Fundings

State governments led the nation's initial responses to the challenge of energy system transformation a decade ago and since then have developed a broad array of cleantech development tools, ranging from financial support tools and net metering to incubators, cluster supports, and workforce training.

Companies more than doubled their investments in mergers and acquisitions in 2011.

Renewable energy investment rose 5 percent to $260 billion in 2011, following 31 percent growth in 2010 and 1 percent in 2009.

Warren Buffett’s energy company, MidAmerican Energy Holdings Co., made a strong push into solar this past December.

Year-to-date through Q3 2011, U.S. clean tech investments rose by 73% to $1.1 billion, as compared to the same period last year.

Private equity firm Warburg Pincus has agreed to provide up to $355 million to investment company First Green Partners.

Google is spending $94 million and teaming up with KKR to develop four solar energy farms.

Energy supplier NextEra Energy Resources’ Golden Winds LLC has raised $131 million from JPMorgan Chase.

U.S. developers added 449.2 megawatts of solar power in the third quarter. That’s up 140 percent from the 187.3 megawatts in the same quarter last year.

U.S. clean tech start-up companies and large energy companies alike are forming partnerships with Chinese firms.