell designs also struggled to perform at low temperatures, but later modifications to the technology have ensured that this has now been addressed. The service life of fuel cells is also now comparable to that of other vehicles, with a PEM expected to last for 7,300 hours under cycling conditions.
Hydrogen vehicle is a 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.
Use of Hydrogen in Internal Combustion Engines PART 1 & PART 2
WHAT WE KNOW SO FAR
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 ended 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.)
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What is a Hydrogen Car?
Like all-electric vehicles, fuel cell electric vehicles (FCEVs) use electricity to power an electric motor. In contrast to other electric vehicles, FCEVs produce electricity using a fuel cell powered by hydrogen, rather than drawing electricity from only a battery. During the vehicle design process, the vehicle manufacturer defines the power of the vehicle by the size of the electric motor(s) that receives electric power from the appropriately sized fuel cell and battery combination. Although automakers could design an FCEV with plug-in capabilities to charge the battery, most FCEVs today use the battery for recapturing braking energy, providing extra power during short acceleration events, and to smooth out the power delivered from the fuel cell with the option to idle or turn off the fuel cell during low power needs. The amount of energy stored onboard is determined by the size of the hydrogen fuel tank. This is different from an all-electric vehicle, where the amount of power and energy available are both closely related to the battery's size.
Key Components of a Hydrogen Fuel Cell Electric Car
Battery (auxiliary): In an electric drive vehicle, the low-voltage auxiliary battery provides electricity to start the car before the traction battery is engaged; it also powers vehicle accessories.
Battery pack: This high-voltage battery stores energy generated from regenerative braking and provides supplemental power to the electric traction motor.
DC/DC converter: This device converts higher-voltage DC power from the traction battery pack to the lower-voltage DC power needed to run vehicle accessories and recharge the auxiliary battery.
Electric traction motor (FCEV): Using power from the fuel cell and the traction battery pack, this motor drives the vehicle's wheels. Some vehicles use motor generators that perform both the drive and regeneration functions.
Fuel cell stack: An assembly of individual membrane electrodes that use hydrogen and oxygen to produce electricity.
Fuel filler: A nozzle from a fuel dispenser attaches to the receptacle on the vehicle to fill the tank.
Fuel tank (hydrogen): Stores hydrogen gas onboard the vehicle until it's needed by the fuel cell.
Power electronics controller (FCEV): This unit manages the flow of electrical energy delivered by the fuel cell and the traction battery, controlling the speed of the electric traction motor and the torque it produces.
Thermal system (cooling) - (FCEV): This system maintains a proper operating temperature range of the fuel cell, electric motor, power electronics, and other components.
Transmission (electric): The transmission transfers mechanical power from the electric traction motor to drive the wheels
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.
Hydrogen cars: advantages and disadvantages
Although hydrogen cars are yet to make any significant impact on the global stage, the movement away from fossil fuel-powered vehicles to those with zero emissions is gathering steam (no hydrogen-car pun intended), making it likely that hydrogen cars will eventually be seen on Australian roads.?
Compared to EVs and combustion-engine vehicles, hydrogen cars state their case as an attractive option thanks to their superior range, quick refuelling time and, most importantly, the ability to operate without releasing harmful carbon dioxide into the Earth’s atmosphere.?
The key advantage of the hydrogen system, though, is weight. Because a hydrogen fuel cell and hybrid battery is roughly equivalent in weight to a petrol or diesel combustion system, it means hydrogen fuelled trucks, buses, or even utes can maintain both their payload and driving range, making hydrogen best-suited to replace diesel rather than petrol in the automotive ecosystem.
In fact, Hyundai's plan to roll out hydrogen globally, is to lead with commercial vehicles like its Xcient truck rather than its Nexo SUV, as it says commercial routes are the fastest way to help spread the required infrastructure.
The key advantage of hydrogen fuel cell tech is that it has the right traits to be able to replace diesel for heavy vehicles.
However, the key disadvantage of hydrogen vehicles, preventing or slowing their adoption worldwide, is the requirement for a high level of investment in infrastrucutre, paticularly refuelling bowsers compared to electric vehicles.
Hydrogen refuelling stations require the fuel to be compressed?and refrigerated, adding costs to on-site locations, and to support a high volume of vehicles, they require multiple reservoirs.
Hydrogen Storage
There have been concerns raised over the storage of hydrogen in the cars themselves. Once pumped into the car, the gas is held in a high-pressure cylinder, leading some to worry about the safety of storing a highly flammable gas in the vehicle. However, all of the cars on the market need to pass stringent safety tests.
With regard to transportation, there has been research related to using ammonia borane, a hydrogen storage compound, from which the hydrogen can be separated using a membrane. This offers transportation advantages as ammonia is easier to safely store in tankers than pure hydrogen.
