Evidence accumulates that the biofuel recycling step in Sustainability is not only feasible, but here today: Greenfuel just announced production of commercial-quality biofuels from CO2 scavenged from an Arizona powerplant (h/t: Cervus @ GCC).
Further, they mentioned that the CO2 capture efficiency is as high as 80% during daylight hours. This is astounding, and it strongly suggests that a closed-loop system is feasible:
So long as the volume of the greenhouses is large enough to store CO2 and supply oxygen overnight, this requires no exhaust to the atmosphere; it can turn all biomass input into electricity PLUS liquid biofuels. It could even burn its own biofuels to make carbon-free electricity, cycling the carbon in a closed loop. We don't need fuel cells right away; we can start with small gas turbines and work up from there.
What are we waiting for?
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