Never mind solar energy, how about converting the kinetic force from a footstep into electricity. Every time someone steps on the tile, they generate 7 watts of power. The energy is stored within batteries and then used to power lighting when it's needed.
Pavegen has worked with brands such as Coca-Cola and Siemens. The company has tiles at Heathrow terminal three and are planning an installation outside the White House. During the World Cup the company laid a whole foot pitch with tiles, hooking them up to spotlights so that play could continue after dark.
Lighting isn't the only thing these tiles can generate. When you stand on a tile it could send wireless data, which is useful for crowdflow modelling - seeing how people move through cities. You could use it to control lighting more efficiently. It's also a key way for retailers to know how many people are visiting their shops.
I would think the sky is the limit when looking at the future of these tiles. What a great idea!