A hydrogen vehicle is a type of alternative fuel vehicle that uses hydrogen fuel for motive power. Hydrogen vehicles include hydrogen-fueled space rockets, as well as automobiles and other transportation vehicles. Power is generated by converting the chemical energy of hydrogen to mechanical energy, either by reacting hydrogen with oxygen in a fuel cell to power electric motors or, less commonly, by burning hydrogen in an internal combustion engine.
As of 2021, there are two models of hydrogen cars publicly available in select markets: the Toyota Mirai (2014–), which is the world's first mass produced dedicated fuel cell electric vehicle (FCEV), and the Hyundai Nexo (2018–). The Honda Clarity was produced from 2016 to 2021. A few other companies, like BMW, are still exploring hydrogen cars, while Volkswagen has expressed that the technology has no future in the automotive space, mainly because a fuel cell electric vehicle consumes about three times more energy than a battery electric car for each mile driven. As of December 2020, there were 31,225 passenger FCEVs powered with hydrogen on the world's roads. —
As of 2019, 98% of hydrogen is produced by steam methane reforming, which emits carbon dioxide. It can be produced by thermochemical or pyrolytic means using renewable feedstocks, but the processes are currently expensive. Various technologies are being developed that aim to deliver costs low enough, and quantities great enough, to compete with hydrogen production using natural gas.
The benefits of hydrogen technology are fast refueling time (comparable to gasoline) and long driving range on a single tank. The drawbacks of hydrogen use are high carbon emissions when hydrogen is produced from natural gas, capital cost burden, low energy content per unit volume at ambient conditions, production and compression of hydrogen, the investment required in filling stations to dispense hydrogen, transportation of hydrogen to filling stations, and lack of ability to produce or dispense hydrogen at home.
Automobiles, buses, forklifts, trains, PHB bicycles, canal boats, cargo bikes, golf carts, motorcycles, wheelchairs, ships, aeroplanes, submarines, and rockets can already run on hydrogen, in various forms. NASA used hydrogen to launch Space Shuttles into space. A working toy model car runs on solar power, using a regenerative fuel cell to store energy in the form of hydrogen and oxygen gas. It can then convert the fuel back into water to release the solar energy. Since the advent of hydraulic fracturing the key concern for hydrogen fuel cell vehicles is consumer and public policy confusion concerning the adoption of natural gas powered hydrogen vehicles with heavy hidden emissions to the detriment of environmentally friendly transportation.
In 2013 the Hyundai Tucson FCEV was launched, it was a conversion of the Tucson and available in left-hand drive only and became the first commercially mass produced vehicle of its type in the world. Hyundai Nexo, which succeeded the Tucson in 2018, was selected as the "safest SUV" by the Euro NCAP in 2018 and was rated as "Good" in a side crash test conducted by the Insurance Institute for Highway Safety (IIHS)
Toyota launched the world's first dedicated mass produced fuel cell vehicle (FCV), the Mirai, in Japan at the end of 2014 and began sales in California, mainly the Los Angeles area and also in selected markets in Europe, the UK, Germany and Denmark later in 2015. The car has a range of 312 mi (502 km) and takes about five minutes to refill its hydrogen tank. The initial sale price in Japan was about 7 million yen ($69,000). Former European Parliament President Pat Cox estimated that Toyota would initially lose about $100,000 on each Mirai sold. At the end of 2019, Toyota had sold over 10,000 Mirais. Many automobile companies have introduced demonstration models in limited numbers (see List of fuel cell vehicles and List of hydrogen internal combustion engine vehicles).
In 2013 BMW leased hydrogen technology from Toyota, and a group formed by Ford Motor Company, Daimler AG, and Nissan announced a collaboration on hydrogen technology development. By 2017, however, Daimler had abandoned hydrogen vehicle development, and most of the automobile companies developing hydrogen cars had switched their focus to battery electric vehicles.
A record of 207.297 miles per hour (333.612 km/h) was set by a prototype Ford Fusion Hydrogen 999 Fuel Cell Race Car at the Bonneville Salt Flats, in August 2007, using a large compressed oxygen tank to increase power. The land-speed record for a hydrogen-powered vehicle of 286.476 miles per hour (461.038 km/h) was set by Ohio State University's Buckeye Bullet 2, which achieved a "flying-mile" speed of 280.007 miles per hour (450.628 km/h) at the Bonneville Salt Flats in August 2008.
Fuel-cell buses are being trialed by several manufacturers in different locations, for example, the Ursus Lublin. Solaris Bus & Coach introduced its Urbino 12 hydrogen electric buses in 2019. Several dozen have been ordered and are expected to be delivered in 2020 and 2021.
Trams and trains
In March 2015, China South Rail Corporation (CSR) demonstrated the world's first hydrogen fuel cell-powered tramcar at an assembly facility in Qingdao. The chief engineer of the CSR subsidiary CSR Sifang Co Ltd., Liang Jianying, said that the company is studying how to reduce the running costs of the tram. Tracks for the new vehicle have been built in seven Chinese cities. China plans to spend 200 billion yuan ($32 billion) through 2020 to increase tram tracks to more than 1,200 miles.
As of 2019 Hydrogen fuel cells are not suitable for propulsion in large long-distance ships, but they are being considered as a range-extender for smaller, short-distance, low-speed electric vessels, such as ferries. Hydrogen in ammonia is being considered as a long-distance fuel.
In 2007, Pearl Hydrogen Power Source Technology Co of Shanghai, China, demonstrated a PHB hydrogen bicycle. In 2014, Australian scientists from the University of New South Wales presented their Hy-Cycle model. The same year, Canyon Bicycles started to work on the Eco Speed concept bicycle.
In 2017, Pragma Industries of France developed a bicycle that was able to travel 100 km on a single hydrogen cylinder. In 2019, Pragma announced that the product, "Alpha Bike", has been improved to offer an electrically-assisted pedalling range of 150 km, and the first 200 of the bikes are to be provided to journalists covering the 45th G7 summit in Biarritz, France. If successful, Lloyd Alter of TreeHugger responded to the announcement, asking "why … go through the trouble of using electricity to make hydrogen, only to turn it back into electricity to charge a battery to run the e-bike [or] pick a fuel that needs an expensive filling station that can only handle 35 bikes a day, when you can charge a battery powered bike anywhere. [If] you were a captive fleet operator, why [not] just swap out batteries to get the range and the fast turnover?"
General Motors' military division, GM Defense, focuses on hydrogen fuel cell vehicles. Its SURUS (Silent Utility Rover Universal Superstructure) is a flexible fuel cell electric platform with autonomous capabilities. Since April 2017, the U.S. Army has been testing the commercial Chevrolet Colorado ZH2 on its U.S. bases to determine the viability of hydrogen-powered vehicles in military mission tactical environments.
Motorcycles and scooters
ENV develops electric motorcycles powered by a hydrogen fuel cell, including the Crosscage and . Other manufacturers as Vectrix are working on hydrogen scooters. Finally, hydrogen-fuel-cell-electric-hybrid scooters are being made such as the Suzuki Burgman fuel-cell scooter and the . The Burgman received "whole vehicle type" approval in the EU. The Taiwanese company APFCT conducted a live street test with 80 fuel-cell scooters for Taiwan's Bureau of Energy.
Quads and tractors
Companies such as Boeing, Lange Aviation, and the German Aerospace Center pursue hydrogen as fuel for manned and unmanned aeroplanes. In February 2008 Boeing tested a manned flight of a small aircraft powered by a hydrogen fuel cell. Unmanned hydrogen planes have also been tested. For large passenger aeroplanes, The Times reported that "Boeing said that hydrogen fuel cells were unlikely to power the engines of large passenger jet aeroplanes but could be used as backup or auxiliary power units onboard."
