Renewable energy sources, while free of emissions, also has environmental limitations, meaning energy storage is more important.
Renewable energy generation continues to expand, from residential solar power installations to off-shore wind power, to the point where some locations could even eliminate their dependency on fossil fuels, if not for one little problem. Of course, I’m talking about intermittency, which prevents most renewable energy sources from permanently replacing fossil fuels. While fossil fuels burn any time of day, the wind doesn’t always blow, the sun doesn’t always shine, and rain doesn’t always fall, so some kind of backup power is needed.
Right now, Washington State is experimenting with different kinds of backup power for its expanding renewable energy industry, specifically wind power installations, providing some $14 million in grant money for different companies to work out the best path forward. Snohomish County Public Utility District One, which already has smart grid grant money in the works, has received about half the grant money this time around, is developing grid-scale lithium-ion battery and vanadium flow battery systems.
The vanadium flow battery, developed by UET, using technology developed by the Pacific Northwest National Laboratory (PNNL), has at least a couple of advantages over lithium-ion battery technology. The liquid electrolytes are stored in separate tanks, only interacting with each other, via the cell membrane, to release or take on a charge. Otherwise, the battery can hold its charge far longer than lithium-ion, which makes it a good candidate for grid-scale renewable energy backup energy storage, as long as a good US source of vanadium can be found, that is. When the wind stops blowing, the batteries kick in to provide enough power to keep things going.
Image © PNNL