Will Pumped Hydro Energy Storage Really Get The US To More Wind & Solar?

May 25th, 2019 by Tina Casey

For all the whiz-bang cutting edge developments in new battery technology, good old fashioned pumped storage hydropower is still the number one bulk energy storage system currently available in the US. The big question is how to deploy pumped hydro in ways that funnel more wind and solar power into the US grid — and guess what, the US Department of Energy is on it. No, really!

US Energy Department Hearts Water Batteries

For those of you new to the topic, pumped hydro energy storage is exactly what it says: you pump water uphill to one reservoir. Ideally that happens when you have excess energy available to run your pumps, like at night.

Basically what you’ve done is create a gigantic “water battery.” When you need more electricity to meet peak daytime demand, you let the water flow downhill to a hydropower station.

Pumped storage hydro is already a thing in the US. According to the National Hydropower Association, pumped hydro accounts for about 97% of utility-scale energy storage in the US.

That probably explains why the US Department of Energy is all over pumped hydro like white on rice. In the latest development, last month the agency announced a new round of $7.5 million in funding for innovative approaches to hydropower development that include pumped hydro.

GE Tapped For New Pumped Hydro Energy Storage Research

One of the pumped hydro awardees was GE, through a partnership between its Research and Energy Consulting arms.

The team won $1.25 million in funding to conduct an 18-month study aimed at assessing how pumped hydro can “enable higher penetrations of renewable energy” into the nation’s grid.

Do tell! If you’re thinking that’s a rather odd assignment considering how much energy the White House is pumping into preserving US coal jobs, join the club.

Nevertheless, the Energy Department has been pitching wind and solar energy hand over fist along with all sorts of hydropower. In addition, GE has some new pumped hydro technology up its sleeve.

Energy Storage Under The Microscope

Until the recent drop-off in wind and solar costs, the Energy Department’s vision of grid optimization through pumped hydro was so much pie in the sky. Pumped hydro does account for almost all of the utility-scale storage in the US, but the Federal Energy Regulatory Commission only lists 24 projects currently in operation, and a lot of those first started pumping decades ago.

The low low cost of renewable energy has changed the game, and more pumped hydro projects are now in the works.

Renewable energy critics may complain that the intermittent nature of wind and solar are handicaps, but pumped hydro energy storage turns a liability into a benefit.

Here’s the explainer from GE:

When paired with a wind and/or solar farm, the idea is that you could utilize excess power generated from these renewable installations to drive a pump that pushes water up into the PSH reservoir. Once in the reservoir, this energy can be released whenever it is needed most to supplement a grid’s overall power needs.

Thank you Captain Obvious, but the devil is in the details. GE still has to come up with a science-based accounting of the potential for reducing costs.

Power Systems Engineer Yazhou Jiang, the project leader from GE, describes the challenge:

For this study, we will examine just how viable PSH [pumped storage hydro] could be as a long-term solution. One of the factors we will examine very closely is how quickly it can be activated to respond to rapidly changing power loads and highly variable renewables.

Got all that? The basic idea is to see if and how modern pumped hydro technology can respond quickly and efficiently to the more nimble, renewables-integrated grid of today.

What About Renewable Hydrogen?

Yes, what about it? “Splitting” water is another interesting pathway for storing renewable energy. If you take apart H2O molecules with an electrical current supplied by wind or solar power, suddenly you have renewable hydrogen gas.

That’s a big development. Hydrogen is commonly used in industrial processes, including food processing, but the primary source for hydrogen today is fossil natural gas. Yikes!

So, what are the opportunities for merging pumped hydro energy storage with, wind, solar, and renewable hydrogen production?

Good question! If you have an answer, drop us a note in the comment thread.

Meanwhile, CleanTechnica has reached out to GE to see if renewable hydrogen is one of the angles they’re considering for the new pumped hydro study, so stay tuned.

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Photo: Pumped hydro energy storage via National Hydropower Association.









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