Blending Aesthetics & ENERGY

Japan's gorgeous cultural emblem has taken on a new level of meaning. It will help the resource-poor island nation generate more of its own energy.
By Eric Kroh
Every year in Japan, the blossoming of the sakura, or flowering cherry tree, is an occasion for rejoicing. The reveling begins in late March, when the sakura trees in the southern island of Kyushu put forth their buds. The celebration then spreads north with the flowering of the trees until the last cherry trees bloom on the island of Hokkaido in May.

The flowering period for sakura trees is brief. Mere days after opening, the flowers fall to the ground, carpeting the earth with delicate pink petals. Yet the short-lived display is so spectacular that, upon sight of the first buds, the Japanese have been known to drop everything and head to the best viewing locations to eat, drink and play music.

Moreover, wood from the cherry, a national symbol, is used for woodblock prints and magnificent furniture. This year, the sakura trees bear an additional gift for the Japanese-that of renewable electricity and heat.

As the cherries blossomed in March, Japan's largest wood-gas-to-energy power plant began operations in the Yamagata prefecture, about 250 miles north of Tokyo. Located in the city of Murayama, the plant runs exclusively on gasified wood chips and tree trimmings culled from nearby forests that include tens of thousands of cherry trees.

The plant was installed by Yokohama-based JFE Environmental Solutions Corp., a subsidiary of the steel and engineering conglomerate JFE Group. Operating the plant is electricity company Yamagata Green Inc. of Murayama, itself a subsidiary of Japan Biomass Development Co. Ltd., a Tokyo-based renewable-energy development firm.

Small but Sophisticated
Wood biomass can help Japan realize its goal of reducing its greenhouse gas emissions in compliance with the Kyoto

Under that 160-nation agreement reached in 1997, Japan has pledged to reduce its greenhouse gas emissions 6 percent below 1990 levels by 2012. Japan has also promised to reduce its emissions of carbon dioxide to 1.056 billion tons by 2010, according to Japan's Agency for Natural Resources and Energy in the Ministry of Economy, Trade and Industry.

"This plant becomes a very important initiative in the Japanese renewable energy sector to help increase the biomass share out of the total energy in Japan and to meet the targets in the Kyoto Protocol," says Yamagata Green Power President Makoto Suzuki. The facility, he adds, can eliminate 9,000 tons of carbon dioxide emissions annually.

The power plant's heart is two Jenbacher gas engines from GE Energy's Jenbacher business in Jenbach, Austria. (GE Energy is a unit of General Electric Co. of Fairfield, Conn., in the United States.) Most Jenbacher engines run on natural gas. The ones installed in the Murayama plant, however, are designed to run specifically on gasified biomass and produce a combined output of up to three megawatts of electricity.

That makes the Murayama plant small. Wood-burning power plants typically produce more than 10 times as much power. Nevertheless, the Murayama plant is the most sophisticated of its kind in Japan and the only plant operating on a scale that is economically viable, says Michael Zainer, distributor and agent manager at Jenbacher. The rest of the 10 or so plants operating in Japan are test plants on the order of 50 to 300 kilowatts of output-a fraction of the size of the Murayama facility.

Moreover, some of these smaller plants were shut down because the gasification technology didn't work-mostly because the biogas could not be adequately cleaned. The fact that the Murayama plant is operational demonstrates that the technology is maturing, Zainer says.

The principal benefit of the gasification process is that it is more efficient than other ways of producing electricity from biomass material, says Martin Schneider, a spokesperson at Jenbacher.

In the gasification process, the wood is heated to more than 1,200 degrees. Fahrenheit in a low-oxygen environment. At that temperature, the wood releases a mixture of carbon monoxide and hydrogen gases, which in turn is cooled and cleaned of tar and particulates using a gas-scrubbing method and a wet electrostatic precipitator.

The gas can then be burned like natural gas to spin a turbine in the engine that generates the power.

A plant the size of the Murayama facility can provide sufficient heat to meet the annual demands of 1,200 households, although the Murayama plant will not be used for heating.

The gasification process converts 28 percent of the available energy in the wood to electricity, according to Schneider-a significant improvement over power generation from directly burning wood, which converts only about 18 percent to 22 percent.

