Hey, hey, "why not, it is unproven" is not valid in support of calculating on the assumption of genetically engineering an organism that doesn't even exist in concept. Stick to 8% efficiency, please.

The technology to grow algae on a massive scale, harvest them, and turn the green goo into liquid fuel is already unproven, but clearly feasible given what we know. The question is one of losses along the way, so let's ignore the losses and compute the theoretical capacity. After all, this 10% biofuels and 20% renewables is an EU goal for 2020, not for 2100 (at which point maybe postulating genetically engineered superalgae that can photosynthesize at the theoretical quantum efficiency of photosynthesis just might be legitimate).

We have met the enemy, and it is us — Pogo