By 2050, a Quarter of the World's Power Could Come from This

 One source of energy is hardly used at all, but there is a study that says come 2050, it could account for 25 percent of the world's energy needs.

 What's your guess -- nuclear, hydrogen, wind? You can quit guessing, because you've never even heard of it: concentrated solar power. No, it's not the same thing as the solar energy you are thinking of. To distinguish them, the one you are thinking of is called photovoltaic solar power. They both rely on the sun for the energy, but from there they diverge, as is evidenced by the fact that photovoltaic solar has become the cheapest way to produce electricity, while concentrated solar power (CPS) is the most-expensive renewable energy in the world.

CPS doesn't simply absorb the sun's energy, it uses mirrors and/or lenses to concentrate a large area of sunlight into a receiver. The concentrated sunlight then drives a heat engine -- most often a steam turbine.

Where CPS has the advantage over photovoltaic solar is in storage. The heat can be stored as heat, so the electricity can be generated 24/7, whether it is day or night. Since the major knock on photovoltaic solar is that it only works when the sun is shining, this is big.