With the advancements in solar cell technology & electric cars, I'm thinking that a solar roof on the house, Tesla powerwall battery, and electric car combination might eventually be a great transportation arrangement, if civilization falls apart. For Daily Local Commuting: - Electric Car & Solar Roof on House: You can drive locally every day, without worrying about running out of power, as long as you come home to recharge the electric car. - Gasoline-powered Car: If you drove every day, you would run out of fuel pretty quickly, unless you stored a gigantic mountain of gasoline in your backyard. For Driving Cross Country: - Electric Car & Solar Tarp in Trunk: You'd run out of electric power after ~200 miles. But with advancing solar technology, you might be able to eventually carry enough solar tarp in your trunk to recharge the electric car. Drive 200 miles at night (before sunrise or after sunset). Layout solar tarp during the day, to recharge. In theory, you could drive 100-200 miles every 2 days. - Gasoline-powered Car: You'd run out of gas after ~300 miles. If civilization has fallen apart, it might be hard to find gasoline. Driving cross country might be nearly impossible. Some Data: The cost of solar power has fallen dramatically in the last decade or so. www.youtube.com/watch?v=tYT1b7cvvmY www.youtube.com/watch?v=CV_gHVneHoM In sort parts of the world, solar is already becoming cheaper than coal & gas for electricity generation. http://fortune.com/2016/12/15/solar-electricity-energy-generation-cost-cheap/ The latest electric cars (Tesla Model 3, Chevy Bolt, etc) cost around $35,000, and have around 200 miles of range. 30 minutes of charging gives you 170 miles of range (supercharging station) or 10 miles of range (regular charging). Tesla solar roof (looks like normal roof tiles), powerwall battery (to store excess solar power during the day, especially when you're out driving the car), and electric car. www.youtube.com/watch?v=ilTn-Wv0a_I My solar tarp idea is the weakest link. The current technology & efficiency isn't good enough to charge a car. But with the dramatic advancements in the solar industry, and falling costs, it could be a reality in the near future. Thoughts?