This is a little dated, but while looking for other information I found this unique design for roofing tiles:
A roof tile that harnesses solar energy to heat water and generate electricity, has been invented by an Australian industrial designer.
The plastic tile is filled with solar cells and connects to a house's hot water system and electrical wiring.
Sebastian Braat, a graduate of the University of Western Sydney, says the tiles are designed with urban dwellings in mind - particularly the new generation of so-called "McMansion" style suburban homes.
It may not look great, but think of the electrical savings.
Braat says it takes about 200 tiles to generate a maximum of 1.5 kilowatts - more than enough for an average three-bedroom suburban house over a year.
Other researchers suggest looking at how the roof's pitch may change the efficiency of the tiles as well as how so many joins may lead to increased leaks in the roof.