Photos: Solar festival as green as it gets

In addition to alternative-energy cars, companies displayed an array of electric bicycles. Thunderstruck Motors of Santa Rosa, Calif., showed off electric bikes and motorcycles it has either modified or built from scratch. The company has sold more in the last two months than in the past year.

This green, sporty Grasshopper bike costs $2,250 and can typically travel 30 miles per hour. Its aluminum frame houses a lead acid battery that lasts for up to five years. While that model is hawked as an alternative to gas-powered all-terrain vehicles, the company's orange, $2,000 Jackalope is better suited for leisurely commutes. It uses a lithium-ion battery that could last a decade.