In addition to the fuel tanks of vehicles and transportation issues, the hydrogen needs to be stored at hydrogen filling stations. The low ignition energy, coupled with hydrogen’s high combustion energy, and the fact that the gas tends to leak from tanks, has led to explosions at hydrogen filling stations. Again, this is an obvious factor that needs to be addressed ahead of the widespread use of hydrogen vehicles.
Hydrogen Infrastructure
In order to make hydrogen fuel cell cars the transport of the future, there is a real need to improve the infrastructure around the vehicles. This will involve increasing the number of global and UK hydrogen fuel stations,? which will either need to be supplied by compressed hydrogen tube trailers, liquid hydrogen tank trucks, hydrogen pipelines or, alternatively, use some form of dedicated on-site production. Creating this infrastructure to match that of the needs of the consumer could prove costly, even as some propose the creation of home hydrogen fuel stations.
HYDROGEN REGULATIONS CODES AND STANDARDS
Another factor that could delay the widespread use of hydrogen are the necessary codes and standards for safety and storage of the gas. These will need to be developed for a variety of hydrogen electric vehicles and across different nations.
Hydrogen Fueling Stations (U.S.A.)
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.
HYDROGEN STATIONS
The refuelling process in a hydrogen station is very similar to that of a conventional petrol station, although the hydrogen is supplied at high pressure
Renewable energies
Green hydrogen is produced with renewable energy.
Water
The water used for electrolysis must contain salts and minerals to conduct electricity
Electrolyser
It uses electric current to separate hydrogen from oxygen in water
Compressor
It increases the pressure of hydrogen to store it
Tanques
O hydrogen é armazenado em tanques de alta press?o – 500 bar
Dispenser
Depending on the size, it delivers between 60 and 120 g/s for vehicles from 200 kg/day up to 2,000 kg/day.
Cooler
The supply requires that the hydrogen be refrigerated.
Hydrogen tank
The hydrogen tanks are located in the upper part
Fuel cell
Generates the electricity needed to move the vehicle
Electric motor
In charge of bus traction.
Conjunto de baterias
Buses typically have 5 tanks of 7.5 kg each at 350 bar, for a total of 37.5 kg of hydrogen.
??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 Buusiness 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.
DISADVANTAGES OF HYDROGEN CARS TODAY
Improvements to Hydrogen Vehicle Technology and Infrastructure
Many of the perceived negatives of hydrogen cars can be addressed with investment in infrastructure and technology. Dedicated fuelling stations for hydrogen are more expensive than implementing charging stations for electric vehicles and, unless the take-up of hydrogen vehicles increases, this investment is unlikely to be promoted. This creates something of a Catch-22 situation, whereby the infrastructure is needed to support the take-up of hydrogen vehicles but, without the take up of hydrogen vehicles, the need for the infrastructure could be brushed aside as unnecessary. That said, the UK government and the EU are already backing a drive to increase the number of available hydrogen filling stations.
The technology driving the vehicles themselves is also set to improve over time and this technology is also set to become cheaper as the range for hydrogen cars increases. Cheaper costs, improved efficiency and greater supporting infrastructure will all serve to drive consumer confidence and take-up of hydrogen cars in the future.
Hydrogen Fuel Cell Vehicles in Action
A few examples of hydrogen being used in the real world:
As hydrogen fuel cell technologies expand, a sector that could greatly benefit is seaports. Replacing diesel engines across a variety of port applications can significantly reduce air pollutants associated with diesel emissions. Many other fuel cell applications are under development, including for port drayage trucks, yard tractors, cargo handlers (top loaders), switcher locomotives, and marine vessels such as harbor craft.
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.?
Differences Between Fuel Cell Cars and Electric Cars
While the traditional combustion engine looks set to become a thing of the past, hydrogen fuel cell vehicles face stiff competition from other electric vehicles.
While both battery electric vehicles and hydrogen fuel cell vehicles offer emission-free driving, battery-powered vehicles can use the existing infrastructure to recharge, although they need to be plugged in for longer periods of time and still have questions over range.
It is a question of which technology can address their particular challenges to become the favoured form of transport for the future.
FAQs
Are Hydrogen Cars Safe?
Hydrogen fuel cell cars are as safe as conventional vehicles – if not safer! Hydrogen is a clean energy source which makes up 70% of all matter in the universe. While it is safer to handle than petrol or diesel, the high combustibility of hydrogen has led to some concerns.
However, because hydrogen is lighter than air, this is not a real concern should the hydrogen be able to vent out into the atmosphere. Rather than staying put and burning like liquid fuels would, hydrogen will rise quickly into the air before it can ignite in any quantity.
