Energy Network Indicators

Each year, network companies must report on their performance and outputs under Ofgem’s RIIO (Revenue = Incentives + Innovation + Outputs) network price controls. To ensure value for money for consumers, the price controls limit the amount by which network costs can rise and stipulate levels of performance. These network indicators give a snapshot of our monitoring.

Our network indicators

Select a sector from the below to view our network indicators in detail and for an overview of our monitoring themes.

If you have feedback on the indicators, please contact us

    Network highlights at March 2019

    The 2017/18 annual reports for network company performance under RIIO show that they are performing well for customers. The companies are meeting or on track to meet most of their targets.

    • Since the beginning of RIIO-ED1, the number of power cuts across GB has reduced by 11%, and the duration of power cuts has reduced by 9%. 
    • Customer service continues to improve with the majority of network companies meeting or beating customer service targets in 2017/18. Scores in both electricity distribution and gas distribution currently stand at 8.8 out of 10.
    • Electricity distribution and electricity transmission network companies have reduced the carbon footprint of their networks in the past three years by over 850,000 CO2e.
    • In 2017/18 gas distribution networks had connected over 64,100 fuel poor homes to the gas grids since the start of the price control in 2013. This is just over 70% of the RIIO-GD1 target.
    • The gas distribution networks continue to undertake the long-term programme of replacing risky iron mains on their networks, as mandated by the Health and Safety Executive (HSE). In 2017-18, five of the eight networks have now exceeded their target level of risk removed for the price control; the remaining three networks are ahead of schedule to achieve their targets for the price control.
    • Most of the companies are underspending their allowances.  Spending traditionally increases further into the price control when they deliver large, capital-intensive projects. Ofgem requires the companies to share savings from underspending with customers.

    So far, since the start of RIIO in 2013 Ofgem has secured additional savings of over £6 billion for consumers by a combination of reduced revenues or voluntary contributions from companies.  

    What do the network companies report on?

    The RIIO price controls are designed to encourage network companies to play a full role in delivering a sustainable energy sector, and to do so in a way that brings consumers value for money. Under RIIO, each company has to deliver and report on a range of outputs:

    • Reliability: We expect companies to improve network reliability and reduce the number and duration of power interruptions.
    • Connections: Companies will provide a better service for customers wanting to connect to the network.
    • Customer Service: We incentivise companies to deliver good customer service and listen to stakeholders.
    • Social Obligations: Companies will do more to help vulnerable customers, particularly during power interruptions.
    • Environmental: Companies must reduce their carbon emissions and other environmental impacts.
    • Safety: Companies are funded to ensure the network remains safe and meets Health and Safety Executive standards.

    You can find out more at: The energy network: how it works for you

    All electricity transmission charts and data (RIIO-T1)

    There are three electricity transmission network ownersopen key term pop-up. They operate the high voltage network carrying electricity across GB. 

    The RIIO-T1 price control runs from 1 April 2013 to 31 March 2021. The data presented here gives a snapshot of the network owners’ financial performance and their performance against key RIIO-T1 outputs for consumers.

    Chart

    Source: RIIO electricity transmission annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of customer satisfaction with electricity transmission owners under the RIIO-T1 price control. It shows three scores comprising customer satisfaction over the completed years of the price control.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Electricity - transmission

    Data Table

    Customer satisfaction with network owners: Electricity transmission (RIIO-T1)
    Network ownersYear 1 stakeholder engagement incentive reward scoreYear 2 stakeholder engagement incentive reward scoreYear 3 stakeholder engagement incentive reward scoreYear 4 stakeholder engagement incentive reward scoreYear 5 stakeholder engagement incentive reward scoreYear 1 stakeholder survey scoreYear 2 stakeholder survey scoreYear 3 stakeholder survey scoreYear 4 stakeholder survey scoreYear 5 stakeholder survey scoreYear 1 customer survey score (NGET only)Year 2 customer survey scoreYear 3 customer survey scoreYear 4 customer survey scoreYear 5 customer survey score
    National Grid Electricity Transmission5.7566.2575.17.537.747.537.77.887.417.47.547.47.74
    Scottish Power Transmission4.95.56.256.256.47.47.16.97.98.3
    Scottish Hydro Electricity Transmission5.4665.43.256.57.78.28.78

    More information

    Customer satisfaction with network owners: At-a-glance summary

    • The performance of all Transmission companies was broadly in line with their previously reported figures within the Price control. The exception to this was Scottish Hydro Electricity Transmission who had a small decrease in it's Stakeholder Engagement Incentive score. 