"The standard technology today is burning the wood in a boiler and producing some steam" to generate electricity, Schneider says. "But with the gasification and using the gas in a gas engine, you can increase electric yield by 50 percent."

Cost and Cleanup
Even so, the process is costly. Schneider estimates the typical investment for a biomass power plant to be between $7,500 and $8,500 per kilowatt, or about $25 million for the Murayama plant. Consequently, government incentives and significant demand for heat need to be in place for wood gasification to be a viable source of energy, Schneider says.

The process holds the greatest promise in central Europe and Canada, where winters are particularly cold and plenty of wood is available. Jenbacher already has 10 biogas engines in operation in Europe, and says another 10 will be commissioned this year.

Murayama's facility resembles a decade-old plant in Denmark. Both use updraft gasifiers developed by Danish biomass energy company Babcock & Wilcox Vřlund A/S, which licensed the technology to JFE Environmental Solutions.

Another obstacle to commercial viability for wood-biomass gasification is the expense of gas cleanup, says Jacques Beaudry-Losique, manager of the biomass program at the U.S. DOE's Energy Efficiency and Renewable Energy division.

Beaudry-Losique estimates that one-third of the capital cost associated with biomass gasification plants is cleaning particles and tar from the gasified biomass material. "Once you clean up gas so operating costs are reasonable, it will be a competitive technology," he says.

He estimates that biomass gasification technology will eventually reach a point at which power plants can achieve an output of 25 to 50 megawatts, compared with the two to three megawatts typical now. The scale of biomass-gasification plants will be limited more by the availability of local feedstock than by the technology itself, he says.

In Japan, wood is an attractive source for biomass energy because of the abundance of supply, says Kazuyiki Takada, who works on the promotion and demonstration of biomass technology at New Energy and Industrial Technology Development Organization. NEDO was established by the Japanese government to develop alternatives to energy from oil. "Woody biomass resources are very important because they represent one of the biggest potential utilizable biomass resources in Japan," Takada says.

Nevertheless, collection and transportation is a challenge, says Takada. Forestry work has little appeal to the Japanese, who seek better jobs in Japan's usually vigorous economy. Too few workers are available to gather waste wood from forests and get it where it needs to go. "There is currently a lack of an established, comprehensive system to connect upstream biomass energy-conversion technology for collection and transport to downstream technology to utilize the converted energy," Takada says.

That supply chain requires work on a regional level, connecting local production with local consumption and involving municipal governments and local citizens, Takada says. To that end, NEDO promotes demonstrations of biomass energy to educate people about the technology.

60 Tons Per Day
The Murayama plant is an example of how regional cooperation on biomass energy could work. The forests of Yamagata supply the Murayama power plant with nearly 60 tons of wood chips daily to fuel the gas engines. Because the forests are near by, wood transportation costs are minimal. The arrangement is also beneficial for forest keepers, who would otherwise have to pay to have the wood trimmings trucked out. Electricity from the Murayama plant supports plant operations. The rest is sold to industrial customers.

For now, however, wood-biomass energy is expensive. While the Murayama plant is fully operational, it was built with help from government subsidies. The Japanese government, via the Agency for Natural Resources and Energy, covers one-third of the initial costs for biomass power generation facilities, not including construction costs. Takada hopes the growth of regional biomass systems, as well as the development of high-performance forestry machinery, will decrease initial costs for biomass energy producers and bring more plants on line.

Meanwhile, though, woody biomass plants aren't economically viable without government incentives, but the Japanese government seems willing to support a network of plants in the range of three to five megawatts, Zainer says.

Under Japan's current goals, ANRE predicts that biomass used for electricity and thermal energy will displace the equivalent of 1.7 billion gallons of oil per year, or about 1 percent of Japan's total energy supply. Historically, Japan has been dependent on oil for much of its energy needs. About half of the oil and coal used in Japan is converted into electricity.

While the lignin content of wood makes it difficult to convert into biofuels, which would directly replace oil in the energy supply, the production of electricity from wood via gasification could replace a significant amount the oil and coal that is converted into electricity.

The pleasures of the blossoming of Japanese cherry trees are fleeting-but biomass from the legendary sakura could contribute to development of a domestic energy supply that would provide the country with long-term benefits.

Eric Kroh is a Chicago-based journalist who writes and creates multimedia content about biofuels and the environment.