I’ve been hearing for decades that hydrogen would make a great fuel for transportation, and it’s still being promoted as a “green” energy source — pure, clean, portable, efficient. You burn the hydrogen, and the only emission is water vapor. What could be cleaner? (Illustration: Fuel cell car. Credit: Peter Welleman.)
One might raise questions like, “Will it make my car explode like the Hindenburg?” or “If hydrogen is so great, why aren’t we making hydrogen cars instead of electric cars?”
Those are worthy questions, but our purpose in this “Damage Done” series is to investigate the environmental effects of energy sources and technologies. Their safety and their feasibility can certainly enter into the discussion, but the real questions we’re trying to get at are: What does the production and consumption of energy do to the environment, and how do the various energy sources stack up against one another in measurable ways in terms of their environmental impacts?
Hydrogen vehicles basically come in two flavors:
- The internal-combustion hydrogen vehicle, a vehicle powered by an engine similar to a gasoline internal combustion engine (ICE) but modified to burn hydrogen; and
- The hydrogen fuel-cell vehicle, which combines hydrogen with oxygen in a chemical reaction to produce electricity — the electricity is then used to drive an electric motor.
So far, many vehicle manufacturers have built prototypes and demonstration vehicles, but no hydrogen vehicles are commercially available. In an October 2011 report, the U.S. Department of Energy (DOE) said that the agency’s efforts had reduced the cost of fuel cells by 80 percent since 2002, from $275/kW to $49/kW. The goal is to reach $30/kW by 2017. Agency-supported programs had deployed 170 fuel cell electric vehicles and 24 hydrogen fueling stations for demonstration purposes. Vehicles had traveled over 3 million miles, and fueling stations had dispensed over 140,000 kg of hydrogen.
“Key results include demonstrating fuel cell system efficiency of up to 59% (more than double the efficiency of gasoline internal combustion engines), fuel cell system durability of 2,500 hours (about 75,000 miles), and a driving range of more than 250 miles between refueling,” the agency says. “The program also validated that one vehicle achieved 430 miles on a single fill of hydrogen.”
DOE financial assistance has been used to deploy more than 830 fuel cells for companies such as AT&T, FedEx, Whole Foods, Sysco, Wegman’s and Coca-Cola. These fuel cells are being used primarily for backup power and forklift applications. The agency believes that “success in these early markets will help pave the way for longer term success of fuel cells in larger markets, such as transportation.”
The Hydrogen Highway: Cleaner Skies Ahead?
Given the nascent state of any hydrogen-vehicle market, you might think that the technology hardly deserves the attention of the prestigious “Damage Done” series. However, hydrogen-fueled transportation has been promoted as one of the “green” solutions to the energy problems of the world and the United States in particular.
In 2004, California Governor Arnold Schwarzenegger signed an executive order to develop a plan for a “Hydrogen Highway,” a chain of hydrogen fueling stations, a project that was later funded by the state legislature. On signing the executive order Schwarzenegger said:
The goal of the California Hydrogen Highway Network initiative is to support and catalyze a rapid transition to a clean, hydrogen transportation economy in California, thereby reducing our dependence on foreign oil, and protecting our citizens from health harms related to vehicle emissions. We have an opportunity to deal with these problems by investing in California’s ability to innovate our way to a clean hydrogen future, thus bringing jobs, investment, and continued economic prosperity to California. We have an opportunity to prove to the world that a thriving environment and economy can co-exist.
In his 2003 State of the Union Address, President George W. Bush called for a major commitment to the development of hydrogen transportation, citing the environmental benefits:
In this century, the greatest environmental progress will come about not through endless lawsuits or command-and-control regulations, but through technology and innovation. Tonight I’m proposing $1.2 billion in research funding so that America can lead the world in developing clean, hydrogen-powered automobiles.
A single chemical reaction between hydrogen and oxygen generates energy, which can be used to power a car — producing only water, not exhaust fumes. With a new national commitment, our scientists and engineers will overcome obstacles to taking these cars from laboratory to showroom, so that the first car driven by a child born today could be powered by hydrogen, and pollution-free.
Join me in this important innovation to make our air significantly cleaner, and our country much less dependent on foreign sources of energy.
(Subsequently, the Obama administration has greatly reduced funding for hydrogen technology “in order to focus on technologies deployable at large scale in the near term,” according to the DOE.)