    Relevance and further information

    • We want electricity transmission network owners to understand consumers’ needs and proactively engage with them to make sure these are met.
    • Network owners receive an annual financial reward or penalty based on their survey scores. Rewards can be up to 0.5% of annual revenues per company.
    • There is also a stakeholder engagement incentive discretionary reward, which is an annual panel assessment of stakeholder engagement. 

    Methodology

    For the customer and stakeholder satisfaction surveys incentive, companies may be rewarded or penalised depending on their performance against the targets set. The methodology for this incentive is outlined in the network owner’s licence conditions.

    Ofgem and an independent panel of experts conduct the assessment for the stakeholder engagement incentive.

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    Chart

    Source: RIIO electricity transmission annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of company performance on network connections delivered on time over the completed years of the RIIO-T1 price control. 

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Electricity - transmission

    Data Table

    Network connections by transmission owners: Electricity transmission (RIIO-T1)
    Year 1 not on timeYear 1 on timeYear 2 not on timeYear 2 on timeYear 3 not on timeYear 3 on timeYear 4 not on timeYear 4 on timeYear 5 not on timeYear 5 on time
    National Grid Electricity Transmission01390235028001870189
    Scottish Power Transmission2502860116063159
    Scottish Hydro Electricity Transmission047098088059049

    More information

    Network connections by transmission owners: At-a-glance summary

    In 2017/18 a total of 189 applications were submitted from parties seeking to connect to the electricity transmission network, all of which were delivered on time.

    Relevance and further information

    Electricity transmission owners are required to deliver timely and effective connections to the network.

    Under the price control, we expect companies to provide a good service for customers wanting to connect to the network.

    Methodology

    Each year, network companies must report on their performance under the RIIO-T1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

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    Chart

    Source: RIIO electricity transmission annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of company performance on reliability and availability of energy. It shows the volume of electricity not supplied by electricity transmission owners. ‘Energy not supplied’ means the volume of energy to customers that is lost as a result of faults or failures on the network.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Electricity - transmission

    Data Table

    Volume of energy not supplied: Electricity transmission (RIIO-T1)
    Year 1 actualYear 1 targetYear 2 actualYear 2 targetYear 3 actualYear 3 targetYear 4 actualYear 4 targetYear 5 actualYear 5 target
    National Grid Electricity Transmission1353168.73164.53166.831639.7316
    Scottish Power Transmission42.22252.822513.922510.32253225
    Scottish Hydro Electricity Transmission35.6120106.112001204.412024.3120

    More information

    Volume of energy not supplied: At-a-glance summary

    • All three transmission operators have significantly outperformed their targets in year five (2017-18) of the RIIO-T1 price control.

    Relevance and further information

    • Ofgem sets targets for each transmission owners’ level of energy not supplied.
    • Under the price control, we expect companies to maintain network reliability and reduce the number and duration of power cuts.

    Methodology

    Each year, network companies must report on their performance under the RIIO-T1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

    close

    Chart

    Source: RIIO electricity transmission annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of environmental impact. It shows company performance against an emissions reduction target electricity transmission owners must deliver for consumers under RIIO-T1.

     We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Please note: NGET’s historic SF6 loss figures have been adjusted in line with a 2017 revision Methodology Statement in Respect of SF6 Gas Leakage.

    Policy Areas:

    • Electricity - transmission

    Data Table

    Sulphur Hexafluoride (SF6) emissions: Electricity transmission (RIIO-T1)
    Y1 Actual emissionsY1 Target emissionsY2 Actual emissionsY2 Target emissionsY3 Actual emissionsY3 Target emissionsY4 Actual emissionsY4 Target emissionsY5 Actual emissionsY5 Target emissions
    NGET10110120569544121589744122991100012349961512450
    SPT730573495592441619388707460782
    SHETL335151339173272224253253327340

    More information

    Sulphur Hexafluoride (SF6) emissions: At-a-glance summary

    • In 17/18 all three transmission operators outperformed against their target emissions levels of SF6. 
    • Scottish Hydro Electricity  Transmission's leakage rate is, again above the target figure and will therefore be penalised under the incentive mechanism, although the level is marginal. 
    • Scottish Hydro Electricity  Transmission and Scottish Power Transmission reported a reduction in SF6 leakage from the previous year. 

