If I spot solar panels on a building, I immediately think that the occupants care about the environment. It's even more impressive on a commercial building because it takes extra money and effort to make it happen (just as with many green advances). But not all solar panels are built equally. The earliest ones weren't incredibly efficient and didn't actually generate that much usable energy. The latest in solar panel technology is called photovoltaics, and they've come much further than just a few panels on the roof. How impressive would it be to see an entire building covered in panels that harnessed the power of the sun? The thing is, you might never know it's happening.
Traditional solar panels stand out from the rest of the building and sit on top of the regular roof structure. Photovoltaic (PV) panels actually replace traditional structures, making them more cost-efficient from the start. They can even be semi-transparent, replacing windows and skylights. The term "photovoltaic" means that electric current is immediately generated in the panels when they're exposed to sunlight. These panels can theoretically create a closed grid -- a building that can generate and use its own electricity. Most of the buildings using PV panels now (such as the CIS Tower in England) feed the power they generate to the national power grid because a stand-alone system requires a way to store the power (such as batteries).