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The potential for exploiting geothermal energy in the United Kingdom on a commercial basis was initially examined by the Department of Energy in the wake of the 1973 oil crisis. Several regions of the country were identified, but interest in developing them was lost as petroleum prices fell. Although the UK is not actively volcanic, [1] a large heat resource is potentially available via shallow geothermal ground source heat pumps, shallow aquifers and deep saline aquifers in the mesozoic basins of the UK. [2] Geothermal energy is plentiful beneath the UK, although it is not readily accessible currently except in specific locations. [3]
Geothermal energy in the United Kingdom, though underutilised, has significant potential. [4] [5] The country's geothermal resources could theoretically meet all of its heating demand for the next century. [6] Recent developments, particularly in Cornwall such as the Eden Project and the Langarth Garden Village, include geothermal heating plants and power projects, with plans to generate 12 MW of electricity by 2027. However, challenges such as lack of government support, financial incentives, and a clear regulatory framework hinder broader adoption. [7] With better policy, the UK could establish up to 360 plants by 2050, reducing carbon emissions and providing jobs. [8]
Ancient legend credited the early Celtic kings with the discovery of the thermal springs at the Roman Baths in Aquae Sulis (modern city of Bath) which then fell into disrepair during the Dark Ages and were not rediscovered until the 18th century, along with the springs at Buxton in the Peak District.[ citation needed ]
The geothermal potential of the UK was investigated by a program funded by the UK government and the European Commission that ran from 1977 until 1994, [9] and saw a Hot Dry Rock experiment drilled in Carnmenellis granite of Cornwall. The project, which was never intended to produce electricity, was a rock mechanics experiment to research the hydraulic stimulation of fracture networks at temperatures below 100 °C (212 °F). Three wells were drilled to a total vertical depth of 2.6 km (1.6 miles) where the bottom-hole temperature was around 100 °C. In 1994, the Hot Dry Rock project was closed, and research effort was transferred to the European Geothermal Project at Soultz-sous-Forêts. [9]
Geothermal energy development in the UK has been limited, partly due to the lack of high enthalpy resources, but also due to the availability of cheap fossil fuels. [9] However, when comparisons are made to countries in a similar tectonic setting, it is clear that the UK is underutilising this potential resource. The lack of geothermal development has largely been a result of the availability of North Sea natural gas during the 1980s and 1990s. [9]
Interest in the geothermal energy resources of the UK rose again in the 2000s, as a potential way of addressing some of the UK's "energy gap" [ broken anchor ]
There is what may be mistakenly known as geothermal energy at shallow depths but it is technically solar energy; the upper 10 to 15 m (33 to 49 ft) of ground is heated by solar radiation and not (except in rare exceptions) geothermal energy. This acts a heat store and can be exploited in a number of different ways. This heat can be utilised by ground source heat pumps that can substantially reduce heating bills and reduce the associated carbon footprint. The heat from the sun is conducted downwards into the ground. At a depth of about 15 m, ground temperatures are not influenced by seasonal air temperature changes and tend to remain stable all year around at about the mean annual air temperature (9 to 13 °C (48 to 55 °F) in the UK). Hence, the ground at this depth is cooler than the air in summer and warmer than the air in winter. This temperature difference is exploited by ground source heat pumps that are used for heating and/or cooling of homes and office buildings. [10]
Groundwater in Permo-Triassic sandstones in the UK has the potential to provide an exploitable geothermal resource at depths of between 1 and 3 km (0.62 and 1.86 miles). Since 1979 the basins of principal interest are East Yorkshire and Lincolnshire, Wessex, Worcester, Cheshire, West Lancashire, Carlisle, and basins in Northern Ireland. In addition, some of these basins are in areas of elevated heat flow, or are overlain by less thermally conductive strata, providing in effect an insulating layer. [10] The following table lists the primary UK Geothermal aquifer resources [10] for areas where the temperature is greater than 40 °C and the transmissivity is greater than 10 Dm, except as indicated:
