4 ways to store sunlight

Renewables are going to need a lot of backup. Low-carbon storage technologies could be the answer.

On the Catalyst with Shayle Kann podcast this week:

The good news: The U.S. has about 47 days’ worth of energy stored up for later use. The bad news? Virtually all of it is in the form of fossil fuels: coal, oil and natural gas. By comparison, if you add up all the energy stored in batteries, pumped hydropower and other zero-carbon storage, it might amount to just a few seconds’ worth, if that.

The small scale of zero-carbon energy storage is a big problem. We’re building out intermittent renewables quickly, and we need enough energy storage to back up wind when turbines slow down and solar when the sun isn’t shining. 

But there are technologies that could get us there. In this episode, Shayle talks to his colleague Andy Lubershane, who is a partner and head of research at Energy Impact Partners. Andy recently wrote a piece called Four ways to store sunlight, which compares lithium-ion batteries, heat storage, iron-air batteries and hydrogen. Andy and Shayle cover topics including:

  • The storage trifecta: short-duration, diurnal and multiday seasonal.

  • Andy’s guess at how low the price of lithium-ion batteries could go.

  • The benefits of using heat storage and hydrogen despite their low round-trip efficiencies.

  • Why molten-salt heat storage didn’t take off.

  • High hopes for iron-air batteries’ low costs.

  • Blending hydrogen into gas turbines.

  • How all these technologies are competing against carbon capture and storage.

Recommended resources:

Catalyst is a co-production of Post Script Media and Canary Media.

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