In Britain, the Reaction Engines A2 has been proposed to use the thermodynamic properties of liquid hydrogen to achieve very high speed, long distance (antipodal) flight by burning it in a precooled jet engine.
A hydrogen internal combustion engine (or "HICE") forklift or HICE lift truck is a hydrogen fueled, internal combustion engine-powered industrial forklift truck used for lifting and transporting materials. The first production HICE forklift truck based on the Linde X39 Diesel was presented at an exposition in Hannover on May 27, 2008. It used a 2.0 litre, 43 kW (58 hp) diesel internal combustion engine converted to use hydrogen as a fuel with the use of a compressor and direct injection.
A fuel cell forklift (also called a fuel cell lift truck) is a fuel cell powered industrial forklift truck. In 2013 there were over 4,000 fuel cell forklifts used in material handling in the US. The global market was estimated at 1 million fuel cell powered forklifts per year for 2014–2016. Fleets are being operated by companies around the world. Pike Research stated in 2011 that fuel-cell-powered forklifts will be the largest driver of hydrogen fuel demand by 2020.
Most companies in Europe and the US do not use petroleum powered forklifts, as these vehicles work indoors where emissions must be controlled and instead use electric forklifts. Fuel-cell-powered forklifts can provide benefits over battery powered forklifts as they can be refueled in 3 minutes. They can be used in refrigerated warehouses, as their performance is not degraded by lower temperatures. The fuel cell units are often designed as drop-in replacements.
Many large rockets use liquid hydrogen as fuel, with liquid oxygen as an oxidizer (LH2/LOX). An advantage of hydrogen rocket fuel is the high effective exhaust velocity compared to kerosene/LOX or UDMH/NTO engines. According to the Tsiolkovsky rocket equation, a rocket with higher exhaust velocity uses less propellant to accelerate. Also the energy density of hydrogen is greater than any other fuel. LH2/LOX also yields the greatest efficiency in relation to the amount of propellant consumed, of any known rocket propellant.
A disadvantage of LH2/LOX engines is the low density and low temperature of liquid hydrogen, which means bigger and insulated and thus heavier fuel tanks are needed. This increases the rocket's structural mass which reduces its delta-v significantly. Another disadvantage is the poor storability of LH2/LOX-powered rockets: Due to the constant hydrogen boil-off, the rocket must be fueled shortly before launch, which makes cryogenic engines unsuitable for ICBMs and other rocket applications with the need for short launch preparations.
Overall, the delta-v of a hydrogen stage is typically not much different from that of a dense fuelled stage, but the weight of a hydrogen stage is much less, which makes it particularly effective for upper stages, since they are carried by the lower stages. For first stages, dense fuelled rockets in studies may show a small advantage, due to the smaller vehicle size and lower air drag.
LH2/LOX were also used in the Space Shuttle to run the fuel cells that power the electrical systems. The byproduct of the fuel cell is water, which is used for drinking and other applications that require water in space.
In 2020, Hyundai began commercial production of its Xcient fuel cell trucks and has shipped ten of them to Switzerland. It plans to sell to additional markets, including the US by 2022.
Internal combustion vehicle
Hydrogen internal combustion engine cars are different from hydrogen fuel cell cars. The hydrogen internal combustion car is a slightly modified version of the traditional gasoline internal combustion engine car. These hydrogen engines burn fuel in the same manner that gasoline engines do; the main difference is the exhaust product. Gasoline combustion results in emissions of carbon dioxide, carbon monoxide, NOx, particulates and unburned hydrocarbons, while the main exhaust product of hydrogen combustion is water vapor.
In 1807 Francois Isaac de Rivaz designed the first hydrogen-fueled internal combustion engine. In 1965, Roger Billings, then a high school student, converted a Model A to run on hydrogen. In 1970 Paul Dieges patented a modification to internal combustion engines which allowed a gasoline-powered engine to run on hydrogen US 3844262 .
Mazda has developed Wankel engines burning hydrogen, which are used in the Mazda RX-8 Hydrogen RE. The advantage of using an internal combustion engine, like Wankel and piston engines, is the lower cost of retooling for production.
Fuel cell cost
Hydrogen fuel cells are relatively expensive to produce, as their designs require rare substances, such as platinum, as a catalyst, In 2014, former European Parliament President Pat Cox estimated that Toyota would initially lose about $100,000 on each Mirai sold. In 2020, researchers at the University of Copenhagen's Department of Chemistry are developing a new type of catalyst that they hope will decrease the cost of fuel cells. This new catalyst uses far less platinum because the platinum nano-particles are not coated over carbon which, in conventional hydrogen fuel cells, keeps the nano-particles in place but also causes the catalyst to become unstable and denatures it slowly, requiring even more platinum. The new technology uses durable nanowires instead of the nano-particles. "The next step for the researchers is to scale up their results so that the technology can be implemented in hydrogen vehicles."
The problems in early fuel-cell designs at low temperatures concerning range and cold start capabilities have been addressed so that they "cannot be seen as show-stoppers anymore". Users in 2014 said that their fuel cell vehicles perform flawlessly in temperatures below zero, even with the heaters blasting, without significantly reducing range. Studies using neutron radiography on unassisted cold-start indicate ice formation in the cathode, three stages in cold start and Nafion ionic conductivity. A parameter, defined as coulomb of charge, was also defined to measure cold start capability.
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.
According to Ford Motor Company, a hydrogen fuel-cell vehicle would generate only three-fifths as much carbon dioxide as a comparable vehicle running on gasoline blended to 10 percent ethanol. Although methods of hydrogen production that do not use fossil fuel would be more sustainable, currently renewable energy represents only a small percentage of energy generated, and power produced from renewable sources can be used more efficiently in electric vehicles and for non-vehicle applications.
The challenges facing the use of hydrogen in vehicles include chiefly its storage on board the vehicle. While the well-to-wheel efficiency for hydrogen from the least efficient manner of producing it (electrolysis) is less than 25 percent, it still exceeds that of vehicles based on internal combustion engines.
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 (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, and 85% of hydrogen produced is used to remove sulfur from gasoline. Hydrogen can also be produced from water by electrolysis at working efficiencies of 65–70%. Hydrogen can also 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 gasses, a consequence that would also result from the on-board reforming of methanol into hydrogen. Analyses comparing the environmental consequences of hydrogen production and use in fuel-cell vehicles to the refining of petroleum and combustion in conventional automobile engines do not agree on whether a net reduction of ozone and greenhouse gasses would result. Hydrogen production using renewable energy 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. As of 2016, 14.9 percent of U.S. electricity was produced from renewable sources. 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.
Compressed hydrogen in hydrogen tanks at 350 bar (5,000 psi) and 700 bar (10,000 psi) is used for hydrogen tank systems in vehicles, based on type IV carbon-composite technology.
Hydrogen has a very low volumetric energy density at ambient conditions, compared with gasoline and other vehicle fuels. It must be stored in a vehicle either as a super-cooled liquid or as highly compressed gas, which require additional energy to accomplish. In 2018, researchers at CSIRO in Australia powered a Toyota Mirai and Hyundai Nexo with hydrogen separated from ammonia using a membrane technology. Ammonia is easier to transport safely in tankers than pure hydrogen.
