Sequel, a fuel cell-powered vehicle from General Motors

filler neck for hydrogen of a BMW, Museum Autovision, Altlußheim, Germany

A hydrogen vehicle is a vehicle that uses hydrogen as its on-board fuel for motive power. The term may refer to a personal transportation vehicle, such as an automobile, or any other vehicle that uses hydrogen in a similar fashion, such as an aircraft. The power plants of such vehicles convert the chemical energy of hydrogen to mechanical energy (torque) in one of two methods: combustion, or electrochemical conversion in a fuel-cell:

• In combustion, the hydrogen is burned in engines in fundamentally the same method as traditional gasoline cars.
• In fuel-cell conversion, the hydrogen is reacted with oxygen to produce water and electricity, the latter of which is used to power an electric traction motor.

The molecular hydrogen needed as an on-board 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. Hydrogen can also be produced from water by electrolysis. If the electricity used for the electrolysis is produced using renewable energy, the production of the hydrogen would (in principle) result in no net carbon dioxide emissions.

Hydrogen is an energy carrier, not an energy source, so the energy the car uses would ultimately need to be provided by a conventional power plant. A suggested benefit of large-scale deployment of hydrogen vehicles is that it could lead to decreased emissions of greenhouse gases and ozone precursors.^[1] Further, the conversion of fossil fuels would be moved from the vehicle, as in today's automobiles, to centralized power plants in which the byproducts of combustion or gasification can be better controlled than at the tailpipe. However, there are both technical and economic challenges to implementing wide-scale use of hydrogen vehicles, as well as better and less expensive alternatives. The timeframe in which challenges may be overcome is likely to be at least several decades, and hydrogen vehicles may never become broadly available.^[2][3][4][5]

The Hype about Hydrogen: Fact and Fiction in the Race to Save the Climate (see below) is a book by Joseph J. Romm, published in 2004 by Island Press and updated in 2005. Romm is "one of the world’s leading experts on clean energy, advanced vehicles, energy security, and greenhouse gas mitigation."^[2]

The gist of the book is that hydrogen is not economically feasible to use for transportation, nor will its use reduce global warming, because of the cost and greenhouse gases generated during production, the low energy content per volume and weight of the container, the cost of the fuel cells, and the cost of the infrastructure. The author argues that a major effort to introduce hydrogen cars before 2030 would actually undermine efforts to reduce emissions of heat-trapping greenhouse gases such as carbon dioxide.^{[6][7][8] [9]}

Research and prototypes

Hydrogen powered Ford Focus

Hydrogen does not come as a pre-existing source of energy like fossil fuels, but rather as a carrier, much like a battery. It can be made from both renewable and non-renewable energy sources. A potential advantage of hydrogen is that it could be produced and consumed continuously, using solar, water, wind and nuclear power for electrolysis. Currently, however, hydrogen vehicles utilizing hydrogen produce more pollution than vehicles consuming gasoline, diesel, or methane in a modern internal combustion engine, and far more than plug-in hybrid electric vehicles.^[6][4] This is because, although hydrogen fuel cells generate no CO₂, production of the hydrogen creates additional emissions.^[7] While methods of hydrogen production that do not use fossil fuel would be more sustainable,^[8] currently such production is not economically feasible, and diversion of renewable energy (which represents only 2% of energy generated) to the production of hydrogen for transportation applications is inadvisable.^[4]

The recorded number of hydrogen-powered public vehicles in the United States was 200 as of April 2007, mostly in California,^[9] and a significant amount of research is underway to try to make the technology viable. The common internal combustion engine, usually fueled with gasoline (petrol) or diesel liquids, can be converted to run on gaseous hydrogen. However, the more energy efficient use of hydrogen involves the use of fuel cells and electric motors. Hydrogen reacts with oxygen inside the fuel cells, which produces electricity to power the motors. One primary area of research is hydrogen storage, to try to increase the range of hydrogen vehicles, while reducing the weight, energy consumption, and complexity of the storage systems. Two primary methods of storage are metal hydrides and compression.

The current land speed record for a hydrogen powered vehicle is 207.279 mph set by a prototype Ford Fusion Hydrogen 999 Fuel Cell Race Car at Bonneville Salt Flats in Wendover, Utah on August 16, 2007. The car was designed and built by Ford engineers in collaboration with Ohio State University, Ballard Power Systems and Roush.

