There are still problems with any plant-based biofuels, but they're problems with scaling, crop rotation, pesticides, and the current state of the art of ag in countries where sugarcane is grown.
But the energy return of sugarcane ethanol is high enough to make it non-silly.
Sure, solar is great, except current technology is really bad at using it.
This sounds like the Chinese soda analogy [1] in a different form. The fact that we only need 0.01% doesn't indicate the ease of capturing 0.01% in the form of usable energy.
[1] http://lake.blogs.com/my_weblog/2006/05/the_chinese_sod.html
I can never understand why people trot out this sentiment. Humans are a biological species subject to normal ecological principles. One of those principles is that, in the absence of a limiting factor in our environment, we will grow. If energy availability is removed as a limiting factor, we will grow ("gettin' larger in waist and taste") until it is again. Anyone who pretends otherwise has not stepped outside to notice all the millions/billions of people clamouring for food, clean water, jobs, holidays, new computers, clothes, homes, education, etc etc. Imagining that, unlike every time in the past where human societies have chafed against resource limits and hoped that just a little more would fix everything, this time human needs will finally be satisfied, is the oldest fallacy in the book. It's just not how life works.
You live in a valley full of aurochs, horses, and boars, more than any man could eat. Taking just a fraction of these bountiful riches would give us all the food we could ever need.
On the other hand: what is stopping us now from combining salt evaporation ponds with sweet water production in e.g. the coastal regions of the Sahara?
No, that's the whole point!
Humans surely cater to farming using oil, and we would be a lot worse without it.
But in the end food came from two sources: energy from the sunlight and CO2 (matter) from the atmosphere. (Well, then we could say we're eating car emissions).
Unless you're converting oil directly into food (let's say carbohydrates), no, all energy from plants comes from solar energy. You could of course have a giant oil powered lamp that produces light and shine that over the crop.
Every time I buy a new laptop, I can't imagine how I'll fill up the drive, but I know I will.