Today’s Solutions: July 06, 2022

How the Japanese are trying to slash energy use and CO2 emissions—by installing fuel cells in people’s backyards.

Winifred Bird | April 2009 issue

Yasushi Kawamori has a power plant in his backyard. Not the kind that belches clouds of CO2 into the atmosphere, but the kind that’s small (about the size of a refrigerator and a suitcase placed side by side), quiet (a faint thumping is just audible) and emits a fraction of the carbon dioxide a coal-fired plant would. The system uses a hydrogen fuel cell to convert natural gas into electricity; heat from the reaction generates hot water for himself, his wife and their two children. It’s called a fuel cell cogeneration system, and Kawamori is more than happy to have it in his backyard. “We’re making electricity at our own home, and the heat from that electricity gets used, so it’s really efficient,” he says. “I like that it’s cost-effective and good for the environment.”

The cogeneration system—also called a combined heat and power, or CHP, unit—at the Kawamoris’ home is part of a trial underway at Osaka Gas, where Kawamori works. Since 2005, the company has been testing fuel cell systems made by Toshiba and ENEOS; so far, 224 homes are involved. Trials by companies including Panasonic, Ebara Ballard and Toyota are also underway at 3,000 more homes throughout Japan, while Korea, Germany and Denmark are among the other countries experimenting with the technology.

Until recently, hydrogen has been limited to powering systems on NASA’s Space Shuttle. Now, fuel cells are at work in cars and, as these experiments show, hydrogen can work on a domestic scale, too. In fact, fuel cell technology could make energy independence for every home a real possibility, a crucial goal given the volatility of oil prices and the accelerating problems caused by climate change.

“Hydrogen is an energy carrier—energy is stored in its chemical bonds,” explains John Turner, a principal scientist at the National Renewable Energy Lab’s Center for Electric & Hydrogen Technologies & Systems in Golden, Colorado. “We know we can make enough hydrogen to power our society. In the future, hydrogen may be everything.” With commercial sales scheduled for this year, and partnerships among gas companies, manufacturers and the government already in place, Japan is at the forefront of global efforts to get hydrogen fuel cells into homes. Last fall, the world’s largest “hydrogen town project” kicked off in Maebaru City in southern Japan, with the installation of 150 residential fuel cell systems (see box on the following page).

The Kawamoris, who live in a comfortable two-story house in a quiet residential section of Osaka, hardly fit the “eco-warrior” image one might associate with a family testing out such cutting-edge technology. Yasushi’s wife, Kumiko, writes for the community paper and likes to play tennis; 19-year-old Moeko hopes to go into the cosmetics industry; and 17-year-old Shogo recently gave up baseball to pursue his latest obsession, the electric guitar. They’re exactly the kind of average family Japanese companies are counting on to make hydrogen mainstream.

Kumiko says her children prompted the family to experiment with the technology. “We heard the company was looking for families to try out this new system,” she says, resting her elbows on her polished dining room table. “The kids were getting interested in environmentally friendly things, especially our son—he was starting to think people who are interested in the environment are cool.” Shogo tells another story. “Actually,” he explains, “I wasn’t that serious when I said we should try it, but my mom took me seriously. It’s the first time we’ve done something like this.”

The Toshiba system was installed a year ago, and since then, says Kumiko, pointing to the neatly organized chart where she records monthly utility expenses, “Our electricity bills suddenly got really cheap.” The Kawamoris’ energy bills fell an average of $43 per month, because the cogeneration unit is 30 to 40 percent more efficient than conventional heating and electrical systems.

Home heating and power account for one-fourth of global energy consumption, according to a study by the economic research company McKinsey Global Institute. So savings on that scale could make a significant dent in energy use, and thus in CO2 emissions. Yet fuel cell cogeneration systems depend on natural gas to produce electricity, so emit some carbon dioxide. And with an average generation capacity of 1 kilowatt (kW), they don’t meet all home electricity needs; an electric clothes dryer, for example, can use up to 5 kW, and even toasters consume about 1 kW. That makes the technology more of a first rather than final step towards a hydrogen economy, but proponents say that in the future, hydrogen could come from more sustainable sources like biomass, waste gas from landfills or even water.

While hydrogen is the simplest and most abundant element, it’s rarely found on Earth in its elemental form. Instead, it bonds with other elements to form everything from water to hydrocarbons. Breaking those bonds, or the bonds between two hydrogen atoms in its gaseous form, H2, releases energy—the energy that becomes electricity in Toshiba’s cogeneration fuel cell system and others like it. The question is, Where do we get the hydrogen?

