Investigation of the geothermal potential of abandoned coalfields in the Yorkshire region
Dr Chrysothemis Paraskevopoulou (SEE), Prof. Quentin Fisher (SEE),Project partner(s): Mr Nick ShawContact email: email@example.com
Reducing greenhouse gas emissions is a major global challenge. Geothermal energy has a huge potential to contribute to a reduction in greenhouse gas emissions, which is a major global research challenge. To this end, the current research project aims to better understand the potential use of abandoned coal mines as a source of geothermal energy. The project will be of interest to someone looking for a multidisciplinary project involving fieldwork, laboratory analysis and numerical modelling in the broad areas of engineering and engineering geology, geothermal engineering and geomechanical modelling. The research will place the successful candidate in an ideal position to gain future employment in industry or academia.
The demand for energy has rapidly increased as technological advancements progress and new needs for energy consumption rise. Energy for heating contributes to almost 50% of the world’s energy consumption and is expected to increase in the following decades. Climate change and environmental awareness lead us to find more sustainable solutions. Consequently, new renewable energy resources for heating are currently in demand. The coal industry thrived in the UK during the past centuries, contributing significantly to the national economy. However, since coal production stopped underground mines were abandoned and flooded. This study aims to investigate the feasibility of using the heat of the mine water to produce energy. Two areas of uncertainty need to be investigated. First, the amount of energy available and the best means for its extraction; secondly confirming the long-term stability of the mines and surrounding areas. The study will be focused on the West Yorkshire region, specifically the area between Sheffield and Leeds. The project will use geological data from boreholes and other wells that are already available. Mine records and groundwater data will be used to assess the volume of the in-situ heat within the mine-water. Then the stability of the mines and open cavities will be assessed to understand the risk of eventual collapse and consequent surface ground movements such as sinkholes, micro-earthquakes or groundwater impacts. As well as using the mine records and geological data, the project will involve site visits to the abandoned mines in the Yorkshire region.
The EU’s Renewable energy directive set a new target of at least 27%of final energy consumption in the EU to be from renewable sources by 2030. In the UK and other developed countries approximately half of energy consumption is related to space heating and cooling. The UK has potentially large resources of low enthalpy heat suitable for district heating, utilising heat pumps as required. One largely untapped resource is water within abandoned coal mines. Coal mines usually provide a source of temperature of about 12-18 oC. Extracted mine water can be passed through a heat exchanger, before connection to the heat pump and distribution system. However, despite some initial site specific studies undertaken by the Brit Geothermal Consortium based at Durham University and in the Universities of Glasgow and Strathclyde, there has been no large scale resource assessments in most coal field areas. There are also remain uncertainties regarding long-term mine stability, especially how this would be affected by utilisation of the thermal resource. In the Yorkshire region, the area of interest, the National Mining Museum scheme at Caphouse near Wakefield had previously studied the mine water management in the coalfield but the regional extent of the geothermal resource and its potential have not been demonstrated especially in regards re-entering and accessing the old coal mines after they stopped being operational and they were abandoned.
This study aims to investigating the feasibility of extracting geothermal energy from abandoned coal mines with flooded network galleries and shafts at various depths in the West Yorkshire Coalfield area between Leeds and Sheffield. Specific objectives will be to:
1. assess the quantity of heat available and the most appropriate means to exploit it;
2. determine potential heat users in the adjacent communities; and
3. assess the risk of future mine instability in the aging underground assets, especially given their change in use.
A)The project will examine the feasibility of using the mine-water of the abandoned mines in the Yorkshire region to produce heat energy by accessing all data available from existing boreholes and past reports (Coal Authority) and visiting the coal mine sites wherever possible. A critical factor is to achieve flow within the mine water that is being assisted in the void spaces and the increased permeability of host rock resulting from the past coal mining activity.
B)A preliminary assessment will be conducted to estimate the potential number of heat users in the communities / urban areas contiguous to the using open street map data and a GIS platform.
C)The long-term stability of the coal mines will be assessed as both pumping of the water the wells drilled for water production and re-injection (where it is proven financially feasible especially in deep mines) may deteriorate might cause stability issues affecting the in-situ stress conditions. Numerical analyses to capture the hydromechanical and geothermal effects on the geomechanical behaviour of the coal and surrounding rocks will include sensitivity analysis.