Are Hydrogen Cars the Future?
As we move away from the use of fossil fuels, clean hydrogen could become part of a mix of energy sources for vehicles, along with biofuels, hybrid technologies, autogas, and more.
However, clean hydrogen looks like a very promising fuel of the future to power everything from cars to aeroplanes, long haul freight, steel production and domestic heating!
Despite hydrogen's limitations, countries around the world are seeing it as a viable alternative energy source for everything from cars and buses to air planes. If we can find a cost-effective way to make hydrogen production more environmentally friendly and build out the necessary refueling infrastructure, FCEVs could mean a huge leap forward for green transportation.
Are Hydrogen Cars Better than Electric?
Hydrogen cars offer many of the same benefits associated with electric vehicles (EV), such as the lack of polluting emissions. However, hydrogen cars also have some advantages over their electric counteparts, in that they are much faster to refuel and currently offer a greater range than EVs.
Will Hydrogen Cars Replace Electric?
The main barrier to the uptake of hydrogen cars is the supporting infrastructure. Without plenty of accessible places to refuel, as is the case with petrol stations, it is difficult to see hydrogen cars as an alternative to electric cars, that already have more refuelling infrastructure in place.
However, there is a prediction that hydrogen will be rolled out for heavy goods vehicles, buses, and rail as well as being used in shipping and aviation. As this use increases, so the supporting infrastructure will also develop, paving the way for hydrogen cars to become an increasingly viable option and quite possibly replacing electric. ???
Are Hydrogen Cars good for the Environment?
Hydrogen cars are good for the environment because they do not produce the same emissions as petrol or diesel vehicles. Hydrogen-powered fuel cell vehicles emit only water (H2O) and warm air.
However, that is not the whole story, as hydrogen production plays a large part in exactly how environmentally friendly the car is. If the hydrogen is produced through electrolysis, using electricity from renewable energy sources such as wind power,? then this ‘green hydrogen’ is perfectly clean and environmentally friendly.
Compared to fossil fuel use, hydrogen cars using green hydrogen are certainly good for the environment.
Can Hydrogen Cars Run On Water?
Hydrogen cars, in effect, are run on water should the hydrogen be created by electrolysis. This is where electricity is used to split water into hydrogen and oxygen.
In theory, this could be done inside the vehicle by taking electricity from the cars electrical system to electrolyse water held in a tank to create a gaseous mixture of hydrogen and oxygen.
However, it is currently better to produce hydrogen at scale and then transport and store it, either under pressure or as a liquid at extremely cold temperatures.
How do Hydrogen Cars Refuel?
Hydrogen cars refuel in much the same way as petrol or diesel cars refuel. Rather than recharging a battery, as with electric vehicles, hydrogen cars can go to a pump to have their tanks filled with hydrogen gas. Refuelling a hydrogen car is also much faster than recharging batteries, taking around 3-5 minutes to refill the tank.
Where do Hydrogen Cars Refuel?
Hydrogen cars need to refuel at hydrogen refuelling stations (HRS), which can pump pressurised hydrogen into the vehicle in much the same way as when refuelling with petrol or diesel.
There is currently a lack of HRSs across the world, but with advances in transportation and storage infrastructure, they could become as commonplace as today’s gas stations.
How do Hydrogen Cars Store Hydrogen?
Hydrogen can be stored as either a gas or a liquid. Gas storage is typically the method used by hydrogen cars, using high-pressure tanks of 350–700 bar (5,000–10,000 psi) tank pressure.
The Toyota Mirai, for example, stores compressed hydrogen fuel in three 10,000-psi carbon-fibre-reinforced high-pressure tanks; one in the centre of the car, one under the rear seat, and one underneath the battery housing.
Are Hydrogen Cars Fast?
As with any other car, some hydrogen cars are faster than others. For example, the Toyota Mirai takes 9.1 seconds to reach 60 mph, but the H2 Speed can accelerate to the same speeds in just 3.4 seconds. Plus, the H2 Speed can reach a top speed of 186mph (299km/h), showing that hydrogen cars do have the capability to drive fast.
Distribution
Most hydrogen used in the United States is produced at or close to where it is used—typically at large industrial sites. The infrastructure needed for distributing hydrogen to the nationwide network of fueling stations required for the widespread use of fuel cell electric vehicles still needs to be developed. The initial rollout for vehicles and stations focuses on building out these distribution networks, primarily in southern and northern California.
Currently, hydrogen is distributed through three methods:
Creating an infrastructure for hydrogen distribution and delivery to thousands of future individual fueling stations presents many challenges. Because hydrogen contains less energy per unit volume than all other fuels, transporting, storing, and delivering it to the point of end-use is more expensive on a per gasoline gallon equivalent basis. Building a new hydrogen pipeline network involves high initial capital costs, and hydrogen's properties present unique challenges to pipeline materials and compressor design. However, because hydrogen can be produced from a wide variety of resources, regional or even local hydrogen production can maximize use of local resources and minimize distribution challenges.
