The company put out an RFP (request for proposal) last month to solar electric suppliers and expects to receive responses early this month, according to a representative. The move is part of a long-term plan to convert to renewable energy sources.
Wal-Mart is keeping the details of the proposal under wraps as the process is still ongoing.
However, one person who saw the proposal said that if completed, it could amount to a significantly large installation--on the order of 100 megawatts of power over the next five years.
"To put that into perspective, the solar system currently being installed at Google headquarters in California--the largest single corporate solar installation in history--is 1.6 MW, about 1/60th the size," wrote Joel Makower, a clean-technology consultant who saw the proposal but is not bidding on it.
Makower said the Wal-Mart proposal called for a system that could be replicated across its stores in five states and make use of available roofing space.
Wal-Mart has set up experimental stores in McKinney, Texas, and Aurora, Colo. These stores are already using renewable power sources, including solar and wind.
"We will continue to use the learnings from those stores to find ways to achieve our renewable energy goals in our other stores across the nation," said spokesman Kory Lundberg.
Corporations take a shine to solar
Although Wal-Mart's bid may not result in any investment, the move is significant as an indicator of growing corporate interest in sustainable practices and technologies.
Installing solar power is a well understood--and potentially visible--way to use renewable energy. Aided by government incentives such as tax breaks, solar electric systems are becoming more cost-effective as solar companies devise new technologies and target specific markets.
Google is using a flat-panel solar power system installed by a subsidiary of Energy Innovations, a company that specializes in solar systems for flat roofs like those found in office parks.
Microsoft, too, has gotten into the solar game. Last year, it equipped its Silicon Valley headquarters with more than 2,000 solar panels capable of generating 480 kilowatts at peak capacity.
Electronics manufacturer Sharp last year started operation of a plant in Kameyama, Japan, which is capable of generating 5.2 megawatts of power through solar photo voltaics.
Renewable energy is central to Wal-Mart's environmental efforts as well. The company has a vice president of corporate strategy and sustainability, Andy Ruben, and its corporate policy is to reduce its "carbon footprint" and greenhouse gas emissions.
Its three specific, long-term environmental goals are: using 100 percent renewable energy; creating zero waste and selling products from sustainable resources.
In a speech in October of last year, Wal-Mart president and CEO Lee Scott provided more detail on the company's short-term goals (click for PDF), including a commitment to invest $500 million a year in energy efficiency and technologies to reduce greenhouse gas emissions.
Scott said the company intends to reduce greenhouse gases from its retail locations around the world by 20 percent in the next seven years.
In the next four years, he said the company is working to develop building prototypes that will be 25 to 30 percent more energy efficient and produce up to 30 percent fewer greenhouse gas emissions.
(Clarification: Google is using a subsidiary of Energy Innovations, not the parent company, for installation of its solar panel system.)
