brimstoneSalad wrote: ↑
Sun Mar 10, 2019 12:59 am
The trouble with carbon capture is it works best at the flue, so at best you're basically bringing fossil fuels down in emissions closer to nuclear. Is it more realistic to advance adding carbon capture to fossil fuels? Sure. And I think we should do that, along with promoting nuclear power and use of solar etc. where it makes sense.
Are we talking about capturing methane from landfills, etc.?
Methane from landfills is important but only of minor impact (14% of methane emissions in the US, EPA).
The IPCC assessment is about Carbon Capture and Storage (CCS) in coal and gas power plants. It includes your remarks on higher emissions by CCS, than nuclear. Beside CCS, BioEnergy CCS (BECCS) in bioenergy power plants might turn out to be import. As it is a technologically promising way to get CO2 out of the atmosphere. Actually, the latter plays a crucial role in all still possible scenarios staying below 2K, let alone 1,5K. This technology is way more effective than forestation, which does not have a substantial climate impact as it also changes the albedo, but this is a different story. I can provide further information if you are interested.
In the economic analysis, which is the basis of this IPCC assessment, a discount rate of 5% is used. This discount rate do a favor to fossil fuels with lower building cost and higher operation costs than nuclear. However, it represents well used discount rates in economic assessments considering opportunity costs. Furthermore, the cost estimates of the technologies are quite divergent. I am not aware of all assumptions made for these estimates. They are substantially based on expert assessment of costs of technologies. Here is the economic assessment:
Higher cost by excluding technologies (%):
No CCS: 138 (29-297)
Nuclear phase out: 7 (4-18)
Limited solar/wind: 6 (2-29)
Limited bioenergy: 64 (44-78)
PDF p.17 of https://www.ipcc.ch/site/assets/uploads ... makers.pdf
(Another interesting information from the same table SPM.2 is the rise of costs by delaying mitigation.)
This does not imply, that one should advocate CCS over nuclear and renewables. The take home message would be to employ all technologies, because exclusion of any makes it more costly. Excluding CCS and/or BECCS might make emission targets even unachievable from an economic perspective.
Most economists favor a market approach, with either cap and trade or a carbon tax. This would be technologically neutral. However, in my opinion it might be worth considering to have some additional support for nuclear and renewables as they are considerable better regarding broader air pollutants.