Utility Works to Unlock Smart-Grid Potential of Solar-Storage

It’s day six of the storm-induced power outage that has crippled much of the Eastern United States under unrelenting heat and painfully slow repairs. The unmistakable irony for more than 1 million people still without power on Thursday is that the sweltering sun that followed the brutal storms was tailor-made for rooftop PV with battery storage — a combination that keeps the lights on even in a blackout.

That certainly would have cooled some of the frustration of those sitting with air conditioners idle. The reality, though, is the areas hit hardest by the outages are not among the hottest markets in residential solar. And storage remains in its infancy for grid-tied systems. Across the globe, solar with storage is seen as commendable but not yet viable. Even those who understand the technology are often deterred by the cost, even though it gets around the challenges of intermittency.

But there’s work being done to learn more about the pairing of solar and storage, and how it would impact loads, integration and, ultimately, customers. During an outage, the benefits are obvious. But there are everyday benefits as well.

Earlier this year, Kyocera announced plans to introduce a residential solar-battery system in the Japanese market as early as this summer. The impetus was last summer’s energy shortage that followed the shutdown of nuclear reactors. The thinking was that some Japanese residents would be willing to pay a premium for solar-battery pairing. It remains to be seen whether solar plus storage will catch on in Japan.

Now, the Sacramento Municipal Utility District is launching its own effort to better understand the potential benefits of battery storage for its customers. The utility, considered to be among the leaders in renewable generation and integration, is rolling out an 18-month program in which 42 solar-powered households in a Rancho Cordova subdivision will be powered in part by lithium-ion batteries. Under the program, 15 homeowners will have batteries installed in their garage while 27 homes will share three larger batteries placed in common areas of the subdivision.

The batteries inside the homes are about the size of a mini-fridge and they can power a household for up to three hours, depending on load. The larger batteries hold about three times the capacity. SMUD is also using monitoring devices in the homes and on the batteries to get minute-by-minute information on when energy is being used.       

The project will help the utility better gauge how battery storage integrates with a smart grid. The utility’s grid operators will also be able monitor and manage the batteries individually or as a fleet. While the overriding goal is to assess the technology, SMUD is also interested to learn more about how storage impacts the monthly bill.

“The aim of the program is to learn whether or not batteries can ease load demand and provide more electricity when renewable energy sources such as solar and wind power aren’t sufficient,” said SMUD Assistant General Manager for Power Supply & Grid Operations Paul Lau. “The project will also help us better understand how battery storage and solar mesh with time-of-use rates, where customers pay more for electricity during peak hours and less during low-demand times. The batteries provide power during peak demand, so customers could save money by not drawing all their power from the grid during those hours.”

According to some reports, each of the smaller batteries costs about $25,000. The program itself costs $5.9 million, about $4.3 million of which comes from a Department of Energy grant.

Lead image: Candlelight via Shutterstock.

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Renewable Energy World's content team members help deliver the most comprehensive news coverage of the renewable energy industries. Based in the U.S., the UK, and South Africa, the team is comprised of editors from Clarion Energy's myriad of publications that cover the global energy industry.

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