General Motors announced last week that it is looking at ways to reduce energy and water use, by turning to renewable energy at all of its manufacturing plants. The company also said it plans to make fifty percent of its 160 manufacturing operations landfill-free by the end of 2010.

With Earth Day happening this week, this announcement by GM is a wise move at exactly the right time. With GM struggling to rebound after getting hit hard by the economy and unpredictable fluctuations in the prices of gas, the carmaker is taking a proactive approach to being green.

GM is already a very solar-power friendly company– it’s plant in Zaragoza, Spain, has the world’s largest rooftop solar photovoltaic power installation. It covers about 2 million square feet of roof at the plant with about 85,000 solar panels. The company has two of the largest solar power installations in the United States–in Rancho Cucamonga and Fontana, California.

GM’s plants did metal scrap sales of more than $1 billion last year, and recycled 17,000 tons of wood, 20,000 tons of cardboard, and 4,000 tons of plastics