Using geothermal energy to future-proof the energy mix

By Alison Auld, Shift Geothermal

Geothermal energy: a consistent renewable energy source (illustration: Shift Geothermal)
Geothermal energy: a consistent renewable energy source (illustration: Shift Geothermal)

Geothermal power generation is witnessing rapid growth worldwide, with installed capacity having grown by approximately 75% in the last 5 years. It can provide a consistent renewable energy source, in contrast to the intermittency of most other renewables, but there are also real challenges to pursuing the recovery of geothermal energy.

The costs and risks of drilling down deep enough to recover geothermal heat are high, thus increasing the challenge of making a business case in all but the most lucrative projects. An alternative concept Shift Geothermal is developing is to use existing oil and gas assets to recover geothermal energy.

Many oil and gas fields produce huge volume of hot water as a by-product which is disposed of. Traditionally this hot water is seen as less valuable than the fossil fuels produced, but the balance may be changing as climate change mitigation looms.

By taking this approach, the offshore location of many of the wells, the aging condition of offshore platforms, and scaling the technology for them remain real engineering challenges. However, the major risks from drilling and exploration for geothermal energy are not applicable, as the wells already exist, and production is underway, meaning that the risk has already been absorbed by the oil and gas companies.

Reducing emissions
The offshore energy landscape is increasingly diverse, with offshore wind turbines, electricity interconnectors, hydrogen electrolysers, and carbon capture and storage all vying for space. We can expect the infrastructure to continue developing, so exporting flexible on-demand electricity from ex-hydrocarbon, now geothermal power plants, back to shore could be a realistic possibility in the not-too-distant future.

In the meantime, continued extraction of fossil fuels is the reality of our short-term energy future. Blue hydrogen production requires natural gas, and chemicals and plastics from oil are still necessary. In this context, an immediate action could be to decarbonise some or all of the energy required for oil and gas production with geothermal energy.

The greenhouse gas emission footprint of oil and gas production is significant – a typical platform could require approximately 25 MW electrical capacity, and this is usually met by using turbines fuelled with natural gas. As the economic pressure grows from a strengthening carbon price, the cost of electricity increases and so does regulator pressure to decarbonise operations, it would seem logical to review whether geothermal energy can improve operating costs and decrease greenhouse gas emissions.

Shift Geothermal proposes the use existing oil and gas assets to recover geothermal energy
Shift Geothermal proposes the use existing oil and gas assets to recover geothermal energy (photo: Shift Geothermal)

Catalyst for projects
To realise the huge potential of this untapped energy source, Shift Geothermal, a non-profit organisation of respected academics and industry experts, has launched a bid to establish a new National Centre for Geothermal Energy in the UK. The organisation is seeking government and industry support to accelerate coordinated research and act as a catalyst for projects. It will identify and progress demonstrator and at scale projects and lobby for legislative and regulatory structures to establish geo-energy as part of the future energy mix. 

Clean geothermal energy can come in many forms with new and ground-breaking ideas continually being developed. Crucially, the energy produced is not dependent on weather conditions and has a high capacity for electrical power output compared to other low carbon sources.

Catalyst for research
The landscape of geothermal energy development is extending to low-temperature power conversion. With concentrated efforts to mature the technologies commercially viable conversion efficiencies may now be possible. The value of the opportunity is not purely the geothermal energy resource but also the knowledge and expertise developed over decades of subsurface engineering in the oil and gas industry. Further technology development is still required to turn this theoretical resource into a viable opportunity, but data shows the geothermal resource is too significant to ignore.

A new National Centre for geo-energy would not only galvanise support for this burgeoning industry but act as a catalyst for research and test projects to scale geo-energy using oil and gas infrastructure, helping to secure jobs and opportunities for the supply chain.

Dr Alison Auld, director of Shift Geothermal, is a mechanical engineer whose extensive knowledge of power generation and energy consumption has allowed her to work across industry, government and academia in practical delivery, advisory and research capacities. Her roles have included reducing energy consumption and GHG emissions across the Scottish malt whisky industry. She has also worked as a senior engineer for the UK government, a role which included exploring and evaluating innovation and providing technical support in the fields of unconventional oil and gas, geothermal energy, and industrial waste heat recovery. While serving in Whitehall, Auld provided engineering and technical support to various teams within DECC and managed projects to provide evidence to inform future government policy decisions. Alison’s significant body of research on energy related topics includes pioneering work on the generation of electricity from coproduced fluids from oil wells which has informed much of the current development in this area.