High-speed cars, buses, bicycles, cargo bikes, golf carts, motorcycles, wheelchairs, ships, airplanes, submarines and rockets already can run on hydrogen, in various forms at great expense. NASA uses hydrogen to launch Space Shuttles into space. There is even a working toy model car that runs on solar power, using a reversible 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.^[10]

Hydrogen fuel difficulties

For more details on this topic, see Fuel cell.

While fuel cells themselves are potentially highly energy efficient, and working prototypes were made by Roger E. Billings in the 1960s, at least four technical obstacles and other political considerations exist regarding the development and use of a fuel cell-powered hydrogen car.

Fuel cell cost

Currently, hydrogen fuel cells are costly to produce and fragile. Scientists are studying how to produce inexpensive fuel cells that are robust enough to survive the bumps and vibrations that all automobiles experience. Also, many designs require rare substances such as platinum as a catalyst in order to work properly. Such a catalyst can also become contaminated by impurities in the hydrogen supply. In the past few years, however, a nickel-tin catalyst has been under development which may lower the cost of cells.^[11] Fuel cells are generally priced in USD/kW, and data is scarce regarding costs. Producer Ballard is virtually alone in publishing such data. Their 2005 figure was $73 USD/kW (based on high volume manufacturing estimates), which they said was on track to achieve the U.S. DoE's 2010 goal of $30 USD/kW. This would achieve closer parity with internal combustion engines for automotive applications, allowing a 100 kW fuel cell to be produced for $3000. 100 kW is about 134 hp.^[12]

Freezing conditions

Freezing conditions are a major consideration because fuel cells produce water and utilize moist air with varying water content. Most fuel cell designs are fragile and cannot survive in such environments at startup but since heat is a byproduct of the fuel cell process, the major concern is startup capability. Ballard announced that it has already hit the U.S. DoE's 2010 target for cold weather starting which was 50% power achieved in 30 seconds at -20 °C.^[13] Although this is a good step, there still has to be many more improvements in that area for fuel cells to be strong enough to hold up to hard weather. Jackob Anderson estimates that 75% power should be generated within 25 seconds of startup at -15 °C.^[14]

Service life

Although service life is coupled to cost, fuel cells have to be compared to existing machines with a service life in excess of 5000 hours^[15] for stationary and light-duty. Marine PEM fuel cells reached the target in 2004^[16] Research is going on especially for heavy duty like in the bus trails which are targeted up to a service life of 30.000 hours.

Low volumetric energy

For more details on this topic, see Hydrogen storage.

Hydrogen has a very low volumetric energy density at ambient conditions, equal to about one-third that of methane. Even when the fuel is stored as a liquid in a cryogenic tank or in a pressurized tank, the volumetric energy density (megajoules per liter) is small relative to that of gasoline. Because of the energy required to compress or liquefy the hydrogen gas, the supply chain for hydrogen has lower well-to-tank efficiency compared to gasoline.^[6] Some research has been done into using special crystalline materials to store hydrogen at greater densities and at lower pressures.

Hydrogen production cost

For more details on this topic, see Hydrogen production.

Molecular hydrogen can be derived chemically from a feed stock, such as methanol, but can also be produced electrochemically from water. Current technologies for manufacturing hydrogen use energy in various forms, totalling between 25 and 50 percent of the higher heating value of the hydrogen fuel, to produce, compress or liquefy, and transmit the hydrogen by pipeline or truck.^[17] Electrolysis, currently the most inefficient method of producing hydrogen, uses 65 percent to 112 percent of the higher heating value on a well-to-tank basis.^[18] Environmental consequences of the production of hydrogen from fossil energy resources include the emission of greenhouse gases, a consequence that would also proceed from the on-board reforming of methanol into hydrogen. Studies comparing the environmental consequences of hydrogen production and use in fuel cell vehicles to the refining of petroleum and combustion in conventional automobile engines find a net reduction of ozone and greenhouse gases in favor of hydrogen.^[1] Hydrogen production using renewable energy resources would not create such emissions or, in the case of biomass, would create near-zero net emissions assuming new biomass is grown in place of that converted to hydrogen. The scale of renewable energy use today is insufficient and would need to be greatly increased to meet demand for widespread use in transportation. For example, hydroelectricity accounts for approximately 6 percent of global energy use, whereas other renewable resources, such as geothermal, solar and wind comprise only about 1.4 percent of energy production as of 2004.^[19] Development of renewable sources faces barriers, and although the amount of energy produced from renewable sources is increasing, as a percentage of worldwide energy production, renewables decreased from 8.15% in 2000 to 7.64% of total energy production in 2004 due to the rapid increase in coal and natural gas production.^[19] However, in some countries, hydrogen is being produced using renewable sources. For example, Iceland is using geothermal power to produce hydrogen,^[20] and Denmark is using wind.^[21]

