NATIONAL HARBOR, Md.—Silicon translates sunshine into electricity—and Earth receives enough sunshine in a daylight hour to supply all of humanity's energy needs for a year. But despite being as common as sand, photovoltaic panels made from silicon—or any of a host of other semiconducting materials—are not cheap, especially when compared with the cost of electricity produced by burning coal or natural gas. The U.S. Department of Energy (DoE) aims to change that by bringing down the cost of solar electricity via a new program dubbed "SunShot," an homage to President John Kennedy's "moon shot" pledge in 1961.



"If you can get solar electricity down at [$1 per watt], and it scales without subsidies, gosh, I think that's pretty good for the climate," notes Arun Majumdar, director of the Advanced Research Projects Agency–Energy (ARPA–e), the DoE's high-risk research effort. "With SunShot, the goal is to reduce the cost of solar to [$1 per watt] in the next six years."



As it stands, melting silicon or depositing thin layers of copper indium gallium selenide, then manufacturing photovoltaic modules and installing them on rooftops or in large arrays in the desert, can cost as much as $10 per watt. And whereas some technologies can deliver modules for roughly $1 per watt, installation at least doubles that.



"We are making solar for the masses…to get to [a] cost point that is viable," said Bruce Sohn, president of Columbus, Ohio–based First Solar, the world's largest thin-film photovoltaic manufacturer, which claims it can produce its modules for less than $1 per watt, on a panel at ARPA–e's second annual summit on March 1. "We are looking to make something that can compete head to head with fossil fuels over the long term."



As part of the new SunShot initiative, DoE committed some $27 million to fund novel methods for producing solar cells and their components—like 1366 Technology's effort to grow pure silicon wafers directly rather than hewing them from long ingots of the material or Solexant's effort to build thin-film solar cells from semiconducting materials that are neither toxic nor rare. The goal is to produce solar modules at roughly 50 cents per watt with attendant hardware and installation costing the same amount. To reach that target the photovoltaic cells will have to convert at least 20 percent of the sunlight that shines on it into electricity and cost only 25 cents per watt by 2017. "The future of the U.S. depends on three securities: national, economic and environmental. The foundation of all of this is innovations in energy technology," Majumdar said in his own speech to the summit. "The future is still up for grabs. How do we win the future? Invent affordable clean technology. Make them locally, sell them globally."



Of course, harvesting the sun's power is not limited to photovoltaic panels. The DoE push also will incorporate efforts to create solar-thermal power plants that can store the heat of the sun for 12 to 17 hours by 2020, along with attempting to address some of the issues surrounding permitting, inspection and connection of solar systems to the electricity grid. "We want change, we want innovation, we want to overthrow the old energy order," said former California governor Arnold Schwarzenegger in a summit keynote address. "We want a new era of energy and a new era of American competitiveness."



Already, electricity from the sun costs roughly the same as that generated from burning fossil fuels in places like Hawaii, which remains the only state to rely on imported oil for the bulk of its power. And solar power represents the fastest-growing sector of electricity generation. U.S. solar production in 2010 increased by nearly one gigawatt (billion watts), although that represents roughly the amount of electricity one nuclear power plant can produce. But even at that pace of adoption—spurred by both federal and state government largesse—solar still produces less than 1 percent of all U.S. electricity. And in 2035, by which time the DoE's Energy Information Administration (EIA) predicts that solar will have grown fastest among all energy resources (increasing sevenfold), all renewables put together, solar included, will only provide 14 percent of U.S. electricity.



The EIA has often been wrong in such long-term forecasts, but competing with natural gas—newly cheap thanks to the vast resources tapped by fracking in the eastern U.S.'s Marcellus Shale Formation—may prove difficult, even with SunShot. "Natural gas has low capital cost, higher fuel cost but overall lowest costs," noted EIA Administrator Richard Newell at the ARPA–e conference. "There are significantly higher costs for other power sources."



Yet, even at a higher price, solar can offer benefits, which is why Duke Energy has invested $50 million putting solar arrays on the roofs of grocery stores and some of its other large customers. "Distributed solar can be thought of as a distributed resource, a multiple value resource," Duke Chief Technology Officer David Mohler told ARPA–e attendees. "The proper comparison for that is not the cost of a bulk power system, it's the cost and benefit of having an embedded resource."



And flexible solar cells in sheets have already found novel applications powering the telecommunications and other electronic equipment of U.S. Marine units deployed in Afghanistan. Small-scale solar is also booming in places such as Kenya that do not have an electricity grid for charging cell phones or batteries that power lights at night. "We will need every energy resource we can lay our hands on," said Kurt Yeager, executive director of the Galvin Electricity Initiative, an effort to develop the smart grid in the U.S. "There are two billion people in the world without access to electricity. Security means giving them energy."



Of course, the DoE has already invested some $1 billion in solar energy research since the turn of the century, funding efforts to develop "black" silicon or cells employing quantum dots. "If renewables are cost-competitive with fossil fuels then it's a very, very different world," Secretary of Energy Steven Chu said at the ARPA–e summit.



Yet, despite inventing the technology in the 1950s and more than 30 years of government support, the U.S. share of the global market for photovoltaic modules is down from more than 40 percent in 1995 to just 6 percent in 2011. China's Jiangsu Province alone—home to Suntech Power, the world's largest maker of photovoltaic panels—has begun investing more than $152 million a year in solar technology since 2009.



"Just because we lost the lead doesn't mean we can't get it back," Chu said. "We still have the opportunity to lead the world in clean energy…but time is running out."