The hydrogen infrastructure consists of hydrogen-equipped filling stations, which are supplied with hydrogen via compressed hydrogen tube trailers, liquid hydrogen tank trucks or dedicated onsite production, and some industrial hydrogen pipeline transport. The distribution of hydrogen fuel for vehicles throughout the U.S. would require new hydrogen stations that would cost between 20 billion dollars in the US, (4.6 billion in the EU). and half trillion dollars in the US.
As of 2021, there were 49 publicly accessible hydrogen refueling stations in the US, 48 of which were located in California (compared with 42,830 electric charging stations). By 2017, there were 91 hydrogen fueling stations in Japan.
Codes and standards
, as well as codes and technical standards for hydrogen safety and the storage of hydrogen, have been an institutional barrier to deploying hydrogen technologies. To enable the commercialization of hydrogen in consumer products, new codes and standards must be developed and adopted by federal, state and local governments.
In 2003, George W. Bush announced an initiative to promote hydrogen-powered vehicles. In 2009, President Obama and his Energy Secretary Steven Chu stripped the funding of fuel cell technology after concluding that the technology was still decades away. Under heavy criticism, the funding was partially restored.
In 2013, Senator Byron L. Dorgan said that "The Energy and Water Appropriations bill makes investments in our nation’s efforts to develop safe, homegrown energy sources that will reduce our reliance on foreign oil. And, because ongoing research and development is necessary to develop game-changing technologies, this bill also restores funding for Hydrogen energy research." The same year, the U.S. Department of Energy gave 9 million dollars in grants to speed up technology development, 4.5 million for advanced fuel cell membranes, $3 million to 3M to work on membranes with improved durability and performance, and 1.5 million to the Colorado School of Mines for work on simpler and more affordable fuel cell membranes. US investments in fueling were planned in 2014.
Critics claim the time frame for overcoming the technical and economic challenges to implementing wide-scale use of hydrogen cars is likely to last for at least several decades. They claim that the focus on the use of the hydrogen car is a dangerous detour from more readily available solutions to reducing the use of fossil fuels in vehicles. In May 2008, Wired News reported that "experts say it will be 40 years or more before hydrogen has any meaningful impact on gasoline consumption or global warming, and we can't afford to wait that long. In the meantime, fuel cells are diverting resources from more immediate solutions."
Critiques of hydrogen vehicles are presented in the 2006 documentary, Who Killed the Electric Car?. According to former U.S. Department of Energy official Joseph Romm, "A hydrogen car is one of the least efficient, most expensive ways to reduce greenhouse gases." Asked when hydrogen cars will be broadly available, Romm replied: "Not in our lifetime, and very possibly never." The Los Angeles Times wrote, in 2009, "Hydrogen fuel-cell technology won't work in cars. ... Any way you look at it, hydrogen is a lousy way to move cars." The Economist magazine, in 2008, quoted Robert Zubrin, the author of Energy Victory, as saying: "Hydrogen is 'just about the worst possible vehicle fuel'". The magazine noted the withdrawal of California from earlier goals: "In  the California Air Resources Board, an agency of California's state government and a bellwether for state governments across America, changed its requirement for the number of zero-emission vehicles (ZEVs) to be built and sold in California between 2012 and 2014. The revised mandate allows manufacturers to comply with the rules by building more battery-electric cars instead of fuel-cell vehicles." The magazine also noted that most hydrogen is produced through steam methane reformation, which creates at least as much emission of carbon per mile as some of today's gasoline cars. On the other hand, if the hydrogen could be produced using renewable energy, "it would surely be easier simply to use this energy to charge the batteries of all-electric or plug-in hybrid vehicles." As of 2019, 98% of hydrogen is produced by steam methane reforming, which emits carbon dioxide.
A 2009 study at UC Davis, published in the Journal of Power Sources, similarly found that, over their lifetimes, hydrogen vehicles will emit more carbon than gasoline vehicles. This agrees with a 2014 analysis. The Washington Post asked in 2009, "[W]hy would you want to store energy in the form of hydrogen and then use that hydrogen to produce electricity for a motor, when electrical energy is already waiting to be sucked out of sockets all over America and stored in auto batteries"? The Motley Fool stated in 2013 that "there are still cost-prohibitive obstacles [for hydrogen cars] relating to transportation, storage, and, most importantly, production."
Volkswagen's Rudolf Krebs said in 2013 that "no matter how excellent you make the cars themselves, the laws of physics hinder their overall efficiency. The most efficient way to convert energy to mobility is electricity." He elaborated: "Hydrogen mobility only makes sense if you use green energy", but ... you need to convert it first into hydrogen "with low efficiencies" where "you lose about 40 percent of the initial energy". You then must compress the hydrogen and store it under high pressure in tanks, which uses more energy. "And then you have to convert the hydrogen back to electricity in a fuel cell with another efficiency loss". Krebs continued: "in the end, from your original 100 percent of electric energy, you end up with 30 to 40 percent." The Business Insider commented:
Pure hydrogen can be industrially derived, but it takes energy. If that energy does not come from renewable sources, then fuel-cell cars are not as clean as they seem. ... Another challenge is the lack of infrastructure. Gas stations need to invest in the ability to refuel hydrogen tanks before FCEVs [fuel cell electric vehicles] become practical, and it's unlikely many will do that while there are so few customers on the road today. ... Compounding the lack of infrastructure is the high cost of the technology. Fuel cells are "still very, very expensive".
In 2014, Joseph Romm devoted three articles to updating his critiques of hydrogen vehicles made in his book The Hype about Hydrogen. He stated that fuel cell vehicles still had not overcome the high cost of the vehicles, high fueling cost, and lack of fuel-delivery infrastructure. "It would take several miracles to overcome all of those problems simultaneously in the coming decades." Moreover, he wrote, "FCVs aren't green" because of escaping methane during natural gas extraction and when hydrogen is produced, as 95% of it is, using the steam reforming process. He concluded that renewable energy cannot economically be used to make hydrogen for an FCV fleet "either now or in the future." GreenTech Media's analyst reached similar conclusions in 2014. In 2015, Clean Technica listed some of the disadvantages of hydrogen fuel cell vehicles as did Car Throttle. Another Clean Technica writer concluded that "while hydrogen may have a part to play in the world of energy storage (especially seasonal storage), it looks like a dead end when it comes to mainstream vehicles." A 2016 study in the November issue of the journal Energy by scientists at Stanford University and the Technical University of Munich concluded that, even assuming local hydrogen production, "investing in all-electric battery vehicles is a more economical choice for reducing carbon dioxide emissions, primarily due to their lower cost and significantly higher energy efficiency."
A 2017 analysis published in Green Car Reports concluded that the best hydrogen-fuel-cell vehicles consume "more than three times more electricity per mile than an electric vehicle ... generate more greenhouse gas emissions than other powertrain technologies ... [and have] very high fuel costs. ... Considering all the obstacles and requirements for new infrastructure (estimated to cost as much as $400 billion), fuel-cell vehicles seem likely to be a niche technology at best, with little impact on U.S. oil consumption. The US Department of Energy agrees, for fuel produced by grid electricity via electrolysis, but not for most other pathways for generation. A 2019 video by Real Engineering noted that, notwithstanding the introduction of vehicles that run on hydrogen, using hydrogen as a fuel for cars does not help to reduce carbon emissions from transportation. The 95% of hydrogen still produced from fossil fuels releases carbon dioxide, and producing hydrogen from water is an energy-consuming process. Storing hydrogen requires more energy either to cool it down to the liquid state or to put it into tanks under high pressure, and delivering the hydrogen to fueling stations requires more energy and may release more carbon. The hydrogen needed to move a FCV a kilometer costs approximately 8 times as much as the electricity needed to move a BEV the same distance. Also in 2019, Katsushi Inoue, the president of Honda Europe, stated, "Our focus is on hybrid and electric vehicles now. Maybe hydrogen fuel cell cars will come, but that’s a technology for the next era."