    Relevance and further information

    • SF6 is an extremely effective electrical insulator and so is used in high-voltage switchgear and other electrical equipment. It is also a potent greenhouse gas.
    • Electricity transmission owners are incentivised to limit their emissions of SF6. Ofgem target levels of emissions that we expect companies to beat. 

    Methodology

    Each year, network companies must report on their performance under the RIIO-T1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

    close

    Chart

    Source: RIIO electricity transmission annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of financial performance. It shows our estimates of electricity transmission owners’ return on regulatory equity (RoRE). It is our current view of an eight-year average RoRE over RIIO-T1.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Electricity - transmission

    Data Table

    Return on regulatory equity: Electricity transmission (RIIO-T1)
    Network companiesCurrent eight-year view
    National Grid Electricity Transmission (excl. System Operator)10.4%
    Scottish Hydro Electricity Transmission10.4%
    Scottish Power Transmission8.0%

    More information

    Return on regulatory equity (RoRE): At-a-glance summary

    • It ranges from 10.4% for National Grid Electricity Transmission & Scottish Power Transmission to 8% for Scottish Hydro Electricity Transmission.

    Relevance and further info

    • RoRE helps us monitor the financial performance of network companies under the price control.
    • RoRE should be compared to the cost of equity allowed at the start of the price control. For all electricity transmission owners, this was 7.0%
    • No electricity transmission owners are forecast to earn returns below their cost of equity.
    • The numbers include the impact of the Mid-Period Review and National Grid’s voluntary deferral.

    Methodology

    • Our RoRE calculation measures companies’ performance for the RIIO-1 period, this includes the first five years actual return and their forecast performance for the remaining three years of RIIO-1.
    • We report RoRE values for the companies compared against the assumptions we set for RIIO-1. Our RoRE now includes their actual and forecast financing (cost of debt) and tax performance. This is a new way of reporting RoRE, and values may not be comparable with the values we have published in the past. 
    • Our calculation assumes all outputs will be delivered. 
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    Chart

    Javascript is required to render chart Expenditure vs allowance: Electricity transmission (RIIO-T1).

    Source: RIIO electricity transmission annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of financial performance. It compares electricity transmission owners’ realised total expenditure for their regulated business activities against their allowance for each year of the RIIO-T1 network price control.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Electricity - transmission

    Data Table

    Expenditure vs allowance: Electricity transmission (RIIO-T1)
    Network companiesYear 1 expenditureYear 1 allowanceYear 2 expenditureYear 2 allowanceYear 3 expenditureYear 3 allowanceYear 4 expenditureYear 4 allowanceYear 5 expenditureYear 5 allowance
    National Grid Electricity Transmission (TO only)1.52.11.21.71.21.51.21.31.11.3
    Scottish Power Transmission0.30.40.30.50.40.40.40.20.20.3
    Scottish Hydro Electricity Transmission0.20.10.40.30.60.40.50.40.40.4

    More information

    Expenditure vs allowance: At-a-glance summary

    • National Grid Electricity Transmission (TO only) and Scottish Power Transmission both report total expenditure below the annual revenue allowance in 2017-18. National Grid Electricity Transmission reported an underspend of £0.2 billion (14%) and Scottish Power Transmission reported an underspend of £0.1 billion
    • Scottish Hydro Electricity Transmission report total expenditure in line with revenue allowance in 2017-18. 

    Relevance and further information

    • This chart is an indicator of company financial performance against cost allowances for the first four years of RIIO-T1.
    • We set the total amount each company can spend ahead of the price control (company ‘allowances’) and monitor their actual spend (‘total expenditure’) against these amounts annually.
    • Network companies are allowed to retain a part of any savings achieved, with the rest being passed on to consumers.