Aquifer/Basin name | Geologiocal Formation | Geothermal resource (Exa-joules) | Identified resource(1) (Exa-joules) | Depth (m) |
---|---|---|---|---|
East Yorkshire and Lincolnshire | Sherwood Sandstone | 99 | 6.7 | ? |
Basal Permian Sands | 6.7 | 0.9(2) | ? | |
Wessex | Sherwood Sandstone | 22.9 | 3.2(3) | 1,700 to 2,200 |
Worcester | Permo-Triassic (undifferentiated) | 12 | 1.4 | 2,500 |
Cheshire | Sherwood Sandstone | 16.9 | 2.1 | 4,000 |
Permian, including some Triassic | 27.9 | 3.8 | 4,000 | |
Northern Ireland | Sherwood Sandstone | 35.4 | 4.7 | ? |
(1) Identified resource calculated assuming an end of process heat rejection temperature of 30 °C; direct use of the fluid, and re-injection of the fluid after use. (2) Transmissivity ≥5 Dm |
In the 1980s, the United Kingdom Department of Energy undertook a research and development programme to examine the potential of geothermal aquifers in the UK. However, after some initial success drilling a well in the Wessex Basin in 1981, it was deemed too small to be commercially viable. The project was abandoned by the Department of Energy, but Southampton City Council refused to let the project fall and took the decision to create the UK's first geothermal power scheme. This was undertaken as part of a plan to become a 'self sustaining city' in energy generation, promoted by then leader of the city council Alan Whitehead. The scheme was eventually developed in conjunction with French-owned company COFELY District Energy and the Southampton Geothermal Heating Company was then established. Construction started in 1987 on a well to draw water from the Wessex Basin aquifer at a depth of 1,800 m (5,900 ft) and a temperature of 76 °C (169 °F). [11]
The scheme now heats a number of buildings in the city centre, including the Southampton Civic Centre, the WestQuay shopping centre, Royal South Hants Hospital, Solent University and the Carnival offices; and is part of an enlarged city centre district heating system that includes other combined heating, cooling and power sources. [12] [13] As of 2011 the district heating and cooling scheme provides annually 26 °CGWh of electricity and over 40 °CGWh of heat. [14] Brine from the geothermal well provided 18% of the total district heating mix, with fuel oil (10%) and natural gas (70%) making up the rest. The electricity generated from the scheme is used by Associated British Ports via a private electrical connection to the Port of Southampton, with any surplus electricity sold back to the grid. [12] [ failed verification ]
In 2014, Stoke-on-Trent City Council announced plans for a £52 million project to create a district heating network powered by geothermal energy. [15] This will provide heating, in the form of hot water, to local customers. Work started in 2017 and the first customers will be connected in early 2019. [16] [17]
Another area with great potential for geothermal energy is in the North Sea, on the continental shelf where the Earth's crust is thin (less than 10 km [6.2 miles]). The offshore platforms extract hydrocarbons from this region, but each year the output falls by 5% and soon it will be uneconomic to continue using these platforms for fossil fuel extraction. An alternate use could be geothermal power generation. A 1986 work on this was undertaken by Total Energy Conservation and Management Co. Ltd. An overview document was produced called "Single Borehole Geothermal Energy Extraction System for Electrical Power Generation". [18]
The average geothermal gradient in the UK is 26 °C, 47 °F per kilometre (42 °C, 76 °F per mile) depth. [10] There is no deep geothermal power generation in the UK. The granite regions of South West England, the Lake District and Weardale and the Eastern Highlands of Scotland are considered most likely to have the best prospects for power generation. [19] In addition to using geothermally heated aquifers, Hot-Dry-Rock geothermal technology can be used to heat water pumped below ground onto geothermally heated rock. Starting in 1977, trials of the technology were undertaken at Rosemanowes Quarry, near Penryn, Cornwall.
