Tom has not done any research on the amount of land that would be required for 30% of the country's energy to be generated via solar. He just uses his gut.
For residential use, solar panels can be installed on roofs. Yes, the sun doesn't always shine. But battery technology has evolved, so that whatever power is generated but not immediately used can be stored at low cost. And of course, such houses would still be plugged into the existing grid.
And metro NYC is a poor example for the amount of vacant land available. Power can be and is transmitted over long distances. There is PLENTY of empty land in the US, and guess what--much of it is in the sunny Southwest. For example, the Primm solar complex, south of Vegas, when completed, will generate enough power to serve the needs of 250,000 people. And it covers about five square miles of previously empty and unused land.
Due to the stupidity of Republicans, we're still burning fossil fuels when we don't need to, but simple economics will eventually decide the issue. I'd like to see renewable energy come into common use because it's more socially and ecologically responsible, but I'll settle for "cheaper." Trump's desperate desire to pander to his "base" is extending the dying era of fossil fuels, but he and they will soon be irrelevant.