“The cleanest way is water and sunlight; that’s the ultimate answer,” says Peter Pintauro, chair of the chemical and biomolecular engineering department at Vanderbilt University in Nashville, Tennessee. One way to do that is to use solar or wind energy to split water into oxygen and hydrogen gas, with the help of a simple device called an electrolyzer. The resulting energy can be stored and used in residential, industrial and automotive applications. The potential to integrate transportation and electricity infrastructures is an added appeal of hydrogen; Honda is working with U.S. fuel cell maker Plug Power on a fuel cell that would generate energy for your car and home at the same time. And Osaka Gas is looking into combined solar-hydrogen systems.

For the time being, however, almost all residential fuel cells use natural gas. Here’s how it works. First, the gas (made up mostly of methane, a hydrocarbon) is piped to the house and enters a device called a reformer, where a reaction using steam turns it into hydrogen gas and carbon monoxide (CO). The poisonous CO then reacts with oxygen to become carbon dioxide and is released, while the hydrogen gas enters the fuel cell “stack” and splits into two protons and two electrons. These energy-carrying electrons become a DC electric current, which is used in the home before returning to the fuel cell. The Toshiba system generates 700 watts; others make 1 kW. The electrons then combine with the hydrogen protons and oxygen to form water.

However, only a portion of the energy stored in the molecular bonds is transformed into electricity. The rest—60 percent or more—escapes as heat. But instead of wasting that heat as most conventional electric plants do, home fuel cell systems use it to make hot water. The Toshiba system can store 53 gallons (200 liters) of water at 140 degrees Fahrenheit (60 degrees Celsius), enough to meet the daily needs of the average Japanese family of four. (A back-up on-demand gas water heater is also included in the unit). This is where the major efficiency gains come in, since the same energy source produces both hot water and electricity.

With two teenage children—including a daughter on the lacrosse team—the Kawamori family runs through the 53 gallons of hot water in the tank most days and has to fall back on the gas water heater while they wait for it to fill again. “With the kids around, the stored water is gone before you know it,” says Kumiko. “I don’t know the best way to use the system yet; for example, how to adjust when we’re using electricity and hot water.”

Despite these drawbacks, the system has allowed the family to dramatically, and effortlessly, reduce energy consumption. Generating electricity on site boosts the efficiency of home CHP systems an additional 10 percent or so, since no electricity is lost on the way from the power plant to the home. After all, the power plant is right outside. Tokyo Gas estimates that compared to standard gas boilers and electricity from the grid, their 1 kW systems use 26 percent less primary energy and emit 40 percent less carbon dioxide—a savings equivalent to driving 3,735 miles (6,000 kilometers) less each year. “It’s easy to see we’re doing something good for the environment,” says Shogo. “It’s fun to see how much energy we’re saving. I think this technology is going to be great for the future.”

Vanderbilt University’s Pintauro, who’s researching ways to make fuel cells even more efficient, points out that the advantages of decentralized energy generation go beyond lower emissions. “There is more and more resistance to power lines in your backyard,” he says. “What’s nice is most homes have access to natural gas. The infrastructure exists. It’s quite easy to put a cogeneration fuel cell in homes.” The systems also tend to be a more reliable source of electricity than the conventional grid, since gas lines rarely go down.

But for Kumiko Kawamori, the biggest benefit has been a small monitor on her kitchen wall that came with the system. “You can see how much electricity you’re using and how much is being produced” by the fuel cell, she says, demonstrating by switching on the microwave; after a few seconds, the number on the monitor jumps from .5 to 1.7 kW. Kawamori says she’s noticed that the air-conditioners and, surprisingly, the vacuum cleaner are also big electricity users. “I thought, ‘Oh wow, I’m using so much energy!’” she says. “It was something that until then I had been totally unconcerned with.”

Fuel cell cogeneration systems could reach as many as 1.8 billion homes per year, says a spokesperson at Canadian fuel cell maker Ballard Power Systems, which supplies some of the Japanese CHP units (see the next page). The main obstacle to that goal, experts agree, is cost. Manufacturers say families can expect to save $500 to $800 per year on energy bills, but the appliance itself is projected to cost about $10,000, though this will vary by manufacturer. Even given a 10-year lifetime for the unit, the upfront cost wipes out any savings in monthly bills. Manufacturers are working to improve the lifetime, but until a large-scale, competitive manufacturing infrastructure is in place, prices will likely stay high. Government support may be one way to bridge that gap. The appliance in the Kawamoris’ yard was paid for largely by government subsidies; Japan’s 2009 budget for fuel cells is $426 million.

