The retailer partnered with SolarCity for the installation of the panels, which contribute to the store’s objective of being 100% powered by renewable sources.

Walmart Pacific Division senior vice president Kimberly Sentovich said, "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."

SolarCity CEO Lyndon Rive added, "Walmart is showing other businesses that you can create jobs and reduce air pollution by using better energy."

The rooftop installation is expected to generate 70m kWh of renewable energy per annum and contribute to the reduction of 21,700 tons of CO2.

The company is looking to install rooftop solar installations on 75% of its stores, about 130, in California by the end of 2013.