Biofuels: Grain versus waste products?

"Waste products make a better biofuel than traditional British crops such as rapeseed and grain because of the energy it takes to grow them, a former chairman of Shell Trading and Transport said on Thursday." (more)

While I agree that grains might not necessarily be an extremely efficient source of biofuels, grains are still better than foreign oil.

Nonetheless, what if a drought wipes out your crops? Inevitably, grains are not a complete answer to foreign oil.

Still, not all grains are considered fairly. For example, hemp - not marijuana - is an extremely potent crop. No I don't mean hemp is an extremely potent crop in terms of getting you high, but in terms of its use as a biofuel.

Hemp grows like a weed, doesn't need fertilizers and makes the soil healthier than before it was planted. Yet, the government tries to pretend that hemp and marijuana are the same. Why?

Of course, biofuels are only part of the picture. Sure waste products might be more efficient than grains, but grains are still much better than foreign oil, especially when America subsidizes farmers to grow crops that are not even used. More important, if the government were not so biased against some crops, such as hemp, perhaps grains would offer more in the fight against foreign oil.

Why is the government so biased?