In addition to the inherent losses of energy in the conversion of feed stock to produce hydrogen which makes hydrogen less advantageous as an energy carrier, there are economic and energy penalties associated with packaging, distribution, storage and transfer of hydrogen.^[6]

Hydrogen infrastructure

For more details on this topic, see Hydrogen infrastructure.

For more details on this topic, see Hydrogen highway.

In order to distribute hydrogen to cars, the current gasoline fueling system would need to be replaced, or at least significantly supplemented with hydrogen fuel stations. Hydrogen stations are being built in various places around the world.^[22] Private and state initiatives like California's "California Hydrogen Highway" are already starting the infrastructure transition in advance of any manufacturers mass producing hydrogen cars.^[23] Replacement of the existing extensive gasoline fuel station infrastructure would cost a half trillion U.S. dollars in the United States alone.^[24]

Political considerations

Most of today's hydrogen is produced using fossil energy resources.^[25] While some advocate hydrogen produced from non-fossil resources, there could be public resistance or technological barriers to the implementation of such methods. For example, the United States Department of Energy currently supports research and development aimed at producing hydrogen utilizing heat from generation IV reactors. Such nuclear power plants could be configured to cogenerate hydrogen and electricity. Hydrogen produced in this fashion would still incur the costs associated with transportation and compression or liquefaction assuming direct (molecular) hydrogen is the on-board fuel. Recently, alternative methods of creating hydrogen directly from sunlight and water through a metallic catalyst have been announced. This may eventually provide an economical, direct conversion of solar energy into hydrogen a very clean solution for hydrogen production.^[26]

Some in Washington advocate schemes^[27] other than hydrogen vehicles to replace the petroleum-based internal combustion engine vehicles. Plug-in hybrids, for example, would augment today's hybrid gasoline-electric vehicles with greater battery capacity to enable increased use of the vehicle's electric traction motor and reduced reliance on the combustion engine. The batteries would be charged via the electric grid when the vehicle is parked. Electric power transmission is about 95 percent efficient and the infrastructure is already in place (though substantial grid expansion would be needed if a sizeable fleet of plug-in hybrids were to be deployed.) Tackling the current drawbacks of electric cars or plug-in hybrid electric vehicles is believed by some to be easier than developing a whole new hydrogen infrastructure that mimics the obsolete model of oil distribution. A plug-in hybrid transportation system would face the same thermodynamic hurdles as would a system of hydrogen vehicles relying on electrolysis for its molecular hydrogen. The current electric grid, which is dominated by fossil energy resources in the United States, has a fuel-to-power efficiency of roughly 40 percent. Both the plug-in hybrids and the electrolytic hydrogen system would be subject to these comparative inefficiencies.

United States President George W. Bush was optimistic that these problems could be overcome with research. In his 2003 State of the Union address, he announced the U.S. government's hydrogen fuel initiative,^[28] which complements the President's existing FreedomCAR initiative for safe and cheap hydrogen fuel cell vehicles. Critics charge that 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. K.G. Duleep speculates that "a strong case exists for continuing fuel-efficiency improvements from conventional technology at relatively low cost."^[5] Challenging perspectives to many such critics of hydrogen vehicles in particular and of a hydrogen economy in general were presented in the contentious, 2006, documentary film, Who Killed the Electric Car?

