- Share of Generation from coal saw a substantial decrease in 2019.
- T&D losses decreased by 0.9 %, accounted for 7.6 % of total demand in 2019.
- Interruptions in the flow of electricity through interconnections between UK and EU is not expected in any post Brexit scenario.
With the end of the Post-Brexit transition period on 31st December (2020), eyes have focused on the United Kingdom’s electricity grid and how it will function and adjust with the change. The UK is the union of the countries on the island of Great Britain, Wales, Scotland and England, plus Northern Ireland. So how the electric grid will be impacted concerns the respective governments, including regulatory authorities in the UK and European Union, and also private sector power producers in both markets.
Power Technology Research will present an overview of UK’s electricity grid, including generation, transmission and distribution, and will discuss future prospects of cross-border interconnections and reactive power requirements of UK’s grid.
Total electricity demand in UK in 2019 was 346 TWh which was 2 % lower than 2018. The majority of the demand came from ‘final consumption’ (end users other than the energy sector) accounting for 85.4 % (295 TWh) of total demand. Energy industry use accounted for 6.9 % (24TWh) of total demand and losses accounted for 7.6 % (26TWh).
More recently, electricity generation and consumption for 3Q2020 remained low compared to the same period the previous year, down 3.4%, but there was a slight increase compared with 2Q 2020. Most of the decrease in consumption was attributed to a reduction in industrial and commercial demand (both affected by Covid-19).
Electricity in the UK is supplied by the public distribution system (PDS) which includes high voltage transmission network and the lower voltage distribution network. The Major Power Producers (MPP) group supply the majority of electricity, 269 TWh in 2019, but this is down 4% year over year. The remaining electricity comes from ‘other generators’ who supply their surplus to the grid and ‘net imports’ that supply through interconnections. The contribution of other generators to electricity grid increased substantially in 2019, up 8 % to 51.5 TWh.
Small scale renewable schemes for instance ‘feed in tariffs’ have also contributed to the generation of ‘other-generators’. Other-generators and auto-generators generate power as part of their industrial or commercial activity specifically for their own use. In 2019, 10.9 % of industrial demand of electricity was provided by ‘other-generation’ and 9.3 % of commercial demand was met by ‘other-generation’.
Since the introduction of feed in tariffs in April 2010 in the UK, domestic electricity generation and consumption increased radically but despite the increase in self-generated electricity, it makes up only 1.6% of domestic consumption. In 2019, the domestic sector consumed 1.7 TWh of self-generated electricity.
The UK is a net importer of electricity and imports increased to 24.6TWh (10.8 %) in 2019 year over year. Imports account for about 7% of the UK’s consumption. In January of 2019 the GB-Belgium interconnector started operation and this interconnection accounts for about 5 TWh. The majority of imports came from the Netherlands and France, while the UK is a net exporter to Ireland. Exports to Ireland, increased in 2019 to 3.4 TWh (52%). The capacity of the interconnections is about 5,000 MW.
Figure 1: Shares of electricity generation by fuel.
The major fuel sources in the UK are coal, gas, nuclear and renewables. As we can see in Figure 1, the share of generation from coal saw a substantial decrease from 5.1 % in 2018 to 2.1 % in 2019 where renewables share in generation mix increased from 33.1 % in 2018 to 37.1 % in 2019. Gas contributed the largest share in the generation of electricity, at 40.6 %, followed by renewables which contributed 37.1 % in 2019. Nuclear, coal and other fuels contributed 17.3%, 2.1% and 2.8% respectively.
For the latest period, 3Q 2020, electricity generation showed a decrease of 1.5% year over year. Renewables, primarily wind, comprised about 40% of total generation showing an increase of 9%. Planned maintenance outages in nuclear plants reduced the supply by 20% and had to be offset by an increase in fossil fuels generation (about 2.6% increase). Altogether fossil fuels accounted for 42.5% of the supply mix for this last quarter.
