Capture, use, transport and storage of CO2 require energy which results in GHG emissions and other environmental impacts. Current CCS technologies with 85–90% CO2 capture rates typically provide around 50–70% overall CO2 emission reduction. Increasing the emission reduction above 80% requires CO2 capture rates that exceed 90%. Most of the CO2 emissions associated with CCS are related to capturing and transportation the CO2 as they rely mainly on fossil fuels (Burger et al., 2024). Net CO2 emissions related to CCU supply chains may depend on the need for hydrogen and the overall energy input, especially electricity (Garcia‐Garcia et al., 2021). Assessing CO2 emissions related to electricity demand is not straightforward, as system level consequences may be very different from those attributed to a specific supply chain (Soimakallio et al., 2011).
Land use effects related to bio-CCS or bio-CCU technologies depend on the case and assumptions. Deployment of bio-CCS or bio-CCU may potentially lead to increased biomass utilisation (i.e. increased harvests) or reduce the desirability of minimizing biomass use. However, biomass use is not affected if capture of CO2 is applied in existing bioenergy plant that would have continued emitting CO2 into the atmosphere in the reference system (i.e. without CO2 capture). On the other hand, if capture of CO2 is applied in a new bioenergy plant which would have not been built without the capture of CO2, or if the capture of CO2 results in continuation of biomass use that would have otherwise ceased, then biomass use increases compared to the reference system without deployment of CCUS. If increased biomass use leads to increased harvests, the harmful effects of harvesting on land ecosystem carbon stocks may exceed the credits biomass capture and use and/or storage provides for decades (Fuss et al., 2018; Soimakallio et al., 2021).
If land use is affected by bio-CCS or bio-CCU technologies, for example maintaining intensive land use practices, then the broader environmental and sustainability issues, such as harmful biodiversity and social impacts are related to deployment of these technologies. In addition, CO2 storage is subject to risks related to overpressure, which could lead to pollution of potable water, to seismic activity or to leaks (Fuss et al., 2018). These risks need to be addressed for sustainable deployment of these technologies.
The EU RED III directive (2023/2413) provides sustainability criteria for renewable energy sources, including renewable fuels of non-biological origin, which means liquid and gaseous fuels derived from renewable sources other than biomass (EU, 2023j). These criteria capture certain direct GHG emissions that are considered to be part of supply chain emissions. However, they exclude indirect market-mediated effects and direct land use effects, which means that potentially the most significant consequences are ignored (Soimakallio & Koponen, 2011). At the moment, it is an open question what kind of sustainability criteria are to be applied for bio-CCS, but the CRCF draft methodology states that individual operators shall ensure compliance with RED III criteria (ICF, 2025).
Funding is currently distributed through national schemes with varying project requirements and sustainability criteria. This experimentation phase provides opportunities to study climate impacts and broader public consultation about the role of CCUS. Recently the Swedish Energy Agency commissioned a nation-wide survey to study how knowledge, attitudes and perception of the general public with regards to CCS in Sweden (Swedish Energy Agency, 2025b) The study found broad interest in learning more about CCS, what technology means in practice, safety and costs.
Overreliance on future technologies for meeting climate targets presents a significant risk of failure. For example, CCUS projects may be delayed or not implemented in a required scale due to technical issues, acceptance or high costs. In addition, CCUS technologies may deliver lower overall climate benefits than expected. These risks should be taken into account in climate strategies by maintaining high ambition in emission reductions across the economy.