At its inception more than 15 years ago, the Ivanpah solar power plant was envisioned as a facility that would bring advanced technology to help drive the transition to low-cost renewable energy sources. The US Department of Energy (DOE) and Ivanpah’s investors joined forces to build the world’s largest concentrating solar power (CSP) facility, in California’s Mojave Desert.
Ivanpah is a 386 MW solar concentrating thermal power plant consisting of three individual units (see photograph). It demonstrated that CSP technology was a viable and innovative renewable energy source, selling about two-thirds of the power it generates to the Pacific Gas and Electric Company (PG&E), and the rest to Southern California Edison (SCE), under purchase power agreements (PPAs) running until 2039.
Ivanpah proved to be a successful demonstration of CSP technology, however it has been surpassed by solar photovoltaics due to much lower capital and operating costs.
It is much more complicated than PV. Ivanpah, for example, on its 3500 acre site, employs no less than 173 500 heliostats, each with two mirrors, focused on boilers (Rentech type D) located atop three 140 m high towers, which provide steam to Siemens-supplied steam turbines.
One of the potential merits of CSP relative to PV is that it can include thermal energy storage as an inherent feature, however this was not the case for Ivanpah.
In accordance with regulatory requirements, in 2023 PG&E sought proposals for restructuring or terminating its renewable PPAs with Ivanpah to reduce the cost to its customers. In January 2025, Ivanpah’s owners and the DOE finalised negotiations with PG&E to terminate their two long-term purchase power agreements, allowing DOE to maximise the recovery of its loans and provide savings for California ratepayers.
Unit 2, contracted to SCE, is not covered under this agreement. But as of early March 2025 similar discussions were underway between SCE, the plant owners and DOE, with a view to buyout of the contract covering unit 2.
Regulatory approvals before the California Public Utility Commission (CPUC) and at the federal level are underway. When a final order is received, Ivanpah will begin the process of closing its units in early 2026 after more than ten years of providing renewable energy to two of California’s largest utilities.
Once deactivated the units will be decommissioned, providing an opportunity for the site to potentially be repurposed for PV electricity generation.