Meanwhile, home fuel cell cogeneration systems are helping establish the technology, manufacturing infrastructure and public awareness essential for the hydrogen economy to become viable. The Kawamoris, and the thousands of other households involved in the trials, are sharing their experiences with their family and friends, and as they do, interest in hydrogen power spreads. “Friends often come to our house, and they ask about the fuel cell, so I explain how it works,” Kumiko says. “People in this neighborhood are finally, little by little, becoming aware of environmental issues.”

It “gets people thinking about generating energy in their own homes,” says the National Renewable Energy Lab’s Turner. “You have a mini power plant in your basement—‘Hey look, I’m generating energy right here!’ The next step is, ‘Well, gosh, I’ll put [solar] panels on my roof, get an electrolyzer and I’m doing everything at home!’” He’s convinced that given the political will to make the transition, a sustainable energy system built on hydrogen is within reach. “We have the technology. We can do this. If we start down this road, we cannot fail.”

Fukuoka: Japan’s hydrogen hot spot

With home cogeneration units slated to hit the market in April, one area of Japan is getting a running start on promoting hydrogen. The Fukuoka region, on the southern island of Kyushu, is home to a massive project that’s bringing together government, industry and academia to build a hydrogen-powered community. “We think hydrogen is the best method for solving our energy crisis,” says Hiroyasu Tashiro of the Fukuoka regional government’s Department for the Promotion of New Technology and Industry. “We want as many people as possible to use fuel cell technology.”

In February, cogeneration systems using liquefied petroleum gas were installed in 150 homes in Maebaru, nicknamed Fukuoka Hydrogen Town. The appliances will be used to collect data in a study aimed at lowering costs and extending the lifetime of the technology. It’s the largest project of its type in the world. “This is the first time so many residential fuel cells have been concentrated in one area,” says Tashiro, who notes that aside from being happy about lower electricity bills, many Maebaru families are proud to be reducing CO2 emissions.

Meanwhile, scientists at Kyushu University’s new hydrogen research facility are working out some of the technological difficulties hindering widespread industrial and automotive use of hydrogen. For instance, since hydrogen is the smallest element, it tends to diffuse into metals and other materials when stored under high pressure. That can weaken holding tanks and car parts, reducing the working life of the hydrogen infrastructure.

So scientists at the university are researching the behavior of the element to address such problems. “Creating infrastructure and cars that are both safe and affordable is our top goal right now,” says Yukitaka Murakami, director of Kyushu University’s Hydrogenius Research Center. Training the next generation of engineers and increasing public acceptance of hydrogen are equally important, Murakami says. “If people don’t understand this technology, we’re not going to avoid global warming.”

Ballard Power tries to make fuel cells competitive with conventional energy

At Ballard Power, a small firm on the outskirts of Vancouver, even the forklifts are powered by hydrogen fuel cells. The company has been developing fuel cell technology for more than 25 years, long before climate change hit the headlines and hybrid cars filled driveways. When the media suddenly fell in love with hydrogen in the late 1990s, touting it as an ideal environmentally friendly fuel, the publicly traded company’s stocks soared, and investment flowed in. But when enthusiasm shifted to electric, battery-powered cars like the Prius, Ballard fell out of favor.

In 2007, with hydrogen cars still an estimated seven years from commercial availability, Ballard decided to sell most of its automotive division to carmakers Daimler and Ford, and focus on alternative fuel cell applications that promise faster profitability, such as back-up power units for the telecommunications market and batteries for forklifts, as well as combined heat and power units like those it supplies to Japan. The company is betting these applications will bring hydrogen into the mainstream—and Ballard into the black —well before hydrogen cars are on the road. “We’ve arrived at a tipping point in public opinion, the media and among public officials” about the need for new clean energy sources, says CEO John Sheridan.

Making fuel cells affordable enough to compete with conventional energy sources is key to market success. In the case of cogeneration systems, that means halving cost and improving lifetime to 15 years. To do that, the company is researching how to reduce the pricey platinum catalyst used in the cells, increase automation on the assembly line and simplify components. “Our biggest challenges technically at this point are how to lower costs and how to make [the fuel cells] more durable,” says Ballard’s chief technology officer, Chris Guzy. “But the technology is moving very fast now.”

A growing part of Ballard’s business is power units for buses, which company leaders see as ideal vehicles for spreading public awareness about fuel cells. Their technology will power 20 buses in Vancouver during the 2010 Winter Olympics, which the company claims is the largest hydrogen-powered bus fleet in the world.

“Fuel cells are the only source of power we know of that is pollution-free,” says James A. Cusumano, former research director at Exxon and co-author of Freedom From Mid-East Oil. “There is nothing else on the horizon that would not pump more CO2 or nuclear waste into the environment.”

Winifred Bird, who has a solar water heater on her roof, lives in Japan and writes about science and nature.

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