Geothermal and thermal storage modelling

What we can help you with

Where should wells be placed, how much heat can be stored, and how will temperatures evolve over years of operation? Simulation makes it possible to investigate these questions before construction and to assess changes to existing installations.

We work with industrial partners and research organisations to:

• Model coupled fluid flow and heat transport in porous and fractured formations.
• Assess storage capacity, thermal losses and long-term temperature development.
• Investigate well placement, interactions between wells and alternative operating strategies.
• Optimise heat production and seasonal storage subject to operational constraints.
• Develop simulation tools and methods for model updating and decision support.

Contact our Applied Computational Science research group to discuss modelling a new installation, improving operations or developing simulation tools for your application.

Heat production and seasonal storage

Geothermal installations extract heat from the subsurface, while underground thermal energy storage allows surplus heat to be retained for periods of greater demand. Both require an understanding of how heat and fluid move through the ground, and how wells and geological conditions affect system performance.

Our work covers aquifer thermal energy storage (ATES), high-temperature ATES (HT-ATES) and borehole thermal energy storage (BTES). We also study systems in which flow through fractures has a significant influence on heat transport.

Through longstanding collaboration with industrial partners and researchers at the University of Geneva, we have developed open-source simulation software for these applications. This work draws on our experience in numerical methods and reservoir simulation, adapted to the challenges of heat production and storage.

From planning to operational support

Before construction, digital models can be used to compare well configurations, system dimensions and operating strategies. During operation, models can help interpret temperature and production trends and assess changes such as additional wells or a different seasonal balance between heat extraction and storage.

We develop technology to support digital twins in which physics-based models are updated using measurements and operational data. This includes model calibration, sensitivity analysis and optimisation, as well as connections between subsurface models, surface installations and operational constraints.

We also work with reduced models that allow many alternatives to be assessed quickly. The choice of model depends on the question, the available data and the decisions the calculations are intended to support. We can help adapt the tools and provide training in building and using the models.

Open and differentiable simulation tools

Our software development builds on many years of experience with MRST. We extend this expertise through Fimbul.jl, a geothermal simulation toolbox written in Julia and built on JutulDarcy.jl and Jutul.

Fimbul combines efficient computation with differentiable models. This makes it possible to calculate how results depend on model parameters and control variables, and to use this information for model calibration and optimisation of design and operation. Open source code allows the methods to be inspected and the tools to be extended to new applications.

Selected projects

• GHOST DigiT: Digital solutions for geological heat storage
• Digitalization of multi-reservoir geothermal systems for optimal control of heat production and peak-load management

Publications

• Klemetsdal, Andersen and Møyner (2025). Fimbul.jl – Fast, Flexible, Robust, and Differentiable Geothermal Energy Simulation in Julia. Sixth EAGE Global Energy Transition Conference & Exhibition.
• Klemetsdal and Andersen (2024). Proxy Models for Rapid Simulation of Underground Thermal Energy Storage. Fifth EAGE Global Energy Transition Conference & Exhibition.
• Andersen and Klemetsdal (2024). Conceptualizing, Simulating and Optimizing the Integrated Operation of a Multi-Component UTES System. 85th EAGE Annual Conference & Exhibition.
• Minakov et al. (2024). Basin-Scale Modeling of the Baia Mare Geothermal and Ore-Forming System. 85th EAGE Annual Conference & Exhibition.
• Klemetsdal et al. (2023). Modelling and optimization of shallow underground thermal energy storage. Geoenergy.
• Collignon, Klemetsdal and Møyner (2021). Simulation of Geothermal Systems Using MRST. Book chapter in Advanced Modeling with the MATLAB Reservoir Simulation Toolbox.
• Collignon et al. (2020). Evaluating thermal losses and storage capacity in high-temperature aquifer thermal energy storage (HT-ATES) systems with well operating limits: insights from a study-case in the Greater Geneva Basin, Switzerland. Geothermics.
• Collignon et al. (2020). 3D Basin-Scale Groundwater Flow Modeling as a Tool for Geothermal Exploration: Application to the Geneva Basin, Switzerland-France. Geochemistry, Geophysics, Geosystems.

Read more

• GHOST DigiT: Results, demonstrators and further reading on underground thermal energy storage.
• Predictive digital twins for optimal operation of GeoTermos. Presentation at the GeoTermos Festival 2025 (PDF, in Norwegian).
• A breakthrough could play a key role in the future energy system. Opinion piece in Altinget, June 2025 (in Norwegian).