The world’s largest solar power plant, Karmuthi in Tamil Nadu, India, covers an area of almost 4 square miles, and is expected to power 150,000 homes.

That’s impressive, but tiny compared to what Elon Musk has in mind.

Think 100 square miles powering the whole of the United States.

Speaking at the recent National Governors Association Summer Meeting in Rhode Island, Elon Musk told the 30 gathered United States governors that it’s possible to power the entire United States with solar energy.

“If you wanted to power the entire U.S. with solar panels, it would take a fairly small corner of Nevada or Texas or Utah; you only need about 100 miles by 100 miles of solar panels to power the entire United States,” Musk said. “The batteries you need to store the energy, to make sure you have 24/7 power, is 1 mile by 1 mile. One square-mile. That’s it.”

This message from the CEO of Tesla Inc. should come as no surprise. He has made his passion for sustainable energy provision clear on many occasions and has been laying the groundwork for a while. The first clue is in the new company name. Tesla Motors will be known as Tesla Inc. in the future, in line with Tesla becoming an energy company.

The second clue is Tesla’s acquisition of SolarCity Corp., in November 2016 – a solar company Musk helped his cousins start in 2006.

“Solar and storage are at their best when they’re combined. As one company, Tesla (storage) and SolarCity (solar) can create fully integrated residential, commercial and grid-scale products that improve the way that energy is generated, stored and consumed,” explained a statement on Tesla’s website. The acquisition is a crucial part of Musk’s “Master Plan” he drew up in 2006 to accelerate the advent of sustainable energy.

To start off, Musk told the assembled governors, combining rooftop solar and utility-scale solar plants is the way to go. The former would be on the rooftops of houses in the suburbs in order to avoid building huge transmission lines in neighborhoods. Utility-scale solar plants could power areas other than the suburbs.

Tesla is already receiving orders for its Solar Roofs. It comes with an integrated Powerwall that stores energy collected during the day.

The company claims that Solar Roof is more affordable than conventional roofs because in most cases, its cost will be offset by the reduction or complete elimination of electricity bills.

Until transition from fossil fuel to solar can be completed, we’ll have to depend on other renewables, continued Musk. “We’ll need a combination of utility-scale solar and rooftop solar, combined with wind, geothermal, hydro, probably some nuclear for a while, in order to transition to a sustainable situation.

“Rooftop solar, utility solar; that’s really going to be a solution from the physics standpoint. I can’t really see another way to do it.”

So, it’s like this. Musk wants the U.S. to implement solar power as a sustainable energy source for the country and his companies, Tesla Inc. and SolarCity Corp. are poised and ready to spearhead the undertaking. Energy gathered through SolarCity’s Solar Roof can be stored in a Tesla Powerwall or Powerpack to provide energy for American homes. If you happen to have an environmentally friendly electric car, a Tesla model or otherwise, Tesla can charge that for you at your home.

Now, that’s a neat, over-all strategy for all the energy needs of American families. Just what one would expect of a utility company.