Dear Wal-Mart: Thank you for proving me wrong.

Like others in the green space, I was skeptical back in 2008 when the giant retail chain that everyone loved to hate announced that they were embracing renewable energy solutions. The first five stores were a nice start – but not many of us conceived that the company might make a truly laudable effort to diversify its energy consumption.

Four years later, and over 150 U.S. solar projects later, they’re now the retail leader in renewable energy – beating out other big names such as Apple and Ikea. By year’s end, they hope to have as much as 90 megawatts of capacity in place.

At the unveiling of the 100th California location to have solar installed, Kimberly Sentovich, Senior Vice President of the Pacific Division for Walmart, said sustainability is about living better.

“By using one of California’s greatest resources – sunshine – and employing renewable technology with our California-based partners, we will continue developing solutions that are both good for the environment and good for business.”

According to a report by Businessweek, Wal-Mart is adding an additional 100 solar-powered locations in 2012. They hope to have as many as 1,000 online by 2020. “We are trying to show folks that you can not only pursue these sustainability initiatives, they also make business sense,” Marty Gilbert, director of energy at Wal-Mart, told the site.

In addition to solar, the company also has 26 fuel-cell projects and a 1.1MW wind turbine store coming online in Red Bluff, California next month.

Photo credit: Wal-Mart