This is a great read about a way to create biodiesel with algae farms.
The more I read about hydrogen and fuel cells the more I don't think that it is the future. Where do you get the hydrogen? How do you transport it? How do you store it in a vehicle in a cost effective manner that gives you a 200 mile distance between fuelings? These are major issues with no easy answers.
Instead I think the future energy source for transportation will be a liquid rather than a gas. This liquid will have to be created renewably. The best way that I could think of would be to be able to turn either wind power or solar power into some type of liquid that can store energy. I thought biodiesel would be good as it basically is a way of concentrating solar energy. But then I did the math on how much land would be needed to fuel all of the vehicles in the US from soybeans and the number was huge (like larger than all of the farm land in the US). And given the fact that in the next century water could be the new oil, using massive amount of water and land to create fuel for our vehicles probably wont work (if you are feeling guilty about using too much oil right now, just wait until that fuel is grown and all the land and water needed to fuel your car could be used to grow food for starving people).
Then I read this article and found out about creating biodiesel form algae farms. This looks promising.
To replace all transportation fuels in the US, we would need 140.8 billion gallons of biodiesel, or roughly 19 quads (one quad is roughly 7.5 billion gallons of biodiesel). To produce that amount would require a land mass of almost 15,000 square miles. To put that in perspective, consider that the Sonora desert in the southwestern US comprises 120,000 square miles.Basically you have algae on a big pool of water and then shoot in carbon-dioxide (I don't get why you need to shoot in CO2 rather than just use what is in the air). The algae are genetically modified to maximize the amount of vegetable oil they produce. You collect the algae and get the oil, then put in some ethanol and other goodies to create biodiesel.
That 15,000 square miles works out to roughly 9.5 million acres far less than the 450 million acres currently used for crop farming in the US, and the over 500 million acres used as grazing land for farm animals.
They answer a lot of good questions but two that are missing are:
1) Given the current state of the art, how much would it cost to create a gallon of biodiesel? Based on this article it looks like $4 a gallon. Expensive but not extremely so.
2) Compared to other ways of harvesting solar energy (solar panels, solar electrical power plants that use mirrors and steam) how does the efficiency of collecting the solar energy compare? How do they compare economically (this is a little bit of an apple vs. orange comparison because one is creating liquid fuel and the other electricity)?
So I would put my money on this technology rather than hydrogen and fuel cells.
via Change This (.pdf)