Friday, August 10, 2012

Could flowing liquid batteries be key to a renewable grid?

Aaron Shinkle, a graduate student in the group of professor Charles Monroe, prepares a liquid battery test cell. Photos by Joseph Xu, College of Engineering Communications.

So-called flow batteries could be the answer to storing solar, wind, and other renewable energy on the scale that power companies need, but it will take engineers and scientists to get them to that level.

“People say they’re putting a solar panel on their house,” said Charles Monroe, professor of chemical engineering. “They don’t say they’re putting a gigantic battery in their attic.”

But if homeowners want to get the most out of those solar panels, they had better install a means to store the energy they harvest. And that’s just the small version of the problem – as renewable energy sources integrate with the grid on a large scale, batteries fit for power stations are a crucial piece of the puzzle.

With current lithium-ion technology, batteries the size of semi-truck trailers can hold 500 kilowatt hours (kWh) – or enough to power about fifteen US houses for a day. Unfortunately, they degrade somewhat with each recharge and survive for only about a thousand recharges. In order to develop batteries that can hold as much energy as lithium-ion designs and also last for many years, Monroe’s team has joined forces with that of Levi Thompson, a fellow professor of chemical engineering.