Feasibility Report of a Deep Geothermal Single Well, Aberdeen Exhibition and Conference Centre

Report of study which examined the technical, logistical, contractual and economic feasibility of installing a deep geothermal single well system at the new site of the Aberdeen Exhibition and Conference Centre.

Regulatory Review

In January 2016, the Scottish Government produced the regulatory guidance document "Geothermal Heat in Scotland"[48]. In conducting our review, we have followed the guidance within this document and we have undertaken preliminary consultations with the three key bodies who would have responsibility for the "regulation and control of activities" for the specific project near Aberdeen.

At the proposed site there will be two regulatory bodies whose requirements the DGSW system must legally comply with: the Scottish Environment and Protection Agency (SEPA) and Aberdeen City Council (ACC). Further to this, although not legally required, the well construction and drilling methodology should also be compliant with and approved by the On-Shore Health and Safety Executive. Aberdeen is not within a Coal Mining locality and therefore no consultation with the Coal Authority would be necessary for this specific project.

We have contacted all three of these agencies and the requirements for the AECC site are understood to be as follows:

Scottish Environment and Protection Agency (SEPA) Requirements

The laws and regulations governing Deep Boreholes fall into two broad categories. The first is General Scottish law, in which the specific laws and systems relating to the management of the Scottish Water environment are termed the Water Framework Directive (WFD). The second is the "Water - Controlled Activities Regulations (CAR)" which is overseen by SEPA. Licences for drilling and abstraction from deep boreholes are controlled by SEPA and two application forms must be submitted, along with all the supporting studies and documentation detailed in the forms. For boreholes greater than 200m, details on the depth, geology, casing, cementing, drilling fluids and chemicals will need to be provided to include:

  • National Grid reference for the top of the well head and for the bottom of the borehole (if there is any lateral deviation underground)
  • Details and locations of any other nearby deep boreholes, faults or mine workings
  • Approach for dealing with drilling fluid loss and/ or artesian flow
  • Details of integrity testing of the borehole to ensure proper construction
  • A Water Features Survey to include abstractions, surface waters, springs and wetlands within 1200m of both the top and the bottom of the borehole.
  • Baseline environmental monitoring
  • Details of proposed ongoing environmental monitoring to ensure integrity of the borehole.
  • Details of an Action Plan in case of adverse Environmental impact
  • Decommissioning plans - temporary sealing and long-term decommissioning

If the abstracted groundwater contains naturally occurring radioactive materials (NORM) then a Radioactive Substances Act (RSA) authorisation may be required for the discharge. This applies if the borehole is associated with a NORM Industrial Activity (oil and gas etc.). This would also require sampling of the groundwater prior to abstraction.

The abstraction and recharge licences for a deep geothermal single well will be discussed once we have drilled the well and understand the level of potential bleed flow that the well will sustain. The nature of the discharge licence will also be dependent on the quality and chemical composition of the geothermal water. This will be determined once the well has been drilled.

SEPA have indicated that the application process is likely to take approximately 4 months to complete. However, given that this project would be the first application of this type, we believe that 6 months might be more appropriate.

For the licence application the following documentation will need to be completed:

  • Deep borehole drilling: Regulatory Method (WAT-RM-11) Licensing Groundwater Abstractions including Dewatering.
  • Licence application for deep boreholes: Form A, Form K
  • Water features survey
  • Groundwater monitoring (if required). SEPA Technical Guidance Note Hydrogeological Risk Assessment for Landfills and the Derivation of Control and Trigger Levels

For the AECC site, some of the environmental studies have already been completed as part of the recent planning application for the new centre. We also have documentation relating to the recent application to the Environment Agency in England for a similar type of well which will be a useful reference point.

Requirements of Aberdeen City Council

Arup recently worked with Geothermal Engineering Ltd on a Planning submission for a deep geothermal single well system at the Crewe Campus of Manchester Metropolitan University. The project received planning permission on the 23rd of September 2015. We intend to use the documentation developed for this project as a guideline for the AECC site.

