[DaoVeles]

I have seen efficiency figures vary from as low as 0.1% upwards of 10% but it seems difficult to quantify.

My shoot from the hip intuitive thought is that the massive amount of plant matter it took to make petroleum demonstrates how inefficient it is to get energy in that chemical state. A fools errand to try and do it over.

It has been said that Coal/Gas/Oil is a half billion years of stored solar energy. That is wildly inaccurate for many reasons, but even if we are using a few thousand years of stored energy, that is still a wide gap to cover.

[pfdietz]

The 10% is for algae, I think. And that requires juicing the liquid with enough CO2 so they can continue to photosynthesize. If you're DACing that much CO2, you might as well just sequester it.