The renewed interest in solar panels on cars is less about the panels themselves becoming better, and more about the fact that hybrid and electric cars, and their infrastructure, are better. In other words, it's easier and more affordable than ever for consumers to go buy a readily available electric or hybrid car, and these cars are more efficient, easier to charge, and have fewer compromises overall than EVs and hybrids of just a couple generations ago. That means there are more people who can take advantage of solar power to run a car, and that solar power will literally go farther than it would have in the past.

That said, solar panel technology has improved, too. It's more affordable and easier for most consumers to incorporate into a home or garage update, but solar-powered cars still have a long way to go.

In fact, it's unlikely that we'll see a car that can be fully powered by a solar panel integrated into the roof, because a panel that size is just too small to produce the power needed. EnergySage, a company that helps consumers research and shop for solar technology, estimates that a car completely covered in solar panels could only power an electric car for a maximum of 25 miles a day, and that's assuming weather and other conditions are absolutely perfect. Yet, EnergySage argues a solar panel that gives a car a boost of just a few miles a day is still worth the investment.