Consenting Regime

The consenting for any Deep Geothermal Single Well (DGSW) in Scotland would be under the remit of the Scottish planning regime, notably the Town and Country Planning (Scotland) Act 1997 and the Planning etc. (Scotland) Act 2006. No electricity is to be produced via the well, which will only produce heat from water at a peak thermal output of approximately 400kW or 2GWh per annum. As such, no consent would be required under the Electricity Act 1989.

Unlike hydraulic stimulation or 'fracking' the DGSW does not require the breaking up of the rock to create a permeability pathway in order to operate. Due to public concerns surrounding fracking and the current Scottish Government 'Moratorium on Fracking' in Scotland[49], it is considered that single well technologies with no requirement for underground hydraulic stimulation, are most likely to advance through the planning process.

The following sections report the key aspects of the consenting regime with respect to environmental impact assessment (EIA), habitat regulations assessment (HR) and planning application requirements. Further information on the consenting regime can be found in current regulatory guidance on the matter.

Environmental Impact Assessment

The drilling of a DGSW is potentially a form of development that requires environmental impact assessment (EIA) under the Town and Country Planning (Environmental Impact Assessment) (Scotland) Regulations 2011. The basis for whether EIA is required is dependent on whether the proposal constitutes Schedule 1 development (types of development where EIA is always required) or Schedule 2 development (types of development where EIA may be required based on certain criteria).

Geothermal wells are unlikely to be categorised as Schedule 1 development, but they are potentially classed as Schedule 2 development under section 2 (extractive industries) part (d)(i), or section 3 (Energy Industry) part (a). Whether or not they are Schedule 2 development depends on the proposed development breaching either of the following criteria:

1. The area of works exceeds 1 hectare if classed as an Extractive Industry or 0.5 hectares if classed as Energy Industry; or

2. The drilling is within 100m of a controlled source (surface water); or

Given the proposed realignment of controlled waters within the AECC site, there is the potential that the proposed location for the geothermal well could be within the 100m limit of a controlled source depending on the receiving environment and the scale of development. Discussion with ACC has identified that they do not believe that the any of the water courses within or near the site would fall under the definition of 'controlled waters' as per the EIA regulations although a screening opinion should be submitted at an early stage. The Council expect that the AECC would be looked at cumulatively rather than as a main part of any EIA for the geothermal development.

Habitats Regulations Assessment

Depending on proximity to, and likelihood of affecting, Natura 2000 sites (including Special Protection Areas, Special Areas of Conservation and Ramsar sites), the DGSW may require a Habitat Regulations Assessment (HRA) under the Conservation (Natural Habitats, &c.) Regulations 1994, as amended. Under HRA, the qualifying interests of the site will be assessed to determine whether significant effects resultant from a development are likely to affect the integrity of the site, and if so, how they can be mitigated.

Proposals where mitigation of significant effects is not possible will only be permitted where there are no alternative solutions and where there are reasons of overriding public interest relating to the proposals. Where a European priority species or habitat is affected, reasons of overriding public interest can only relate to human health, public safety, beneficial effects of primary importance for the environment, or other reasons subject to the opinion of the Scottish Ministers.

Future consultation with Scottish Natural Heritage will determine the requirement for any HRA associated with the DGSW.

Planning Application

Under the consenting regime, a full planning application will be necessary in line with the requirements of the Town and Country Planning (Scotland) Act 1997 and the Planning etc. (Scotland) Act 2006. Under the 2006 Act, planning applications in Scotland are either classed as national, major or local development. These developments are defined below in Figure 19.

Figure 19: Hierarchy of planning applications in Scotland[50]

Figure 19 Hierarchy of planning applications in Scotland

Any future planning application for a geothermal well at the AECC site is likely to be a local development, which as described above, may need to be supported by an EIA. The application would be submitted to ACC and would need to include any other relevant information included on the ACC planning application validation checklist.

