Walmart’s been adding solar to scores of stores across the country—it has more than 100 stores with solar in California alone!—as it plans to become 100 percent renewably powered. Today (May 15) it announced that it’s completed solar arrays at eight stores in Massachusetts, which will provide it with roughly 2.8 million kilowatt hours of onsite generation annually.

The company has aggressively been building out solar on its stores and other buildings.  It’s also been boosting its purchase of renewable energy both directly and indirectly. And its doing so across the world. “Walmart has 280 renewable energy projects in operation or under development, and continues to test solar, fuel cells, microwind, offsite wind projects, green power purchases and more,” the company said.

By the end of 2012 the company had bested most utilities in the amount of renewable energy it was using. At that point it had sourced 21 percent of its energy from renewable sources, with 17 percent of that coming from the grid. For instance, 348 Walmart stores in Mexico are supplied with wind power via Eléctrica del Valle de Mexico. This year it plans to boost its renewable energy purchases to up to 75 percent of its use.

The company announced the eight new solar-powered stores at an event at its Walpole store, which has an array installed and owned by Connecticut-based Greenskies Renewable Energy, LLC. "Working on this and other Massachusetts solar installations with Walmart has been a great experience for us," said Greenskies Senior Vice President Andrew Chester. Walmart buys the power from the system under a power-purchase agreement with the company. The eight installations are part of a larger, 27-store project announced last April with Greenskies. The entire project will add about 10.5 megawatts of solar to Walmart stores in the state.

"The stores in Massachusetts demonstrate our commitment to increasing the share of renewable energy that powers our stores and improving energy efficiency," said David Ozment, senior director of energy at Walmart. "We believe in helping our customers live better by providing every day low cost and more environmentally friendly alternatives, like renewables. It's our goal to eventually be supplied by 100 percent renewable energy." The company has publicly stated that it plans to reach that goal by 2020.

The retail giant, while somewhat infamous for not using union labor itself, noted that Greenskies used Massachusetts union labor to install the array and that the inverter was made by Massachusetts-based Solectria Renewables.