|Oct 07, 2019

Key milestone towards World’s largest “Solar-after-Sunset” project in Guam

Key milestone towards

World’s largest “Solar-after-Sunset” project in Guam


  • 100% “Solar-after-Sunset” with batteries storing the entire daily solar production to supply green power in the evening to Guam Power Authority’s customers
  • 300 MWh of storage, more than twice the size of the largest lithium battery currently operating in the world, to be provided by ENGIE EPS
  • estimated 1.2 million tons of CO2 to be avoided over systems’ lifetime
  • 30% reduction in electricity generation cost expected against current fuel surcharge rate, mainly reliant on fossil fuels

Paris – Milan, 7 October 2019 –  ENGIE EPS has been informed that the Power Authority of Guam, a U.S. territory in the Western Pacific, has selected ENGIE as successful bidder for the construction of two Solar-plus-Storage projects under a 20-year power purchase agreement, in the context of Phase III of the “Renewable Energy Resource” program. The Guam Power Authority (GPA) is now considering ENGIE, the lowest bidder amongst those qualified in the competitive tender process, for contract award.

The two “Solar-after-Sunset” systems proposed by ENGIE integrate more than 50 MWp of solar PV with approx. 300 MWh of battery energy storage to render 100% of the daily solar production available for up to 7 hours after sunset.

ENGIE EPS will supply the innovative battery storage design and act as full energy storage solution provider and system integrator, supported by its strategic partner Samsung SDI.

Carlalberto Guglielminotti, Chief Executive Officer at ENGIE EPS commented “We are proud to contribute to Guam Power Authority’s pioneering vision. This is an iconic project which sets a paradigm shift for the zero-carbon transition: ENGIE EPS’s technological edge makes it now possible to provide solar power at night cheaper than conventional generation”.

The project is scheduled to be online in July 2022 to deliver over 85 GWh of clean dispatchable energy annually, in line with the island’s target of sourcing over 25% of energy from renewables.

ENGIE will now work with GPA to obtain the approvals for the 20-year power purchase agreement by the Consolidated Commission on Utilities and the Guam Public Utilities Commission. Formal award is expected by GPA after this process is completed and at the end of the regulatory recourse period.


Key milestone towards World’s largest “Solar-after-Sunset” project in Guam

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