"Yet, despite its benefits and growing popularity, biodiesel might not be the fuel of the future because, as demand grows, the amount of land needed to produce the oils could become untenable, experts say."
I don't ever see a warning about this issue when the subject is ethanol, which is supposed to cover much of the US in new corn fields.
What we need are high-rise greenhouses where 100 acres of corn, etc. could be raised on a foot print as small as a baseball field.