President Bush's hydrogen car goals, in the opinion of some writers, are slipping away because "there are quicker, cleaner, safer and cheaper ways to reduce the tail-pipe emissions from cars and trucks that pollute the air and contribute to global warming." According to physicist and 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."^[5] General Motors disagrees with that sentiment and has announced that it will start hydrogen vehicle production in 2010. However, GM's chief engineer on the fuel cell project, Mohsen Shabana, said hydrogen infrastructure would not be in place by then, and he noted that GM had produced only two test units of the Sequel (pictured above) so far.^[29] As an article published in the March/April 2007 issue of Technology Review argued,

In the context of the overall energy economy, a car like the BMW Hydrogen 7 would proba­bly produce far more carbon dioxide emissions than gasoline-powered cars available today. And changing this calculation would take multiple breakthroughs--which study after study has predicted will take decades, if they arrive at all. In fact, the Hydrogen 7 and its hydrogen-fuel-cell cousins are, in many ways, simply flashy distractions produced by automakers who should be taking stronger immediate action to reduce the greenhouse-gas emissions of their cars.^[4]

GM has announced that it plans to introduce more than 100 hydrogen powered Chevrolet Equinox cars into the U.S. market beginning with the third quarter of 2007.^[30]

Alternatives

PHEVs

A 2006 article, "Hybrid Vehicles Gain Traction", in Scientific American (April 2006), co-authored by Joseph J. Romm and Prof. Andrew A. Frank, argues that ICE-based hybrid cars that can be plugged into the electric grid (Plug-in hybrid electric vehicles), rather than hydrogen fuel-cell vehicles, will soon become standard in the automobile industry.^[31]

EVs

Battery electric vehicles, such as the General Motors EV1 are typically more efficient than fuel cell-powered vehicles on a well-to-wheel basis.^[32] For this reason, Battery vehicles are gaining popularity, particularly with the introduction of new models like the Tesla Roadster.^[33].

Hydrogen internal combustion

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. As in hydrogen fuel cell vehicles, the volume of the vehicle that the tank occupies is significant. Research is underway to increase the amount of hydrogen that can be stored onboard, be it through high pressure hydrogen, cryogenic liquid hydrogen, or metal hydrides.

In 1807, François Isaac de Rivaz built the first hydrogen-fueled internal combustion vehicle. However, the design was very unsuccessful. It is estimated that more than a thousand hydrogen-powered vehicles were produced in Germany before the end of the World War II prompted by the acute shortage of oil.^{[verification needed]}

Mazda has developed Wankel engines to burn hydrogen. The Wankel engine uses a rotary principle of operation, so the hydrogen burns in a different part of the engine from the intake. This reduces intake backfiring, a risk with hydrogen-fueled piston engines. However the major car companies such as DaimlerChrysler and General Motors Corp, are investing in the more efficient hydrogen fuel cells instead.^[34] Ford Motor Company is investing in both fuel cell and hydrogen internal combustion engine research. Because of the large heat exchanger necessary for fuel cells and their limited load change and cold start capability, they are certainly first choice as range extender for battery electric vehicles. The Wall Street Journal, reviewing BMW's new internal combustion hydrogen vehicle concluded:

A more efficient route for car makers would be to focus on high-mileage gasoline-powered vehicles. They are far simpler and less sexy than hydrogen cars... but for now they stack up as the cleaner option. ^[35]

Automobiles

For more details on this topic, see List of fuel cell vehicles.

Many companies are currently researching the feasibility of building hydrogen cars. Funding has come from both private and government sources. In addition to the BMW and Mazda examples cited above, many automobile manufacturers have begun developing cars. These include:

Hyundai Tucson FCEV in the background (on the left) and Toyota Highlander FCHV in the foreground (on the right) during UC Davis's Picnic Day activities

• BMW — The BMW Hydrogen 7 is powered by a dual-fuel Internal Combustion Engine and with an Auxiliary power based on UTC Power fuel cell technology. The BMW H2R speed record car is also powered by an ICE. Both models use Liquid Hydrogen as fuel.
• Daimler AG — F-Cell, a hydrogen fuel cell vehicle based on the Mercedes-Benz A-Class.
• Ford Motor Company – Focus FCV, a hydrogen fuel cell modification of the Ford Focus, and E-350 buses, which began being leased in late 2006.
• General Motors — multiple models of fuel cell vehicles^[36] including the Hy-wire and the HydroGen3
• Honda – currently experimenting with a variety of alternative fuels and fuel cells with experimental vehicles based on the Honda EV Plus, most notable the Honda FCX, powered by a front-mounted 80 kW AC electric motor, with 20 kW pancake motors providing supplemental power to the rear wheels. Electrical energy is provided by a 100 kW hydrogen fuel cell, with regenerative braking energy stored in ultracapacitors. The first production version of the FCX, dubbed the FCX Clarity, was announced at the 2007 Greater Los Angeles Auto Show. The vehicle is expected to be available in limited numbers for lease only in the Los Angeles area. mid-2008.^[37] In November 2007, Honda announced its new Home Energy Station IV that uses steam reforming of natural gas to derive hydrogen from both the steam and natural gas in equal parts. The Home Energy Station IV is 75-percent smaller than older units and provides hydrogen for a car as well as heat and electricity for the home.
• Hyundai — Tucson FCEV, based on UTC Power fuel cell technology
• Mazda - RX-8, with a dual-fuel (hydrogen or gasoline) rotary-engine^[38]
• Mazda - Mazda Premacy Hydrogen RE Hybrid, with a dual-fuel (hydrogen or gasoline) rotary-engine ^[39]
• Nissan — X-TRAIL FCV, based on UTC Power fuel cell technology.
• Morgan Motor Company – LIFEcar, a performance-oriented hydrogen fuel cell vehicle with the aid of several other British companies
• Toyota – The Toyota Highlander FCHV and FCHV-BUS^[40] are currently under development and in active testing. In November 2007, ten new hydrogen powered Prius cars were delivered to three companies in Iceland by VISTORKA, a shareholder in Icelandic New Energy. [3]