Heat-only projects are generally considered to have the greatest potential in the UK because the resource is more widespread and shallower. This includes the hot aquifers (i.e. subterranean bodies of water) in the North East, Wessex, Cheshire, and Northern Ireland.[ clarification needed ] The UK's only existing geothermal heat-generating station (heat only) is at Southampton, where an 1,800 m (5,900 ft) borehole taps into the edge of the aquifer under Wessex and provides heat to the Southampton District Energy Scheme. The borehole is being refurbished. [19]
In 2008, a planning application was submitted for a hot rocks project on the site of a former cement works at Eastgate, near Stanhope in County Durham. The geothermal plant will heat the Eastgate Renewable Energy Village, the UK's first geothermal energy model village. [20] However this was shelved in 2010. [21]
In 2010 planning permission for a commercial-scale geothermal power plant was granted by Cornwall Council. [22] The plant will be constructed on the United Downs industrial estate near Redruth by Geothermal Engineering. The plant will produce 3 MW of renewable electricity. Drilling commenced at the site in November 2018. [23]
In December 2010, the Eden Project in Cornwall was given permission to build a Hot Rock Geothermal Plant. Drilling was planned to start in 2011, but as of May 2018, funding is still being sought. [24] The plant will be on the north side of the Eden Project, a showcase for environmental projects at Bodelva, near St Austell. It should produce 3-4 MW of electricity for use by Eden with a surplus, enough for about 3,500 houses, going into the National Grid. [25] [26]
The Deep Geothermal Challenge Fund of the Department of Energy and Climate Change has provided more than £4.5 million in grants to support the following projects: [19] Power projects
Heat-only projects
In early 2013, the government pulled a multimillion-pound grant from Geothermal Engineering Ltd for the £50 million United Downs Deep Geothermal Power project, after the company failed to secure the necessary additional investment to meet the terms of the grant. [27] By 2016, the company had managed to secure £30 million funding for the project from a combination of the European Regional Development Fund, Cornwall Council and private investors, thus financing the UK's first commercial hot rocks power scheme. In 2019, the company had finished drilling the two geothermal wells; the production well to a depth of 5,275 m (17,306 ft) and the injection well to 2,393 m (7,851 ft). The hot water reaches 250 °C (482 °F), and can yield around 60 MW of heat and 10 MW electrical energy. In 2021, the power plant is expected to be commissioned. [28] [29]
Newcastle University Science Central Borehole Project, at 1,800 m (5,900 ft) is the deepest geothermal well drilled for nearly 30 years. [30] [31] built on the former Tyne Brewery in the city. The temperature profile of 3.9 °C (7.0 °F) per 100 m is higher than that found in Weardale. [32] The project failed as flow rates of hot water from the borehole were not great enough to be exploitable, leaving the development to be heated by conventional sources. [33]
A report for the Renewable Energy Association prepared by the engineering consultants Sinclair Knight Merz in 2012 identified the following key findings: [34]
On 30 May 2012, the UK government signed a Memorandum of Understanding with the Icelandic government on a number of energy issues, including supporting the development of deep geothermal energy in the UK. [19]
The REA published a new report in 2023 reporting on the nature, current status, future potential, and challenges for the development of geothermal energy infrastructure in the United Kingdom. [6] The report set out the following conclusions:
In summary, while the potential for geothermal energy in the UK is considerable, especially for heating, it remains underdeveloped due to policy and regulatory challenges. Addressing these issues could help the country capitalise on its geothermal resources for a greener energy future.
Geothermal power in Iceland refers to the use of geothermal energy in Iceland for electricity generation.
Geothermal energy is thermal energy extracted from the Earth's crust. It combines energy from the formation of the planet and from radioactive decay. Geothermal energy has been exploited as a source of heat and/or electric power for millennia.
Energy development is the field of activities focused on obtaining sources of energy from natural resources. These activities include the production of renewable, nuclear, and fossil fuel derived sources of energy, and for the recovery and reuse of energy that would otherwise be wasted. Energy conservation and efficiency measures reduce the demand for energy development, and can have benefits to society with improvements to environmental issues.
Geothermal heating is the direct use of geothermal energy for some heating applications. Humans have taken advantage of geothermal heat this way since the Paleolithic era. Approximately seventy countries made direct use of a total of 270 PJ of geothermal heating in 2004. As of 2007, 28 GW of geothermal heating capacity is installed around the world, satisfying 0.07% of global primary energy consumption. Thermal efficiency is high since no energy conversion is needed, but capacity factors tend to be low since the heat is mostly needed in the winter.
Eastgate is a village in the civil parish of Stanhope, in County Durham, England. It is situated in Weardale, a few miles west of Stanhope. In the 2001 census Eastgate had a population of 163.
District heating is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements such as space heating and water heating. The heat is often obtained from a cogeneration plant burning fossil fuels or biomass, but heat-only boiler stations, geothermal heating, heat pumps and central solar heating are also used, as well as heat waste from factories and nuclear power electricity generation. District heating plants can provide higher efficiencies and better pollution control than localized boilers. According to some research, district heating with combined heat and power (CHPDH) is the cheapest method of cutting carbon emissions, and has one of the lowest carbon footprints of all fossil generation plants.
Geothermal gradient is the rate of change in temperature with respect to increasing depth in Earth's interior. As a general rule, the crust temperature rises with depth due to the heat flow from the much hotter mantle; away from tectonic plate boundaries, temperature rises in about 25–30 °C/km (72–87 °F/mi) of depth near the surface in the continental crust. However, in some cases the temperature may drop with increasing depth, especially near the surface, a phenomenon known as inverse or negative geothermal gradient. The effects of weather, the Sun, and season only reach a depth of roughly 10–20 m (33–66 ft).
