Psst! There's a team of engineers in Canada working on spray-on solar cells. They've got a prototype that applies colloidal quantum dots—a relatively new nanotechnology material that's still under study for whether they could work in solar panels—via spray.

A group of scientists in India have developed a way to recycle discarded lithium-ion laptop batteries into easily charged sources of light and power. Researchers in Bangalore developed prototype devices that can be used to provide hours of light to people who don't have access to the electrical grid.

If completed, the crowdfunded BEHA plane will pair two battery-powered electric turbines with solar panels, wind turbines, and a separate biodiesel engine, to fly through the sky with as small an environmental footprint as possible. BEHA stands for "Bio Electric Hybrid Airplane," and it joins the growing ranks of new aircraft designed to take advantage of multiple fuel sources. Call them "skybrids."

Virtually all homes point their solar panels south, where they can best capture rays from the sun when it rises in the southeast and sets in the southwest. That way, residents collect the most power possible throughout the day, which they can use in their own homes or sell to the grid (if they have any power leftover). But critics say the panels would actually do more good facing west, where they could capture sunlight during the midday and afternoon when energy is most needed.

You could call it a rainy-day fund. A team of MIT researchers has built an all-liquid battery prototype that's designed to store excess energy from solar and wind power plants. When the sun isn't shining, or the wind isn't blowing, future versions of this battery could release energy captured during more productive times into nations' power grids.

Propane, the gas that fuels your barbecue (and perhaps one day your car), may soon have a new, renewable source.