The UK’s biggest energy suppliers of gas and electricity are British Gas, EDF Energy, E. On UK, Npower, Scottish Power and SSE. The locations of the MPP companies can be seen in Figure 2. Following is list of the MPPs:
AES Ballylumford Ltd†*, AES Kilroot Power Ltd, Anesco Ltd, Baglan Generating Ltd†, Banks Renewables Limited, BayWa R.E Ltd, Black Hill Wind Ltd, British Energy Generation Ltd (Eng & Wales), British Solar Renewables Ltd, Calon Energy Ltd†, Carrington Power Ltd, Centrica Barry Ltd, Centrica Brigg Ltd, Coolkeeragh ESB Ltd, Corby Power Ltd, Coryton Energy Company Ltd, Cubico Sustainable Investments Ltd, Drax Power Ltd†, E.ON UK plc, Ecotricity Ltd, EDF Energy (Cottam Power) Ltd†*, EDF Energy Renewables Ltd, Eneco Wind UK Ltd*, EP Langage Ltd†*, EP SHB Ltd, EPR Ely Ltd, EPR Eye Ltd, EPR Glanford Ltd, EPR Scotland Ltd, EPR Thetford Ltd, Falck Renewables Wind Ltd, Fellside Heat and Power Ltd*, Ferrybridge Mulitfuel Energy Ltd, First Hydro Company, Fred Olsen Renewables Ltd, FS Shotwick Ltd*, GLID Wind Farms Topco†, Greencoat Solar I LLP*, Greencoat UK Wind Plc†*, Indian Queens Power Ltd*, John Laing Environmental Assets Group, Kentish Flats Ltd, Lightsource Renewable Energy Ltd†*, Londonwaste Ltd†, Lynemouth Power Ltd, Magnox Electric Ltd, Marchwood Power Ltd, Octopus Investments Ltd, Orsted Burbo (UK) Ltd†, Peel Energy Ltd*, Pennant Walters Ltd*, Peterborough Power Ltd†, REG Windpower Ltd, Renewable Energy Solutions Services Ltd†*, Renewable Energy Systems (Aviva)†, Renewable Energy Systems (OI)*, Renewable Energy Systems (Penmanshiel)*, Renewable Energy Systems (TRIG)*, Renewable Energy Systems Limited (Glenmont)†*, Riverside Resource Recovery Ltd*, Rocksavage Power Company Ltd, RWE Npower (Kielder), RWE Npower Ltd, RWE Npower Renewables Ltd, RWE Npower Renewables Ltd (Offshore)*, RWE Renewables*, Saltend Cogeneration Company Ltd*, Scira Offshore Energy Ltd, Scotia Wind (Craigengelt) Ltd*, Scottish & Southern Energy plc†*, Scottish & Southern Energy Plc (Fiddlers Ferry)†*, Scottish & Southern Energy Plc (Medway and Keadby), Scottish & Southern Energy plc (Networks), Scottish Power Renewables UK Ltd, Seabank Power Ltd*, SembCorp Utilities (UK) Ltd, SembCorp Utilities (UK) Ltd (Wilton 10), Severn Power Ltd, SIMEC Uskmouth Power Ltd, Slough Heat and Power Ltd, South East London Combined Heat and Power Ltd, Spalding Energy Company Ltd, Statkraft Energy Ltd, Statkraft Wind UK Ltd, SUEZ Recycling and Recovery (UK) Ltd (Wilton 11)*, Temporis Capital Ltd, Third Energy UK Gas Ltd, Toucan Energy Services Ltd, Uniper UK Ltd†, Ventient Energy Services Ltd, Viridor Waste Management Ltd*, VPI Immingham LLP, Wadlow Energy Ltd, Willmount Ltd,Wise Energy Ltd and WPO UK Services Ltd†.
Offshore wind generation for 3Q 2020 was a bit over 8TWh. This was an increase of 11% year over year in production, and the capacity of offshore generation increased 6% to close to10.4 GW. The cumulative installed onshore and offshore wind generation capacity in 3Q 2020 was 24.5GW.
Following is a list of wind farm producers:
Banks Renewables Limited, BayWa R.E Ltd, Black Hill Wind Ltd, Ecotricity Ltd, EDF Energy Renewables Ltd, Eneco Wind UK Ltd, Falck Renewables Wind Ltd, Fred Olsen Renewables Ltd, GLID Wind Farms Topco, Greencoat Solar I LLP, Greencoat UK Wind Plc, John Laing Environmental Assets Group, Kentish Flats Ltd, Orsted Burbo (UK) Ltd, Peel Energy Ltd, Pennant Walters Ltd, REG Windpower Ltd, Renewable Energy Systems (Aviva), Renewable Energy Systems (OI), Renewable Energy Systems (Penmanshiel), Renewable Energy Systems (TRIG), Renewable Energy Systems Limited (Glenmont), RWE Npower Renewables Ltd, RWE Npower Renewables Ltd (Offshore), RWE Renewables, Scira Offshore Energy Ltd, Scotia Wind (Craigengelt) Ltd, Scottish & Southern Energy plc, Scottish Power Renewables UK Ltd, Statkraft Wind UK Ltd, Temporis Capital Ltd, Ventient Energy Services Ltd, Wadlow Energy Ltd, Willmount Ltd, WPO UK Services Ltd.
With a little over 4 TWh solar generation for 3Q 2020, this showed a decrease of 10% year over year, due to a decrease in average daily sun hours. This decrease was in spite an increase of 1.9% in capacity, to about 257 MW, year over year. The cumulative installed solar capacity in 3Q 2020 was 13.5GW.
Following is a list of solar farm producers:
Anesco Ltd, British Solar Renewables Ltd, Cubico Sustainable Investments Ltd, Ecotricity Ltd, Eneco Wind UK Ltd, FS Shotwick Ltd, Greencoat Solar I LLP, Kentish Flats Ltd, Lightsource Renewable Energy Ltd, Octopus Investments Ltd, REG Windpower Ltd, Renewable Energy Solutions Services Ltd, Renewable Energy Systems (TRIG), Scotia Wind (Craigengelt) Ltd, Scottish & Southern Energy plc, Toucan Energy Services Ltd, Wise Energy Ltd.
