Thermogeological Assessments
Igne’s thermogeological assessments evaluate ground conditions for geothermal systems, ensuring accurate feasibility, efficient design, and long-term performance.
Thermogeological Assessments
Understanding how heat behaves underground is fundamental to designing and delivering effective geothermal energy systems.
About
Thermogeological Assessments
Thermogeological assessments provide the crucial data that engineers and developers need to make confident decisions before drilling begins.
At Igne, our in-house specialists deliver comprehensive, high-resolution thermogeological assessments that unlock the potential of below-ground heat, reduce risk, and optimise system performance.
The explanation
What is geothermal energy and why does it need assessing?
Geothermal energy is the naturally occurring heat within the Earth. This renewable resource can be extracted and used to heat (or even cool) buildings and infrastructure.
However, successful geothermal projects don’t start with drilling. They start with data.
A thermogeological assessment investigates the physical, chemical, and thermal characteristics of the ground. It provides detailed insights into:
- The temperature gradient with depth
- Thermal conductivity of soil and rock layers
- Groundwater flow and temperature
- Soil and bedrock composition
- Subsurface stratigraphy and structure
This data helps to accurately model how heat can be exchanged between the ground and a heat pump system, ensuring long-term reliability and efficiency.
Thermal Response Test
How boreholes are used to access & understand underground heat
Before geothermal boreholes can be drilled, you need to know exactly what lies beneath the Earth’s surface.
Thermogeological assessments typically involve drilling a test borehole, known as a Thermal Response Test (TRT) well, which is then used to gather real-world data about subsurface thermal properties.
Igne provides both TRT borehole installation and ongoing monitoring.
From there, computer modelling is used to simulate how heat will behave in the ground over time, depending on the type of system being installed. For closed loop systems, this means predicting the behaviour of circulating heat transfer fluid. For open loop systems, it involves modelling how water is extracted and re-injected into aquifers.
Igne has delivered borehole assessments for every kind of geology, from fractured limestone to clay-bound sedimentary formations. With expert insight and industry-specific experience, we can predict heat behaviour even in complex or challenging conditions.
Getting it right
Essential for System Design, Sizing & Performance
Thermogeological data ensures that your geothermal system is not only fit-for-purpose, but also cost-efficient. Without accurate modelling, systems can be over-engineered (increasing cost) or underperforming (reducing lifespan and efficiency).
With a robust thermogeological assessment from Igne, you can:
- Determine the exact number and depth of boreholes required
- Understand seasonal and long-term system behaviour
- Assess feasibility of open loop versus closed loop options
- Estimate return temperatures and required flow rates
- Ensure compliance with GSHPA and MCS standards
We work closely with consultants, mechanical and electrical engineers, planners, and developers to ensure geothermal design is fully integrated with your building systems and operational goals.
The applications
Where are thermogeological assessments especially valuable?
Thermal modelling is essential for almost every geothermal system, but it is particularly valuable in:
- Data centres and server farms (where cooling demands fluctuate)
- Hospitals and schools (with critical reliability needs)
- District heating networks (serving multiple buildings)
- Retrofits of large buildings with unknown subsurface conditions
- Minewater geothermal and aquifer-based open loop systems
By understanding how much heat you can extract without long-term thermal depletion, you can futureproof your investment and make confident, sustainable decisions.
Invaluable insight
Optimising Open Loop Geothermal Systems
Igne has particular expertise in open loop geothermal drilling. Open loop systems involve abstracting groundwater, extracting its heat via a heat pump, and re-injecting it back into the aquifer it came from. Thermogeological assessments are critical here, as you must understand:
- The temperature and yield of the aquifer
- Distance and separation between abstraction and reinjection wells
- Risk of thermal interference or short-circuiting
- Chemical composition of groundwater (for equipment compatibility)
Open loop systems tend to have a smaller surface footprint than horizontal closed loop systems, as they go vertically into the ground. This makes them ideal for space-limited sites or urban developments.
Sustainability
Thermal Sustainability & Environmental Assurance
A key advantage of open loop systems is their sustainability. Because water is re-injected into the same aquifer, the environmental impact is minimal. Thermogeological assessments demonstrate that the system will not deplete groundwater resources or cause downstream heating or cooling effects.
At Igne, our assessments are always carried out in accordance with Environment Agency and Scottish Environment Protection Agency guidelines, ensuring that every design meets environmental permitting standards and delivers long-term thermal balance.
FAQ
Frequently Asked Questions about Thermogeological Assessments
- How deep does a thermal response test borehole need to be?
Typically between 50 and 400 metres, depending on your system requirements. Deeper installations may be needed for high-demand buildings.
- How long does a thermal response test take?
Usually between 3 and 7 days, depending on test type and site conditions.
- Can I use desktop modelling instead of real-world testing?
You can, but it comes with increased risk. Real-world testing provides far more reliable data for system sizing and performance.
- Do I need a thermogeological assessment for a closed loop system?
Yes, even for closed loop systems, understanding the thermal conductivity, ground conditions and ground temperature is essential for design.
- Is this service available across the UK?
We have delivered assessments across England, Wales, Scotland and Northern Ireland, in all geological settings.
- Why choose Igne for thermogeological assessments?
Igne is a trusted partner to consultants, developers, and renewable energy providers across the UK. With decades of drilling and ground modelling experience, we provide not only the testing and data, but the expertise to interpret and apply it to your project’s unique needs.
The next step
Call the experts & get it right
Our team understands the practical constraints of construction programmes and works collaboratively to ensure your geothermal solution is designed right first time.
Thermogeological assessments are the bedrock of successful geothermal systems. Whether you’re looking to power a public building, private development or entire district heating network, Igne will ensure your design is built on evidence, not estimates.
Get in touch today to speak with our geothermal team and find out how we can support your project from test borehole to final commissioning.
Open Loop Geothermal Drilling
Igne delivers open loop geothermal systems that extract and return groundwater for heating and cooling, combining hydrogeological insight with drilling expertise.
Closed Loop Geothermal Drilling
Igne installs closed loop geothermal systems to deliver efficient, low-carbon heating and cooling without groundwater abstraction.
Minewater Geothermal Boreholes
Igne taps into the heat of flooded coal mines with specialist minewater geothermal boreholes, transforming industrial legacy into low-carbon energy for the future.