Here’s a roundup of some of the day’s most interesting cleantech activity:

NRG invests big in solar — The power plant company announced yesterday a $450 million solar ranch in California with SunPower, and in October it said it would invest $300 million in the 392-megawatt Ivanpah solar thermal plant that BrightSource Energy is building in the Mojave Desert of California. The company’s recent moves reflect an overall optimism about solar in the U.S., Earth2Tech writes.

GM to hire 1,000 EV engineers — General Motors said it’s making 1,000 hires to boost its electric vehicle line. CEO Dan Akerson said the company wants to lead the industry in adopting vehicle electrification technologies. Its range extender, the Chevrolet Volt, is now on sale and recently won Motor Trend’s car of the year. With Chevy’s recent pledge to spend $40 million on green projects to offset carbon emissions, it looks like the new GM wants to appear pretty green.

Tool maker spends $150M to enter solar market — Hydraulic and electrical tools manufacturer Actuant is buying Mastervolt, which makes power electronics that are used in photovoltaics. The $150M deal will allow Wisconsin-based Actuant to expand into the solar market, Reuters reports.

ABB to buy Baldor Electronics in energy-efficiency push — The Swiss engineering company is buying the industrial motor firm to bolster its North American operations. Industrial motors are responsible for 25 percent of all energy generated, Reuters writes, so the purchase gives ABB a chance to jump on energy efficiency opportunities. ABB has also made big smart grid moves in the past.

Germany hooked on solar tarriffs — According to an analysis by Greentech Media, politicians may shy away from making further cuts in solar subsidies because there are so many green jobs in the country. Germany has fueled nearly half of the world’s solar growth through feed-in tarriffs, but has pared them down recently, worrying industry watchers.