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The Coming Storage Boom: Project Proposals Nearly Double California's Storage Target

California storage boom future

California’s push to transform the market for grid-scale energy storage is working even better than expected — at least on paper.

Last year, California created a mandate calling for 1,325 megawatts of energy storage projects by 2020, to be scaled up every two years. The first installment of proposals due this year adds up to 200 megawatts.

As of mid-2014, more than 2,000 megawatts of energy storage projects have applied to interconnect with the state’s grid, according to recent data from state grid operator California ISO (PDF). In other words, project developers have received the market signal of a 1.3-gigawatt mandate and proposed enough storage to provide nearly double that amount over the coming years.

The list includes 1,669 megawatts of standalone battery storage, 44 megawatts of other standalone storage, 255 megawatts of batteries combined with generation projects, and a 90-megawatt project combining solar and batteries. They are all seeking interconnection under the initiative’s “Cluster 7” window, which closed on April 30, 2014. (A project-by-project breakdown of all the applications is available in PDF.)

What’s more, CAISO only tracks projects seeking interconnection to the high-voltage transmission grid, said Heather Sanders, the grid operator’s director of smart grid technologies and strategy, at last week’s Intersolar conference. That leaves out all the distribution-grid-connected and customer-sited storage systems, which make up a combined 875 megawatts of the state’s 1.3-gigawatt target.

However, just because a storage project is in the queue doesn’t mean it will be built, Sanders noted. (We’ve seen the same thing in solar in the past.) At this point, proposals don’t even require any money from the applicants. That step will come only after a first-phase study to determine the costs of individual projects.

Sanders compared the present storage rush to the early days of California’s renewable portfolio standard, when wind and solar power interconnection requests added up to enough projects to supply three times the mandate’s needs. Still, it’s certainly a sign that the storage mandate has provided a massive boost in interest from developers.

It’s also a challenge for CAISO and the other state agencies tasked with coming up with ways to value storage, she noted. One challenge is coming up with rules for a resource that both absorbs and discharges electricity, unlike traditional generation resources that only produce power, she said. That may sound like a simple problem to solve, but it will actually require significant reworking of the regulations for valuing both sides of the equation.

CAISO is also working on fitting energy storage into its new rules for flexible, multi-hour grid resources to help it manage the so-called duck curve problem. That’s the situation increasingly occurring on California’s grid, when lots of distributed solar generation pushes midday energy use way down, then fades away just as a steep rise in evening energy usage sets in.

How many hours of continuous ramp should these flexible resources provide? And should smaller-scale storage be aggregated into larger blocks for multi-hour availability? Those are some of the questions being asked in this process, she said. Energy storage paired with solar and wind power accounts for a growing portion of the capacity now being proposed, which further complicates how it should be treated.

Finally, CAISO isn’t ruling out the potential for distribution-grid-connected, or even customer-sited, energy storage to play a role in grid markets and programs. That brings the state’s utilities into the picture, as well as customer-owned systems being installed under the state’s Self-Generation Incentive Program.

Indeed, the complications involved in pulling distributed, independently owned assets into grid markets make the matter of transmission-connected storage seem simple by contrast.

Photo Credit: California Storage Boom/shutterstock

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Jeff St. John's picture

Thank Jeff for the Post!

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Thomas Garven's picture
Thomas Garven on Jul 24, 2014 2:35 pm GMT

Well what can I say other than its a good start.  Today the CAISO [Southern California Grid] is planned to peak out at about 41,000 MW so even if all of the projected projects were build we would be a LONG WAY from todays peak.  But did I mention that at least this was a good start.

However, it would have covered much of the 8,000 MW of renewables generated yesterday which again – is a good thing.  Please notice I have not mentioned costs, LOL.  

Have a great day everyone.  


John NIchols's picture
John NIchols on Jul 24, 2014 7:28 pm GMT

It’s also a challenge for CAISO and the other state agencies tasked with coming up with ways to value storage, she noted  Translation – We need to figure out who we are going to fleece for the subsidies, so that the numbers work for the promoters, as we proceed with the next boondoggle. 

Nathan Wilson's picture
Nathan Wilson on Jul 25, 2014 6:57 am GMT

There seems to be a common idea floating around that energy storage, especially batteries, are a new technology, and if we just incentivize the first round of deployments, costs will fall, and the rest will pay for themselves.

Well, batteries are actually made in huge volumes already,  tens of millions of cells per year, for the US market alone.   And for grid-scale applications, they are still an order of magnitude away from being cost effective.

Robert Bernal's picture
Robert Bernal on Jul 27, 2014 11:25 pm GMT

Money (partially from a carbon tax) needs to be put into pure scientific research into how to employ whatever best nuclear for making clean liquid fuels and/or molten salt (heat) storage in the safest possible manner (i.e, smaller reactors at sea?) and at the lowest possible costs (factory built and standardized deployment). At the same time we need to remove any non-intrinsic barriers immediately, such as non scientific, anti-nuclear and anti-industrial legistlative measures which impede this obvious step UP from excess CO2.

Imagine the many TWh of storage that would be needed to back the renwables if it wasn’t for fossil fuels, especially, without global grids and during long “lulls”!

If just one large country would do this, then it is most probable that many others (except unfortunately, the U.S. and Germany) would follow suit.

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