There are tradeoffs between centralized and distributed production to consider. Producing hydrogen centrally in large plants cuts production costs but boosts distribution costs. Producing hydrogen at the point of end-use—at fueling stations, for example—cuts distribution costs but increases production costs because of the cost to construct on-site production capabilities.
The Hydrogen and Fuel Cell Technologies Office (HFTO) is developing onboard automotive hydrogen storage systems that allow for a driving range of more than 300 miles while meeting cost, safety, and performance requirements.
Why Study Hydrogen Storage
Hydrogen storage is a key enabling technology for the advancement of hydrogen and fuel cell technologies in applications including stationary power, portable power, and transportation. Hydrogen has the highest energy per mass of any fuel; however, its low ambient temperature density results in a low energy per unit volume, therefore requiring the development of advanced storage methods that have potential for higher energy density.
How Hydrogen Storage Works
Hydrogen can be stored physically as either a gas or a liquid. Storage of hydrogen as a gas typically requires high-pressure tanks (350–700 bar [5,000–10,000 psi] tank pressure). Storage of hydrogen as a liquid requires cryogenic temperatures because the boiling point of hydrogen at one atmosphere pressure is ?252.8°C. Hydrogen can also be stored on the surfaces of solids (by adsorption) or within solids (by absorption).
Research and Development Goals
HFTO conducts research and development activities to advance hydrogen storage systems technology and develop novel hydrogen storage materials. The goal is to provide adequate hydrogen storage to meet the U.S. Department of Energy (DOE) hydrogen storage targets for onboard light-duty vehicle, material-handling equipment and portable power applications. By 2020, HFTO aims to develop and verify onboard automotive hydrogen storage systems achieving targets that will allow hydrogen-fueled vehicle platforms to meet customer performance expectations for range, passenger and cargo space, refueling time, and overall vehicle performance. Specific system targets include the following:
The collaborative Hydrogen Storage Engineering Center of Excellence conducts analysis activities to determine the current status of materials-based storage system technologies.
The Hydrogen Materials-Advanced Research Consortium (HyMARC) conducts foundational research to understand the interaction of hydrogen with materials in relation to the formation and release of hydrogen from hydrogen storage materials.
Challenges
The 2010 U.S. light-duty vehicle sales distribution by driving range.
Comparison of specific energy (energy per mass or gravimetric density) and energy density (energy per volume or volumetric density) for several fuels based on lower heating values.
High density hydrogen storage is a challenge for stationary and portable applications and remains a significant challenge for transportation applications. Presently available storage options typically require large-volume systems that store hydrogen in gaseous form. This is less of an issue for stationary applications, where the footprint of compressed gas tanks may be less critical.
However, fuel-cell-powered vehicles require enough hydrogen to provide a driving range of more than 300 miles with the ability to quickly and easily refuel the vehicle. While some light-duty hydrogen fuel cell electric vehicles (FCEVs) that are capable of this range have emerged onto the market, these vehicles will rely on compressed gas onboard storage using large-volume, high-pressure composite vessels. The required large storage volumes may have less impact for larger vehicles, but providing sufficient hydrogen storage across all light-duty platforms remains a challenge. The importance of the 300-mile-range goal can be appreciated by looking at the sales distribution by range chart on this page, which shows that most vehicles sold today are capable of exceeding this minimum.
On a mass basis, hydrogen has nearly three times the energy content of gasoline—120 MJ/kg for hydrogen versus 44 MJ/kg for gasoline. On a volume basis, however, the situation is reversed; liquid hydrogen has a density of 8 MJ/L whereas gasoline has a density of 32 MJ/L, as shown in the figure comparing energy densities of fuels based on lower heating values. Onboard hydrogen storage capacities of 5–13 kg hydrogen will be required to meet the driving range for the full range of light-duty vehicle platforms.
To overcome these challenges HFTO is pursuing two strategic pathways, targeting both near-term and long-term solutions. The near-term pathway focuses on compressed gas storage, using advanced pressure vessels made of fiber reinforced composites that are capable of reaching 700 bar pressure, with a major emphasis on system cost reduction. The long-term pathway focuses on both (1) cold or cryo-compressed hydrogen storage, where increased hydrogen density and insulated pressure vessels may allow for DOE targets to be met and (2) materials-based hydrogen storage technologies, including sorbents, chemical hydrogen storage materials and metal hydrides, with properties having potential to meet DOE hydrogen storage targets.