Though battery technology may not yet be ready for the masses, MIT has developed a new material that stores sunlight to be released later as heat. Here's an excerpt:
The sun is always hanging in space, blasting out more energy than we could even use here on Earth. However, sunlight is much less consistent at ground level. You have to contend with nighttime, clouds, and inclement weather to use solar energy, and that means storing it. Researchers from MIT have developed a material that might make it feasible to store energy from the sun as heat that can be released on-demand.
Most methods for storing solar energy are based on batteries, which have been notoriously slow to improve. This new material could make the process more efficient by storing energy via a chemical reaction for later release as heat. At that time, you could use the heat for anything you want. It’s an incredibly adaptive material as well, in the form of a transparent polymer film. It could be built into car windshields to remove ice, or as a layer in your favorite sweater to keep you warm on a chilly day.