3 ms·

Assuming you get the energy for the process to make it from renewable sources, how 'green' would the useful energy in terms of fuel be at the end?

kaybe 13y ago
As green as it gets, since the CO2 that is released from burning the fuel has been taken out of the atmosphere by the algae a short time before that. The only issue is to take care of the byproducts and algae production process, which can create local pollution issues - cheaper not to do it, but nothing that hasn't been done before in sufficient scale.
- kevingadd 13y ago
  And it sounds like this particular process is less reliant on dangerous chemical catalysts and produces less byproducts, so it's a plus in that regard.
- VLM 13y ago
  Don't forget capex... need the plant to depreciate slowly enough / be ecologically profitable enough that the ecological value of the biofuel produced exceeds the coal burned to make the concrete and steel to make the plant. Its not just bulk concrete but SCADA control systems and catalysts and exotic stuff like that. Without crude oil, its an open question if the high capex algae plant will win, or just have humans sow and harvest and press sunflower seeds into sunflower oil which works perfectly well in Diesel engines and the "plant" doesn't really have a capex (a wood press and some cloth filters?). Of course its not as if only capex has an environmental cost, a couple thousand human ag laborers has a certain environmental impact too, even if (especially if?) you treat them inhumanely. During the recent ethanol bubble, some stills never refined enough EtOH to make up their cost of production much less the ecological costs of building the plant. If it takes 100K barrels of diesel equiv to make an ethanol bubble era plant, and the plant only refines 10K barrels of EtOH before the bubble crashes, that's a net loss of 90K barrels from the planet not a gain to the planet of 10K barrels. Those numbers are kind of made up, but not as much as you'd think.
- njharman 13y ago
  > As green as it gets The massively polluted by oil derivative combustion atmospheres of L.A., Mexico City and Beijing beg to differ.
  - crpatino 13y ago
    I think the original question was more in terms with carbon footprint, which would be indeed neutral (as long as it happens to have a positive EROEI, which is not even mentioned in the article). Of course local pollution is a concern, but it will always be wherever there are high concentration of people around.

kaybe 13y ago

As green as it gets, since the CO2 that is released from burning the fuel has been taken out of the atmosphere by the algae a short time before that. The only issue is to take care of the byproducts and algae production process, which can create local pollution issues - cheaper not to do it, but nothing that hasn't been done before in sufficient scale.

kevingadd 13y ago
And it sounds like this particular process is less reliant on dangerous chemical catalysts and produces less byproducts, so it's a plus in that regard.
VLM 13y ago
Don't forget capex... need the plant to depreciate slowly enough / be ecologically profitable enough that the ecological value of the biofuel produced exceeds the coal burned to make the concrete and steel to make the plant. Its not just bulk concrete but SCADA control systems and catalysts and exotic stuff like that. Without crude oil, its an open question if the high capex algae plant will win, or just have humans sow and harvest and press sunflower seeds into sunflower oil which works perfectly well in Diesel engines and the "plant" doesn't really have a capex (a wood press and some cloth filters?). Of course its not as if only capex has an environmental cost, a couple thousand human ag laborers has a certain environmental impact too, even if (especially if?) you treat them inhumanely. During the recent ethanol bubble, some stills never refined enough EtOH to make up their cost of production much less the ecological costs of building the plant. If it takes 100K barrels of diesel equiv to make an ethanol bubble era plant, and the plant only refines 10K barrels of EtOH before the bubble crashes, that's a net loss of 90K barrels from the planet not a gain to the planet of 10K barrels. Those numbers are kind of made up, but not as much as you'd think.
njharman 13y ago
> As green as it gets The massively polluted by oil derivative combustion atmospheres of L.A., Mexico City and Beijing beg to differ.
- crpatino 13y ago
  I think the original question was more in terms with carbon footprint, which would be indeed neutral (as long as it happens to have a positive EROEI, which is not even mentioned in the article). Of course local pollution is a concern, but it will always be wherever there are high concentration of people around.