The Solar Energy Generating Systems (SEGS) facility in California’s Mojave Desert retired five of its solar plants (SEGS 3 through 7) in July 2021 and plans to retire a sixth (SEGS 8) in September 2021, based on information submitted to EIA and published in our Preliminary Electric Generator Inventory. After SEGS 8 is retired, only one solar thermal unit at SEGS will remain operating (SEGS 9). SEGS, which began operating in 1984, is the world’s longest-operating solar thermal power facility.