Figure 2: Location of Major Power Producers in UK.
Majority of electricity in UK is supplied by public distribution system which is comprised of interconnected high voltage transmission network and the lower voltage distribution network.
Currently there are three Transmission Operators in Great Britain permitted to develop and maintain the high voltage system. National Grid Electricity Transmission for the network in England and Wales (NETS), Scottish Power Transmission Limited for southern Scotland (SP Transmission) and Scottish Hydro Electric Transmission for northern Scotland and the Scottish island groups (SHE Transmission). Northern Irealnd is part of the single electricity market with the Republic of Ireland.
The system as a whole is operated by a single entity, National Grid Electricity System Operator (NGESO). Alongside day to day balancing of supply and demand NGESO is responsible for the safe and efficient transmission of electricity from the generation side to distribution side.
National Grid’s business segments include:
- UK Electricity Transmission.
- UK Gas Transmission.
- National Grid Ventures and other activities.
- UK Regulated Gas and Electricity Distribution and Transmission Networks.
The NETS network has 7200 kms of overhead lines,1560 kms of underground cables and 346 substations. SP Transmission has 3700 kms of overhead lines, over 600 km of underground cables and 150 substations. SHE Transmission has more than 5000 kms of overhead lines, and underground cables and 114 substations.
Distribution companies reduce the high voltage electricity coming from generation to a lower voltage through a substation at City gates. After that voltage is again reduced to a lower level through a step-down transformer before it is fed to consumers.
There are 14 licensed authorized distribution network operators in UK where each operator is responsible for a regional distribution service area. These licensed Distribution Network Operators (DNOs) are owned by 6 different groups.
Electricity North West Limited
- Northern Powergrid (Northeast)
- Northern Powergrid (Yorkshire)
Scottish and Southern Energy
- Scottish Hydroelectric Power Distribution
- Southern Electric Power Distribution
ScottishPower Energy Networks
- SP Distribution
- SP Manweb
UK Power Networks
- London Power Networks
- South Eastern Power Networks
- Eastern Power Networks
Western Power Distribution
- Western Power Distribution (East Midlands)
- Western Power Distribution (West Midlands)
- Western Power Distribution (South West)
- Western Power Distribution (South Wales)
Along with these 6 major groups, there are also a number of smaller networks owned and operated by independent network operators located within the service areas of DNOs.
Figure 3: Transmission and distribution networks map in UK.
Transmission and Distribution Losses
Losses in the T&D sector decreased by 0.9 % in 2019 if compared with losses in 2018. T&D losses account for 7.6 % (26 TWh) of total demand. Losses consist of three components:
Transmission losses: Account for 29 % of total losses reaching 26 TWh.
Distribution losses: Account for 67 % of total losses and stood at 17.8 TWh.
Theft or meter fraud: 3.6 % of total losses and lie just under 1 TWh.
Regulatory Bodies in UK
Ofgem (Office of Gas and Electricity Markets) is a non-Ministerial government department, an independent National Regulatory Authority and is recognized by EU directives. Its role is to protect consumers and deliver greener sustainable/fairer energy system.
The responsibility of Ofgem includes:
1) Working with government, industry and consumer groups with an aim to deliver a net zero economy with consumers bearing the least amount of burden.
2) Eradication of sharp and bad practices, making sure all consumers are treated fairly especially the vulnerable consumer base.
3) Enable competition and innovation in a bid to reduce retail prices and invention of new products and services for consumers.
Although Ofgem coordinates with the government, energy industry and other stake holders it is independent of these bodies. This arrangement and the regulatory body itself is recognized within legal framework determined by the UK government and EU. Ofgem priorities cover the period to the end of 2023 when the default tariff price cap ends and the government does the next Spending Review.
Gas and Electricity Markets Authority
Ofgem is governed by the Gas and Electricity Markets Authority (GEMA) consisting of non-executive and executive members and a non-executive chair. Non-executive members bring experience and technical expertise from wide range of fields relevant to GEMA’s function for instance:
3) Consumer and social policy
4) Science and the environment
5) Finance and investment
6) European Energy Issues
The Secretary of State at Department for Business, Energy and Industrial Strategy (BEIS) appoints the members and these include five non-executive directors. GEMA decides strategy, and sets policy priorities while also deciding on a range of regulatory roles, for example, price controls and enforcement of policies.
Since 1986, GEMA’s powers are provided under various energy Acts, the most recent being the Enterprise Act of 2002(where these acts are subject change keeping in view the situation). To maintain financial independence as Ofgem operates with the costs it recovers from licensed companies which are obligated to pay annual license fee.
UK’s power grid depends on power supply from European counterparts where since the BREXIT a lot of uncertainty prevailed regarding the future of interconnections between UK and EU Countries. As per Ofgem which regulates the power sector in UK, interruption in the flow of electricity is not expected in any scenario.
As far as reactive power requirements are concerned, it goes hand in hand with the uptake of wind power in the generation mix of country. According to Power Technology Research, 27 projects, mainly employing STATCOM technology to compensate reactive power in the grid, have either been installed or set to be installed in 2021.
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