You don’t need to install solar panels on your roof to join the renewable-energy revolution. You don’t even need a roof. New York City start-up Mpowerd has developed Luci, a line of low-cost inflatable solar-powered lanterns that have applications for both the developed world (camping trips, backyard parties, checking the fuse box) and regions where electricity is scarce. When deflated, the lamps, which come in five designs, flatten out to the size of a pancake. When they’re inflated, a few hours’ worth of sunlight powers LEDs that give off a night’s worth (up to 12 hours) of illumination. From $10; mpowerd.com.