The Fuel Cell and Hydrogen Energy Association says on its web site:
When using pure hydrogen, there are zero greenhouse gas emissions. When using other hydrocarbons as fuel, the emissions are still far less than with conventional combustion technologies (think ounces of carbon monoxide instead of pounds). In fact, fuel cell power plants are so low in emissions that some areas of the United States have formally exempted them from air permit requirements.
Are such claims about the environmental friendliness of hydrogen justified?
To answer that question, I turn to a source I’ve found valuable throughout this “Damage Done” series by the production and consumption of energy: the 2010 National Academy of Sciences (NAS) report Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. One of the most useful features of this study is that it imposes measures of environmental damage on a broad range of energy sources allowing for side-by-side comparisons of both conventional and “green” energy. (Photo: Hydrogen fueling station, UK. Credit: UK Department for Business, Innovation, and Skills, CC BY-ND 2.0.)
About the potential for hydrogen vehicles, the authors of the NAS report write that “hydrogen fuel cell vehicles (HFCVs) can yield large and sustained reductions in U.S. oil consumption and GHG emissions, but several decades will be needed to realize these potential long-term benefits.” They cite a study concluding that by 2020 2 million HFCVs could be operating in the U.S. out of a total fleet of 280 light-duty vehicles. That number could grow to 25 million by 2030 and even account for more than 80 percent of new vehicles by 2050. All of this assumes “that technical goals are met, consumers readily accept HFCVs, and policy instruments are in place to facilitate the introduction of hydrogen fuel and HFCVs through the market transition period.”
NAS estimates damages for hydrogen vehicles according to the figures in the following table, comparing hydrogen to damages from gasoline-fueled vehicles.
|Mean health and other non-GHG damages (2005, dollars per vehicle mile traveled, $/VMT)||Mean 2005 health and other non-GHG damages (dollars per gallon of gasoline equivalent, $/gge)||Carbon dioxide equivalent emissions of GHGs (2005, CO2 equivalents/VMT)|
|Light-duty gasoline vehicle||
|Hydrogen gaseous vehicle||
As you can see, the data used by the NAS point to greater health and other non-GHG damages for hydrogen vehicles than for gasoline vehicles. Greenhouse gas emissions are significantly lower. The conventional damages for hydrogen versus gasoline are accrued during different parts of the product lifecycle, the NAS explains: “Hydrogen fuel cells have far larger emissions from the fuel stage and the vehicle-manufacturing stage than gasoline vehicles, which is about fully offset by lower emissions in the operation stage and to a lesser extent in the feedstock stage.”
Distributed Generation: A Possible Niche for Hydrogen?
It looks to me as if the real problem with prevailing technologies for hydrogen is that hydrogen has to be produced from another energy source, and right now that usually means fossil fuels. So, environmentally, hydrogen suffers from a similar problem to that of electric vehicles (EVs) — the technology’s lifecycle inherits negative environmental effects from the original energy source. (Photo: See-through Toyota hydrogen car. Credit: Marufish, CC BY-SA 2.0.)
However, as with EVs, hydrogen vehicles’ lifecycle environmental effects could possibly decrease if the hydrogen could be produced by a cleaner source; say, solar or wind power.
Technologies such as the EV and the hydrogen fuel cell could benefit from the emergence of a distributed power generation model. Under such a scenario, power gets generated at the local level — perhaps at the level of the community, the neighborhood, or the household, using renewable sources. EV batteries or hydrogen fuel cells serve as storage in an integrated system that produces its energy using clean sources. Also, because electricity doesn’t have to be transported over long-distance power lines, less waste occurs.
This could be the optimal scenario for hydrogen, especially in the near- and medium-term.
So, further development of hydrogen technologies for transportation seems like a valuable pursuit, and evidently a number of vehicle manufacturers feel the same way — see this link for a list of new hydrogen vehicles developed by various manufacturers by year. (Photo: Mazda RX8 hydrogen car, Norway. Credit: Zero Emission Resource Organization, CC BY 2.0.)
For now, hydrogen does not appear to improve over the environmental “externalities” of fossil fuels. But the potential is there — it’s really too soon to judge the ultimate value of the technology.
That’s my take. What do you think about hydrogen as a source of transportation energy: green and clean, or dark and dirty? Use the comment space below to present your thoughtful comments, well-reasoned arguments, relevant research findings or foaming lunatic rants.