Upstart Energy Share: Solar Power Upstart Energy Visit Website 425 Williams Place, Apt. 5 San Mateo, CA 94401 (510) 367-3789 About Map About We inspire homeowners and organizations to go solar with confidence. We teach the benefits of solar, provide affordable & clean energy solutions, and help you lower your carbon footprint. What's Nearby? Distance: 5 10 15 20 25 50 mi.