Monday, April 27, 2015

Look What’s Cooking in the World of Renewable Energy

“There is a tenth of a percent of an efficiency gain here and cost reductions there that have added up to make solar very competitive.”

The hope is that silicon wafers will cut the cost of solar power by more than 20 percent in the next few years. (Credit: 1366 Technologies) Click to Enlarge.
Technological advances, including photovoltaics that can convert higher percentages of sunlight into energy, have made solar panels more efficient.  At the same time economies of scale have driven down their costs.

For much of the early 2000s, the price of a solar panel or module hovered around $4 per watt.  At the time Martin Green, one of the world’s leading photovoltaic researchers, calculated the cost of every component, including the polycrystalline silicon ingots used in making silicon wafers, the protective glass on the outside of the module, and the silver used in the module’s wiring.  Green famously declared that so long as we rely on crystalline silicon for solar power, the price would likely never drop below $1/watt.

The future, Green and nearly everyone else in the field believed, was with thin films, solar modules that relied on materials other than silicon that required a fraction of the raw materials.

Then, from 2007 to 2014, the price of crystalline silicon modules dropped from $4 per watt to $0.50 per watt, all but ending the development of thin films.

The dramatic reduction in cost came from a wide number of incremental gains, says Mark Barineau, a solar analyst with Lux Research.  Factors include a new, low-cost process for making polycrystalline silicon; thinner silicon wafers; thinner wires on the front of the module that block less sunlight and use less silver; less-expensive plastics instead of glass; and greater automation in manufacturing.
“Getting below $1 [per watt] has exceeded my expectations,” Green says.  “But now, I think it can get even lower.”
A Matter of Size
While solar power is just starting to reach grid parity, wind energy is already there.  In 2014, the average worldwide price of onshore wind energy was the same as electricity from natural gas, according to Bloomberg New Energy Finance.

As with solar, the credit goes to technological advances and volume increases.  For wind, however, innovation has mainly been a matter of size.  From 1981 to 2015 the average length of a wind turbine rotor blade has increased more than sixfold, from 9 meters to 60 meters, as the cost of wind energy has dropped by a factor of 10.

Read more at Look What’s Cooking in the World of Renewable Energy

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