Last summer, Alta Devices announced a record in the efficiency of an individual solar cell, at 27.6 percent conversion of the sun's energy to electricity. The same company has now set an efficiency record for an entire solar panel, at 23.5 percent. The record was independently confirmed by the National Renewable Energy Laboratory (part of the Department of Energy).
Alta Devices makes solar panels using gallium arsenide cells, a more efficient material than the generally cheaper silicon-based cells. To keep prices down, though, the company uses very small amounts of gallium and arsenic, creating a layer of gallium arsenide only one micron thick. They are still only in a pilot production stage for the new panels, but are apparently starting to plan for full scale, commercial production.
The efficiency records are impressive, but translating some of the best ideas to a growing market is never an easy task. As we've seen before, records falling don't necessarily change the solar market overnight. And yet every incremental improvement is an important step toward bringing solar power into a truly competitive range with fossil fuel electricity.
The president and CEO of Alta Devices, Chirstopher Norris, said in a press release last summer: "We are committed to using new scientific understanding, such as internal light generation and extraction, to push the limits of solar cell and module efficiencies while simultaneously driving production costs down through other important developments. The goal of achieving the $1 per installed watt target set by the Department of Energy has energized our entire company.”
The DOE goal he mentioned is part of the SunShot initiative. The idea is to bring solar down to six cents per kilowatt-hour by the end of the decade, which would put it right in the range of coal and natural gas. Achieving this will require improvements in a range of solar tech, from ideas like these thin gallium arsenide cells to solar thermal technology. But it would have a huge impact: according to the DOE itself, if the SunShot is achieved it "will enable solar-generated power to account for 15–18 percent of America's electricity generation by 2030." This will be quite a feat, as we're still hovering below one percent today.
Image via Lance Cheung