• Volkswagen also has hydrogen fuel cell cars in development.

Supporting these manufacturers are fuel cell and hydrogen engine research and manufacturing companies. The largest of these is UTC Power, a division of United Technologies Corporation, currently in joint development with Hyundai, Nissan, and BMW, among other auto companies. Another major supplier is Ballard Power Systems. The Hydrogen Engine Center is a supplier of hydrogen-fueled engines.

Most, but not all, of these vehicles are currently only available in demonstration models and cost a large amount of money to make and run. They are not yet ready for general public use and are unlikely to be as feasible as plug in biodiesel hybrids.

Mazda leased two dual-fuel RX-8s to commercial customers in Japan in early 2006, becoming the first manufacturer to put a hydrogen vehicle in customer hands.

BMW also plans to release its first publicly available hydrogen vehicle in 2008, as does Honda.

Buses

Main article: fuel cell bus

Fuel cell buses (as opposed to hydrogen fueled buses) are being trialed by several manufacturers in different locations. The Fuel Cell Bus Club is a global fuel cell bus testing collaberation.

Hydrogen was first stored in roof mounted tanks, although models are now incorporating inboard tanks. Some double deck models uses between floor tanks.

Bicycles

Hydrogen bicycle

Pearl unveiled a hydrogen bicycle at the 9th China International Exhibition on Gas Technology, Equipment and Applications in 2007.

Motorcycles

ENV is developing electric motorcycles powered by a hydrogen fuel cell, including the Crosscage and Biplane.

Airplanes

For more details on this topic, see Hydrogen planes.

Companies such as Boeing and Smartfish are pursuing hydrogen as fuel for airplanes. Unmanned hydrogen planes have been tested and Boeing is currently planning a manned flight for 2008.

References

See also

Sustainable development Portal

External links

Wikimedia Commons has media related to:

Hydrogen vehicles

• California Fuel Cell Partnership
• Clean Energy Partnership
• C-Net - Hydrogen: More Polluting than Petroleum?
• Does a Hydrogen Economy Make Sense?
• EERE - FreedomCAR
• European Fuel Cell Forum
• Hydrogen Cars Now
• National Alternative Fuels Training Consortium - Technical Library
• ELECTRIC MOBILITY NEWS PORTAL
• Toronto Star article on hydrogen trains dated October 21, 2007
• NOVA - Video on Fuel Cell Cars (aired on PBS, July 26, 2005)
• Physorg - The Car that Makes its Own Fuel
• Sandia National Laboratory - Hydrogen Engine
• Spirit of Ma'at - Video of an engine running on hydrogen from water
• UK Low Carbon and Fuel Cell Knowledge Transfer Network
• New Hydrogen-Powered Land Speed Record from Ford
• Who Killed The Electric Car? (2006)

The Hype about Hydrogen

Author	Joseph J. Romm
Language	English
Publisher	Island Press
Publication date	2004
ISBN	ISBN 1-55963-703-X ISBN 1-55963-704-8

Cover of German version

The Hype about Hydrogen: Fact and Fiction in the Race to Save the Climate is a book by Joseph J. Romm, published in 2004 by Island Press and updated in 2005. The book has been translated into German as Der Wasserstoff-Boom.^[1] Romm is "one of the world’s leading experts on clean energy, advanced vehicles, energy security, and greenhouse gas mitigation."^[2]

