Researchers at University of California at Berkeley announced a record in thermophotovoltaic efficiency, now at 29 percent, but with a few tweaks, soon to be at 50 percent. This is great news for small drones, which could stay up for days, but possibly not a be-all, end-all for larger, more conventional electric aircraft. Let’s examine the potential and the pitfalls involved. The researchers’ “groundbreaking physical insight” and “novel design” applies thermophotovoltaic principles that are “an ultralight alternative power source.” Eli Yablonovitch, professor of electrical engineering and computer science (EECS), wrote in a paper published in the Proceedings of the National Academy of Sciences, ““Thermophotovoltaics are compact and extremely efficient for a wide range of applications, from those that require as little as 100 watts, [such as] a lightweight unmanned aerial vehicle, to 100 megawatts, [providing] electricity for 36,000 homes. In comparison, a 100-megawatt combined cycle power plant is massive,” Expanding on work he and his students published in 2011, Yablonovitch …