Can technology unlock unburnable carbon?

A new white paper suggests that if carbon capture and storage (CCS) technology can be refined, it will enable the world to use more of its ‘unburnable carbon’.

Currently, CCS technology is capable of capturing approximately 85–90% of total CO2 emissions, with the remaining 10–15% of residual emissions emitted into the atmosphere. In the new study, researchers from the Sustainable Gas Institute at Imperial College London argue that if these residual emissions could be reduced to around 1–5%, this would enable the world to unlock much more of its fossil fuel reserves, whilst staying within target limits for global temperatures.

The concept of ‘unburnable’ carbon first emerged in 2011. It stemmed from observations that if all known fossil fuel reserves are extracted and used, then CO₂ emissions would exceed the world’s carbon budget and have a significant negative effect on the global environment. Governments agreed at the Conference of the Parties in Paris (COP21) meeting to limit global warming to less than 2°C. To achieve this a large proportion of fossil fuels would need to remain untouched or unburnable.

Now, researchers from Imperial have developed models that predict the impact of CCS on the use of fossil fuel resources, assuming the technology continues to improve its capture rates. They calculate that that the CCS technology could enable more of these unburnable fossil fuel resources to be unlocked over this century, while still limiting global warming to 2°C.

The overall message from the report is that CCS is an important technology, which needs to be implemented globally alongside alternative low carbon sources, such as renewable energy, if climate targets are to be met this century.

Previous studies exploring the impact of CCS on unburnable carbon have only considered a timeframe of up to 2050 – during which time CCS would be expected to have a relatively small impact on the amount of fossil fuels that can be used.

In the new white paper, the team extended the timeframe to 2100. The modelling showed that up to a third more fossil fuel resources could be consumed globally, than if CCS was not in use, while still remaining in 2°C limitations.

Calculations up to 2050 show that around 3,500 to 5,000 exaJoules could be consumed if CCS was implemented globally, but by 2100 this increases to 14,000 to 16,000 exaJoules. The team say that is enough energy to power the US for 140 to 160 years.