Walmart just recently announced to make their supply chain greener by 2015. They want to cut 20 million metric tons of green house gases and to do so, they have asked their supply chain to look for greener alternatives. This is great that big companies are starting to do this more and more. This may also help Walmarts bottom line and make them more profitable in the future. So Walmart has everything to gain from this.
Google has set its sites on developing a new technology that can cut energy consumption by half in a building using a new mirror technology. This new technology should be ready in about 3 years or sooner. The sun heat would heat this mirror material and create steam to run a turbine. Google is investing in 2 companies for this new technology. If this technology turns out to be feasable they could reduce green house gas by 2x.