With climate change showing negative effects around the world, it is more important than ever to use renewable energy when possible to save the world’s resources and fight global warming.

The need for clean, renewable energy has spurred research for harnessing energy sources like wind and solar. Because of this, solar panels have become really efficient and cheap. If placed strategically, solar panels today are strong enough now to power entire cities.

Unfortunately, the most strategic place for them is on the sides of skyscraper buildings. Putting them on the roof is not the best option because the buildings are so tall, the roofs do not get enough sunlight to effectively power solar panels.

Most of the light goes through the windows into the building. Putting solar panels on the side of the building would effectively shut out all the outside light into the building, which isn’t good for employees or for sustainability because it would cause the need for more electricity to make up for the loss of light inside.

Solar panels are dark because of the sheets of silicon crystals that absorb the light. But new technology is being developed that might let cities run on solar power without making the buildings go dark.

Solar panel windows are the next invention of the renewable revolution. These are semi-transparent windows that have microscopic silicon pieces called quantum dots. These dots catch the shortest wavelengths of sun and let the longer ones through.

The dots re-emit the captured energy in longer wavelengths. These wavelengths will bounce within the glass instead of escaping because of a process called total internal reflection. This energy will not be reabsorbed by other quantum dots, however, because it was turned into longer wavelengths and the dots only catch short wavelengths.

Because of the light is absorbed by the windows, the glass is not completely transparent. But that is not much different than normal skyscraper windows, which are designed to reflect some of the sun’s rays to keep the building cooler inside.

Solar windows are going to be a huge help in the future in helping cities become more sustainable and to help everyone reduce their carbon footprint and fight a lot of the environmental issues that come from overusing fossil fuels.

However, right now there are still issues with the current technology. They are still expensive to make and difficult to manufacture. In addition, they are not very powerful. But after several years of development, solar windows could be the new norm on skyscrapers.