Assessing carbon capture and mineralization storage in the Olkaria Geothermal Field, Kenya

Kenya’s primary energy demand is expected to increase sevenfold by 2040 in-line with its vision for accelerated economic and industrial development. Central to this is the development of Kenya’s geothermal sector, currently accounting for 48.4% of electricity consumed. National laws and policies target an increase in geothermal capacities from 865 to 5,000 MWe by 2030. As geothermal development accelerates, cumulative geothermal-related CO2 emissions are expected to rise, such that the risk of a carbon lock-in may increase if mitigation practices are not implemented. This study aims to determine the carbon capture and mineralization (CCM) storage capability of Kenya’s most developed geothermal field; Olkaria, using the Olkaria IV Geothermal Power Plant as its case study. Reaction path models reveal that the Olkaria Trachyte (ROT) has 0% carbon sequestration because of increased competition for divalent cations with epidote, chlorite and zeolite phases at high reservoir temperatures (270°C). Whereas the Olkaria Basalt (ROB) can sequester up to 84% of injected CO2 provided the pH of the fluid mixture is ~ 9. Assuming present-day carbon capture efficiencies from geothermal exhaust streams (56% CO2 captured) hold true for a Kenyan CCM case-study, 34,773 tCO2 yr-1 of Olkaria IV’s emissions can be stored in ROB. Furthermore, a comprehensive review of Kenyan geothermal-related environmental regulations and accessibility to international climate finance for mitigation projects, suggests that legislation and multilateral finance mechanisms could act to support the deployment of CCM activities in Kenyan geothermal industries.

Short Bio
Charlotte Barlow is an MSc. Geology student at the University of Iceland, completing her studies focusing on coupling geothermal energy to carbon capture and storage (CCS) systems, graduating in June 2022. After completing her Geology BSc. at the University of St. Andrew’s in 2020, she was inspired by the Icelandic carbon capture and storage (CCS) company, CarbFix, to continue her studies focusing on the expansion of carbon mineralization storage to other geographical locations. Having grown up in Southern Africa, Charlotte values ensuring that green innovative energy practices are transferred to the Global South, in order for nations to build climate-resilient economies and fulfill development goals. In September 2022, she will be moving to Oxford to work as a Graduate Analyst for Aurora Energy Research.