Auto manufacturing plants may not come to mind when you think about environmentally-friendly buildings, but GM is trying to change that. The company's new Lansing, Michigan facility is the first auto plant to receive a gold certification from the U.S. Green Building Council's Leadership in Energy and Environmental Design program.

By using recycled materials, turning off lights where robots are the only workers, and collecting rainwater for flushing toilets, GM expects to save 20 percent on its construction and energy costs.

The auto industry, which has received plenty of valid criticism for only improving fuel economy and reducing emissions when forced to by the government, is trying hard to convince consumers that they do care about their footprint.

In Ford's 2005 sustainability report, CEO Bill Ford wrote:

"We have made sustainability a long-term strategic business priority. The reason is simple: we are a 100-year-old company, and we want to become a 200-year-old company. Sustainability is about ensuring that our business is innovative, competitive and profitable in a world that is facing major environmental and social changes."

Of course saving $1 million per year, as GM expects, is motivation enough to be energy efficient. It is much easier to justify constructing green buildings, but hopefully more industrial heavyweights will consider retrofitting existing plants to save with energy efficient devices.