Jun 25, 2021 Elon Musk, one of the world’s richest men, says a $50,000 abode near Brownsville, Texas, is his primary home these days. He has tweeted that he’s made some improvements to the house, without specifying what they are. But earlier this year, Tesla Inc. employees traveled to Brownsville to install the company’s Solar Roof on that bungalow and several other houses on Weems Street that are owned by another Musk company, SpaceX. The construction project gave Musk an up-close look at a challenge that’s been vexing him. Musk has many priorities competing for his attention, but recently he has become intensely focused on Tesla’s Solar Roof, a niche product that enjoys demand from wealthy consumers but has proven to be a bear to install more cost effectively. While Solar Roof is only a small slice of Tesla’s business, it is essential to Musk’s vision for the company to evolve from an electric-car maker to something much grander: a one-stop shop for a household’s clean energy needs. Tesla’s stated mission is to “accelerate the world’s transition to sustainable energy,” and Musk has been talking up the benefits of solar and the “free fusion reactor in the sky” for years.