Safety and supply
Hydrogen fuel is hazardous because of the low ignition energy (see also 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.
Comparison with other types of alternative fuel vehicle
Plug-in hybrid electric vehicles, or PHEVs, are hybrid vehicles that can be plugged into the electric grid and contain an electric motor and also an internal combustion engine. The PHEV concept augments standard hybrid electric vehicles with the ability to recharge their batteries from an external source, enabling increased use of the vehicle's electric motors while reducing their reliance on internal combustion engines. The infrastructure required to charge PHEVs is already in place, and transmission of power from grid to car is about 93% efficient. This, however, is not the only energy loss in transferring power from grid to wheels. AC/DC conversion must take place from the grid's AC supply to the PHEV's DC. This is roughly 98% efficient. The battery then must be charged. As of 2007, the Lithium iron phosphate battery was between 80-90% efficient in charging/discharging. The battery needs to be cooled. As of 2009, "the total well-to-wheels efficiency with which a hydrogen fuel cell vehicle might utilize renewable electricity is roughly 20%. ... The well-to-wheels efficiency of charging an onboard battery and then discharging it to run an electric motor in a PHEV or EV, however, is 80%... four times more efficient than current hydrogen fuel cell vehicle pathways." A December 2009 study at UC Davis found that, over their lifetimes, PHEVs will emit less carbon than current vehicles, while hydrogen cars will emit more carbon than gasoline vehicles.
Internal combustion engine-based compressed natural gas(CNG), HCNG, LPG or LNG vehicles (Natural gas vehicles or NGVs) use methane (Natural gas or Biogas) directly as a fuel source. Natural gas has a higher energy density than hydrogen gas. NGVs using biogas are nearly carbon neutral. Unlike hydrogen vehicles, CNG vehicles have been available for many years, and there is sufficient infrastructure to provide both commercial and home refueling stations. Worldwide, there were 14.8 million natural gas vehicles by the end of 2011. The other use for natural gas is in steam reforming which is the common way to produce hydrogen gas for use in electric cars with fuel cells.
A 2008 Technology Review article stated, "Electric cars—and plug-in hybrid cars—have an enormous advantage over hydrogen fuel-cell vehicles in utilizing low-carbon electricity. That is because of the inherent inefficiency of the entire hydrogen fueling process, from generating the hydrogen with that electricity to transporting this diffuse gas long distances, getting the hydrogen in the car, and then running it through a fuel cell—all for the purpose of converting the hydrogen back into electricity to drive the same exact electric motor you'll find in an electric car." Thermodynamically, each additional step in the conversion process decreases the overall efficiency of the process.
A 2013 comparison of hydrogen and battery electric vehicles agreed with the 25% figure from Ulf Bossel in 2006 and stated that the cost of an electric vehicle battery "is rapidly coming down, and the gap will widen further", while there is little "existing infrastructure to transport, store and deliver hydrogen to vehicles and would cost billions of dollars to put into place, everyone's household power sockets are "electric vehicle refueling" station and the "cost of electricity (depending on the source) is at least 75% cheaper than hydrogen." By 2018, the cost of EV batteries had fallen to below $150 per kWh.
Early electric car designs offered limited driving range causing range anxiety. For example, the 2013 Nissan Leaf had a range of 75 mi (121 km), More recent EV models generally have considerably greater range; for example, the 2020 Tesla Model S has a range of more than 400 mi (640 km). Most US commutes are 30–40 miles (48–64 km) per day round trip, and in Europe, most commutes are around 20 kilometres (12 mi) round-trip
In 2013 John Swanton of the California Air Resources Board, who saw EVs and hydrogen vehicles as complementary technologies, stated that EVs had the jump on fuel-cell autos, which "are like electric vehicles were 10 years ago. EVs are for real consumers, no strings attached. With EVs you have a lot of infrastructure in place. The Business Insider, in 2013 commented that if the energy to produce hydrogen "does not come from renewable sources, then fuel-cell cars are not as clean as they seem. ... Gas stations need to invest in the ability to refuel hydrogen tanks before FCEVs become practical, and it's unlikely many will do that while there are so few customers on the road today. ... Compounding the lack of infrastructure is the high cost of the technology. Fuel cells are "still very, very expensive", even compared to battery-powered EVs.
- "Toyota Unveils 2015 Fuel Cell Sedan, Will Retail in Japan For Around ¥7 Million". transportevolved.com. 2014-06-25. Archived from the original on 2018-11-19. Retrieved 2014-06-26.
- "A portfolio of power-trains for Europe: a fact-based analysis" (PDF). iphe.net. Archived (PDF) from the original on 15 October 2017. Retrieved 15 April 2018.
- "Honda discontinues hydrogen-fuelled Clarity FCV due to slow sales". June 16, 2021. Retrieved July 29, 2021.
- International Energy Agency (IEA), Clean Energy Ministerial, and Electric Vehicles Initiative (EVI) (2021-04-29). "Global EV Outlook 2021: Accelerating ambitions despite the pandemic". International Energy Agency. Retrieved 2021-05-17.CS1 maint: multiple names: authors list (link) Go to the Global EV Data Explorer tool and choose "EV Stock", "Cars" and "World" for global stock, and "Country" for the country stock.
- "Realising the hydrogen economy" Archived 2019-11-05 at the Wayback Machine, Power Technology, October 11, 2019
- Romm, Joseph. Tesla Trumps Toyota: Why Hydrogen Cars Can’t Compete With Pure Electric Cars" Archived 2014-08-21 at the Wayback Machine, ThinkProgress, August 5, 2014.
- "Wind-to-Hydrogen Project". Hydrogen and Fuel Cells Research. Golden, CO: National Renewable Energy Laboratory, U.S. Department of Energy. September 2009. Archived from the original on 26 August 2009. Retrieved 7 January 2010.. See also Energy Department Launches Public-Private Partnership to Deploy Hydrogen Infrastructure Archived 2014-06-07 at the Wayback Machine, US Dept. of Energy, accessed November 15, 2014
- Berman, Bradley (2013-11-22). "Fuel Cells at Center Stage". The New York Times. Archived from the original on 2014-11-07. Retrieved 2013-11-26.
- Davies, Alex (2013-11-22). "Honda Is Working On Hydrogen Technology That Will Generate Power Inside Your Car". The Business Insider. Archived from the original on 2013-11-25. Retrieved 2013-11-26.
- Cox, Julian. "Time To Come Clean About Hydrogen Fuel Cell Vehicles" Archived 2014-07-15 at the Wayback Machine, CleanTechnica.com, June 4, 2014
- Thames & Kosmos kit Archived 2012-07-12 at the Wayback Machine, Other educational materials Archived 2009-02-07 at the Wayback Machine, and many more demonstration car kits Archived 2007-12-26 at the Wayback Machine.
- "Global Hydrogen Fuel Cell Electric Vehicle Market Buoyed as OEMs Will Launch 17 Vehicle Models by 2027, IHS Says". IHS Inc. 4 May 2016. Archived from the original on 2 March 2021. Retrieved 13 May 2016.
- "The World's First Mass-Production of FCEV". Archived from the original on 18 November 2018. Retrieved 18 November 2018.
- "Hyundai ix35 Fuel Cell". Hyundai. Archived from the original on 18 November 2018. Retrieved 18 November 2018.
