Here’s the latest action we’re following today on the GreenBeat:

Solyndra star fades, admits to mistakes — Once-bright rooftop solar startup Solyndra (pictured) has had its share of troubles lately. After raising $1 billion, the company was forced to slash costs, close a factory and cancel an IPO. Now its $535 million loan guarantee from the Department of Energy is under investigation by Congress. Its recent $75 million secured debt round forced several equity investors to convert their preferred equity into common stock, devaluing their holdings, according to VentureWire. Those investors were rushed into the round by the DOE to show the company still has investor support (and thus justify the loan), the article says, citing a source. Solyndra CEO Brian Harrison told the Wall Street Journal the company made the twin mistakes of expecting too much growth and not putting enough focus on market development.

Khosla says new biofuels IPO coming — Billionaire venture capitalist Vinod Khosla’s Khosla Ventures has seen its investments in biofuels startups Amyris and Gevo result in public offerings in the past few months, and Khosla apparently expects one more to happen in the next four weeks or so, according to a transcript of a talk he gave at a recent conference. Earth2Tech bets the IPO will come from either KiOR or Coskata.

BMW wants to sell 30,000 electric cars a year — The luxury automaker recently launched an eco-friendly sub-brand of cars, which includes the i3 all-electric city car and the i8 plug-in hybrid sports car. The company plans to launch the i3 in 2013 and wants to sell 30,000 of the cars a year by 2014, Autoblog Green reports. Germany has been fretting about falling behind in the global automotive space as major players like Nissan and Chevrolet have moved to launch electric cars, according to the WSJ.

U.S. solar growth dependent on fundraising –– The U.S. solar industry could double its installations this year thanks to the economic recovery and momentum from the previous year, but a Reuters analysis found that solar’s reliance on subsidies could make investors wary. While panel costs continue to decline, the viability of government support for subsidies remains in question. Still, investors seem to have a healthy appetite for large solar projects. The current tax equity market is not sufficient for demand from solar project developers in need of financing. The industry would likely need to raise about $10 billion to reach forecasted supply of 1.6 gigawatts this year.

Samsung to develop electric car batteries for U.S. market — The Korean electronics manufacturer will develop advanced batteries for electric cars through a joint development partnership with the U.S. Advanced Battery Consortium, which consists of GM, Ford and Chrysler. The company expects its electric vehicle battery sales to expand through the venture and expects to put in half of the $8.4 million needed for the project.