Sizewell C looks at capturing CO2 from the atmosphere using nuclear heat

SIZEWELL C, in the UK, is developing plans to demonstrate how heat from a nuclear plant could be used to power direct air capture (DAC) technology to suck CO2 emissions from the atmosphere.

Sizewell C and ports operator Associated British Ports plan to lease land at Lowestoft port where they will build a demonstrator for a DAC process in partnership with the universities of Nottingham and Birmingham, and engineering firms Helical, Atkins, and Altrad Babcock. Last year, the partners received £3m (US$3.7m) in funding from the UK government to design a demonstrator capable of capturing 100 t/y of CO2. This followed successful pilot trials at the University of Nottingham in 2021. Whereas conventional DAC technology relies on electricity or natural gas to power the process, the partners want to use low-carbon heat from nuclear operations to drive the CO2 capture and extraction. If the demonstrator proves successful, the collaborators say they will install a commercial-scale DAC plant close to the Sizewell C nuclear facility, and pipe heat to it through underground pipelines to fuel capture of 1.5m t/y of CO2.

The technology relies on a heat-driven solid adsorbent to capture CO2 from the air. Once saturated with CO2 it is transferred to a desorber loop where heat is used to release the CO2, which can then be sent for storage. The regenerated absorbent is returned to the absorber loop to capture more CO2.

The UN Intergovernmental Panel on Climate Change (IPCC) has said that large-scale deployment of CO2 removal technologies is needed to meet net zero targets. The technology is in the early stages of deployment with the IEA reporting last year that 18 plants had been installed around the world, capturing a combined 10,000 t/y of CO2. Capture costs are estimated to vary from around US$250–US$600/t of CO2, but these are expected to fall as technologies are scaled up and rolled out. The US Department of Energy launched an initiative in 2021 aimed at bringing costs down to less than US$100/t over the coming decade. Nottingham’s Cheng-Gong Sun, who helped develop the heat driven DAC process that Sizewell plans to install, has said he expects the technology has the potential to meet this target.

The Royal Society has warned that process heat produced at nuclear plants is proving a wasted opportunity and could be put to use producing hydrogen or providing domestic heating.

While still at relatively small scale, efforts are underway to increase the use of DAC. The US government announced last year that it would invest US$3.5bn creating four large-scale DAC hubs.

Sizewell C is being developed by EDF. It plans to build a 3.2 GW nuclear power station next to its existing Sizewell B station in Suffolk. The project was granted development consent last year and is expected to start generating power in the early 2030s.