Following discussions between Arup and Aberdeen Council, our Planning application for the AECC would cover the following topics:

1. Introduction

a. Background
b. Need for development
c. Geothermal heat
d. Project background

2. Context

a. Site description
b. Site character
c. Surrounding uses
d. Landscape
e. Climate
f. Transport access
g. Utilities

3. Environmental issues

a. Noise
b. Transport
c. Landscape
d. Contamination

4. Planning policy context

a. Introduction
b. National policy and guidance
c. Local policy
d. Planning history

Aberdeen Council currently has no specific guidance or policy documents on geothermal projects. However they have stated that the principle of renewable energy sources is supported generally by both Scottish Government national guidance and the Councils Local Development Plan. The most relevant LDP policy would be Policy R8 (Renewable and low carbon energy developments). The Council anticipates there being some public or Councilor interest in such a development as it is not something the city has any experience of. Therefore, although it is likely that there proposal would be categorised as a local development rather than a major development, which has statutory consultation, some level of public consultation, which could be agreed with the Council, would be beneficial. The application would be looked at independently of the AECC application as either could potentially take place without the other.

On-Shore Health and Safety Executive (HSE)

We have discussed the deep geothermal single well with HSE as part of the development at the site in Crewe. For onshore drilling for petroleum there are two main sets of Health and Safety legislation:

1. The Borehole Sites and Operations Regulations 1995 (BSOR)

2. The Well Aspects of the Offshore Installations and Wells (design and Construction, etc.) Regulations 1996 (DCR)

From a legal point of view there is no need to submit any information on a geothermal well to the Health and Safety Executive to comply with the Borehole Sites and Operations Regulations 1995 [BSOR] unless it is located in a mining area. Currently, newer technologies such as geothermal wells are a grey area as far compliance with legislation is concerned. However, developers will need to comply with the Construction Design and Management Regulations and other Health and safety legislation.

As deep drilling always has inherent risks, HSE has proposed that we should work to the highest standards available, namely the BSOR. This would include submitting the following to HSE as a matter of course. We would also suggest that other potential projects in Scotland follow the same course. The information required by HSE is listed below:

