The u.s. just hit a major milestone for energy storage — which is also great news for solar – the washington post electricity per kwh

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The finding, by the research firm GTM Research and the industry trade group the Energy Storage Association, predicts sharp growth in an industry that was barely on the radar a few years ago. Much of the subsequent growth has been inside homes but also at the scale of the electric grid, where batteries can help power companies decide when to deploy their growing store of electricity generated from renewable sources such as solar.

The new report finds that installations of energy storage — overwhelmingly dominated by lithium ion batteries — grew 27 percent to 431 megawatt hours in 2017. But the growth is expected to be more than double in 2018, up to 1,233 megawatt hours (or 1.233 gigawatt hours), the group predicts.

A gigawatt hour in this context refers to the ability to store or discharge 1 billion watts for the period of one hour. That could be accomplished by installations that store energy for only an hour, but also by installations that store or release a half-billion watts but do so for two hours, or a quarter-billion watts for four hours — and so on. Batteries vary in how much power they are able to discharge at one time, and on how much energy they are able to store.

The enthusiasm is reflected by Tesla, a major battery manufacturer that announced a home storage system, the Powerwall, in 2015. The company said in its latest earnings announcement that in 2018, “we aim to deploy at least three times the storage capacity we deployed in 2017.”

“The Holy Grail is essentially to be able to have this large-scale bulk energy storage that’s just moving energy, many megawatts across days or even weeks,” Hittinger said. “There would be dozens or hundreds of gigawatt hours of market there, but only if somebody can deliver it for maybe $100 a kilowatt hour or so.”

California has been at the center of this activity, thanks to the Self-Generation Incentive Program, which provides rebates for customers to install storage in their homes (or businesses). Other states have also dived in, with Maryland recently launching a tax incentive for installing energy storage systems.

Large businesses and institutions are also deploying storage assets. Because these consumers often get billed different rates depending on when they are using power, having storage lets them lower their costs by shifting usage around in time, Manghani said.

“A lot of these systems that we are starting to see come online is utilities looking for not just renewable power, but renewable power during the peak hours,” Manghani said. The hours when power companies typically need to be able to provide the most electricity is in the evening, when people get home from work and start switching on all their gizmos — but that’s when the solar energy resource is fading or even gone.

“There are several of these [contracts] where the developer is deploying storage to store solar generation during the middle of the day and then dispatch these storage assets during evening hours, when the relative value of those electrons or those kilowatt hours is much higher in the evening hours,” Manghani said.

Still, at the scale of the entire U.S. electric grid, a gigawatt hour of energy storage is remains quite small. The United States has the capacity to generate more than 1,000 gigawatts of simultaneous electricity from all of its various types of power plants.

An older, more established technology, called hydroelectric pumped storage, also exists and has served the grid for some time. Here, water is pumped uphill behind a dam and then held there — and released when energy is needed. The United States has more than 20 gigawatts of pumped storage capacity.

President Trump’s solar tariffs could slow down the energy storage market, the new research finds, since energy storage is so frequently paired with solar and the tariffs are already expected to slow the pace of solar installation by raising prices. Raising the cost of solar panels also naturally raises the cost of paired solar-storage systems.

“It’s almost a bootstrapping process here, where the storage industry is going after these high-value, low-market-size opportunities for now, and that builds experience and brings down the cost, so that they can compete for somewhat larger markets that require a lower cost product,” Hittinger said. “And the game is to work down this cost curve.”