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Traditional Hawaiian blessing as construction of solar PV plants with 300MWh battery storage begins

Power purchase agreements with initial terms of 20 years were signed with utility Hawaiian Electric for the two projects in 2018. Image: Clearway Energy Group.

Construction of two large-scale solar-plus-storage projects has begun on the Hawaiian island of O’ahu, totalling 76MW of solar PV and 300MWh of battery storage, by Clearway Energy Group.

Clearway, a developer, owner and operator of renewable energy assets around the US and in the portfolio of independent infrastructure fund manager Global Infrastructure Partners said last week that ground was broken on its Mililani I Solar and Waiawa Solar Power projects after a traditional Hawaiian blessing. Construction is expected to be complete in 2022.

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The company signed 20-year initial term power purchase agreements (PPAs) for the two power plants with the state’s main utility, Hawaiian Electric Company (HECO) in 2018. Mililani I will have 39MW PV capacity and a 39MW / 156MWh battery energy storage system (BESS) and Waiawa 36MW of PV paired with a 36MW / 144MWh BESS according to documents filed with the Hawaiian Public Utilities Commission.

The power plants will continue the trend of renewable assets — and increasingly hybrid resources pairing renewables with batteries — to help to reduce the island state’s reliance on expensive imported fossil fuels which can fluctuate in price, while reducing greenhouse gas (GHG) emissions and assisting Hawaii to reach its goal of achieving 100% renewable energy by 2045.

“Our ongoing focus on renewable energy in the State of Hawai‘i is key to rebuilding our local economy and improving energy reliability for a more resilient future,” state governor David Ige said.

“Thanks to Clearway and our partners, we can celebrate this major milestone together as we take another step toward our goal of 100% renewable energy by 2045.”

Clearway said the two projects represent a combined US$280 million investment and after creating more than 460 local union jobs during construction will contribute in excess of US$10 million in taxes. Construction activities are being led by Moss Solar, the solar division of infrastructure project group Moss.

Moss Solar and Clearway have already worked together on three large-scale solar projects on O’ahu totalling 110MW that were originally proposed by developer SunEdison before it went into bankruptcy. PPA deal terms were renegotiated by Clearway with HECO at a lower price and the projects went ahead, with completion of all three announced in September 2019. The project partners teamed up with the O’ahu Kamehama Schools district on those projects and have done so again for the two new ones.

As construction began last week, HECO president and CEO Scott Seu said that Clearway's existing three projects had helped the utility achieve its 2020 renewable portfolio standard (RPS) of 35%. “Additional large projects with storage like these will help us continue to decarbonise our energy system by reducing our dependence on imported fossil fuels,” Seu said. 

Last year HECO undertook a massive renewable energy tender process, resulting in the utility submitting contracts from an auction process seeking up to 460MW / 3GWh of resources on the islands of Maui and O’ahu. The awarded contracts include a mix of solar, solar-plus-storage and standalone energy storage. The process was delayed by the COVID pandemic, but HECO began announcing winning bids in mid-2020, with developers including ENGIE EPS, Plus Power, AES Distributed Energy and HECO itself among those awarded projects.

Also on O’ahu, in September 2020, developer 174 Power Global, a subsidiary of Hanwha Group, signed a US$185 million contract for a 60MW PV plant with 240MWh of energy storage from which power will be sold to HECO under a 20-year PPA. In other recent news, HECO signed a deal with residential virtual power plant (VPP) developer Swell Energy to deploy 25MW of solar on customer rooftops paired with 80MW of home batteries across O’ahu, Maui and Hawaii Island to provide capacity to the network and absorb surplus wind and solar generation as well as providing frequency response grid services.

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