Carbon sequestration

[wertoiuy]

Math time!

First of all, using forests to produce biomass is actually a really poor strategy, as newly growing forests of fast-growing trees are poor at sequestering carbon. Forests are amazing carbon sinks, but only for mature, slow-growing forest. This is due to the massive amount of biological diversity provided by this environment, most of which isn't included in biomass. Land is much better used as forested habitat than as farmed forest. Biomass production is most effective with typical crops such as corn and wheat. About 60% of the biomass comes from the grain portion.

So for conversion of coal and natural gas powerplants to consume biomass:
- 66% of power comes from coal and natural gas.
- 66% of US energy consumption (adjusted for use in gas-burning heaters as well as powerplants) is 4,419,360,000 Gigajoules/year.
- Each ton of typical non-tree biomass produces 3.7 gigajoules
- 1,194,400,000 tonnes of biomass/year therefore necessary to meet demands
- This needs 173,100,000 acres of land farming corn in addition to that which already is farmed to meet food demands (current land usage for corn farming is 90,000,000)
- This translates to 270000 square miles, or roughly the size of Texas
- This is just for the US, which has one of the lowest population densities in the world. Countries such as India, China, and most of Western Europe are heavy polluters with little land left to spare.

Perhaps algae, kelp, or bamboo could be more efficient, but I don't believe it would be enough. Personally I like solar panels installed on house roofs, and just placed in the deserts of the Southwest. Ultimately, what it boils down to though: There are WAY too many people and none of them live very efficiently.

[dkeller_nc]

Yep. This is the issue with most carbon sequestration schemes, as well as the idea of "get the base load from solar power". It's not that the basic idea isn't technically correct, it's the that the math just doesn't work out.

Certainly some of the US's peak load demands can be supplied with wind/solar/biomass combustion. But the base load demand is far too high to make those sources practical. Just a quick back-of-the-envelope calculation for base load generation by means of solar power would lead one to the conclusion that you'd need to cover Arizona with solar cells. Never mind the environmental degradation from the mining and refining of the minerals required to make all of those solar arrays.

Rather unfortunately, most optimistic declarations that I see in regards to renewable generation at large scale leaves out careful analysis that includes all factors. One such omission that's extremely common is neglecting line losses that occur in generating electricity and delivering it via grid systems to distant consumers. Such a system would be necessary to deal with the power demands of unfavorably located population and industry (such as the northern US).

[orcafood]

I agree solar cells will require serious recycling programs because the amount of mining and transition metals necessary. Imagine if wires could be come up with that had no resistance. Game over, humans win. Or perhaps an efficient battery, now no more motorized cars/engines. Digging up transition metals efficiently will become very important for energy storage and transmission. Then imagine how efficiently we will need to recycle the metals. Completely impossible with today's global mindset.

Originally Posted by dkeller_nc

Yep. This is the issue with most carbon sequestration schemes, as well as the idea of "get the base load from solar power". It's not that the basic idea isn't technically correct, it's the that the math just doesn't work out.

Certainly some of the US's peak load demands can be supplied with wind/solar/biomass combustion. But the base load demand is far too high to make those sources practical. Just a quick back-of-the-envelope calculation for base load generation by means of solar power would lead one to the conclusion that you'd need to cover Arizona with solar cells. Never mind the environmental degradation from the mining and refining of the minerals required to make all of those solar arrays.

Rather unfortunately, most optimistic declarations that I see in regards to renewable generation at large scale leaves out careful analysis that includes all factors. One such omission that's extremely common is neglecting line losses that occur in generating electricity and delivering it via grid systems to distant consumers. Such a system would be necessary to deal with the power demands of unfavorably located population and industry (such as the northern US).

[karimwassef]

back to... ALGAE to save the planet (carbon sequestration + later can be used for energy production later with CO2 recapture)





ALGAE oil to JET fuel

[Frogmanx82]

CO2 is necessary for life. If humans hadn’t come along to release it the planet would eventually have died out from a carbon shortage. See my sig. Free the Carbon!