    Methodology

    Each year, network companies must report on their performance under the RIIO-T1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

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    Chart

    Javascript is required to render chart Estimated network costs per domestic customer (GB average).

    Source: Ofgem analysis of network companies’ cost information .

    Information correct as of: March 2019

    This chart shows our estimate of trends in the annual cost of the different components of network charges for a domestic customer with a fixed amount of consumption. Balancing Services Use of System charges are not included in the chart.

    Click the ‘more information’ tab above for a summary of the latest trends, an explanation of network costs and for further detail on how we calculate the costs.

    Policy Areas:

    • Electricity - distribution
    • Electricity - transmission
    • Gas - distribution
    • Gas - transmission

    Data Table

    Estimated network costs per domestic customer (GB average)
    Annualised network costsElectricity (transmission)Electricity (distribution)Gas (transmission)Gas (distribution)
    Apr-1532969120
    May-1532969120
    Jun-1532969120
    Jul-1532969120
    Aug-1532969120
    Sep-1532969120
    Oct-1532969120
    Nov-1532969120
    Dec-1532969120
    Jan-1632969120
    Feb-1632969120
    Mar-1632969120
    Apr-16391019120
    May-16391019120
    Jun-16391019120
    Jul-16391019120
    Aug-16391019120
    Sep-16391019120
    Oct-16391019120
    Nov-16391019120
    Dec-16391019120
    Jan-17391019120
    Feb-17391019120
    Mar-17391019120
    Apr-1737909114
    May-1737909114
    Jun-1737909114
    Jul-1737909114
    Aug-1737909114
    Sep-1737909114
    Oct-1737909114
    Nov-1737909114
    Dec-1737909114
    Jan-1837909114
    Feb-1837909114
    Mar-1837909114
    Apr-1835859113
    May-1835859113
    Jun-1835859113
    Jul-1835859113
    Aug-1835859113
    Sep-1835859113
    Oct-1835859113
    Nov-1835859113
    Dec-1835859113
    Jan-1935859113
    Feb-1935859113
    Mar-1935859113
    Apr-19358710114
    May-19358710114
    Jun-19358710114
    Jul-19358710114
    Aug-19358710114
    Sep-19358710114
    Oct-19358710114
    Nov-19358710114
    Dec-19358710114
    Jan-20358710114
    Feb-20358710114
    Mar-20358710114

    More information

    Estimated network costs per domestic customer: At-a-glance summary

    • The majority of network costs for a domestic customer are for the use of the gas and electricity distribution networks.
    • For a household whose consumption does not change, on average across GB network costs in 2019/20 will increase for gas distribution, electricity distribution, and gas transmission. For electricity transmission, costs compared to the previous charging year will rise broadly in line with inflation.
    • Actual costs will vary depending on where a customer lives, how much energy they use, and what type of meter they have.

    What are network costs?

    Suppliers are charged for the costs to build, maintain, improve and operate the energy networks. Most of the networks are owned by monopoly businesses. Therefore through regulation, we limit the revenue that these companies can recover from customer charges to run the networks.

    The network charges paid by suppliers vary depending on where their customers live, what type of meter they have, when energy is used and how much energy they use. In total, these charges accounted for approximately a fifth of a dual fuel bill in 2019.

    Different charges apply for the high voltage/pressure transmission networks (which take electricity and gas around Great Britain) and the lower voltage/pressure distribution networks, which connect customers to the overall networks.

    As well as the charges to suppliers that are considered here, electricity generators and gas producers are also charged for their use of the networks. It is important to note that trends in network costs will therefore also affect supplier costs indirectly through wholesale prices.

    Methodology

    • Network costs are calculated by combining charging information published by the network companies with assumptions about consumption and losses for domestic customers.
    • All costs are calculated for medium annual typical domestic consumption values of 12,000kWh for gas and 3,100kWh of electricity, which is held fixed across the charging years. The actual network costs a supplier incurs to serve a customer will depend on how much energy is used, the timing of its use as well as the charges that apply from one year to the next.
    • The costs shown are GB averages, calculated by taking a simple unweighted average of the tariffs that apply in different regions of the country.
    • The costs are expressed in nominal money (i.e. the amount of money a customer ‘pays over the counter’), rather than in real terms (i.e. after adjusting for inflation). For electricity, the costs reported are for a standard unrestricted meter.
    • Balancing Services Use of System charges are not included on the chart. These charges cover the cost of services used to balance the electricity system and internal system operator operating costs.

