At some point during the last year and a half, you’ve probably found yourself thinking: “I really wish the BSR Blog team would live blog a campus event.” Well, the wait is officially over. Tomorrow, Oct. 20 and Friday, Oct. 21 we’ll be posting live updates from the BERC Innovation Expo and Energy Symposium, an exciting event showcasing cutting-edge energy research from UC Berkeley and beyond. If you can’t make it to the events in person (tickets are selling out fast), join us here on our website from 6 – 9 PM Thursday and 9 AM – 6 PM Friday, and we’ll make sure that you don’t miss a thing!

Most of the time, doing something 28% efficiently is nothing to be proud of. But in photovoltaics, it is good enough to set a new world efficiency record—and earn the company that made the record-setting devices millions of dollars in venture capital.

In this case, the lucky company is Alta Devices, which until recently held a low profile in the crowded solar industry. For the last few years, Alta has been quietly developing a novel process for cheaply manufacturing ultra-efficient solar cells. Their hard work appears to be paying off, because last month the company reported that they can make cells that are 28.2% efficient at converting solar energy into electricity. This beats the previous record by more than one percent, a wide margin by the solar industry’s standards.

Alta’s solar cells are made of a semiconducting material called gallium arsenide. Because this is a relatively expensive material, most solar companies use cheaper, less efficient alternatives such as silicon. But Alta came up with a transfer process that allows them to lay gallium arsenide layers that are only one micron thick (about 100 times thinner than a sheet of paper) on each cell.  The thin layers don’t use up much material so they don’t cost very much, but they still generate as much electricity as a thicker layer would.  The company’s goal is to generate electricity at a cost of under 50 cents per watt, which is about twice as cost-effective as the current state-of-the-art.

While impressive, the last few decades of human achievement in photovoltaics pale in comparison to nature’s equivalent technology: photosynthesis. Just look at the numbers—every year photosynthesis produces about 3,000 exajoules (EJ) of chemical energy, or 7 x 10¹⁷ kilocalories, which equates to about half the total energy stored in the world’s petroleum reserves (and approximately the average daily caloric intake of eating champ Joey Chestnut). Compare this to the 0.1 EJ of electrical energy produced annually by man-made photovoltaics. Closing this gap is the key to a sustainable energy future, and unlike nature we don’t have the luxury of waiting billions of years to get there.