- "Euro NCAP Best in Class 2018 - new award for best performing hybrid & electric car of 2018 | Euro NCAP". www.euroncap.com. Archived from the original on 2019-06-24. Retrieved 2019-06-24.
- "2019 Hyundai Nexo 4-door SUV". IIHS-HLDI crash testing and highway safety. Archived from the original on 2019-06-24. Retrieved 2019-06-24.
- European Sales Of Toyota Mirai To Begin This September
- Voelcker, John. "Decades Of Promises: 'Dude, Where's My Hydrogen Fuel-Cell Car?'" Archived 2021-03-02 at the Wayback Machine, Yahoo.com, March 31, 2015
- "Toyota to Offer $69,000 Car After Musk Pans 'Fool Cells'". 2014-06-25. Archived from the original on 2014-06-27. Retrieved 2014-06-27.
- Ayre, James. "Toyota To Lose $100,000 On Every Hydrogen FCV Sold?" Archived 2015-01-03 at the Wayback Machine, CleanTechnica.com, November 19, 2014; and Blanco, Sebastian. "Bibendum 2014: Former EU President says Toyota could lose 100,000 euros per hydrogen FCV sedan" Archived 2014-11-24 at the Wayback Machine, GreenAutoblog.com, November 12, 2014
- "Sales, Production, and Export Results for March 2020 | Sales, Production, and Export Results | Profile | Company". Archived from the original on 2021-03-02. Retrieved 2020-05-11.
- Whoriskey, Peter. "The Hydrogen Car Gets Its Fuel Back" Archived 2017-02-26 at the Wayback Machine, Washington Post, October 17, 2009
- Riversimple plans to lease a vehicle to the public by 2018 "Hydrogen Car You Can Actually Afford" Archived 2016-03-06 at the Wayback Machine, TopGear.com
- LaMonica, Martin. "Ford, Daimler, and Nissan Commit to Fuel Cells". technologyreview.com. Archived from the original on 9 November 2018. Retrieved 15 April 2018.
- Gordon-Bloomfield, Nikki. "Are Hydrogen Fuel Cell Cars Doomed – And Have Electric Cars Won?" Archived 2017-04-06 at the Wayback Machine, TransportEvolved.com, April 4, 2017
- Williams, Keith. "The Switch from Hydrogen to Electric Vehicles Continues, Now Hyundai Makes the Move", Seeking Alpha, September 1, 2017
- "New Hydrogen-Powered Land Speed Record from Ford". Motorsportsjournal.com. Archived from the original on 2010-12-09. Retrieved 2010-12-12.
- "Hydrogen Electric Racing Federation looks to revolutionize motorsports". Autoweek. 9 January 2007. Archived from the original on 17 June 2020. Retrieved 17 June 2020.
- "Ursus Lublin". Archived from the original on 2017-05-01. Retrieved 2017-04-06.
- "Connexxion orders 20 Solaris hydrogen buses for South Holland" Archived 2020-06-26 at the Wayback Machine, Green Car Congress, 15 April 2020
- "China Presents the World's First Hydrogen-Fueled Tram". 21 March 2015. Archived from the original on 6 September 2015. Retrieved 6 May 2015.
- "China's Hydrogen-Powered Future Starts in Trams, Not Cars". March 25, 2015. Archived from the original on 2016-11-25. Retrieved 2017-03-07 – via www.bloomberg.com.
- "Germany launches world's first hydrogen-powered train" Archived 2018-09-17 at the Wayback Machine, The Guardian, September 17, 2018
- "Hydrogen trains: Are these the eco-friendly trains of the future?". BBC News. June 20, 2019. Archived from the original on August 12, 2019. Retrieved August 12, 2019.
- "Could fuel cells soon be used in ship propulsion?". Ship Technology. 2019-03-07. Archived from the original on 2019-07-24. Retrieved 2019-06-18.
- Abbasov, Faig (November 2018). "Roadmap to decarbonizing European shipping" (PDF). Transportenvironment.org. Archived (PDF) from the original on June 25, 2020. Retrieved June 18, 2019.
- Fisher, Sean (September 10, 2007). "Chinese Company Plans Hydrogen Fuel Cell Bike". TreeHugger. Archived from the original on August 19, 2019. Retrieved August 15, 2019.
- "Hydrogen Fuel Cell Bike". Gizmodo. November 9, 2007. Archived from the original on August 19, 2019. Retrieved August 15, 2019.
- Tibu, Florin (September 18, 2014). "Hy-Cycle Is Australia's First Hydrogen Fuel Cell Bicycle. Motorcycles Next, Maybe?". autoevolution.com. Archived from the original on August 19, 2019. Retrieved August 15, 2019.
- Arthur, David (January 30, 2016). "Future Tech: Canyon's Eco Speed hydrogen powered e-bike concept". ebiketips.road.cc. Archived from the original on August 19, 2019. Retrieved August 15, 2019.
- Chaya, Lynn (November 3, 2017). "Pragma Industries' alpha model is a powerful hydrogen-fueled bike". Designboom. Archived from the original on August 19, 2019. Retrieved August 15, 2019.
- Coxworth, Ben. "World's first fuel-cell e-bike gets a big boost in range" Archived 2019-08-15 at the Wayback Machine, NewAtlas.com, August 13, 2019
- Alter, Lloyd. "Hydrogen-powered e-bike cranked up to 93 mile range" Archived 2019-08-15 at the Wayback Machine, TreeHugger, August 14, 2019
- "General Motors establishing new military defense division". AutoNews.com. October 9, 2017. Archived from the original on October 9, 2020. Retrieved October 16, 2018.
- "GM Outlines Possibilities for Flexible, Autonomous Fuel Cell Electric Platform". GM Media Release. October 6, 2017. Archived from the original on April 12, 2019. Retrieved October 16, 2018.
- "Hydrogen scooter by vectrix". Jalopnik.com. 2007-07-13. Archived from the original on 2009-06-03. Retrieved 2010-12-12.
- "Suzuki Burgman fuel-cell scooter". Hydrogencarsnow.com. 2009-10-27. Archived from the original on 2011-01-26. Retrieved 2010-12-12.
- "Fhybrid fuel cell-electric hybrid scooter". Io.tudelft.nl. Archived from the original on 2009-06-04. Retrieved 2010-12-12.
- "SUZUKI - BURGMAN Fuel-Cell Scooter". Archived from the original on 10 March 2015. Retrieved 30 May 2015.
- "Asia Pacific Fuel Cell Technologies, Ltd. --fuel cell systems and fue…". apfct.com. 1 January 2013. Archived from the original on 1 January 2013. Retrieved 15 April 2018.
- "India Showcases Hydrogen Fuel Auto-Rickshaws |". February 21, 2012. Archived from the original on September 20, 2019. Retrieved September 21, 2019.
- Nandi, Jayashree. "IIT-Delhi scientists develop autos that run on hydrogen; cause negligible pollution". The Economic Times. Archived from the original on 2019-09-21. Retrieved 2019-09-21.
- "Autostudi S.r.l. H-Due". Ecofriend.org. 2008-04-15. Archived from the original on 2012-12-09. Retrieved 2010-12-12.
- New Holland Wins Gold for Energy Independent Farm Concept Archived 2012-07-28 at archive.today or Hydrogen-powered tractor in an Energy Independent Farm Archived 2009-07-02 at the Wayback Machine
- "Ion tiger hydrogen UAV". Sciencedaily.com. 2009-10-15. Archived from the original on 2010-12-21. Retrieved 2010-12-12.
