Can basic research bring renewable energies to scale?
The public is heaping pressure on the new presidential administration to increase renewable, domestic sources of energy. But the efforts of politicians and policy makers may amount to very little if science can't catch up. Right now, our global energy future may rest in the hands of basic research scientists.
At the 2009 AAAS meeting, a session titled "Basic Research for Energy Security: A Call To Action," featured speakers who drove home the idea that improving current alternative energy technologies—including silicon solar cells and lithium ion batteries—simply won't be enough to solve the energy crisis. Instead, basic research scientists need to develop new technologies that are cheaper, more efficient, and fit for mass deployment.
"We're going to need more than political will," said Nathan Lewis of the California Institute of Technology, speaking about new technologies in solar panels. "We're going need R&D and technology to get this to scale. Because the scale of energy is enormous, and therefore what works in your back yard or on your roof doesn't apply to scaling globally, unless it's very cheap and very amenable to mass deployment."
Lewis estimates that to fully supply the US with solar energy by 2050, we would need to install solar panels on one million homes a day, every day, for the next forty years. Right now, the most ambitious plan of this kind is in California, where the government plans to put solar panels on one million homes over ten years. But not enough silicon is produced in the world each year to create that many solar cells. Many other solar cell materials would also fall short. To achieve even a portion of this goal requires variety and versatility.
Sometime in the mid-1970s scientists were looking at a wide variety of materials for producing solar cells, but the oil shortage and resulting economic shock that hit the United States pushed those scientists to abandon research and start production. They zeroed in on just a few of the most promising materials, like silicon and platinum, and left the others behind. "I hope this doesn't happen to us today," said speaker Paul Alivisatos of the University of California Berkeley and Interim Director of the Lawrence Berkeley National Laboratory. "It's very important that we keep our minds open about what the solution is going to be, because we're off by a factor of four or five in the cost of a solar cell to where it needs [to be]. And when you're off by that much in a parameter like that, it means you have to keep your mind open."
Alivisatos' own research is investigating nanoscale crystals for solar cells instead of large, single crystals like those used in silicon cells. "With silicon it's like trying to coat the desert with very high quality diamonds," he said. "And the question is, 'Is that necessary?' Is there a way to in fact have the crystals be tiny? If they were tiny it turns out the cost of production would be enormously lower." He also pointed to developments from the polymer electronics community, where scientists are working in blended polymers to create thin films instead of large, heavy lattices, which could mean solar cells made of plastic.
In 2007, great excitement arose around the New Jersey Institute of Technology's breakthrough use of buckyballs (little soccer-ball-like cages of carbon atoms) in solar cells. Using the buckyballs, researchers aimed to build solar cells that could be painted on a surface or printed onto paper. Such a delivery method would be ideal for meeting the scale of global energy needs. The paint-on buckyball solar cells and similar carbon-based technologies have moved from 1% to 5% efficiency over the past few years, but they are still about a factor of two short of where they need to be. "We need to close that gap with new materials and a better understanding of why charges are lost and why we don't collect them all," said Lewis.
"We have to step back and also think about [the renewable energy market] from the perspective of where do we want to end up, not just where we are at this moment," said Alvisatos. "What if we were actually to get terawatt hours of electricity, not just grow the industry that we have today? What would be involved in that?" To achieve 3.2 terawatts of electricity, the amount used in the United States in a year, would mean covering about 60 million acres of land with solar panels (about equal to all rooftops and roads in the country). "That gives you a feeling for the scale of area we have to talk about. It is way beyond any solar installations that exist," continued Alivisatos. "So if we're really to see solar become a big player in our energy consumption, we have to learn to make solar cells on a scale that is unprecedented. We've never made such a scale of sophisticated electronic devices in our history."