Why Open Loop Geothermal Projects Fail
Open loop geothermal schemes don't fail on paper, but they can fail in delivery. At feasibility stage, a scheme can look viable because the resource appears to be there, the modelling supports it, and the numbers can be made to work. But none of that proves a scheme will work in practice.
These systems are delivered in the ground, under regulatory constraint, within live environments, and often with incomplete information. That's where pressure builds, because real conditions rarely behave exactly as the model assumed.
Failure is rarely a single, obvious mistake. More often, projects drift off course.
A yield is slightly lower than expected. Discharge is more constrained than planned. Ground conditions are more complex than the desk study suggested.
Individually, each issue is manageable. Together, they begin to erode viability - technically, commercially, or both. And this is how open loop geothermal projects can fail.
The Real Reasons Projects Come Under Pressure
Ground models are exactly that, just models. They're built on available data, interpreted through experience and best practice, but subsurface conditions are inherently variable.
Aquifers are not uniform. Flow paths are not always predictable. Historical records are often incomplete. And even in well-characterised formations, local variation can significantly affect performance.
Yield may be lower than expected, drawdown may be greater, thermal behaviour may not align with predictions, and water chemistry can introduce operational challenges.
None of this is unusual. What matters is when issues and obstacles are discovered. Projects that rely too heavily on desk studies or optimistic assumptions often face difficult corrections later. Projects that test early and realistically make better decisions sooner.
And a strong geothermal resource on paper is not enough. It must be accessible, controllable, and workable within the physical and operational constraints of the site.
We've seen cases where the resource exists - but historic workings, access constraints, or site conditions mean it can't be practically delivered.
Constraints That Are Often Missed Early
Some of the most common issues aren't technical in the traditional sense, they sit around the edges of the scheme, and only become visible once work is underway.
Discharge is a good example. Abstraction tends to get the attention, but during testing and operation, water has to go somewhere, and not always at the volumes required.
Environmental limits, sewer capacity and regulatory approvals can all restrict what's possible.
Licensing is another constraint. Abstraction and reinjection are controlled activities, not automatic rights. Where licensing is treated as a late-stage formality, it can reshape or delay a project. Where it's treated as a core workstream early on, it becomes manageable.
Pump testing is often the first real point of friction. Space for temporary infrastructure, discharge routes, and surrounding receptors can all constrain what can be done. If those constraints aren't anticipated, testing can be delayed or reduced in scope.
Then there's the reality of live sites. Universities, hospitals, industrial facilities and urban developments are not blank canvases. They bring access restrictions, existing infrastructure, operational pressures and stakeholder constraints that rarely show up fully in early-stage layouts.
The Gap Between Design and Delivery
Open loop geothermal sits across multiple disciplines: hydrogeology, design, drilling, construction, regulation. Failure often happens in the gaps between the disciplines.
Systems can be technically sound, but difficult to deliver. Assumptions go unchallenged. Constraints only become visible once work is underway. Without strong coordination and effective communication, those gaps widen quickly.
One of the most common issues is that systems are designed in isolation from those who will actually deliver them. That's where practical problems often emerge:
- Borehole locations that can't be accessed
- Testing strategies that can't be implemented
- Infrastructure that doesn't fit the site
When delivery input comes late, redesign is almost inevitable. When it comes earlier, those issues tend to be resolved before they become problems.
All ground engineering carries uncertainty. Open loop geothermal is no different. The difference between successful and unsuccessful projects isn't the presence of uncertainty, it's when it's understood, and how it's managed.
Successful schemes are shaped by early, realistic testing of assumptions, a clear understanding of regulatory requirements, practical, deliverable testing strategies and coordination between design, hydrogeology and delivery. And there must always be an allowance for uncertainty in programme and cost
Why Early Delivery Input Matters
There's a structural issue in many projects: the people assessing feasibility are not responsible for delivering the work. That can lead to a gap between what is proposed and what is achievable. As a specialist drilling contractor, we're not responsible for designing systems or modelling aquifers. Our role is to drill, test and deliver boreholes safely and effectively, under real site conditions. We know how ground conditions translate into drilling, testing and operation. We see the constraints that others may not - access, sequencing, discharge, temporary works, and the realities of working on live sites.
Our perspective is valuable, but all too often brought in later than it should be.
Once drilling starts, it's no longer about what should work. It's about what the ground will allow. If you're considering an open loop scheme, it's worth sense-checking that early. We won't replace your designers or hydrogeologists, but we can help you understand what it will take to drill your scheme, test it, and make it work in practice.
Let's assess your site's potential.