Feasibility of Gigatonne-Scale CO2 Storage by 2050

Carbon capture and storage, or CCS, is often touted as a key solution in the fight against climate change. But how much CO2 can we realistically store underground by 2050? A new study challenges some overly optimistic projections and offers a more grounded view of our carbon storage potential.

The Intergovernmental Panel on Climate Change, or IPCC, has projected that we could store anywhere from 1 to 30 billion tonnes of CO2 underground each year by mid-century. However, these estimates don't fully account for real-world limitations. Researchers have now developed a more comprehensive model that considers geological constraints and realistic growth rates for CCS technology.

Their findings? The maximum feasible global storage rate by 2050 is likely around 16 billion tonnes of CO2 per year. That's significantly lower than the IPCC's highest projections. Even more sobering, a more realistic benchmark might be just 5 to 6 billion tonnes annually.

Why such a big difference? The new model takes into account factors often overlooked in previous projections. Not all underground formations are suitable for CO2 storage. Some rocks may be too porous or lack sufficient space. There are also geographical challenges – ideal storage sites might be far from major CO2 sources, making transportation difficult and expensive.

The researchers examined potential storage rates across ten regions with active or planned CCS projects. They found that six areas will largely determine our global storage capacity: the United States, China, the United Kingdom, the European Union, Canada, and the Middle East.

Interestingly, the study suggests the United States could contribute up to 60% of the total global storage. However, if U.S. deployment aligns with current government roadmaps, the global limit drops to about 6 billion tonnes per year – much closer to the researchers' proposed realistic benchmark.

This new analysis reveals a significant gap between some existing projections and what's likely achievable. Many integrated assessment models used for climate planning assume we'll be storing over 10 billion tonnes of CO2 annually by 2050. These models may be overestimating the potential contributions from countries like China, Indonesia, and South Korea.

It's crucial to note that there's still a lot of uncertainty in these estimates. Storage resource calculations can vary by orders of magnitude – the highest estimates might be 10 to 100 times larger than the lowest. This uncertainty can only be reduced through further project development and detailed studies of potential storage sites.

So, what does this mean for our climate change mitigation efforts? While the study suggests significant CO2 storage is possible, it also indicates we may need to temper our expectations. Many current projections could be overly optimistic about the role CCS can play in reducing emissions by mid-century.

This research underscores the importance of using realistic constraints in climate modeling. It doesn't mean we should abandon carbon capture and storage efforts. Instead, it highlights the need for continued research and development of CCS technologies, alongside a diverse portfolio of other mitigation strategies.

As we navigate the challenges of climate change, it's vital that our plans are grounded in achievable goals. This study provides a valuable reality check, helping to align our carbon storage ambitions with what's geologically and technologically feasible. By basing our strategies on more realistic projections, we can better allocate resources and focus on a balanced approach to emissions reduction.

The path to a low-carbon future remains complex, but with clearer understanding of our options, we can make more informed decisions. How will this recalibration of carbon storage potential influence climate policies and investment in various mitigation technologies? That's a question policymakers and researchers will need to grapple with as we continue our efforts to combat climate change.