Latest Solar Power Developments

Stephen DeAngelis

June 8, 2007

Global warming and development are inextricably tied together. The Bush administration rejected the Kyoto Accord because it thought it would hurt the U.S. economy. Although the administration is looking more favorably on voluntary limits, a White House spokesman indicated it would hold firm against concrete long-term targets for reducing greenhouse gas emissions. This position remains disappointing to many U.S. allies [“At Group of 8 Meeting, Bush Rebuffs Germany on Cutting Emissions,” by Sheryl Gay Stolberg, New York Times, 7 June 2008]. China is another country that is resisting emission limits. The Chinese government just issued its first ever environmental policy, but once again development and environmental concerns clash [“China Outlines Modest Environmental Goals,” Maureen Fan, Washington Post, 5 June 2007]. Fan writes:

“China released its first-ever national climate change policy Monday, rejecting mandatory caps on emissions of greenhouse gases as unfair and a threat to the development that has contributed to the country’s meteoric economic growth. Although China is one of the world’s largest producers of carbon dioxide, the government made clear that it will not shoulder the burden necessary for change.”

Development relies heavily on the production of electricity and that production in most countries (France being a notable exception) relies heavily on coal-fired power plants. Environmentalists continue to favor alternative sources of energy such as wind or solar power. Todd Woody, writing in Business 2.0, provides the latest update of what is happening in the solar power sector [“Big Solar’s Day in the Sun,” 5 June 2007]. Woody begins his article at Sandia National Laboratory’s desert testing grounds in New Mexico.

“Six mirrored solar dishes that look like giant flowers with 15-foot stamens come to life. They pivot in unison, slowly tilting to face the sun rising over the jagged peaks of the Manzano ranges. A total of 468 mirrors — 78 on each flower –capture the sun’s rays and concentrate them into beams of light intense enough to melt lead. At each flower’s focal point, suspended on metal struts, is a Stirling engine — a heavy, piston-driven heat engine whose design dates from the Steam Age but is now coming into its own, thanks to the grim calculus of rising oil prices, global warming, and the threat of government-imposed carbon taxes. As the tips of the engines glow white-hot, 150 kilowatts of greenhouse gas-free electricity flows into a power grid. Welcome to the proving grounds of Sandia National Laboratories, a nine-acre field of dreams for solar entrepreneurs and a launching pad for the next era in energy technology: the age of Big Solar.”

As Woody notes, Stirling engines have been around for a long time. They were developed by Robert Stirling in the early 19th century. A Stirling engine is “closed-cycle” system which means that the working gas is permanently contained within the cylinder (click on illustration), Stirling_engine_01 unlike the better known “open-cycle” internal combustion engine, which vents the working fluid to the atmosphere. The Stirling engine is traditionally classified as an external combustion engine, despite the fact that heat can be supplied by non-combusting sources such as solar and nuclear power. That is exactly what is happening at the Sandia test site.

“This is industrial-strength solar energy, sold to public utilities in 20-year contracts measured in gigawatts. Stirling Energy Systems of Phoenix, whose giant flowers are gleaming in the New Mexico sun, has signed agreements to provide up to 900 megawatts of solar energy to San Diego Gas & Electric and another 850 megawatts to Southern California Edison. That’s nearly six times the utility-scale solar power being produced in the United States today.”

Woody implies that solar power is on the cusp of a revolution, with countries around the globe seriously considering how to utilize new solar technologies.

“Unlike in the age of carbon energy, which was driven by gargantuan gas-and coal-burning power stations, there is no single solar technology or one size that fits all. As electricity distribution becomes decentralized, there’s a place for 4,500-acre solar dish arrays as well as small 10-megawatt photovoltaic plug-in farms.”

He describes several of those technologies, beginning with solar trees:

“Stirling CEO Bruce Osborn, … who later this year will begin planting the first of as many as 70,000 ‘solar trees’ in the Mojave Desert — enough to power a million homes — this is indeed the fruition of a lifelong goal. He began working on Stirling dish technology in 1978 as a 22-year-old engineer with Ford Aeronutronic in Newport Beach, Calif. When oil prices crashed in the early 1980s, Ford abandoned the effort, which was taken up first by McDonnell Douglas, then by Southern California Edison, and finally, in 1996, by Stirling, a startup co-founded, improbably enough, by a holistic health entrepreneur named David Slawson. Slawson hired a cadre of old solar hands, Osborn among them, but faced a classic chicken-and-egg dilemma: The Stirling dish is one of the most efficient means of generating electricity from the sun, but without the economies of scale that come with mass production, it couldn’t compete with fossil fuel. Then came the California energy crisis of 2000-2001. Blackouts roiled the world’s eighth-largest economy, sending utilities scrambling for alternative energy sources. Seizing the initiative, Stirling moved its dishes to the Sandia proving grounds and began collaborating with the lab’s scientists. … Besides, the economics of the old power industry don’t necessarily apply to Big Solar. Get a contract for, say, a 500-megawatt gas-powered plant, and investors won’t see a return on their investment for years. Each Stirling dish, however, begins generating electricity — and cash — the moment it’s planted in the ground.”

