Deep geothermal energy regulation
How to comply with environmental permitting regulations to abstract deep geothermal energy.
Conventional geothermal
A conventional scheme uses the energy of deep underground sources of hot water by pumping the hot water out of a borehole. The used water can be discharged back to the ground or to surface water. To operate a conventional scheme you will need the following environmental permissions from the Environment Agency:
- a groundwater investigation consent (GIC)
- an abstraction licence if you abstract more than 20 cubic meters of water a day
- an environmental permit where there are discharges to ground or surface water
An abstraction licence protects the water quantity, not heat. The Environment Agency is not liable for any loss of heat if a new scheme takes heat away from an existing scheme.
Before you apply for an abstraction licence, you will normally have to get a GIC and meet its conditions. This usually includes carrying out a pumping test. Any licence issued will have a time limit of up to 12 (or in some cases 24) years, and a ‘self destruct’ condition in any abstraction licence for deep geothermal schemes - so if no work commences within the self destruct period, the licence ceases to have effect.
Pumping tests
Where the source of water is very deep underground (for example, more than 1km), and there are no other deep geothermal schemes in that aquifer that may be affected, the Environment Agency may not require a pumping test. In these circumstances, they may be satisfied with a desk study and conceptual model of the system, as the abstraction is less likely to cause environmental harm.
This would mean that you could get an abstraction licence before drilling a borehole, provided you can demonstrate that you have a reasonable requirement for water, your abstraction will be sustainable and it will not affect other legitimate water interests or features.
Contact the Environment Agency on 03708 506 506 (call charges) for a pre-application discussion.
As a condition of the abstraction licence, it is likely that you will need to undertake a pumping test and provide the Environment Agency with a refined conceptual model taking account of the pumping test results once drilling is completed.
Subsequent applications from the same deep aquifer
The Environment Agency is likely to require a pumping test as part of the GIC for subsequent applications before granting an abstraction licence. This is because they would need to determine that the proposed abstraction would not affect existing licensed abstractors or other protected rights.
Hot dry rock geothermal
These are schemes where water (from elsewhere) is injected into fractured hot dry rocks, allowed to heat-up, and then taken out of another borehole. The steam or hot water produced can run turbines to generate electricity. If the schemes takes more than 20 cubic metres of water a day from an inland water or borehole to inject into the ground, you will need:
- a GIC
- an abstraction licence
In some schemes, no annual charge will apply if the purpose of the scheme is to generate less than 5 megawatts of power.
You will not need a GIC or licence to abstract heated water from a hot dry rock scheme if it is to be injected into an artificially created chamber within the underground strata.
In these cases, no natural groundwater is present or affected by the process.
Operator’s role and liability
If a scheme unintentionally discharges pollutants to groundwater, the Environment Agency may serve a notice to require a permit or prevent this activity.
There is a possibility that deep geothermal abstractions could cause subsidence or have other impacts on property. It is the developer’s responsibility to assess these and recognise their liabilities for loss or damage to third parties’ property.