The Imperial Irrigation District’s (IID) board has approved a $235 million overhaul of the Unit 4 generator at California’s El Centro Generating Station, replacing a steam turbine in operation since 1968 with six natural-gas reciprocating engines.
The engine replacement is designed to boost capacity, improve reliability and cut long-term maintenance costs. The IID says the station’s current boiler, at 55 years old, is neither reliable nor designed to support renewable integration and grid resiliency.
The new generating units will be built on IID-owned property about 1,100 feet south of the current boiler building, west of Dogwood Avenue and north of Commercial Avenue. Electricity produced by the units will connect to the grid through the El Centro Switching Station. Each unit will measure roughly 24 feet wide, 211 feet long and 18 feet high, with exhaust stacks expected to reach about 120 feet and possibly share a single shroud structure.
The project is a major component within the district’s “Powering Our Community Together” initiative—an investment into more than 270 projects over the next 15 years focused on providing dependable, cost-effective power to its communities through infrastructure modernization. With a total price tag estimated at $235 million, the El Centro Generating Station project is expected to deliver an annual investment return of $12 million, eliminate some $60 million in future maintenance costs and save $5 million each year if the IID joins the Energy Imbalance Market.
Funding for the project will draw from IID’s electric system capital improvement plan, supplemented by internal reserves and debt financing rather than relying on rate increases or outside grants. By structuring the investment around expected operational savings and revenue gains, IID intends to recoup its outlay by avoiding long-term costs and improving asset performance. The utility emphasizes that the anticipated $12 million in annual return helps offset the upfront cost.
The construction phase is expected to span roughly 24 to 26 months. Work will include extending subsurface natural gas lines from the existing boiler building to the new site and removing obsolete structures as needed. The area will be cleared and graded to the proper contour, followed by excavation and boring to establish building foundations. Crews will also trench for fuel, electrical and water utilities, and may construct supporting facilities for equipment storage, maintenance and administration.
Officials say once commercial operation begins in June 2026, the six reciprocating internal combustion engine generators will produce 113 megawatts (MW) of fast-start capacity, increasing energy production by 39 MW. The additional generation will be enough power to energize 39,000 more homes with a reduced risk of outages.
IID serves as a key public power provider in the region, serving about 166,000 electric meters across the Imperial and Coachella Valleys and parts of Riverside and San Diego. This investment marks a major step toward modernizing the grid and meeting future energy demands in the region.
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