Geothermal energy in sedimentary basins in the UK

Hydrogeology Journal (2014) 22: 129141 DOI 10.1007/s10040-013-1054-4

Geothermal energy in sedimentary basins in the UK

Jon Busby

Abstract Deep onshore Mesozoic basins have favourable geothermal aquifers at depth comprising basal Permo-Triassic sandstones. The principal basins are the Wessex and Worcester (southern England), Cheshire (northwest England), Eastern England, Larne and Lough Neagh (Northern Ireland). Measured temperatures are up to 80C and could reach 100C in the deepest parts of some of the basins. Porosity and permeability data from depth are limited, but values high enough to allow adequate yields have been measured in many of the basins. Productive sandstones vary from a few tens of metres to hundreds of metres thick resulting in productive transmissivities. The estimated heat in place (Inferred Geothermal Resource) has been calculated as 2011018 to 3281018J. New heat demand maps illustrate that many of the centres of high heat use are coincident with Upper Palaeozoic basins. Within the Carboniferous and Devonian there are thick sequences of deeply buried arenaceous deposits. Some productive local aquifers occur at shallow depth, but most depend on ssure ow that is anticipated to diminish rapidly with depth. The exception may be the Carboniferous Limestone where warm springs and a pronounced thermal anomaly in Eastern England demonstrate groundwater ow at depth, possibly along pathways of many kilometers.

Keywords Thermal conditions . UK . Geothermal resources . Sedimentary basins . Renewable heat

Introduction

This paper reviews the direct-use geothermal resources that are known and have been assessed in the United Kingdom (UK). There is an increasing requirement for

renewable energy to displace fossil fuels (DECC 2009, 2011) for both electricity generation and heat. Direct-use geothermal resources have been little utilised in meeting the UKs renewable heat requirements. The review concentrates on the thermal resource and the hydrogeology, but does not consider aspects of utilization such as the geochemistry of the groundwater. These resources comprise aquifers at sufcient depth that temperatures are high enough for exploitation without a heat pump. They are frequently referred to as hot sedimentary/saline aquifers (HSA). The possibility of using these HSA resources for electricity generation with a binary cycle is not considered here, mainly because there are very limited possibilities onshore the UK (Jackson 2012). The denitive study of UK HSA resources was undertaken...