A 4-kilowatt photovoltaic system powers The Nature Conservancy's Red Canyon Ranch in Wyoming.Utility PhotoVoltaic Group.
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The oil crises of the 1970s came and went without PV playing a significant role, although other uses of alternative energy sources, such as wind-powered electric generators and solar water heaters, did make a slight impact. But as PV prices enter a freefall, it is being used for much more than powering isolated homes. One promising application is to beef up sagging voltage near the end of utility transmission lines. "You can put small increments of power right where it is needed with PV, rather than spending large sums on infrastructure development," says Gibson of the Utility PhotoVoltaic Group. Still, he admits, despite studies proving the feasibility of this use, "real progress... may still be five years off."
Today, the demand for PV is not limited to environmentalists. "The market has come up significantly in the past two years," says John Bigger, technical director at the Utility PhotoVoltaic Group. "We're seeing a significant increase in demand, most all of the large manufacturers are looking at a waiting list of three to six months or more."
As worldwide PV manufacturing capacity grows by a steady 15 percent per year, the overseas market "has taken off," says John Thornton of the National Renewable Energy Lab. Over the next decade, North America, with its excellent electric grid, will represent a small percentage of global sales. U.S. exports in 1996 were $800 million to $900 million.
PV could be a godsend for the 2 billion-plus people who don't have access to electricity, Bigger says. "There's not enough money to extend existing grids to them right now, so the major alternative is diesel fuel" running generators in isolated villages. Far better, he says, would be to install some solar panels, and gradually build village-based systems powering lights, radios, refrigeration and water pumps.
How big is the market for cells that can provide juice at $3 per watt? Just looking at South Asia, where electricity is in short supply or nonexistent, "You are dealing with one-third of the world population right there," Thornton says. Already, he adds, demand for PV systems is "insatiable." And with each decrease in cost, demand perks up, feeding back to increase manufacturing volume and further reduce costs.
Thin-film technology
One long-heralded cost-cutting technology -- thin film cells -- is set to enter the market in 1997. Today's PV cells are made of crystalline silicon, which require expensive, highly pure silicon. Thin-film cells are cheaper, not just because the material costs roughly 1 percent as much as crystalline cells, but also because they're easier to manufacture. "It's a little analogous to a glass plant," says Thornton. "It's conceivable that you could build plants where it rolls off in sheets."
Against this backdrop, the Sacramento utility district's estimate of $3 per watt of installed cost by 2002 seems reasonable, Thornton says. And at that price, he anticipates that 9 gigawatts (billion watts) PV capacity will be installed in the United States. That would allow the sun's rays to account for roughly one percent of the U.S. generating capacity of 700 gigawatts).
However, Thorton says the actual price of PV will depend on the world market, and if demand exceeds supply, the $3 price may not be reached on scheduled.
And while $3 is cheap, it's not the end of the road, Bigger adds. "In the long term, some people see costs dropping below $1 per watt, although that would be well after 2010."
But what about a traditional drawback of solar power -- its limited availability? The projected 9-gigawatt increase in capacity in the United States would not require nighttime storage, Bigger says, since many utilities get their peak load during peak daylight, around mid-day or in the early afternoon. Clearly, systems in places where alternative electricity is not available would need storage, probably batteries, for nighttime power.
Do I get to pay for the privilege?
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