Biofuels–part 2

So much for algae as an environmentally friendly replacement for fossil fuels.  Scientific American says:

Growing algae for use in biofuels has a greater environmental impact than sources such as corn, switch grass and canola, researchers found in the first life-cycle assessment of algae growth.

The problem, in part, as with many biofuels, is that they cannot grow without using fossil fuel inputs.  The article continues:

The culprit, the researchers say, is fertilizer. Growing algae in open ponds is akin to producing them in a shallow swimming pool, Clarens said, so all of the nutrients -- nitrogen and phosphorus -- needed to keep them alive and boost their production come from outside sources.

And that fertilizer has an environmental impact because it's often made from petroleum feedstocks, Clarens said.

Read the article for more details.  And there is also the entirely separate issue that algae production on a large scale will cost the consumer magnitudes more than its gasoline equivalent.