In renewable energy projects, small isn't necessarily better 

“Small is beautiful,” wrote the economist E.F. Schumacher almost 35 years ago. In most areas of the economy, he reasoned, production had become too big and too centralized.

But he might have been wrong about the subject he knew most about: energy. When it comes to alternative ways of generating power, big may be better.

Wind, solar and other renewable-energy technologies that were once considered more appropriate for single homes or small communities are reaching levels of scale and centralizing that were formerly the province of coal- and natural gas-fired plants and nuclear reactors. In other words, green is going giant.

The companies that are building or dreaming up large projects argue that there are economies of scale to be gained.

In the desert north of Tucson, the Arizona Public Service, an electric utility, is using an array of mirrors to concentrate sunlight and heat mineral oil; the heat vaporizes a liquid hydrocarbon, which runs a generator to make electricity.

But this is no rooftop operation. There are six rows of mirrors, each nearly a quarter-mile, or four-tenths of a kilometer, long, totaling nearly 100,000 square feet, or 9,300 square meters. The project produces one megawatt of power – enough to run a hospital or a large shopping center – but the company that installed it, now called Acciona Solar Power (formerly Solargenix), expects to open a 350-acre, or 140-hectare, plant in Boulder City, Nevada, soon, producing 64 megawatts with similar technology.

Arizona Public Service is one of about a half-dozen utilities that is considering a joint project to build a 250-megawatt plant based on the same technology.

Such projects run counter to some ideas of how alternative energy should be developed. Jeremy Rifkin, the author and futurist who argues that millions of people will soon be generating their own hydrogen from renewable energy, said that waste was built into large central projects because of electrical transmission losses.

“If you go and put it in the desert and bring it back in, you lose 7 to 9 percent on the way,” he said.

More to the point, Rifkin said, home- grown energy is going to be cheaper. “It’s a question of who owns and controls it at the end of the line,” he said. “If you own it on your own, it’s going to be at a cheaper price than if the utility company is going to sell it to you.”

But it is not just corporations that are finding that bigger may be better.

Hull, Massachusetts, is about as far from an oil or gas well as it is possible to get in the United States. Its municipal utility decided in the early 1980s to build a wind turbine, making an asset from the strong breeze coming off the ocean north of Boston. The machine it built could generate 40 kilowatts, enough for a handful of homes.

Five years ago, Hull tried again, still wanting to cut energy costs and also the emissions of greenhouse gases that might one day cause the Atlantic Ocean, which surrounds the town on three sides, to creep up the beaches. It built a wind machine 16 times larger, 660 kilowatts. While the 1985 turbine was on a structure that looked a bit like a ham- radio operator’s antenna, the new one, named Hull 1, was on a 150-foot, or 46- meter, tower.

But it was too small. Last year the town installed Hull 2, which at 1.8 megawatts is three times larger. Now Hull is considering four new turbines that can produce 3.6 megawatts each. “The small one we have, purely aesthetically, is kind of an ugly thing,” said John Murdock, manager of the municipal electric system. With their slow- moving, graceful blades, he said, “the big ones are much more attractive.”

They also make better economic sense, he said. The town put up a tiny turbine, 1,800 watts, this year as an educational tool, for $15,000. If 1,000 families in the area put up such machines, they would have the same output as Hull 2, at a cost of $15 million. Hull 2 cost about $3 million.

Hull’s economics are being repeated around New England and the world. Farther down the Massachusetts coast in Nantucket Sound, for example, entrepreneurs are trying to build the Cape Wind project, 130 turbines producing 3.6 megawatts each.

At Siemens Power Generation, which builds equipment for wind turbines and other generators, Randy Zwirn, chief executive, said that the only limit to wind-turbine size might be how long a blade could be transported to the site. The company’s 3.6-megawatt machine uses a blade that is about 175 feet long.

Other companies want to build even bigger wind turbines with capacities as high as seven megawatts. A larger machine would be even higher – perhaps 250 feet – and could take advantage of the fact that winds are 20 percent stronger at 250 feet than at 150 feet, said Mark Jacobson, an associate professor at Stanford University’s department of civil and environmental engineering.

But in Nantucket Sound, 3.6-megawatt turbines are considered big enough. On a windy day, the 130 machines would produce as much power as a modest-size plant burning coal or natural gas.

There is certainly no point in making the project smaller, said Mark Rodgers, a spokesman for Cape Wind.

“You’ve got costs that include staging, marine construction, placing an electric transmission infrastructure below the seabed, acquisition of maintenance vessels, use of a port facility, spare parts, storage, manning an operations center, insurance and taxes,” he said.

For many of those items, if the project were 50 percent larger or 50 percent smaller, the costs would vary little. “These are things that you’re going to have to do, whether it’s a very small or a very large offshore wind farm,” Rodgers said. “The best bang for the buck is to go large.”

By Matthew L. Wald
International Herald Tribune

iht.com

8 March 2007