Hydrogen và Pin nhiên liệu

Friday, September 15, 2006

Hydrogen: Fuel for Our Future?

Hydrogen: Fuel for Our Future?

Hydrogen Powered Car
Hydrogen-powered cars like this one may be commonplace in the future.

On July 18, BP and GE announced plans to jointly develop up to 15 new hydrogen power plants for generating electricity over the coming decade. The hydrogen will be derived from fossil fuels, including coal and natural gas. While the plants will emit greenhouse gases, the companies will employ carbon capture technologies they claim will reduce carbon dioxide (CO2) emissions by 90 percent. Although the operations will not be pollution-free, some environmentalists welcome the companies’ investment in hydrogen technology as a key development in bringing about a hydrogen economy.

Though often mistaken for an energy source, hydrogen is actually an artificial fuel—like gasoline—that can be used to transport and store energy. Although it can be separated from fossil fuels, its long-term promise lies in its ability to be separated from water through electrolysis, using solar power or other forms of renewable energy. Its most publicized application is in transportation: the hydrogen gas is stored in an on-board tank until combined with oxygen in a fuel cell, where the electrolysis process is essentially reversed, releasing chemical energy via an electrical charge. This electricity can then be used to power electric motors in cars, buses, boats, and other vehicles.

In the short run, fuel cells are also considered a promising source of electricity for some industries and buildings, particularly those that require steady back-up power during blackouts. In this application, hydrogen is most often derived from natural gas and propane, which already have extensive distribution systems in place.

Using fossil fuels to generate hydrogen can result in modestly lower emissions of CO2 and other pollutants than using these fuels as conventional energy sources, though this depends on the efficiency of the technologies involved. In order to get larger reductions, the CO2 must be captured and sequestered, a process that remains experimental and expensive. However, when the hydrogen separation process is based on renewable energy sources, hydrogen use is essentially pollution-free, with the only byproducts being water and heat.

Since 1999, when Iceland announced its plan to become the first hydrogen-based economy in the next 30–40 years, governments and businesses have begun to seriously consider the hydrogen option. In 2000, the small South Pacific island of Vanuatu joined Iceland in making steps towards widespread hydrogen use and deriving 100 percent of its energy from renewable sources. Hawaii, another island rich in renewable resources such as geothermal and wind energy yet still heavily dependent on oil imports, invested in hydrogen research in 2001, hoping to eventually export hydrogen to other states and nations. And California, the United States’ largest gasoline consumer, began developing the world’s first “hydrogen highway” in 2004.

Despite initial enthusiasm, some of these regions are making greater progress than others. Freyr Sverrisson, an independent energy consultant from Iceland, says that so far the Icelandic government has taken little concrete action toward meeting its hydrogen target: it is home to only one hydrogen fueling station, and the country has invested significant funds in the aluminum smelting industry that could have been placed in hydrogen development. By generating a carbon dioxide byproduct, the smelting process is helping Iceland become the world’s fastest growing emitter of CO2. The government is “squandering an opportunity,” Sverrisson says, by choosing to invest in the quick returns of aluminum smelting instead of developing the hydrogen economy with longer-term benefits.

Yet according to Jon Bjorn Skulason, general manager of Icelandic New Energy, the country is just 6–12 months behind the original plan proposed in 1999. In addition to having three operational fuel cell buses and the one fuel cell filling station, Iceland has passed a preemptive law that will eliminate all taxes on hydrogen cars once they begin to be sold domestically. With over 90 percent of citizens in favor of developing a hydrogen economy and continued support for the project from the government and business, Skulason does not foresee any further delays.

California, meanwhile, already boasts 23 hydrogen fueling stations (14 more are slated to be built this year) and has put 137 hydrogen-powered passenger cars and 9 buses on the road, more than any region in the world, according to Chris White of the California Fuel Cell Partnership. Although the partnership is still operating in a “demonstration phase,” notes White, several of its members (many of which are automotive companies) expect to make hydrogen-powered commercial vehicles as early as 2010, and to have showroom cars by 2015. According to White, this is the same way hybrid-electric cars were introduced to the market in the 1990s.

Yet transitioning to a hydrogen economy has raised some concerns. Because hydrogen is odorless and burns with a clear flame, leaks can be difficult to detect, although the gas is so light and disperses so quickly that the chance of an open explosion is considered minimal. (While many associate hydrogen with the 1937 Hindenburg disaster, the explosion of the German airship in fact began with ignition of the blimp’s highly flammable outer covering, not the gas it carried.) Even so, careful engineering is necessary to ensure that hydrogen fuel cell vehicles are safer than gasoline vehicles, according to a 1997 Ford Motor Company study.

“Hydrogen is one of the keys to a new energy economy that relies on solar and wind power rather than fossil fuels,” according to Worldwatch President Chris Flavin. “Private and public investment in hydrogen technology should be increased substantially. But in the next few years, the largest reductions in oil demand and greenhouse gas emissions will come from improved fuel economy and biofuels—both of which are fully competitive today.”


This story was produced by Eye on Earth, a joint project of the Worldwatch Institute and the blue moon fund. View the complete archive of Eye on Earth stories, or contact Staff Writer Alana Herro at aherro [AT] worldwatch [DOT] org with your questions, comments, and story ideas.