In view of the alarming rates of global warming, ongoing discussions in Katowice are evaluating measures of decarbonizing the economy. With the energy sector responsible for the largest contributions to greenhouse gas emissions (GHG), the most sustainable course is undoubtedly to decouple energy production from fossil fuels. However, we still need to do something to reduce the gigatons of carbon dioxide-equivalents that we have already released in the atmosphere.
Carbon dioxide removal (CDR) technologies aim to remove CO2 directly from the atmosphere. To that end, artificial photosynthesis refers to the CO2 fixation reaction which converts CO2 to sugar and other organic compounds using metal-complex photocatalytic systems. On the other hand, carbon capture, utilization, and sequestration (CCUS) extracts carbon dioxide from industrial exhausts, preventing its release.
A combination of ceramic nano-filters and powerful fans are used to filter CO2 from emitted gases. Captured carbon is compressed and liquefied and then it is either transported to be used in other industrial processes or it is stored underground in depleted oil/gas fields or saline formations.
Underground CO2 injection has been also applied in enhanced oil recovery, to support extraction of oil from nearly-depleted fields. However, successful sequestration requires that CO2 is stored in impermeable sites, with low porosity and with absence of faults.
Until recently, these techniques were criticized for being expensive. But reports on recent technological advancements show downward trends for these costs. On the carbon capture front, SaskPower, who have been running a CCUS facility in their Boundary Dam Power Station unit 3, claim that the capital costs of their Shand power plant carbon capture facility will be 67% lower.
This will be achieved with the combination of operational adjustments and second generation carbon capture technologies, which may be applied in other facilities as well, depending on site-specific design. On the front of extracting CO2 from the atmosphere, researchers at the Tokyo Institute of Technology recently published a CO2 reduction method that does not rely on expensive rare catalysts, but on cheaper, more abundant copper and manganese-based complexes, while maintaining high yield in the CO2 reduction.
Forests remain critically more efficient in capturing CO2 than any human invention, and natural climate solutions (conservation, restoration, land management) can provide more than 30% of the cost-effective climate mitigation required to counter global warming, according to a 2017 study. However, we are long past the point of choosing preferred courses of action. There is no point in discussing which approach performs better- urgent, radical measures are necessary, and all available options should be put into practice.