Wal-Mart has committed to double the number of solar energy projects at its U.S. stores in the next six years, with a plan to generate seven billion kilowatt/hours of renewable energy by 2020.

President Barack Obama was scheduled to appear at a solar-powered Wal-Mart store in Mountain View, Calif., on Friday to speak about the importance of energy efficiency.

Obama said more than 300 companies and state and local governments have pledged to use solar technology, and he unveiled his own executive actions aimed at increasing energy efficiency with a goal of reducing U.S. reliance on carbon fuels. 

"The commitments we're announcing today prove that there are cost-effective ways to tackle climate change and create jobs at the same time," Obama said at a sprawling Wal-Mart which gets 15 per cent of its power from solar.

Wal-Mart is the largest commercial solar energy user according to the Solar Energy Industry Association and the U.S. Environmental Protection Associations.

It has found renewable energy lowers costs, according to CEO Bill Simon.

 “We know from experience that investing in energy innovation allows us to save money, reduce carbon pollution, and create jobs. Every day, millions of Americans depend on us to watch every penny so that we can provide the best prices on products they love. Our customers can feel good that we’re watching out for both their wallets and their children’s future,” he said.

Wal-Mart plans to roll out more solar energy projects at stores in the U.S. and Puerto Rico, with a goal of being  100 per cent supply by renewable energy, he said.

Several other large U.S. retailers, including Costco, Macy’s, Staples, Target and IKEA also have made investments in solar energy.

A more companies commit to solar, it creates more certainty in the marketplace and lowers initial costs, Wal-Mart said in a news release, claiming its greenhouse gas emissions have barely increased over the last few years, despite the company’s growth.

Obama was criticized by labour groups for showcasing his energy program at a Wal-Mart, as the company has been criticized  for paying its employees minimum wage and discouraging unions.

Obama said he has a broader campaign to reduce American energy dependence, create jobs in renewable energy and lower heat-trapping emissions blamed for global warming.

Tweaking the mostly Republican opponents of his energy policies in Congress, Obama lamented that lawmakers have "not always been as visionary on these issues as we would like." That's why he's seizing opportunities this year to act unilaterally to advance those goals, Obama said.

"Unfortunately, inside of Washington, we still have some climate deniers who shout loud," Obama said. "But they're wasting people's time on a settled debate."