Cutting module costs is one step. The second, also a major challenge, requires lowering the costs and raising the performance of the electronics that convert direct current from photovoltaic solar power to alternating current used on the grid.
Getting to 'plug and play'
ARPA-E has created a program called ADEPT, for Agile Delivery of Electric Power Technology, that aims to shrink the size and cost of inverters that do the DC-to-AC conversion, miniaturizing them just as was done with the integrated circuits in computers. "There are some fascinating projects of how to reduce costs, improve performance and really get the technological lead over where the rest of the world is," Majumdar said in an interview last year.
One promising idea is to carry out the conversion at high frequency, enabling miniaturization and integration of components, and hopefully, an exponential drop in costs, just as has happened with computer chips, Majumdar said.
Finally, there are the back end, or "balance of system," costs surrounding module installation.
A report by the Rocky Mountain Institute last year concluded that back-end costs, now averaging $1.60 to $1.85 per watt, could be reduced to 60 cents for ground-mounted units and 90 cents for rooftops.
The lower costs would offer "a pathway to bring photovoltaic electricity into the conventional electricity price range," the report concludes.
But that step requires its own revolution, beginning with an automation of installation work and "plug and play" designs that could be hooked up without the need for electricians. Thousands of different local building codes create another drag on costs that needs an answer. These back-of-system costs are about equal to the costs of the modules, and they are not declining as fast as module costs, Majumdar said.
Under Chu, DOE's biggest effort has been the review and selection of solar projects to be funded with the 2009 stimulus money, including the ARPA-E grants. More than 3,600 applicants applied for the initial ARPA-E funding. Only 37, including the 1366 firm, were successful.
The various DOE solar programs had not been linked into a tightly coordinated attack on the $1-per-watt goal as of the end of the 2010, Majumdar said in an interview. "These are disparate programs," he said. ARPA-E was not funded until the stimulus bill passed in 2009. The ADEPT program is also new. "There are other parts of DOE, so we have been putting our heads together to come up with a well-coordinated initiative."
Throwing '$86 billion at the wall'?
DOE's approach has prompted strong opposition from some Republicans. During House debate last spring, Rep. James Sensenbrenner (R-Wis.) called DOE's R&D programs at attempt "to throw another $86 billion at the wall to see what sticks."
He asserted that the administration has shifted focus from basic research to increased spending "on later-stage technology development and commercialization efforts. ... I do not believe that the government ought to be in the business of picking winners and losers; however, that is exactly what the provisions of this legislation attempt to do."
"We need a broader strategy that prioritizes spending, reduces debt, eliminates deficits and provides clarity, stability and the appropriate regulatory environment," Rep. Dana Rohrabacher (R-Calif.) said during the debate. "This legislation makes no choices. It simply authorizes more and more spending."
Van Mierlo counters that it is not just taxpayers who have anted up for this test.
Two investment funds, North Bridge Venture Partners and Polaris Venture Partners, seeded Sachs and van Mierlo with $12 million in startup capital. The $4 million ARPA-E grant was next. That, in turn, helped attract $ 33 million more last year from outside backers, including a South Korean chemical manufacturer and a European clean energy investor. DOE's backing helped validate the project to these funders, van Mierlo said.