In what universe is it a reasonable expectation that the amount of energy required to produce a fuel will be less then them amount of energy it produced when burns? Answer none.
You seem to allude to laws of Thermodynamics here, which is beyond stupid. The energy we expect to extract from the plants comes from the Sun. It is the same energy, that powers the plants, the animals, and the humans. Our bodies manage to harvest this energy with a surplus — and always have.
That some methods of producing "biofuels" end up consuming more fuel than is produced, is the inefficiency of the methods, not the principle.
The question is , is scientifically _possible_ to create an efficient enough process that the energy in the plant material itself
We should not need to answer it — Collectively. If an Individual finds such a way, he should be able to sell such fuel to willing buyers. The existing government mandates are stupid and Illiberal. In addition to violating most basic and obvious human rights, they are also inflating the costs of fuel both for machinery and for humans — because raw materials for biofuels are grown instead of food.