CNN News:可发电的太阳窗来了

What is the world's most widely used source of renewable energy? Solar power, wind energy, hydropower or bio-fuels.
Hydropower, hydroelectricity is used more than any other renewable.
Hydropower is also one of the oldest forms of renewable energy. Wheels spun by the current of flowing water provided power for centuries before electricity caught on. Solar panels as we know them are a much more recent invention. Their development really started advancing in the 1950s. They come with some downsides. Though they're considered a form of clean energy, building the panels themselves and then disposing of old or damaged ones can cause significant harm to the environment.

And the solar windows you're about to see are relatively small. Manufacturers will have to find a way to build larger ones. Owners of skyscrapers will have to decide whether they want to install them. And there are questions about their cost versus modern windows that don't generate electricity. But the company that makes solar windows says the benefits are clear as glass.