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Home solar batteries in Hawaii to provide capacity, grid services through 80MW virtual power plant

Large-scale solar project on Oahu, Hawaii. For the contract with Swell Energy, utility Hawaiian Electric has gone down a different, more distributed route to meeting its energy needs. Image: Hawaiian Electric Companies.

Solar-plus-storage systems at customers’ homes in Hawaii will create a “comprehensive” virtual power plant (VPP) network on three Hawaiian islands of up to 6,000 individual systems.

Swell Energy, a California-headquartered provider of distributed energy storage systems for residential use and pairing with solar photovoltaics (PV), said that it is contracted with the US island state’s main electricity utility, Hawaiian Electric (HECO), to execute the project, which would pair more than 25MW of solar generation with 80MW of battery storage systems.

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The state’s regulator, the Hawaiian Public Utilities Commission (PUC), has approved the contract, Swell Energy said today. In a deal worth US$25 million, systems installed by Swell Energy will provide capacity to the local network when needed as well as perform grid services such as frequency response on the islands of Oahu, Maui and Hawaii.

The batteries will help absorb excess renewable energy generation on the local electricity network, reduce peak demand and provide fast frequency response – which helps to ‘balance’ the grid and keep it working smoothly even when large amounts of intermittent renewable generation are being injected into it – 24 hours a day. The solar-plus-storage systems will “dynamically” respond collectively to the needs of the grid, Swell Energy said.

Swell Energy described the commercial offering as a step beyond the many VPP pilot projects that have been seen in the US and elsewhere through utilities, and although it is fair to say that indeed the majority are still pilots, the Swell Energy-Hawaiian Electric deal is not the only one of its kind. To give just two other examples, the state of South Australia’s VPP programme has been up and running for some time while in the US, residential solar instal and leasing company Sunrun was recently awarded a 5MW contract by utility Southern California Edison to pool the capabilities of connected behind-the-meter (BTM) residential batteries. 

“Our islands have small, stand-alone grids with a high-level renewable generation, which makes them sensitive to supply and demand imbalances. This project is an important opportunity for Hawaiian Electric and Swell Energy to develop an innovative portfolio of customer-sited resources that meet a variety of grid requirements, while providing additional choices and benefits for our customers,” Hawaiian Electric customer energy resources co-director Yoh Kawanami said.

Hawaii is the US state with the most residential rooftop solar generation installed per capita of population and is marking similar trends in battery storage. The state’s renewable energy integration efforts are also extending to large-scale front-of-the-meter (FTM) solar-plus-storage and standalone energy storage facilities: HECO last year tendered for 460MW of solar and around 3GWh of battery storage, while another utility provider Kaua’i Island Utility Cooperative (KIUC) has very recently announced a solar-powered pumped hydroelectric project to be under development that would take Kaua’i island to more than 80% renewable energy when completed.

Swell Energy meanwhile said a few weeks ago that it had created a vehicle to put US$450 million in financing for a number of virtual power plant projects that it is in discussions with utilities and other energy suppliers in the US about, of which the project with HECO is one. At the time, in mid-December, Swell Energy said it had a pipeline of four VPP projects in three US states, aggregating 100MW of solar PV with 200MWh of battery capacity that could be completed by mid-2023.

This article has been amended 19 January to reflect that Swell Energy's financing vehicle has already been created and is being used to support the HECO project, rather than the company still seeking funding, as was originally implied. 

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