Walmart says the company will install five million electric heating and cooling systems in the US by 2020.
The company said it would be installing 1 million of these systems by the end of the decade.
Walmart said it will start installing the systems this year, as part of a broader program to improve its efficiency.
Electric car maker Tesla, meanwhile, is also aiming to ramp up its electric cars.
It will be the first carmaker in the world to build its own electric cars, and will produce the first fully electric Model S by the second quarter of this year.
Tesla’s move follows an announcement by the California Air Resources Board (CARB) that it will approve a plan to build 500 megawatts of renewable energy capacity by 2022.
In the United States, the government has been slow to phase out coal power in recent years.
Earlier this year President Donald Trump signed a controversial order to remove nearly half of the federal coal fleet from the electric grid, and the EPA has said it has found no evidence that climate change is to blame.
A Tesla spokesperson said the company was working hard to get to zero carbon by the year 2020.
The company has a battery storage facility in Fremont, California, where it is also working to develop its electric vehicles, and it has said that it has invested more than $3bn in green energy projects.