Grid-scale batteries are going to have to come in a lot of different packages and configurations if they’re to meet the needs of utilities, grid operators and distributed energy-equipped “prosumers.”And these new formats and functions are going to need to become more standardized to lower the costs and complexities of integrating them into the billion-dollar markets being projected for them.
Energy storage providers and partners are pushing to meet these needs, as we’ve been tracking in our ongoing coverage -- and the pace of innovation is accelerating, as indicated by some of the energy storage announcements we’ve spotted so far this week.
Built-in aggregation capability
One of the more valuable control features for distributed batteries is the ability to aggregate them into a single resource to help meet the large-scale energy and power needs of utilities and grid operators. On Tuesday, energy storage software startup Greensmith announced it’s supporting this kind of aggregation capability in its latest release.
The Rockville, Maryland-based startup is managing projects that range from a 20-megawatt system providing frequency regulation for grid operator PJM to 30-kilowatt behind-the-meter batteries in California, along with newer projects balancing intermittent solar power in Hawaii and Puerto Rico and a new 2-megawatt lithium-ion battery system for Duke Energy.
Greensmith also just raised $5 million from American Electric Power (AEP), a Midwestern utility that’s installed batteries at both the substation and neighborhood grid level. Its community energy storage pilot projects in Ohio didn’t yield sufficiently positive results to lead AEP to commercialize the concept, but Greensmith’s aggregation-ready feature could help the utility put the idea to the test in future projects.
Greensmith’s idea is to provide a control layer for an entire fleet of batteries to integrate them into utility or grid operator market communications system to participate in resource adequacy, frequency response, and other wholesale energy markets. It isn’t the first to attempt this, of course.
Behind-the-meter battery startup Stem has been pioneering the use of distributed storage as a grid market money-maker. It was the first to bid battery capacity into a California pilot project last year, and this month announced it’s bidding more storage capacity into Pacific Gas & Electric’s successor Supply-Side Pilot -- part of a broad array of distributed energy-grid integration experiments happening in the Golden State.
Some well-known solar-storage vendors like Sunverge and SolarCity are also aggregating smaller-scale batteries for grid needs. SolarCity’s new pilot with Southern California Edison is testing the waters, while Sunverge is working with New York utility Consolidated Edison, Ontario, Canada utility PowerStream, and the municipal utility of Glasgow, Kentucky to put together a virtual power plant under the control of Sunverge’s cloud software platform.
Younicos has been aggregating and controlling batteries of different makes and chemical compositions for the past several years, and now it’s coming out with a battery package of its own. On Tuesday, the deep-pocketed German startup launched its Y.Cube, which combines lithium-ion batteries with power conversion hardware in 250- to 500-kilovolt-amp packages.
Prepackaging allows for reduced space requirements and integration costs on the hardware side, and Younicos has embedded its control software in the power converter and battery systems, eliminating the need for additional communications interfaces. Younicos’ main claim to fame is its versatile and real-world-tested control system, which incorporates two dozen different operating modes for different functions that batteries can provide, from long-term solar power-shifting to fast-responding frequency regulation.
This isn’t the first battery system to come with built-in inverters or power converters -- it’s a pretty standard feature of behind-the-meter systems from Stem, Green Charge Networks and Gexpro, to name a few. But it represents a new move into hardware for Younicos, which has roughly 80 megawatts of storage projects under its control, much of it from its purchase of bankrupt startup Xtreme Power.
More utilities are going to be asking for this kind of pre-integration, however. This summer, Southern California Edison announced it was seeking “pre-engineered” storage systems that can be ordered, built, shipped and installed within seven months to meet its fast-changing distribution grid needs.
The state park as microgrid
Vermont utility Green Mountain Power has been making some significant solar-plus-storage efforts in the past year, including its Stafford Hill community microgrid project, its work with Tesla’s energy storage business, and now, its plan to create an “ePark” that runs on its own green power.
Working with the state parks department, GMP will install solar and Tesla Powerwall batteries at the Emerald Lake State Park, which is now supplied by a half-mile-long power line that runs through swamps and forest and which undergoes multiple outages per year. Building enough solar and storage to meet the park’s needs will actually cost about 20 percent less than replacing that line, GMP said in its press release, and cut out the $7,000 to $8,000 per year spent on repairing the current line after outages.
Using batteries to bolster capacity or delay replacement of remote or outage-prone power lines -- capital expenditure deferral, in utility parlance -- is one of the key business cases for energy-storage systems to date. But relatively few of these projects are seeking to do away with the need for grid-supplied power entirely with the implementation of a microgrid.
On the other hand, relatively few microgrids are meant to replace the grid all the time. A slew of new projects underway in New York, California, Hawaii, Texas, New Jersey and Massachusetts are integrating distributed energy resources into semi-autonomous islands of power, capable of backing themselves up during grid emergencies while providing a host of benefits to the grid when they’re still connected.