BrightSource Energy, a clean-energy producer formerly known as Luz II, has raised $89.6m of a planned $100m series E round.
According to a regulatory filing, the money has so far come from 28 investors after advice from Advanced Equities.
Last year, BrightSource raised $176m in its D round from power equipment maker Alstom, the California State Teachers Retirement System and venture capital firms Draper Fisher Jurvetson and VantagePoint Venture Partners and investment bank Morgan Stanley (which was reported to be working on its planned flotation alongside peer Goldman Sachs).
Alstom provided $55m of the series D round to BrightSource as a new investor, its first move into solar power.
BrightSource had previously raised more than $160m, according to company figures and news provider VentureWire.
These previous investors have included Google.org, BP Alternative Energy, StatoilHydro Venture and Black River, which invested in the $115m series B round in May 2008, and Chevron Technology Ventures, Morgan Stanley, DBL Investors (formerly a subsidiary of JP Morgan) and venture capital firms Draper Fisher Jurvetson and VantagePoint Venture Partners that invested in the early-2007 series A round.
The company has also gained a $1.37bn loan guarantee through the US Department of Energy in February last year to help finance its Ivanpah Solar Electric Generating System.