Renewable heat is an application of renewable energy referring to the generation of heat from renewable sources; for example, feeding radiators with water warmed by focused solar radiation rather than by a fossil fuel boiler. Renewable heat technologies include renewable biofuels, solar heating, geothermal heating, heat pumps and heat exchangers. Insulation is almost always an important factor in how renewable heating is implemented.
Energy recovery includes any technique or method of minimizing the input of energy to an overall system by the exchange of energy from one sub-system of the overall system with another. The energy can be in any form in either subsystem, but most energy recovery systems exchange thermal energy in either sensible or latent form.
A ground source heat pump is a heating/cooling system for buildings that use a type of heat pump to transfer heat to or from the ground, taking advantage of the relative constancy of temperatures of the earth through the seasons. Ground-source heat pumps (GSHPs) – or geothermal heat pumps (GHP), as they are commonly termed in North America – are among the most energy-efficient technologies for providing HVAC and water heating, using far less energy than can be achieved by burning a fuel in a boiler/furnace or by use of resistive electric heaters.
Rosemanowes Quarry, near Penryn, Cornwall, England, was a granite quarry and the site of an early experiment in extracting geothermal energy from the earth using hot dry rock (HDR) technology.
Geothermal power in Australia was at one time hoped to provide cost effect, renewable power for Australia. There are locations that have been shown to contain hot granites at depth which hold good potential for development of geothermal energy. Exploratory geothermal wells have been drilled to test for the presence of high temperature geothermal reservoir rocks and such hot granites were detected. However, all these projects have since been abandoned. A small geothermal plant in Queensland experienced problems during commissioning and as at May 2022, remains idle.
The Nesjavellir Geothermal Power Station is the second-largest geothermal power station in Iceland. The facility is located 177 m (581 ft) above sea level in the southwestern part of the country, near Þingvellir National Park and the Hengill mountain range, about 30 km east of central Reykjavík. The power station is owned and operated by ON Power.
Renewable energy in the United Kingdom contributes to production for electricity, heat, and transport.
An enhanced geothermal system (EGS) generates geothermal electricity without natural convective hydrothermal resources. Traditionally, geothermal power systems operated only where naturally occurring heat, water, and rock permeability are sufficient to allow energy extraction. However, most geothermal energy within reach of conventional techniques is in dry and impermeable rock. EGS technologies expand the availability of geothermal resources through stimulation methods, such as 'hydraulic stimulation'.
Geothermal power is electrical power generated from geothermal energy. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations. Geothermal electricity generation is currently used in 26 countries, while geothermal heating is in use in 70 countries.
Geothermal energy is the second most used form of renewable energy in Russia but represents less than 1% of the total energy production. The first geothermal power plant in Russia, which was the first Binary cycle power station in the world, was built at Pauzhetka, Kamchatka, in 1966, with a capacity of 5 MW. The total geothermal installed capacity is 81.9 MW, with 50 MW coming from a plant at Verkhne-Mutnovsky.Two other plants were built on the Kamchatka Peninsula in 1999 and 2002. Two smaller additional plants were installed on the islands of Kunashir and Iturup in 2007. Most geothermal resources are currently used for heating settlements in the North Caucasus and Kamchatka. Half of the geothermal production is used to heat homes and industrial buildings, one third is used to heat greenhouses and 13% is used for industrial processes.
The Eastgate Renewable Energy Village is a multimillion-pound project planned for the village of Eastgate in Weardale, County Durham. The plan is to showcase five different forms of renewable energy and create a complex that includes a hotel, spa, cable car ride, 65 new homes, a cafe, viewing platforms, bird watching centre and connection with the Weardale Railway.
United Downs Deep Geothermal Power is the United Kingdom's first geothermal electricity project. It is situated near Redruth in Cornwall, England. It is owned and operated by Geothermal Engineering (GEL), a private UK company. The drilling site is on the United Downs industrial estate, chosen for its geology, existing grid connection, proximity to access roads and limited impact on local communities. Energy is extracted by cycling water through a naturally hot reservoir and using the heated water to drive a turbine to produce electricity and for direct heating. The company plans to begin delivering electricity and heat in 2024. A lithium resource was discovered in the well.
The Southampton District Energy Scheme is a district heating and cooling system in Southampton, United Kingdom. The system is owned and operated by ENGIE.