Accessing Scotland's geothermal resource: regulatory guidance

Environmental protection

A number of potential direct, and indirect, environmental impacts have been identified as being associated with geothermal heat exploration and production:

• possibility of interaction between discharge and geological formation
• temperature and chemical composition of discharge relative to receiving water
• location of the discharge in relation to groundwater/surface water, direct/indirect to groundwater
• proximity to receptors, such as surface waters, wetlands and other water uses
• risk of thermal breakthrough, taking into account cumulative impacts from nearby schemes
• assessment of the risk of heat or substance pollution

A direct discharge to groundwater has one, or more, of the following:

• it bypasses the unsaturated zone
• it has its source in the saturated zone
• it has its source in the unsaturated zone but seasonal fluctuations in the water table mean that the source will be in direct contact with groundwater from time to time

An indirect discharge either percolates through the unsaturated zone or has its source wholly in the unsaturated zone, (even during seasonal fluctuations in the water table).

The construction of a borehole, the abstraction of water, and the subsequent return of water to the water environment all require authorisation from SEPA for an open loop system. These activities can be authorised by General Binding Rules (GBRs), provided that certain mandatory requirements can be complied with. Where these rules cannot be complied with, a higher level of authorisation will be required.

There are no abstractions or discharges in a closed loop system and SEPA authorisation for these activities is not required. In these systems, authorisation is only required for borehole construction and operation.

The construction and operation of a geothermal borehole less than 200 metres deep is authorised by a GBR. Boreholes greater than 200 metres deep will require a licence.

The abstraction and subsequent return of water in a geothermal heat system is authorised under a GBR provided the following rules can be met:

• water is returned to the same hydraulically connected strata or mine workings from which it was abstracted
• the net abstraction is not more than 10 cubic metres a day
• the chemical composition of the water abstracted has not been altered
• the activity must not be located within 250 metres of any abstraction for human consumption and must not prevent an authorised abstraction

Where these rules cannot be met, separate authorisations for the abstraction and discharge of water will be required from SEPA. More information is available in SEPA’s guide on requirements for activities related to geothermal energy .

Contact SEPA when in doubt about the viability, or impact, of a system.