Why portable solar still has a ways to go

Konarka's Power Plastic:
Konarka, is showing off Power Plastic, a new lightweight, flexible, and cheap material that converts indoor and outdoor light into electricity. Think of it as a solar panel that rolls up like camera film. "Soon you may not even need batteries," Hess says, holding a prototype of a portable device that will recharge your cellphone in an hour. "We can put this stuff anywhere."

... Power Plastic, however, does have its drawbacks. So far it is not nearly as efficient or durable as traditional silicon panels. Konarka's cells convert about 6% of the light that hits them into electricity, whereas silicon solar panels typically are 16% to 20% efficient. Hess says Konarka hopes to double its efficiency within a few years. Power Plastic also doesn't last nearly as long - about five years as opposed to more than 30 with silicon panels. But Hess argues that it doesn't matter because his product will be cheap to replace.

Other alternatives are here by PowerFilm for $250 per roll.