Why are you assuming growth on one plane? Can't these crops be stacked? Also from a hedging perspective, alternative supply from this (assuming fuel is interchangeable) doesn't need to be equal to oil.
Density of plantings affects available sunlight (neighboring plants shield one another).
Any sort of structure in agriculture is hugely expensive because of scale. You're not talking about putting up a backyard trellis, you're talking about building a structure that would cover tens of millions of acres, hundreds of thousands to millions of square miles. That's tremendous.
Farmers normally consider infrastructure such as irrigation ditches, pipes, and harvesting equipment, which comparably are effectively nil scale, to be significant costs of cultivation.
If you think about it, the fact that most farming takes place on little more than scratched earth, and often not even that, speaks to the low level of infrastructure required.
Any sort of structure in agriculture is hugely expensive because of scale. You're not talking about putting up a backyard trellis, you're talking about building a structure that would cover tens of millions of acres, hundreds of thousands to millions of square miles. That's tremendous.
Farmers normally consider infrastructure such as irrigation ditches, pipes, and harvesting equipment, which comparably are effectively nil scale, to be significant costs of cultivation.
If you think about it, the fact that most farming takes place on little more than scratched earth, and often not even that, speaks to the low level of infrastructure required.