Woody next discusses distributed power towers, which he found in California:

“On the approach to Harper Dry Lake, the air begins to shimmer with a bluish tinge, not from heat but from 234 acres of parabolic mirrors that carpet the desert floor of the Mojave. These are Solar Electric Generating Systems VIII and IX, two of nine ‘solar trough’ power plants built after the oil shocks of the ’70s by American-Israeli entrepreneur Arnold Goldman and a company he called Luz. At Harper, long rows of curved mirrors heat tubes of synthetic oil that glow with a white light. The hot oil produces steam, which in turn drives electricity-generating turbines. Despite the plant’s sheer size, the only sound is the low groan of oil moving through the tubes, barely audible over the birds flitting among the gray-green scrub. Luz’s plants still produce 354 megawatts of electricity — enough to light 150,000 homes. … Sensing that solar’s day was dawning again, in 2004, Goldman reassembled much of his old team into a new company: Bright Source Energy. He didn’t go back to the solar trough; he thinks that technology has reached its limits. Instead, his engineers have developed what he calls a ‘distributed power tower.’ Thousands of sun-tracking mirrors — known in the industry as heliostats — focus the rays on a water-filled boiler, heating the liquid to 1,000 degrees Fahrenheit and producing high-pressure steam that drives a turbine.”

Woody next travels the Pacific to Australia to discuss solid-state power plants:

“For more than a decade and a half, John Lasich’s team at Solar Systems in Australia toiled on the concentrating photovoltaic technology he invented in his backyard in the 1980s, surviving on the goodwill and capital investments of a handful of true believers. … But the work paid off last year when Solar Systems won $95 million in Australian government funding toward building the world’s largest photovoltaic power station, a 154-megawatt plant in southeastern Australia. Unlike Stirling dishes, power towers, and other ‘solar thermal’ technologies that use the sun’s heat to drive a generator, photovoltaic plants produce electricity directly from the effect of photons striking semiconducting materials. … Solar Systems will build towers, but instead of a boiler, each tower will hold a receiver containing the world’s most efficient photovoltaic cells. Fields of heliostats will focus the sun’s rays on the towers, making electricity without turbines, generators, or just about any other moving parts. It is, in effect, a solid-state power station. That makes the technology hugely scalable: A 1-megawatt plant should be just as efficient as a 1-gigawatt version. It’s potentially game-changing technology, particularly in a place like Australia that relies on cheap and plentiful but highly polluting coal. … ‘We’re seeing that we can turn sunlight into electricity instantly and at the same efficiency as brown coal,’ Lasich says, noting that his company’s technology and commercial viability underwent three rounds of government scrutiny to win funding. ‘That’s a real watershed.’  And indeed, to get a sense of how Big Solar could alter the economics of power production, you need only head downstairs to Solar Systems’s ‘factory.’ In a 625-square-foot clean room, a Yamaha robot assembles solar modules. That one bot can churn out enough megawatts per year to power a small town. A new facility now being built will boost production by a factor of 10.”

Back in the United States, Woody describes companies wrestling with the problem of installing photovoltaic plants in areas where large arrays are simply not possible.

“The plug-in power plant is the niche targeted by San Francisco startup GreenVolts. Founded in 2005 by Internet marketing veteran Bob Cart, the company’s high-concentration photovoltaic microdish arrays are designed to relieve utilities’ overloaded substations with photovoltaic plants of between 1 and 20 megawatts. Due to their efficiency, they take up about half the land needed by [other PV] plants. … That means they can be built near cities and plugged directly into substations. … GreenVolts’s offices are located above a Jack-in-the-Box one block from the bus station. Until recently, a potted plant was the sole bit of decor and the company’s name was handwritten on a piece of paper stuck to the door. The virtue of the space is that it’s free — PG&E provided it as part of a $120,000 package the company won last year through a green-tech contest. Now GreenVolts has bootstrapped its way into a contract with Avista, a small utility in Spokane, Wash., to build a prototype power plant, and Cart says he expects to sign a second deal with a major utility soon. He brings out a GreenVolts microdish, a dinner-plate-size mirror that concentrates the sun’s energy on a tiny but highly efficient Spectrolab solar cell. The company will place 176 of the microdishes on a rotating platform that sits low to the ground; the mirror and tracking system boost the cell’s efficiency.”

There are other promising solar technologies out there and many of them hold the promise of helping undeveloped countries — who are often cursed (or blessed) with lots of sun and non-agriculturally suitable land. With assistance, they should be able to make money by selling solar generated electricity both within the country and to neighboring states. The real upside of this would be that the country wouldn’t just be selling another natural resource but using it to jumpstart development inside the country at the same time. Win-win doesn’t get much better than that.