Plants absorb sunlight and convert it to energy with nearly perfect efficiency—none of the energy goes to waste. Electrical engineers are always striving for that kind of efficiency, but nowhere is it more pronounced than in solar panels. Even the best of these can only convert about 44 percent of the light it absorbs into usable energy, and that's part of the reason why solar energy doesn't fulfill more of the world's energy needs.

Used car batteries can leech chemicals and create lead pollution when they're incorrectly trashed. A team at MIT believes that this lead can be cut out of the waste stream entirely -- and put to good use creating emissions-free energy.

Rising energy prices usually spark some creative ideas for alternatives, but a new one from a futurist named George Dvorsky is pretty far-fetched: He envisions destroying Mercury and scavenging its rocky remains. The debris could be used to build an array of solar power collectors, a Dyson swarm, around the sun.

That gigantic solar flare that lashed out toward Earth on Saturday is "the geomagnetic storm that just won't go away," the NOAA's Space Weather Prediction Center (SWPC) in Boulder, Colo., said via its Facebook page today. And that appears to be true. Active Region 1302, pictured above, continues to pummel earth with solar energy and could disrupt satellite communications as it continues turning toward us in the days to come.