Photos: Wal-Mart meets alternative energy

To date, Wal-Mart Stores has been dabbling in renewable energy at a couple of "experimental stores." Now it's getting ready for a bigger push into solar power. The retail giant isn't saying much about the order, but one clean-tech consultant who has seen the RFP (request for proposal) says it could amount to some 100 megawatts of power over the next five years.

This picture shows solar panels already in place at the Wal-Mart experimental store in McKinney, Texas, which opened in July 2005. The store was set up to draw its energy first from on-site resources and systems, and then after that from conventional utility sources. The other experimental store, in Aurora, Colo., opened later that year.