The contracts cover five sites located in Hawaii and California and include one of the world’s largest ever solar-plus-storage project portfolios.

The combination of energy storage and solar photovoltaic (PV) resources will provide essential grid reliability to balance an increasing mix of renewable generation.

The portfolio includes the Daggett 2 and Daggett 3 projects, which taken together represent one of the largest co-located photovoltaic plus storage facilities in California, at 482MWac of solar PV and 275MWac/1.1GWh of energy storage. The Daggett projects are in San Bernardino, California, adjacent to the site of a retired coal and natural gas plant.

The AC-coupled energy storage systems will deliver renewable energy during increasingly volatile peak periods and help the state reach its goal of 100% carbon-free electricity by 2045.

Construction has commenced on both projects with expected completion dates in 2023.

Two projects, comprising 75 MWac/300MWh (megawatt-hour) of energy storage, are also being installed at Clearway Energy Group’s Mililani I Solar and Waiawa Solar Power facilities on the Island of Oahu in Hawaii.

“The US is a bellwether for the global energy transition and projects like these demonstrate that decarbonisation is possible on a grand scale anywhere in the world. Energy storage as a flexible balancing power asset is an essential component for a 100% renewable energy future,” enthused Håkan Agnevall, President and CEO, Wärtsilä.

“We are very proud and grateful for being awarded these significant projects, which are major indicators of Wärtsilä’s position as a leading provider of global flexibility solutions for the clean energy transition. We focus on power system optimisation and the integration of different generating assets, providing our customers with the highest reliability at the lowest overall energy cost.

“Across the globe, we have been delivering energy storage systems at increasing scope and scale to help our customers meet their decarbonisation goals.”

The US has ambitions to lead the world in the adoption of clean energy, with a target to achieve a more than 50% reduction in net greenhouse gas (GHG) pollution by 2030.

The Wärtsilä and Clearway projects demonstrate the vital role that solar and storage will play in delivering these targets, and accelerating the transition, by creating low-cost clean energy at scale.

Na Pali Coast, Kauai

For example, the addition of energy storage will help Clearway Energy Group ensure reliable delivery of sustainable energy and contribute to Hawaii’s goal of reaching 100% renewable energy generation by 2045. The projects are Wärtsilä’s first large-scale energy storage systems in Hawaii; construction is expected to finalise in 2022.

A fifth project in the portfolio is for a 147MWac/588 MWh energy storage system that will be connected to the operating 192MWac Rosamond Central solar PV facility in Kern County, California. The energy storage system will increase the effectiveness of the solar facility by performing ancillary services, primarily solar shifting, for the California Independent System Operator.