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I can get on board with solar thermal for distillation and other heat inputs to chemical reactions. But collecting algae isn't free. Past experience with pond

I can get on board with solar thermal for distillation and other heat inputs to chemical reactions. But collecting algae isn't free. Past experience with pond algae growth is that the drying part is indeed extremely expensive (using solar). But if you throw it into a gasifier I like it a lot better since it doesn't need to be as dry, so I guess fermentation might be similar although you need cellulosic ethanol tech to work better first. Still didn't break even against solar at the time though (a decade past), and solar has gotten way better. Maybe the algae tech has improved commensurately, but the tech for biomass handling is much more mature so I'd be a bit surprised if the rate of improvement wasn't much different. The silliest proposal I ever had to write was for why it made sense to take electricity from a power plant, "free hydrogen" and make chemicals. It was so strange, just use the fuel as a precursor to make the chemicals directly instead of burning it... Edit: I said as much in the proposal. We did not win.

blacksqr 7y ago
It's true that collecting algae requires effort to collect and transport. But my ultimate point is that the total energy and resource costs of directly converting seaweed to fuel would be far lower than in OP's proposal. Just as in your power plant anecdote. And you achieve the same goal of removing CO2 from the ocean. Drying pond algae with solar heat is tricky because you can't concentrate the sunlight too much or you get ash instead of dry algae. But with dry distillation the objective is to pyrolize the input, so you can efficiently use concentrated sunlight. >you need cellulosic ethanol tech to work better first. Still didn't break even against solar My proposal isn't competing with solar electricity (which doesn't remove CO2 from the ocean), but with OP's proposal to use solar electricity to produce methanol from CO2 extracted from seawater.
- seunosewa 7y ago
  Biological processes are usually much less efficient than industrial processes, so it would be hard to believe that your proposal is better without lots of evidence. If we relied on legumes for nitrogen fertilization of agricultural soil, we would starve.

blacksqr 7y ago

It's true that collecting algae requires effort to collect and transport. But my ultimate point is that the total energy and resource costs of directly converting seaweed to fuel would be far lower than in OP's proposal. Just as in your power plant anecdote. And you achieve the same goal of removing CO2 from the ocean. Drying pond algae with solar heat is tricky because you can't concentrate the sunlight too much or you get ash instead of dry algae. But with dry distillation the objective is to pyrolize the input, so you can efficiently use concentrated sunlight. >you need cellulosic ethanol tech to work better first. Still didn't break even against solar My proposal isn't competing with solar electricity (which doesn't remove CO2 from the ocean), but with OP's proposal to use solar electricity to produce methanol from CO2 extracted from seawater.

seunosewa 7y ago
Biological processes are usually much less efficient than industrial processes, so it would be hard to believe that your proposal is better without lots of evidence. If we relied on legumes for nitrogen fertilization of agricultural soil, we would starve.