- David Robertson (3 April 2008). "Boeing tests first hydrogen powered plane". The Times. London. Archived from the original on 12 June 2011. Retrieved 3 April 2008.
- "Boeing's 'Phantom Eye' Ford Fusion powered stratocraft". The Register. 2010-07-13. Archived from the original on 2010-07-14. Retrieved 2010-07-14.
- "Hydrogen engines get a lift". Accessmylibrary.com. 2008-10-01. Retrieved 2010-12-12.
- HyICE[permanent dead link]
- Press release: "Fuel Cell Forklifts Gain Ground", fuelcells.org, July 9, 2013
- "Global and Chinese Forklift Industry Report, 2014-2016" Archived 2014-11-29 at the Wayback Machine, Research and Markets, November 6, 2014
- "Fact Sheet: Materials Handling and Fuel Cells" Archived 2012-08-13 at the Wayback Machine; "HyLIFT - Clean Efficient Power for Materials Handling". Archived from the original on 30 April 2015. Retrieved 30 May 2015.; "First Hydrogen Station for Fuel Cell Forklift Trucks in France, for IKEA". Archived from the original on 25 February 2014. Retrieved 30 May 2015.; "Technologie HyPulsion : des piles pour véhicules de manutention - Horizon Hydrogène Énergie". Archived from the original on 4 March 2015. Retrieved 30 May 2015.; and "HyGear Delivers Hydrogen System for Fuel Cell Based Forklift Trucks". Archived from the original on 9 February 2014. Retrieved 30 May 2015.
- "Hydrogen Fueling Stations Could Reach 5,200 by 2020". Environmental Leader: Environmental & Energy Management News, 20 July 2011, accessed 2 August 2011
- "Full Fuel-Cycle Comparison of Forklift Propulsion Systems" (PDF). Archived from the original (PDF) on February 17, 2013.
- "Fuel cell technology". Archived from the original on 3 December 2013. Retrieved 30 May 2015.
- "Creating Innovative Graphite Solutions for Over 125 Years". GrafTech International. Archived from the original on 6 December 2010. Retrieved 30 May 2015.
- College of the Desert, “Module 1, Hydrogen Properties”, Revision 0, December 2001 Hydrogen Properties Archived 2017-07-01 at the Wayback Machine. Retrieved 2015-10-05.
- "NASA - Liquid Hydrogen--the Fuel of Choice for Space Exploration". www.nasa.gov. Archived from the original on 8 February 2018. Retrieved 15 April 2018.
- Sutton, George P. and Oscar Biblarz. Rocket Propulsion Elements Archived 2013-01-02 at the Wayback Machine, Seventh edition, John Wiley & Sons (2001), p. 257, ISBN 0-471-32642-9
- "Fuel cell use in the Space Shuttle". NASA. Archived from the original on 2012-01-25. Retrieved 2012-02-17.
- "UPS begins testing hydrogen fuel-cell delivery truck - Roadshow". Roadshow. Archived from the original on May 3, 2017. Retrieved May 7, 2017.
- O'Dell, John (May 4, 2017). "US Hybrid Jumps into Hydrogen Fuel Cell Truck Arena". Trucks.com. Archived from the original on September 22, 2017. Retrieved May 7, 2017.
- Ryu, Jung (2020-07-07). "Hyundai Starts Mass Production of Hydrogen Trucks". The Chosun Ilbo. Archived from the original on 2020-09-25. Retrieved 2020-09-26.
- "Hyundai XCIENT Fuel Cell Heads to Europe for Commercial Use". Hyundai Media Newsroom. Archived from the original on 2020-09-25. Retrieved 2020-09-26.
- "World's First Fuel Cell Heavy-Duty Truck, Hyundai XCIENT Fuel Cell, Heads to Europe for Commercial Use - Hyundai Motor Group TECH". tech.hyundaimotorgroup.com. Archived from the original on 2020-08-10. Retrieved 2020-09-26.
- Jin, Eun-Soo (2020-09-16). "Hyundai to enter U.S. market with hydrogen trucks in 2022". Korea Joongang Daily. Archived from the original on 2020-09-29. Retrieved 2020-09-26.
- "Emission Standards Reference Guide for On-road and Nonroad Vehicles and Engines" Archived 2020-10-11 at the Wayback Machine, US EPA (2012), accessed October 9, 2020
- "H2Mobility - Hydrogen Vehicles - netinform". Archived from the original on 2 March 2021. Retrieved 30 May 2015.
- "Hydrogen Fuel Cars 1807–1986" Archived 2016-03-31 at the Wayback Machine, Hydrogen Cars Now, accessed April 7, 2016
- "MAZDA NEWSROOM｜ Mazda Starts Leasing Rotary Hydrogen Vehicles｜NEWS RELEASES". Mazda News Releases. Archived from the original on 2021-01-26. Retrieved 2020-08-30.
- The future starts here, at Linde-MH.com; published May 26, 2008; via archive.org; retrieved May 12, 2018
- Eberle, Ulrich; Mueller, Bernd; von Helmolt, Rittmar (2012-07-15). "Fuel cell electric vehicles and hydrogen infrastructure: status 2012". Royal Society of Chemistry. Archived from the original on 2014-02-09. Retrieved 2013-01-08.
- University of Copenhagen (24 August 2020). "Fuel cells for hydrogen vehicles are becoming longer lasting". phys.org. Archived from the original on 2020-09-27. Retrieved 2020-09-18.
- Rossmeisl, Jan (24 August 2020). "Hydrogen vehicles might soon become the global norm". EurekAlert!. Archived from the original on 2020-11-01. Retrieved 2020-09-18.
- Telias, Gabriela et al. RD&D cooperation for the development of fuel cell hybrid and electric vehicles Archived 2014-09-03 at the Wayback Machine, NREL.gov, November 2010, accessed September 1, 2014
- LeSage, Jon. Toyota says freezing temps pose zero problems for fuel cell vehicles Archived 2014-08-01 at the Wayback Machine, Autoblog.com, February 6, 2014
- Mishler, Jeff, Yun Wang, Partha P. Mukherjee, Rangachary Mukundan, and Rodney L. Borup, "Subfreezing operation of polymer electrolyte fuel cells: Ice formation and cell performance loss", Electrochimica Acta, 65 (2012) pp. 127–133
- Wang, Y. "Analysis of the Key Parameters in the Cold Start of Polymer Electrolyte Fuel Cells", J. Electrochem. Soc., 154 (2007) pp. B1041–B1048
- Wang, Y, P. P. Mukherjee, J. Mishler, R. Mukundan, and R. L. Borup, “Cold start of polymer electrolyte fuel cells: Three-stage startup characterization”, Electrochimica Acta, 55 (2010) pp. 2636–2644
- Mishler, J., Y. Wang, R. Lujan, R. Mukundan, and R. L. Borup, "An Experimental Study of Polymer Electrolyte Fuel Cell Operation at Sub-Freezing Temperatures", Journal of the Electrochemical Society, 160 (6) pp. F514–F521 (2013)
- "EERE Service life 5000 hours" (PDF). Archived (PDF) from the original on 2010-05-27. Retrieved 2010-12-12.
- "Fuel Cell School Buses: Report to Congress" (PDF). Archived (PDF) from the original on 2010-12-24. Retrieved 2010-12-12.
- "Helium in Central Kentucky? Cores from the Texaco No. 1 Kirby well, Garrard County, Ky". Archived from the original on 2018-12-15. Retrieved 2018-12-12.
