By Emily Cracknell
CO2 RE’s third Pathfinders Call sought research projects focused on innovation that had the potential to deliver safe and durable GGR storage solutions for at least a 1000 years.
Successful GGR requires that we not only remove, but permanently store significant amounts of CO2 in perpetuity, isolating it from the atmosphere in environmentally safe ways. While the number of GGR techniques, and their potential to responsibly remove CO2 at scale, has increased, progress towards carbon storage capacity has been slower.
These five innovative projects, awarded up to £75,000 each, seek to improve upon carbon storage capacity, an essential component to sustainably meet net-zero emission targets.
Seagrass Enhanced WeatherING: Assessment of the Greenhouse Gas Removal potential of enhanced rock weathering within seagrass meadows (SEWING)
Led by Feifei Deng from the National Oceanography Centre, SEWING aims to evaluate the influence of marine vegetation (seagrass) on weathering rates, and to explore the potential for achieving effective Carbon Dioxide Removal (CDR) by applying Enhanced Weathering (EW) in the sediment of seagrass meadows.
While Enhanced Weathering on land, using fine-grained silicate rock, has the potential to enable atmospheric CDR, achieving long-term storage via this method requires high-weathering rates and effective transport of captured CO2 into the ocean.
SEWING represents the first critical step to evaluate possible synergistic benefits of implementing EW within seagrass meadows, including the potential that EW within seagrass meadows will enhance coastal restoration efforts as EW may provide the nutrients needed to promote seagrass growth and resilience, as well as creating a new source of financial revenue that can support CDR initiatives.
Calcium oxide and lysine functionalised hydrochar: Enhancing carbon dioxide uptake from air and durability of storage in hydrothermally carbonised biowastes (CaLyChar)
Led by Humbul Suleman, from Teeside University, working in collaboration with colleagues from the University of Edinburgh, the project aims to create a functionalised material, CarlyChar, that can directly capture CO2 for years, once carbonised, and permanently store it as a stable carbonate.
CalyChar would be an advanced form of hydrochar, a charcoal-like material formed by using heat and water to treat organic/bio waste in a process known as hydrothermal carbonisation. By combining hydrochar with materials such as amino acids and metal oxides to create CalyChar, the researchers aim to overcome hydrochar’s traditional limitations in CO2 capture.
By 2030, CalyChar has the potential to capture 3.5–5 million tonnes of CO2 in the UK, and nearly 30 million tonnes of CO2 globally, annually, at a cost of around £100 per tonne CO2 – considerably less than current direct air capture technologies. Additionally, CalyChar could be used in bio-concrete and bio-cement, offering long-term carbon storage while creating jobs and driving growth in construction and agriculture.
This project will also explore the environmental impact of adding carbonised material to soils and wetlands, with expert support from the Tees River Trust, a river habitat conservation body in North East England.
Afforestation, BECCS and Biochar Synergy (ABBS)
Led by Ondřej Mašek, from the UK Biochar Research Centre, University of Edinburgh, this project aims to mitigate climate change impacts and maximise atmospheric carbon removal and long-term storage through an innovative triple synergy of Bioenergy with carbon capture and storage (BECCS), biochar production and afforestation/reforestation initiatives.
The triple synergy addresses several critical issues. ABBS provides a solution to the waste management challenges of BECCS by repurposing ash, an unavoidable waste in biochar production. The team’s earlier research has indicated that metals, such as Phosphorus and Potassium in biomass ash act as a catalyst, promoting higher retention of carbon in biochar. This enriched biochar not only sequesters carbon more effectively but can also act as a source of nutrients in soil applications, such as forestry, facilitating better tree establishment and growth in afforestation and reforestation efforts. This integrated approach significantly advances the carbon removal capabilities of these technologies.
Proof of concept for combining mechanochemically processed rock waste to mineralize CO2 from Direct Air Capture (DAC)
Led by Mark Stillings, from University of Strathclyde, this project will explore a novel treatment for mine waste that could transform waste rock into a viable material that can be used to support atmospheric carbon dioxide removal and mineral sequestration.
This project aims to valorise mine waste by mechanochemically increasing the chemical availability of calcium and magnesium which can then be used to mineralise the CO2 from hydroxide-based DAC systems. Mechanochemical treatment involves using the mechanical energy during rock grinding to initiate chemical reactions with effluent gas streams, which would otherwise require high temperatures and pressures to occur. These mechanochemical reactions can alter the chemical availability of metal atoms on the rock surface increasing the availability of carbonate forming metals for use in CO2 sequestration.
If successful, this process can provide an alternative sink for the CO2 . Thereby removing the requirement for chemical regeneration and reducing the energy required for liquid-DAC.
Demonstration of predictive modelling for increased durability of biochar carbon removal
Led by Saran Sohi, from University of Edinburgh, this project will explore an alternative to biomass carbonisation, where simulated ageing will be imposed directly to biochar made from diverse biomass.
The project aims to predict the durability of the biochar, before it has been produced. Traditionally biochar’s carbon storage has been based on direct laboratory observation, which has often given lower estimates of durability due to the uncertainty of projecting forward hundreds or thousands of years.
Using predictive modelling this project will find out whether we could eventually model the value of potential biochar options, based only on the measurable properties of available biomass.
Photo by Ajay Kumar on Unsplash