Minimum Information Required for an Onshore Notification
1 Name and address of operator
  • Operators name & Operators address
  • Name and address of Operator of Site if different to above
2 Particulars of the type of well, its number and its name
  • Exploration, appraisal or development
  • Function to which it will be used if development well, e.g. oil producer, gas producer, water injection
  • The DTI well number. [The DTI numbering system is to be used prior to spud]
3 Particulars of the rig or other plant which is to be used in connection with the operations on the well
  • Name of Drilling Contractor/Name of rig
  • Layout and brief description/capacities of the main equipment, e.g. derrick rating, drawworks hoisting capacity, high pressure mud pump(s), coiled tubing unit, mud storage, solids control equipment, well testing package
4 Particulars of the surface equipment and of the circulating fluids to be used to control the pressure of the well
  • Details of the Well control equipment [BOP, Rotating head, Diverter, Choke Manifold, Mud/gas separator] including size and pressure rating.
  • Details of BOP control unit, e.g. accumulator capacity and sizing
  • Generic fluid type for drilling each section of hole
  • Mud weight for each hole section
  • Generic fluid type for testing, completion, workover operation
  • Mud weight for each operation type; e.g. completion, testing, workover, etc.
5 Particulars, with scale diagrams where appropriate, of - (a) the Ordnance Survey National Grid ref of the location of the top of the well (b) the directional path of the borehole (c) the terminal depth and location (d) its position and that of nearby wells and mine workings relative to each other
  • National Grid reference of surface/target locations
  • Latitude & longitude of surface/target locations
  • Directional plot for non vertical wells: to include vertical section and horizontal section
  • Measured terminal depth and vertical terminal depth
  • Map showing the surface location and entire lateral position of well and all others in the vicinity [either at surface or at sub surface level] together with any mine workings
  • Confirmation that the potential of collision of relevant wells or mine workings have been looked at and that plans are in place to minimise the risks
6 A description of operations to be performed and programme of works including - (a) the dates on which operations on the well are expected to start and finish (b) a diagram showing details of the intended final completion or recompletion of the well
  • Estimated start/finish dates or duration
  • List of operations to be carried out, e.g. re-enter, plug back, sidetrack, test, drill, workover, etc.
  • Summary of the well programme which details the major steps related to safe operations: all main safety related issues would be addressed, e.g. casing pressure details, leak off tests and formation integrity tests to be carried out and required minimum values, cementing programme and method of confirmation of cement tops, testing of barriers prior to removal of BOPs, testing of BOPs, etc.
  • The operational state at the end of operations should be one of completed, abandoned or suspended
  • A schematic of the intended final well state should be included
7 A description of - (a) any activity during operations on the well which will involve a risk of the accidental release of fluids from the well or reservoir; and (b) such hazards
  • Identify those hazards and activities connected with the particular well which have the potential to cause a major accident, e.g. shallow gas, H2S, high pressure, lost circulation, underbalance drilling, DST
  • Identify where SIMOPS are to take place at drilling sites and the policy covering SIMOPS
8 In the case of a well which is to be drilled (a) particulars of the geological strata, and formations and fluids within them through which it may pass and of any hazards with the potential to cause fire, explosion or a blow-out, which they may contain
  • Geological column from surface to TD, detailing measured and vertical depths
  • Est. formation pressures in all permeable and porous zones
  • Est. fracture pressures at intended casing points
  • Prognosed fluid types [e.g. gas, condensate, oil, etc.] presence of gas cap etc., fluid gradient, presence and concentration of toxic gases [e.g. CO2, H2S, etc.]
  • Identify potential producing formations
  • Confirm a specific shallow gas assessment has been completed
  • Particular hazards associated w/well, e.g.: Major loss circ zones, overpressures, salt domes
  (b) the procedures for effectively monitoring the direction of the borehole and the effects of intersecting nearby wells:
  • Survey programme for each section of hole
  • Confirmation that there is a system for programming surveys and for comparing survey data with that of nearby wells and that there are criteria for taking action
  • List nearby wells, which are of special significance with respect to the drilling of the particular well. Provide separation factors for the significant well
  (c) particulars of the design of the well, sufficient to show that it takes account of matters in sub paragraph a) of this paragraph, and that it will, so far as is reasonably practicable, be safe
  • Est. max whd press, during operations
  • Summary of hole sizes/section TDs
  • Summary of casing strings to be run, including setting depth, size, weight, grade and couplings. Kick tolerance and specification if not API grades. Provide details of the wellhead and Xmas tree
  • Details of cementing prog/casing string and for any abandonment or suspension to be carried out
  • Details of testing; surface equipment and shutdown systems
  • Schematic diagram of the proposed completion
9 In the case of an existing well- (a) a diagram of the well (b) a brief history of the well including a summary of previous operations and any problems encountered; and (c) its present status and condition
  • Current casing and completion or suspension diagram
  • List, with dates, of major operations on the well e.g. spud date, drill and suspend, re-enter and redrill, re-enter and complete, major workovers
  • Operational state is abandoned, suspended or completed
  • Details of any known or suspected safety related failure or defect in the well e.g. corrosion problems, Xmas tree valve failure, DHSSV control line failure
  • Details of barriers and fluids in the well
10 In the case of an abandonment operation details of the proposed sealing or treatment
  • Current casing and cementing programme
  • Depths of hydrocarbon bearing strata or aquifer
  • Number and location of barriers
  • Testing of barriers
  • Monitoring of pressure build-up

HSE have also advised us that we should work to the spirit of the DCR. This set of regulations covers a life cycle approach of a well from concept / design, construction, operation, maintenance through to final abandonment. This includes a requirement for a well examination scheme to be in place where an independent and competent person reviews the well design. Again, we would suggest that any geothermal drilling project in Scotland adheres to this process.

Review of Consents at Crewe Project

For a recent DGSW demonstration project near Crewe, the Planning Consent was achieved within 3 months with broad Council and local support. The site was located in an urban area and therefore was a test case for the development of DGSW projects. All documentation associated with this application will be shared with Aberdeen City Council if the project moves forward.


Email: Johann MacDougall

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