- David Z. Morris. "Why Japan wants to transform into a 'hydrogen society' Archived 2016-04-04 at the Wayback Machine" Fortune (magazine), 21 October 2015. Quote: "Unlike gasoline, solar, or nuclear, hydrogen isn’t an energy source—just a method of energy storage. “Hydrogen is an energy carrier in the same sense that electricity is,” says David Keith"
- Schultz, M.G., Thomas Diehl, Guy P. Brasseur, and Werner Zittel. "Air Pollution and Climate-Forcing Impacts of a Global Hydrogen Economy" Archived 2007-08-28 at the Wayback Machine, Science, October 24, 2003 302: 624-627
- "Wind-to-Hydrogen Project". Hydrogen and Fuel Cells Research. Golden, CO: National Renewable Energy Laboratory, U.S. Department of Energy. September 2009. Archived from the original on 26 August 2009. Retrieved 7 January 2010.
- "Hydrogen Fuel Cell Vehicles (FCVs)" Archived 2014-11-10 at the Wayback Machine, Ford Motor Company, accessed November 15, 2014
- F. Kreith, "Fallacies of a Hydrogen Economy: A Critical Analysis of Hydrogen Production and Utilization" in Journal of Energy Resources Technology (2004), 126: 249–257.
- "Hell and Hydrogen". MIT Technology Review. MIT. 1 March 2007. Archived from the original on 31 July 2020. Retrieved 5 June 2020.
- Bossel, Ulf. "Does a Hydrogen Economy Make Sense?", Archived 2008-07-24 at the Wayback Machine Proceedings of the IEEE, Vol. 94, No. 10, October 2006
- Heetebrij, Jan. "A vision on a sustainable electric society supported by Electric Vehicles" Archived 2009-06-17 at the Wayback Machine, Olino Renewable Energy, June 5, 2009
- Romm, Joseph. "Climate and hydrogen car advocate gets almost everything wrong about plug-in cars", Archived 2011-05-28 at the Wayback Machine The Energy Collective, October 6, 2009
- Lambert, Fred. "Toyota admits 'Elon Musk is right' about fuel cell, but moves forward with hydrogen anyway" Archived 2017-10-28 at the Wayback Machine, Electrek, October 26, 2017
- "Electric cars win on energy efficiency vs hydrogen, gasoline, diesel: analysis" Archived 2017-10-29 at the Wayback Machine, GreenCarReports.com, October 10, 2017
- Suplee, Curt. "Don't bet on a hydrogen car anytime soon" Archived 2011-06-04 at the Wayback Machine. Washington Post, November 17, 2009
- Werner Zittel; Reinhold Wurster (8 July 1996). "Chapter 3: Production of Hydrogen. Part 4: Production from electricity by means of electrolysis". HyWeb: Knowledge – Hydrogen in the Energy Sector. Ludwig-Bölkow-Systemtechnik GmbH. Archived from the original on 7 February 2007.
- L. Soler, J. Macanás, M. Muñoz, J. Casado. Journal of Power Sources 169 (2007) 144-149
- "US Energy Information Administration, "World Primary Energy Production by Source, 1970–2004"". Eia.doe.gov. Archived from the original on 2010-06-02. Retrieved 2010-12-12.
- "Frequently Asked Questions" Archived 2016-09-28 at the Wayback Machine, US Energy Information Administration, April 1, 2016
- Iceland's hydrogen buses zip toward oil-free economy Archived 2012-07-24 at archive.today. Retrieved 17-July-2007.
- First Danish Hydrogen Energy Plant Is Operational Archived 2007-09-26 at the Wayback Machine. Retrieved 17-July-2007.
- Eberle, Ulrich; Mueller, Bernd; von Helmolt, Rittmar. "Fuel cell electric vehicles and hydrogen infrastructure: status 2012". Energy & Environmental Science. Archived from the original on 2014-02-09. Retrieved 2014-12-19.
- Lanz, Walter (December 2001). "Hydrogen Properties" (PDF). U.S. Department of Energy. College of the Desert. Energy Density. Archived (PDF) from the original on 2017-07-01. Retrieved 2015-10-05.
On this basis, hydrogen’s energy density is poor (since it has such low density) although its energy to weight ratio is the best of all fuels (because it is so light).
- Zubrin, Robert (2007). Energy Victory: Winning the War on Terror by Breaking Free of Oil. Amherst, New York: Prometheus Books. p. 121. ISBN 978-1-59102-591-7.
- Mealey, Rachel. ”Automotive hydrogen membranes-huge breakthrough for cars" Archived 2019-06-10 at the Wayback Machine, ABC, August 8, 2018
- Gardner, Michael (November 22, 2004). "Is 'hydrogen highway' the answer?". San Diego Union-Tribune. Archived from the original on 13 October 2008. Retrieved 9 May 2008.
- Stanley, Dean. "Shell Takes Flexible Approach to Fueling the Future". hydrogenforecast.com. Archived from the original on January 21, 2008. Retrieved 9 May 2008.
- Romm, Joseph (2004). The Hype about Hydrogen, Fact and Fiction in the Race to Save the Climate. New York: Island Press. ISBN 1-55963-703-X. (ISBN 1-55963-703-X), Chapter 5
- Alternative Fueling Station Counts by State Archived 2016-03-15 at the Wayback Machine, Alternative Fuels Data Center, accessed March 18, 2016
- Jones, Nicola. "Whatever happened to the hydrogen highway?" Archived 2016-03-12 at the Wayback Machine, Pique, February 9, 2012, accessed March 17, 2016
- Voelcker, John. "Energy use for hydrogen fuel-cell vehicles: higher than electrics, even hybrids (analysis)" Archived 2021-03-02 at the Wayback Machine, Green Car Reports, May 4, 2017
- "DOE codes and standards". Hydrogen.energy.gov. Archived from the original on 2011-07-19. Retrieved 2011-01-31.
- Roberts, Joel (29 January 2003). "Bush: $1.2 Billion For Hydrogen Cars". CBS News. Archived from the original on 13 January 2020. Retrieved 13 January 2020.
- "Obama Kills Hydrogen Car Funding". treehugger.com. Archived from the original on 15 April 2018. Retrieved 15 April 2018.
- "Obama, DOE slash hydrogen fuel cell funding in new budget". Autoblog. Archived from the original on 16 April 2018. Retrieved 15 April 2018.
- Jon LeSage. "DOE funds more hydrogen fuel cell research with $4.5m investment". Autoblog. Archived from the original on 23 November 2014. Retrieved 30 May 2015.
- Ken Silverstein. "Obama Administration Wants to Speed Up Hydrogen-Powered Vehicles". Archived from the original on 16 January 2014. Retrieved 30 May 2015.
- "Archived copy" (PDF). Archived (PDF) from the original on 2016-03-26. Retrieved 2016-03-17.CS1 maint: archived copy as title (link)
- www.fornybar.no. "Hydrogenveien Hynor - Fornybar.no". www.fornybar.no. Archived from the original on 5 April 2018. Retrieved 15 April 2018.
- "Archived copy". Archived from the original on 2015-12-08. Retrieved 2015-12-08.CS1 maint: archived copy as title (link)
- Meyers, Jeremy P. "Getting Back Into Gear: Fuel Cell Development After the Hype" Archived 2011-07-25 at the Wayback Machine. The Electrochemical Society Interface, Winter 2008, pp. 36–39, accessed August 7, 2011
- White, Charlie. "Hydrogen fuel cell vehicles are a fraud" Archived 2014-06-19 at the Wayback Machine Dvice TV, July 31, 2008
- Squatriglia, Chuck. "Hydrogen Cars Won't Make a Difference for 40 Years" Archived 2014-03-27 at the Wayback Machine, Wired, May 12, 2008
- Boyd, Robert S. (May 15, 2007). "Hydrogen cars may be a long time coming". McClatchy Newspapers. Archived from the original on 1 May 2009. Retrieved 9 May 2008.
