US-based wind power firm General Compression has raised a further $5.5m, bringing its series B round to $60m, according to a filing made with the Securities and Exchanges Commission on the 2nd of September. Among the backers was the US-based nuclear energy company Duke Energy.
General Compression closed the $54.5m first tranche of its series B round in June, led by private investment company Northwater Capital Management, with Duke, investment firm US Renewables Group (USRG) and venture capital fund Serious Change also participating.
Duke, Northwater and USRG all previously invested in General Compression’s series A round, which closed at $20.9m, in May 2010.
Founded in 2006, General Compression’s wind power system works by storing compressed air underground and releasing it at times when wind dies down, ensuring a steady flow of power.
Equity from the round will be used by General Compression to expand its operations, which is currently constructing a pilot project in Texas in conjunction with energy conglomerate ConocoPhillips, with which it signed a strategic agreement in April 2010.