ARPA-E Summit Put The Spotlight On Energy Innovations

The Obama Administration’s “all of the above” energy strategy was on display at a gathering of technologists, businesspeople, and policy wonks held outside Washington, D.C., last month. The Department of Energy’s fifth ARPA-E summit celebrated advances in solar power, energy storage, transportation, energy efficiency, and more.

ARPA-E, which stands for Advanced Research Projects Agency-Energy, devises research programs and provides early-stage grants to researchers for advanced energy technologies. This year, new technologies found themselves competing for attention with cheap natural gas. Cheryl Martin, acting director of ARPA-E, says the agency’s program objectives now assume that innovations will go up against low-cost, traditional sources of energy.

Attendees could not help but note that ARPA-E’s support for energy innovation includes technologies related to fossil fuels. A highlights video included a project for powering passenger vehicles with natural gas. One of the four technology discussions by ARPA-E program directors was about natural gas production. And a panel session on carbon capture delivered the take-home message that someday, clean CO₂ from power plant emissions will be used in unconventional oil drilling.

Still, a wide range of technologies was on display at the summit’s showcase. Delia J. Milliron brought a set of small windows with a low-cost electrochromic coating being developed by Heliotrope Technologies , a firm she helped found in 2012. In addition to her day job at Lawrence Berkeley National Laboratory’s Molecular Foundry, Milliron is Heliotrope’s chief science officer. It’s been less than a year since her team published its work in Nature, “and already we’ve made a great deal of progress on our prototypes,” she said.

The windows feature niobium oxide glass covalently bound to a layer of tin-doped indium oxide nanocrystals. The coating can switch among transparent, heat-blocking, and heat- and light-blocking phases, she said.

A tour of the showcase was an education in how researchers are exploring the electrical and physical properties of materials to capture, store, use, and transport energy. For example, two firms, the tech start-up Transphorm and the auto parts maker Delphi Automotive, have turned to gallium nitride to convert power from energy sources such as solar panels or batteries to a form usable by electric cars and other devices.

Perhaps the hottest topic at the show was heat. Researchers and companies want to efficiently store heat from the sun so that power can be generated when the sun is not shining. Asegun Henry, an assistant professor of mechanical engineering at Georgia Institute of Technology, was on hand to make the case for using molten tin to store energy at large concentrating solar farms.

Holding heat in tin at 1400 °C is a very efficient way to generate steam and spin a turbine, Henry said, but containing and pumping it creates some materials challenges. His team is testing its ideas with carefully chosen ceramics and plumbing components. The hot metal could also be used in a reactor to generate hydrogen from water.

Finding efficient ways to store energy from solar power plants is crucial, especially once they become a sizable contributor to the energy grid, said Howard Branz, a program director at ARPA-E. “Using solar heat to generate fuel by splitting molecules is one way to generate dispatchable solar energy,” he suggested.

The program Branz directs, called ­FOCUS, has awarded funds to 12 projects that will build hybrid solar prototypes. Each will use photovoltaics to capture energy from the visible spectrum but also concentrate ultraviolet and infrared radiation into heat energy that can be stored. The awards caught the attention of Joseph Dennes, technology manager at DuPont.

“DuPont has been making materials for solar since 1975. So I’m here at the expo in part to examine the photovoltaic space,” Dennes said. “The recent awardees for new types of concentrated solar power are extremely promising and highly efficient. But they will need materials like encapsulants, composites, and ceramics that can withstand high heat for extended times.”

It’s no surprise that Dennes was already aware of the FOCUS awardees. The summit emphasizes networking with potential investors and corporate partners with the goal of quickly moving successful prototypes into commercialization. In addition to Dennes, executives from BASF, Chevron, and Dow Chemical were quietly circulating among the booths.

Daniel Recht traveled to the summit from South Korea in his role with the emerging markets and technologies team of OCI, a maker of polysilicon for solar panels.

“We have to pay attention to what is happening in advanced energy technologies,” Recht explained. “The model of ARPA-E is to first bring in the expertise to find the right projects. Looking from the business side, it’s true that the energy sector has a lot of bad technology, but at ARPA-E you don’t see any dogs.”