- Neil, Dan (February 13, 2009). "Honda FCX Clarity: Beauty for beauty's sake". Los Angeles Times. Archived from the original on 16 February 2009. Retrieved 11 March 2009.
- Wrigglesworth, Phil. "The car of the perpetual future"' Archived 2017-05-20 at the Wayback Machine September 4, 2008, retrieved on September 15, 2008
- "Hydrogen Cars' Lifecycle Emits More Carbon Than Gas Cars, Study Says", Archived 2010-01-06 at the Wayback Machine Digital Trends, January 1, 2010
- Chatsko, Maxx. "1 Giant Obstacle Keeping Hydrogen Fuel Out of Your Gas Tank" Archived 2013-11-26 at the Wayback Machine, The Motley Fool, November 23, 2013
- Blanco, Sebastian. "VW's Krebs talks hydrogen, says 'most efficient way to convert energy to mobility is electricity'" Archived 2013-11-25 at the Wayback Machine, AutoblogGreen, November 20, 2013
- Davies, Alex. "Honda Is Working On Hydrogen Technology That Will Generate Power Inside Your Car" Archived 2013-11-25 at the Wayback Machine, The Business Insider, November 22, 2013
- Romm, Joseph. "Tesla Trumps Toyota Part II: The Big Problem With Hydrogen Fuel Cell Vehicles" Archived 2014-08-21 at the Wayback Machine, CleanProgress.com, August 13, 2014 and "Tesla Trumps Toyota 3: Why Electric Vehicles Are Beating Hydrogen Cars Today" Archived 2015-04-08 at the Wayback Machine, CleanProgress.com, August 25, 2014
- Romm, Joseph. "Tesla Trumps Toyota: Why Hydrogen Cars Can’t Compete With Pure Electric Cars" Archived 2014-08-21 at the Wayback Machine, CleanProgress.com, August 5, 2014
- Hunt, Tam. "Should California Reconsider Its Policy Support for Fuel-Cell Vehicles?" Archived 2014-08-24 at the Wayback Machine, GreenTech Media, July 10, 2014
- Brown, Nicholas. "Hydrogen Cars Lost Much of Their Support, But Why?" Archived 2016-05-15 at the Portuguese Web Archive, Clean Technica, June 26, 2015
- "Engineering Explained: 5 Reasons Why Hydrogen Cars Are Stupid" Archived 2015-10-15 at the Wayback Machine, Car Throttle, October 8, 2015
- Meyers, Glenn. "Hydrogen Economy: Boom or Bust?" Archived 2016-05-15 at the Portuguese Web Archive, Clean Technica, March 19, 2015
- "Battery electric cars are a better choice for emissions reduction". PVBuzz.com. 15 November 2016. Archived from the original on 21 April 2017. Retrieved 16 November 2016.
- "Alternative Fuels Data Center: Fuel Cell Electric Vehicle Emissions". www.afdc.energy.gov. Archived from the original on April 20, 2017. Retrieved May 14, 2017.
- Ruffo, Gustavo Henrique. "This Video Compares BEVs to FCEVs and the More Efficient Is..." Archived 2020-10-26 at the Wayback Machine, InsideEVs.com, September 29, 2019
- Allen, James. "Honda: Now Is The Right Time to Embrace Electric Cars" Archived 2020-11-24 at the Wayback Machine, The Sunday Times, November 4, 2019
- Baxter, Tom (3 June 2020). "Hydrogen cars won't overtake electric vehicles because they're hampered by the laws of science". The Conversation. Archived from the original on 31 July 2020. Retrieved 4 June 2020.
- Kluth, Andreas. "How Hydrogen Is and Isn’t the Future of Energy" Archived 2020-11-24 at the Wayback Machine, Bloomberg.com. November 9, 2020
- Utgikar, Vivek P; Thiesen, Todd (2005). "Safety of compressed hydrogen fuel tanks: Leakage from stationary vehicles". Technology in Society. 27 (3): 315–320. doi:10.1016/j.techsoc.2005.04.005.
- Dobson, Geoff (12 June 2019). "Exploding hydrogen station leads to FCV halt". EV Talk. Archived from the original on 23 June 2019. Retrieved 13 June 2019.
- Woodrow, Melanie (3 June 2019). "Bay Area experiences hydrogen shortage after explosion". ABC news. Archived from the original on 8 June 2019. Retrieved 13 June 2019.
- "US government news release". Pnl.gov. 2006-12-11. Archived from the original on 2009-07-14. Retrieved 2011-01-31.
- "CR4 - Blog Entry: Transformer Efficiency Standards Proposed". 6 November 2006. Archived from the original on 23 August 2010. Retrieved 19 September 2009.
- "Plug-in Hybrid Electric Vehicle 2007 Conference - Home" (PDF). Archived from the original (PDF) on 26 March 2009. Retrieved 30 May 2015.
- Stewart, Ben (4 April 2008). "Chevy Volt Plug-in Car Batteries Ready for 2010 - GM Technical Center". Popular Mechanics. Archived from the original on 4 June 2009. Retrieved 19 September 2009.
- "Car Fueled With Biogas From Cow Manure: WWU Students Convert Methane Into Natural Gas". Archived from the original on 14 May 2011. Retrieved 30 May 2015.
- "Worldwide NGV Statistics". NGV Journal. Archived from the original on 2012-02-20. Retrieved 2012-04-24.
- "The Last Car You Would Ever Buy – Literally: Why we shouldn't get excited by the latest hydrogen cars" Archived 2008-06-20 at the Wayback Machine, Technology Review, June 18, 2008
- "Efficiency of Hydrogen PEFC, Diesel-SOFC-Hybrid and Battery Electric Vehicles" (PDF). 15 July 2003. Archived from the original (PDF) on 21 October 2006. Retrieved January 7, 2009.
- "Information from". cta.ornl.gov. Archived from the original on 2005-02-25. Retrieved 2011-01-31.
- Dansie, Mark. "Hydrogen vs Electric" Archived 2014-09-03 at the Wayback Machine, revolution-green.com, July 4, 2013
- Hanley, Steve. "Envision Energy Says EV Battery Cell Costs Will Fall Below $50/kWh by 2025" Archived 2019-03-02 at the Wayback Machine, CleanTechnica.com, December 7, 2018
- "2013 Nissan Leaf Gets Fuel Economy, Range Improvement, Says EPA" Archived 2013-12-03 at the Wayback Machine, Edmunds.com, May 3, 2013
- Tesla Motors. "Tesla Model S" Archived 2018-09-07 at the Wayback Machine, Tesla Motors, 2020
- "2009 National Household Travel Survey" Archived 2014-10-31 at the Wayback Machine, US Department of Transportation, 12 August 2014,
- EEA Survey Archived 2015-05-18 at the Wayback Machine. European Environment Agency
- Scauzillo, Steve. "L.A. Auto Show drives new green-car market" Archived 2014-11-07 at the Wayback Machine, The Trentonian, November 23, 2013
- California Fuel Cell Partnership homepage
- Fuel Cell Today - Market-based intelligence on the fuel cell industry
- U.S. Dept. of Energy hydrogen pages
- Sandia Corporation – Hydrogen internal combustion engine description
- Inside world's first hydrogen-powered production car BBC News, 14 September 2010
- Toyota Ecopark Hydrogen Demonstration ARENAWIRE, 22 March 2019