Carbon Storage: Geosequestration
A key solution to permanent carbon dioxide (CO2) capture and storage (CCS) is long-term geological sequestration but many believe it just prolongs the oil and gas industry, even though liquid fuels will still be required at least for the foreseeable future during the transition phase until 2050 and beyond e.g., for international container shipping, until alternative high energy liquid fuels (NH3) and new engines are developed in sufficient quantities. If we were willing to stop buying cheap stuff then maybe we wouldn’t have this dilemma!
In order to use CCS, we need to provide incentives to the oil industry i.e., legal mandates or market-based mechanisms/incentives. Legal mandates are possible but unlikely, an international carbon market has been mooted for decades but hasn’t taken off and lastly proven tax incentives. The USA 45Q tax benefit encourages enhanced oil/gas recovery (EOR/EGR) and has been successful because oil companies get the benefit of producing more oil while using CO2 to flush-out reservoirs in decline.
Ordinarily I wouldn’t support this option given that it is adding to the problem, but if captured anthropocentric carbon (natural geological CO2 sources are insufficient) is used to flush-out a ‘reservoir’ the CO2 can be retained permanently when used to replace the hydrocarbons. Providing the depth of the reservoir is greater than 800 meters (>0.8km: 30oC & 100hPa) deep, in order to keep the CO2 in a supercritical liquid state (SCCO2), then this is a win-win situation providing the combustion products are captured/scrubbed and piped back to a reservoir via a central processing hub.
Why a reservoir rather than more extensive saline aquifers or un-mineable coal seams? The answer is simply that STEM development over the last hundred years has already determined the location, size and attributes of suitable reservoirs and how to best re-engineer them as carbon sinks/tanks. Therefore, it makes sense to focus on the proven and more economic option.
Parallel to this is all the efficiency, fugitive reduction, capture, pipeline and processing innovations that will require large investments in retraining and re-engineering, again an economic investment toward a zero carbon future!