Over 200 publications, including Scientific American, Forbes Magazine, and The New York Times, have cited this book. ^{[3] [4] [5]} The book was named one of the best science and technology books of 2004 by Library Journal. ^[2]

The gist of the book is that hydrogen is not economically feasible to use for transportation, nor will its use reduce global warming, because of the cost and greenhouse gases generated during production, the low energy content per volume and weight of the container, the cost of the fuel cells, and the cost of the infrastructure. The author argues that a major effort to introduce hydrogen cars before 2030 would actually undermine efforts to reduce emissions of heat-trapping greenhouse gases such as carbon dioxide.^{[6][7][8] [9]}

Description of the book

The Hype about Hydrogen contends that global warming and U.S. reliance on foreign fuel imports cannot be solved by the hypothetical hydrogen economy that has been advanced as a possible solution to these problems, and that "neither government policy nor business investment should be based on the belief that hydrogen cars will have meaningful commercial success in the near or medium term."

The book explains how fuel cells work and compares different types. It then reviews the difficulties in marketing fuel cells for applications other than transportation and argues that these are in fact easier and more likely to happen soon than transportation applications.

The history of hydrogen and its methods of production are then described. The book claims that the most common and cost-effective method of hydrogen production is from natural gas, which emits large amounts of CO₂ (a greenhouse gas), since it would require too much electric power to produce hydrogen using the electrolysis method. The monetary costs of hydrogen fueling infrastructure for the U.S. are then estimated at half a trillion U.S. dollars, and the book describes additional energy and environment costs to liquefy and compress hydrogen for use in fueling stations.

The book goes on to discuss the hypothetical evolution of the cost of vehicles with fuel cells and with hydrogen-powered internal combustion engines, as well as possible adoption strategies. It then reviews the issue of the greenhouse effect and offers four reasons why hydrogen would not be useful in reducing greenhouse gas emissions:

• Internal combustion engines continue to improve in efficiency.
• Since hydrogen is likely to be made from combustion of fossil fuels, it produces less CO₂ and other greenhouse gases to burn the fossil fuel directly.
• Fuel cells are likely to be much more expensive than competing technologies.
• Fuels used to make hydrogen could achieve larger reductions in greenhouse gas emissions if used to replace the least efficient of the electric power plants.

The book then describes pilot projects in Iceland and California.

In its conclusion, the book states that hydrogen will not be widely available as a transportation fuel for a long time, and describes other strategies, including energy conservation techniques, to combat global warming.

Critical reception

The Hype about Hydrogen was named one of the best science and technology books of 2004 by Library Journal.^[2]

The New York Review of Books stated that the book gives "the most direct answers" to the question on the promise of a near-term hydrogen economy, calling Romm "a hydrogen realist". ^[10]

The environmental community newsletter TerraGreen agrees with Romm in the claim that "the car of the near future is the hybrid vehicle", and cites the book's good reception by Toyota's advanced technologies group. ^[11]

The San Diego Union Tribune's 2004 review noted that Romm's "clear logic" reaches conclusions similar to an authoritative study issued by the National Academy of Sciences. ^[12]

Three UC Davis scientists who also reviewed the book agreed on its basic premises, but claimed that Romm had made selective use of sources, for example, citing the highest cost estimates, adopting extremely high estimates of efficiency for advanced gasoline vehicles, and giving weight to controversial non-peer-reviewed studies. ^[13]

Romm and Prof. Andrew A. Frank co-authored an article, "Hybrid Vehicles Gain Traction", published in the April 2006 issue of Scientific American, in which they argue that hybrid cars that can be plugged into the electric grid (Plug-in hybrid electric vehicles), rather than hydrogen fuel cell vehicles, will soon become standard in the automobile industry.^[14]

See also

• Hydrogen vehicle
• Plug-in hybrid electric vehicle
• Vegetable oil economy
• Who Killed the Electric Car?
• Hell and High Water

References

External links

• Technology Review article on BMW's new hydrogen vehicle, extensively discussing Romm's analysis in the March/April 2007 issue
• September 16, 2005 television interview with Romm about the book and hydrogen cars
• Online excerpts from the book
• Does a Hydrogen Economy Make Sense?
• 2007 Toronto Star article on hydrogen vehicles noting Romm's views