Transition Tools: Carbon Capture

Intro———-Nuclear Technologies———-Carbon Capture———-Artificial Intelligence

Decarbonizing our societies won’t be enough to prevent further global warming and avoid irreversible damage to our ecosystems. While it will surely help mitigate the effects of both crises, the concentration of GHGs in our atmosphere is already too high. We need ways to pull GHGs out of the atmosphere to start reversing global warming [with negative GHG emissions], not just slow it down. Numerous carbon capture solutions can help with that during our transition from fossil fuels to renewables, and afterward.

Carbon Capture Technologies

Switching from fossil fuels to renewable sources of energy will take time, especially since it’ll depend on how fast we can reduce our energy consumption. Even then, completely phasing out fossil fuels will likely be impossible [in the near future] since we’d need every country in the world to get on board – and frankly, some underdeveloped countries have bigger fish to fry right now.

With that in mind, the 100% emission-free world that some had envisioned by 2050 seems unrealistic. However, carbon capture technologies can help reduce emissions coming from the remaining polluters.

Theoretically, there are loads of ways to capture carbon, but 2 technologies in particular stand out for ‘artificial’ carbon capture [i.e. not through basic natural processes]:

  • One of the most practical ways of capturing CO2 emissions is by doing so at the source. For example, carbon capture can take place directly at a fossil fuel power plant, by separating CO2 from other waste gases after combustion.
  • Alternatively, carbon capture can be achieved anywhere on Earth by filtering out CO2 from the atmosphere by taking advantage of some of its chemical properties [‘direct-air’ CO2 capture].

It’s important to note that both these carbon capture systems require energy, which could potentially cause more fossil fuel extraction, and more consumption of other resources depending on the CO2 capture method.

It’s pretty clear from the get-go that capturing CO2 from a fossil fuel power plant’s emissions doesn’t help remove CO2 from the atmosphere – it’s more of an emission control measure if anything. Contrarily, direct-air CO2 capture could remove carbon from the atmosphere. In any case, we have to look at how much carbon can be captured and where it all ends up before evaluating if these systems are useful.

Unproven Technologies

While industrial ‘carbon capture and utilization’ is becoming more common, direct-air technologies remain unproven at the required scale. For example, the world’s largest facility captures only 4,000 tonnes of CO2 from the atmosphere per year. The world emitted 36.42 billion tonnes of CO2 in 2018, and other GHGs were released too.

This 0.00001% capture of global emissions shows why many expert groups, including the IPCC, are skeptical of these new technologies that are often praised as “climate change savers”.

Utilization and Storage

Burying captured CO2 deep underground or on the ocean floor sounds like a good idea, but there’s very little incentive for companies to do so. The buried CO2 can’t be sold to anyone, so it relies on carbon credits and government subsidies. However, due to the very small amount of CO2 that can actually be captured, relying on carbon credits often doesn’t make much financial sense. Additionally, the long-term effectiveness and impacts of underground storage are both highly uncertain.

To get rid of these challenges, some companies have decided to forget the whole storing aspect of carbon capture. Instead, they’ve developed ways to use the CO2 in industrial processes. The clear advantage here is that there’s a financial incentive to capture carbon. Unfortunately, utilization is often more of a CO2-efficiency measure rather than a carbon removing process.

Vegetation

Vegetation is truly the greatest carbon remover. Currently, it absorbs around 25% of our yearly CO2 emissions.

Vegetation is by far the most cost-effective solution, since it stores carbon in biomass [e.g. trunk, roots] and soil free of charge. Also, it can improve biodiversity in select areas, by providing habitats for many species at once. Lastly, this type of carbon capture system doesn’t depend on a steady output of CO2 emitted from a fossil fuel plant, it just takes it straight out of the atmosphere instead. That means carbon storage can continue long after we’ve phased out fossil fuels, which will be necessary.

Challenges

One of the main problems is the uncertainty of how long the carbon will remain stored in the soil. Depending on a variety of factors, that can range from decades to centuries. Additionally, if the ecosystem is later cleared to convert the land for other purposes [e.g. intensive agriculture], carbon stored in biomass and soil can find its way back into the atmosphere.

However, as long as good carbon storing practices are developed and maintained, vegetation and soils will act as carbon sinks.

Growing and burning biomass to remove CO2 from the atmosphere is another increasingly popular solution proposed by climate scientists. Evidently, this only works if the carbon released from burning biomass is captured. The main benefit from this solution is that vegetation can be grown in cycles on a limited amount of land to continuously remove CO2 from the atmosphere. This avoid having full grown trees that capture less carbon use up all the land. Figuring out where to store the large amounts of captured CO2 will be the main challenge for this solution.

Conclusion

In the future, all effective carbon capture technologies will be needed to mitigate climate change. However, investing time and energy into unproven solutions that currently yield insignificant results can do just the opposite.