If, on the one hand, you've got biofuels which represent only a half a percent conversion of sunlight, and let's say you've got photovoltaic cells and concentrated solar power systems, the efficiency of solar in terms of pure conversion is 50-100 times greater.

CNN: Biofuels: What do the experts think?

Back on July 27th, I wrote about how surprised I was to find shares of Power-One (PWER), a provider of renewable energy and energy-efficient power conversion and power management solutions such as photovoltaic inverters used in solar power applications, trade down after reporting blow-out second quarter results.

FORBES: Explain This One, Part 2

Speaking of solar efficiency, this week solar manufacturer Amonix announced that its concentrated photovoltaic technology has set a new efficiency record with a conversion rate of 33.5 percent.

ENGADGET: Inhabitat's Week in Green: Dyson Spheres, bladeless wind turbines and airless bike tires