The Solar Industry Gains Ground

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photograph courtesy of Nasa

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The Graph

To get a sense of just how bright and sunshiny the future looks to the solar-energy industry, consider The Graph: It's a standard affair, projecting solar's share of global energy production over the coming century. The Graph was created by a scientific organization that counsels the German government, but it has since become a prized piece of propaganda, embedded in glossy brochures and PowerPoint presentations by solar companies from California to gray-skied Saxony. At the left-hand, present-tense end of the scale, solar power is a microscopic pencil line of gold against the thick, dark bands of oil and natural gas and coal, an accurate representation of the 0.04% of the world's electricity produced by solar power as of 2006. The band grows slowly thicker for 20 years or so, and then around 2040 a dramatic inversion occurs. The mountain-peak lines indicating the various fossil fuels all fall steeply away, leaving a widening maw of golden light as solar power expands to fill the space. By 2060, solar power is the largest single band, and by 2100 it is by far the majority share.

This has always been solar energy's tantalizing promise, since the first photovoltaic (PV) cells emerged out of Bell Labs in the 1950s to power space probes and ignite the dreams of a generation of giddy utopian dreamers. Solar energy is as plentiful as daylight, as limitless as organic life itself, a fuel that comes free of charge and replenishes itself every time the earth rotates on its axis. Almost all energy, after all, is ultimately stored solar power: Oil, gas, and coal were born of the ancient sunlight that fed prehistoric animals and plants, the wind is set howling by the sun's unequal heating of the atmosphere, and even a campfire draws its warmth from solar power trapped long ago through photosynthesis. Enough radiation from the massive fusion reactor at the center of our solar system hits the earth every hour to fill all of its energy needs for a year.

Fifty years on, the PV cell remains the most effective engine yet devised for the conversion of sunlight into electricity. The core of every PV cell is a semiconductor, traditionally a highly purified wafer of crystalline polysilicon, virtually identical to the "chips" upon which computer circuits are built. When sunlight strikes the semiconductor, its atoms get excited; if the light beam's photons pack a sufficient punch, they knock the semiconductor's electrons loose for collection by the PV cell's circuits, creating an electric current. Assemble a handful of these cells in a glass frame and wire it to a battery or a power grid, and you have got a solar panel (or module, as it's sometimes called in the industry). A small, pollution-free power plant. Compared to splitting an atom or sucking liquefied phytoplankton from 300-million-year-old bedrock, it's practically child's play.

Solar has nevertheless been stuck for decades in the future tense. PV cells have been too inefficient and too expensive, or too reliant on a fickle sun. But the solar industry has recently made a dramatic leap from the feel-good margins to the mainstream. An unprecedented production boom began around 2004, well before the rise and current fall in crude-oil prices; that boom continues unabated and has led to plunging costs, vastly more rational supply chains, and record-setting gains in the efficiency of traditional crystalline silicon cells (the best now conduct electricity at efficiency rates almost 30% better than the lab record of 2003). In the past 50 years, about 10 gigawatts of solar power -- roughly the output of 10 standard nuclear reactors -- have been installed worldwide. But current estimates, which have been modified only upward in recent years, are that 10 gigawatts more will be brought online in 2010 alone.

A new global industry is taking shape before our eyes. A journey through this energy revolution suggests that the age of truly ubiquitous solar may at last have begun. Solar's emerging titans are scattered across three continents and three technological generations -- from established crystalline PV manufacturers in California to newer "thin film" cells now reaching mass-production scale in Germany and to even third-generation compounds being developed in Australia that can be integrated into building materials to deliver power in the darkest shade. Even in this time of enormous financial uncertainty (not to mention a deepening concern, if not panic, about the health of the planet), the sense of boundless potential, the promise of The Graph, is palpable. Erik Straser, who oversees the clean-energy portfolio at Mohr Davidow Ventures in Silicon Valley, puts it this way: "Sometimes I ask myself, 'If this company was successful, would people name libraries and public high schools after it?' Who made the steam engine? Who made the lightbulb? Who will those people be for the 21st century? Who's the person that made mass-market solar affordable?"

A global industry is taking shape, with the hottest spots in Silicon Valley, Germany, and Australia. The age of truly ubiquitous solar may at last have begun.