First law of thermodynamics. The whole point of oil is that it's energy-rich. To make it synthetically, you need to take energy from somewhere - but if you inte

First law of thermodynamics. The whole point of oil is that it's energy-rich. To make it synthetically, you need to take energy from somewhere - but if you intend to use the oil to produce energy, why not use it directly instead of going through the intermediate oil stage. Basically, synthetically-made oil only makes sense only if the process involves an efficient way to turn a widely-available but inferior form of energy into oil. Basically, that's bio-ethanol: already being done, but not feasible at the scale it would take to satisfy all current demand for oil-