From Green Right Now Reports
Solar panels may soon be able to rely on more abundant minerals and metals, than some of the rare elements used today, scientists meeting in Philadelphia this week said.
These advances could make solar energy more affordable and easier to integrate into buildings, and hasten the day when the U.S. could get 50-100 percent of its electricity for buildings from the sun, the researchers said during a panel at the American Chemical Society meeting.
"Sustainability involves developing technology that can be productive over the long-term, using resources in ways that meet today's needs without jeopardizing the ability of future generations to meet their needs," said Harry A. Atwater, Ph.D., a physicist at the California Institute of Technology, in a statement released by the ACS.
"That's exactly what we are doing with these new solar-energy conversion devices."
Specifically, the emerging technology would use copper and zinc, relatively available or “earth abundant” metals, instead of rare indium, gallium and other metals that are not found in large supplies, and are in fact, often confined to certain geography.
China, for instance, mines more than 90 percent of the rare earth metals needed for the batteries used in electric cars, the ACS report noted.
The copper and and zinc required for these new generation solar panels could come from a variety of places around the world. These metals would still need to be mined, however, taking a toll on the environment. Copper mining in the U.S., for instance, has contaminated groundwater and presents a host of waste disposal issues, according to the EPA.
Atwater is collaborating with James C. Stevens, a Ph.D. chemist with The Dow Chemical Company, in a partnership between Cal Tech and Dow Chemical that aims to energize solar panels and devices with more accessible metals.
The two scientists have tested devices made with zinc phosphide and copper oxide that broke records for both electrical current and voltage achieved by existing so-called thin-film solar devices made with zinc and copper, according to the ACS.
The greater efficiency means that new solar devices relying on these chemical compounds could achieve “very high efficiencies, producing electricity at a cost approaching that of coal-fired power plants,” according to Atwater and Stevens.
Atwater said the tipping point for solar — when solar beats coal in the cost of electricity generation — could come within 20 years.
Stevens, who helped Dow Chemical develop an electricity-generating rooftop shingle (the Solar Shingle), reported that his team’s next challenge is to replace the rare elements in those shingles with more sustainable materials.
Once they develop a way to power buildings with affordable, sustainable photovoltaic panels, the nation could look to the sun for at least half of its electricity needs.
"The United States alone has about 69 billion square feet of appropriate residential rooftops that could be generating electricity from the sun," Stevens said.
"The sunlight falling on those roofs could generate at least 50 percent of the nation's electricity, and some estimates put that number closer to 100 percent. With earth-abundant technology, that energy could be harvested, at an enormous benefit to consumers and the environment."
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