The environmental costs of green energy: Biofuels | The Green Geek

The Green Geek has a good article on The environmental costs of green energy: Biofuels. I thought the most telling portion was the following:

It’s known that photosynthesis has an efficiency of around 16 percent. Even if the entire mass of the plant was converted to usable energy, this is already less efficient than using the sunlight directly via photovoltaic panels or concentrated solar power systems, and that’s not even factoring in energy losses during processing and distribution, or thermal and mechanical losses in a vehicle.

In part, this shows how amazing the energy concentration is in our fossil fuels, and how we really need to think of something more than replacing our oil/coal consumption with a "green" substitute.