The Solar Eclipse Provides a Rare Opportunity to Test Grid Storage

by Anna Gretz
August 21, 2017

On The Swell, we do a lot of talking about residential energy storage (because it’s awesome.) A recent post dove into the advantages of home batteries during events like the solar eclipse, but behind-the-meter storage isn’t the only kid of energy storage that has a chance to shine while the sun goes dark. Grid-scale storage is about to flex its muscles, and show everyone why energy storage, on every scale, is important to the future of energy.

Energy storage education is moving fast around the country and the wider world, but many people still don’t know about the superpowers of batteries. Energy storage technology has advanced so much in the recent years that it is now able to charge or discharge energy at any moment, making it exactly what the fragile power grid needs, especially in the case of a solar eclipse. The big problem? The projected path of darkness that marches from Oregon to South Carolina doesn’t have a whole lot of grid storage available. Stretch that path out to include the areas that will experience a 60 to 80 percent obscuring of the sun, however, and you’re going to hit some of the biggest solar plants in the nation… including some in California.

We stated before that CA plans to miss out on about 6,000 megawatts (MW) of solar power between 9 and noon the day of the eclipse, and they’re feeling good about the 3,000 MW of storage capacity they already have available, with more in the works. Because the eclipse will shine a spotlight on an impressive energy storage performance, many battery advocates are hoping the response will include an even greater increase of utility-scale battery installations around the country.

The power and flexibility of energy storage as a large-scale tool is going to be pretty hard to ignore, especially when evaluated next to the alternative--expensive, greenhouse-gas-pumping generators. Most of the areas that are about to experience capacity shortfalls will switch on gas generators to make up for the missing electrons, but there are additional disadvantages on top of the pollution and expense of this option. Big gas generators use huge metal turbines to churn out electricity, and they take a while to ramp up, as well as cool back down after additional electricity is no longer needed. This means that a lot of natural gas plants have a minimum amount of time that they have to run if you want to justify the cost of starting them up, and burning additional fuel. Even though the level of solar energy will catch up in the afternoon of the eclipse, the gas generators will have to keep running, while California throws away gigawatt hours of renewable electricity. Talk about painfully wasteful.

If only there was somewhere we could store all that energy, instead. Oh wait… there is. In fact, energy storage could enable the grid to avoid ramping up generators all together. Battery-stored energy can be deployed at a moment’s notice--way faster and more efficient than a generator. As California’s capacity stands, however, the state won’t be able to go generator-free… during this eclipse at least. But storage can soak up all of the extra solar as the sun comes back out in the afternoon, and be ready for use at the drop of a hat.

The eclipse is basically a perfect example of why we need energy storage… and it’s one of many. The solar eclipse is getting a lot of hype, but electricity supply and demand are always fluctuating, even on a normal day. Energy storage has the potential to strengthen and enhance our utility system 356 days a year.

“Being reliable, being dependable and continuing to build this reputation of being there when needed is really what comes out of this for the [energy storage] industry,” said Matt Roberts, VP of the Energy Storage Association. In other words, if energy storage keeps showing up and doing its job, it’s going to get more gigs in the future.

Lowering costs won’t hurt, either.

Everyone knew that the cost of energy storage was going to keep falling, but no one expected it to fall this fast. In fact, the predictions were so far off that a professor at UC Berkeley, Daniel Kammen, devised a new model to help predict the future cost of energy storage (and other technologies) more accurately. The new model takes into consideration the volume of production, as well as other factors that would impact cost, like patents issued. When you plug batteries into the new model, forecasts look strikingly different than previous predictions… in a good way.

If batteries want to be competitive with internal combustion engines, they need to hit between $125 and $165 per kilowatt-hour. The new prediction model projects that this will happen between 2017 and 2020… so, any day. Yeah, you heard that right. As far as solar energy storage goes, $1 per watt would make residential solar-plus-storage an economical option. Grid-scale, we’re already there. For home batteries, we can count on this happening within the next three years.

This is big news. The world of residential solar and energy storage is about to crash through the barrier of being a niche product for wealthy households, to being a cost-effective investment for pretty much anyone. We’re about to collectively change the way we think about, use, and store electricity.

Distributing the grid this way (scattering power sources and storage instead of having it all stem from one central plant) will strengthen our power system, and make it much more reliable. Solar eclipses, high winds, or other natural disasters will pose much less of a threat to the grid, and give us energy security like we have never seen before.