Most of the energy we use comes from the sun, even if we are not too conscious of it.
Different kinds of solar energy are the most evident example, but the wind is also moved by the energy injected in our atmosphere by the sun, as well as the water of rivers and lakes. All biofuels are generated by photosintesis diven by sunlight and even the fossil fuels were produced that way millions of years ago. They are so energy rich because they concentrate the accumulation of energy in organic compounds produced during a long period of time.The exceptions to energy coing from the sun are only nuclear and geothermal.
So it is not strange to think that the Sun should be our main target to find the solution for our climate change problem. But it is not so easy. The whole earth receives a huge amount or solar energy in form of light but it is not so concentrated, and consequently not so easy to extract and use practically. For this reason photovoltaic cells have evolved slowly for many years (and because of lack of investment and production effort).
Nevertheless, knowadays there are many technological improvements in the solar field that could lead us to a successful energy revolution. The most real one is the steep reduction in price of standard photovoltaic cells, with this trend grid parity will be out of dicussion in many places in short time. But it does not stop there, Heliatek german company says it is able to produce semitransparent cells (link in Spanish) able to be located in windows with sufficient efficiency even at low light conditions and not affected by heat. This would be very interesting as the integration in the buildings could be straightforward, the only problem is the the price is not mentioned. How expensive will it be with respect to the energy produced? I know a tall house near here with a whole surface of glass, it could be a terrific power station. Sometimes it is not the optimun solution what succedes is just a reasonably good one in the right place and right moment, we will see.