A solar-power installation in the Arizona desert uses 100,000 square feet of mirrors
“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 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, Arizona Public Service, an electric utility, is using an array of mirrors to concentrate sunlight and heat mineral oil up to 550 degrees; 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 long, totaling nearly 100,000 square feet. 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 plant in Boulder City, Nev., soon, producing 64 megawatts with similar technology. And 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 believes 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, Mr. 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, Mass., 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 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 B. 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. Earlier this year, the town put up a tiny turbine, 1,800 watts, 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, the 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 Dr. Mark Z. Jacobson, an associate professor at Stanford’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,” Mr. Rodgers said. “The best bang for the buck is go to large.”
While mirrors in the desert cannot operate at the rooftop scale, the kind that can, photovoltaic cells, which turn sunlight into energy, may also work better on a big scale, experts say.
A single-home installation is fine, they say, but not cost-effective. It can become so through large-scale deployment of the kind envisioned by Bud Annan, who was the solar program director at the Department of Energy during the Clinton administration.
Mr. Annan said that the cost of a rooftop solar project was divided between the manufacturing of solar cells and installation. Some progress has been made in reducing manufacturing costs, but both parts of the equation must come down in price, he said.
Now living in Scottsdale, Ariz., Mr. Annan is working with a utility and local real estate developers to try to incorporate solar roofs into 10,000 new houses, all at once. That way, he said, the installers can go from house to house the way carpenters, plumbers and electricians do. “He can standardize his installation, and that whole second half of the equation becomes more manageable for him,” Mr. Annan said.
Clusters of houses might share a bank of batteries, so that they could guarantee a steady power output. Power that a utility can count on is worth more than power that is unpredictable. Solar energy that is connected to a battery system is available even after the sun sets, making it sell for a higher price.
Roger Little, chief executive of the Spire Corporation, a solar cell manufacturer near Boston, said his systems cost $7 or $8 per watt of installed capacity when put on rooftops, which means that the equipment needed to light a 100-watt bulb would cost $700 to $800. Half is for the cells and half is for the rest of the system, including mounting brackets and external wiring.
Mr. Little said he could lower the price to $3.60, but that the first step would have to be replacing typical solar panels, which produce about 160 watts of electricity each, with a 1,000-watt panel. The big panel would require less support material per watt than the smaller ones, he said.
But that panel would be 200 pounds, too heavy to haul up to a roof. The solution, he said, is to install it on the ground, in a big flat spot of desert — which, by the way, would be a wonderful place to build the solar-cell factory, cutting delivery costs to zero. And the bigger the installation, the lower the cost, per watt, of the other equipment required, he said.
Mr. Little is negotiating with the Tucson Electric Company to build a factory in Arizona that would produce 100 megawatts of cells a year, and run it for 10 years or so. Other cities and companies are considering similar ideas. Mr. Little said that at some point his project would turn into a “breeder,” its electric production paying for its operation.
His company already runs factories that make 50 megawatts of new cells a year. The viability of the project depends mostly on whether Congress extends the production tax credit given to renewable and nuclear energy, he said.
Arizona Public Service, which operates the solar generator north of Tucson, seems to be on a campaign to show that there is no green approach that does not work well on a corporate scale. Last year, it started raising algae, feeding them carbon dioxide from a natural-gas-fired power plant, Red Hawk, west of Phoenix. It used the algae to make biodiesel, a vehicle fuel that is more commonly made from soybeans or corn. The company is now installing bigger equipment to test the process on a larger scale.
Even for renewable energy like heating with wood (an idea that has been around for much longer than the term “renewable”), the scale is growing. For example, theUniversity of South Carolina would like to reduce its carbon footprint and lower its natural-gas bill of $6.5 million a year. So this spring it plans to open a plant that will use wood scraps to make electricity, and use steam from the system’s waste heat to warm the campus.
This is not some wood-fired boiler. It is an $18 million gasification project that will heat the wood, mostly chips and bark, to produce a flammable gas, which will be burned in a turbine that resembles a jet engine. And the university will not run it on clippings from trees at the Columbia campus; it will take 14 tractor-trailer loads a day, about 55,000 tons a year.
Because the wood is gasified but not burned, the system, which is similar to one used in Burlington, Vt., produces less nitrogen oxides and less soot than a boiler would, said Jonathan S. Rhone, chief of the Nexterra Energy Corporation of Vancouver, British Columbia, which built the gasifier. But being that clean requires an industrial-size system.
There is another reason that it is not the kind of project that works on a small basis: it will take about 14 years to pay for itself. “We’ve been here 200 years,” said Helen Zeigler, the university business manager. “We can afford to make investments like this.” A 14-year payback would never work on a family budget, she said.