EDP Renewables, SRP Bring 200 MW / 800 MWh Flatland Battery Online

EDP Renewables North America and Salt River Project (SRP) commissioned the 200 MW / 800 MWh Flatland Energy Storage system in Coolidge, Arizona on June 9, 2026 — the largest single battery installation in EDP Group’s global portfolio and Arizona’s largest battery storage project to date. The four-hour lithium-ion system in Pinal County stores enough energy to power roughly 44,500 Arizona homes during periods of peak demand.

What Was Built

Flatland pairs 200 MW of power capacity with 800 MWh of energy storage, giving it a four-hour discharge duration — the configuration utilities increasingly favor for shifting midday solar output into the evening peak. The standalone system uses lithium-ion batteries manufactured in the United States by Tesla. SRP, the Phoenix-area public power utility, takes the output to firm capacity as Arizona load climbs with data center and residential growth. EDP Renewables North America now operates roughly 600 MW of solar and storage across Arizona.

Why It Matters

Arizona is one of the fastest-warming, fastest-growing load pockets in the West, and SRP has leaned on four-hour storage to cover summer evening peaks after solar drops off. At 800 MWh, Flatland is large enough to move the utility’s reserve margin during the hours that matter most. EDP says the project will inject more than $20 million into the local and regional economy over its operating life, including $19.2 million in direct tax revenue for public schools, roads, and emergency services in Pinal County, and that construction supported 142 jobs.

Critical Perspective

A four-hour battery is a peak-shifting asset, not a substitute for firm generation: once its 800 MWh is spent, Flatland recharges before it dispatches again. Its value to SRP hinges on a daily solar surplus to refill it and on how the utility stacks energy, capacity, and ancillary-service revenue against the project’s cost — figures neither partner disclosed. The larger question for Arizona is whether four-hour storage scales fast enough to keep pace with data-center load that runs around the clock, not just at the evening peak.

Sources

• Solar Power World — EDP Renewables commissions 200-MW standalone Arizona energy storage project
• pv magazine USA — EDPR, SRP commission 200 MW / 800 MWh Flatland battery storage project
• PR Newswire — EDP Renewables and SRP Celebrate Completion of 800 MWh Flatland Energy Storage

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