Research and analysis

Low carbon subsurface technologies: identifying potential environmental impacts - summary

Published 21 October 2021

Applies to England

1. Chief Scientist’s Group research report summary

This project examined the potential impact of low carbon subsurface technologies on the environment. This will provide the Environment Agency and others with evidence to help regulate these technologies and prevent unintended environmental impacts in the future.

1.1 Background

The UK government’s ambition to reduce greenhouse gas emissions by 68% of 1990 levels by 2030 is likely to result in changes to the energy mix in the near future. Many new ‘low carbon’ technologies that use the subsurface (below ground) to extract and store green energy and to reduce carbon dioxide (CO2) could potentially be commercialised in the UK in the coming years. The Environment Agency wants to understand the potential environmental risks to air, land and water of these technologies and their use of the subsurface, to prevent environmental harm and/or unintended barriers to their development.

1.2 Approach

The project reviewed available literature to identify the possible environmental impacts of different technologies. These included energy extraction and production, retrievable energy storage and underground hydrogen storage, as well as permanent underground storage of carbon dioxide.

The potential environmental impacts were then used to create source-pathway-receptor (SPR) models for each technology.

The report highlights gaps in understanding about the potential environmental impacts of each of the technologies.

1.3 Findings

The report details specific risks for each technology. The technologies assessed vary in current commercial viability. Some potential environmental impacts are the same for different technologies, whereas others are different. The main risks are:

• Environmental risks/activities/impacts that we understand and can mitigate with a good understanding and/or transferable knowledge from other technologies (for example, drilling of wells).
• Environmental risks that are similar to other technologies, although scale and particularities may be different, and will need specific assessment (for example, seismicity, well corrosion).
• New environmental risks that are poorly understood, such as the impact of storing new/different substances in the subsurface (for example, hydrogen) and specific environmental impacts (for example, subsurface ecology) that will require greater understanding.
• No new geological environments are being proposed for use, but uses may differ and there may be wider use of the subsurface.

1.4 Conclusions

This report summarises potential environmental impacts from low carbon subsurface technologies and identifies some important gaps in knowledge that should be investigated further to inform effective environmental regulation of these technologies in the future.

1.5 Project details

This summary relates to information from the following project:

• Report: SC200005

• Title: Low carbon subsurface technologies: identifying potential environmental impacts

• Project manager: Sian Loveless, Chief Scientist’s Group

• Project executive: Alwyn Hart, Chief Scientist’s Group

• Research Contractor: WSS Energy Consulting, Export House, Cawsey Way, Woking, GU21 6QZ

This project was funded by the Environment Agency’s Chief Scientist’s group, which provides scientific knowledge, tools and techniques to enable us to protect and manage the environment as effectively as possible.

Enquiries: research@environment-agency.gov.uk

© Environment Agency