    The methodology we use to calculate these charges is consistent with our methodology for the Default Tariff Cap. Further details on the calculations are available in our Default Tariff Cap publications.

    Further information

    You can find further information on the different components making up an energy bill at Understand your gas and electricity bill.

    To see how the network fits together, visit The energy network: How it works for you.

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    All electricity distribution charts and data (RIIO-ED1)

    There are 14 electricity distribution network operatorsopen key term pop-up, owned by six ownership groups. They operate the low voltage electricity network, taking energy from the transmission system to homes and businesses.

    The RIIO-ED1 price control runs from 1 April 2015 to 31 March 2023. The data presented here gives a snapshot of the network owners' financial performance and their performance against key outputs for consumers.

    Chart

    Source: RIIO Electricity Distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of customer satisfaction with electricity distribution operators under the RIIO-ED1 price control. Distribution network operators are scored against three broad measures of customer service: customer satisfaction (the 'customer survey score'), stakeholder engagement and complaints handling. This chart shows performance against two of those scores for the third year of the price control. Performance against the complaints handling metric is detailed in the RIIO-ED1 annual report.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

     

    Policy Areas:

    • Electricity - distribution

    Data Table

    Customer satisfaction with network operators: Electricity distribution (RIIO-ED1)
    Distribution network operatorStakeholder engagement incentive reward scoreCustomer survey score
    Electricity North West5.758.47
    Northern Powergrid7.508.64
    Western Power Distribution8.758.93
    UK Power Networks7.258.74
    SP Energy Networks6.358.72
    Scottish & Southern Electricity Networks5.508.60

    More information

    Customer satisfaction with network operators: At-a-glance summary

    • The performance of each distribution network operator group varies across the three broad measures of customer service elements, but overall performance has continued to improve with all DNOs meeting their targets
    • Western Power Distribution performs best across all three measures, while Scottish and Southern Electricity Networks and Electricity Northwest Ltd have most room for improvement.

    Relevance and further information

    We want distribution network operators to understand consumers’ needs and proactively engage with them to make sure these are met.

    There is a financial incentive that encourages distribution network operators to deliver good customer service.  It consists of three elements:

    • customer satisfaction
    • complaints handling
    • stakeholder engagement.

    Methodology

    We set targets, with associated penalties and rewards, for customer satisfaction and complaints.

    Ofgem and an independent panel of experts conduct the assessment for the stakeholder engagement incentive.

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    Chart

    Source: RIIO Electricity Distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of the reliability and availability of the electricity distribution network. It shows the number of interruptions experienced by customers and the average length of interruptions.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Electricity - distribution

    Data Table

    Customer interruptions and minutes lost: Electricity distribution (RIIO-ED1)
    Target for customers interruptedActual number of customers interrupted Target average minutes lost per customer per year Actual average minutes lost per customer per year
    Electricity North West47.4533.2344.2334.63
    Northern Powergrid64.3249.9761.0340.51
    Western Power Distribution62.1753.2742.1731.57
    UK Power Networks53.1236.4745.8032.03
    SP Energy Networks44.6235.9043.5832.09
    Scottish and Southern Electricity Networks65.2756.2455.1451.40

    More information

    Customer interruptions and minutes lost: At-a-glance summary

    • Network operators continue to perform well and exceed their overall targets for 2017-18, however a number of network operators missed individual elements of the targets. SWEST missed its overall CI target resulting in a penalty.
    • Customer interruptions were lowest for Electricity Northwest Ltd and highest for Scottish and Southern Electricity Networks.
    • Customer minutes lost were lowest for Western Power Distribution and highest for Scottish and Southern Electricity Networks.

    Relevance and further information

    • Distribution network operators invest in their network to increase reliability and resilience against severe weather and to protect the network from the effects of climate change.
    • We incentivise distribution network operators to improve the reliability on their network, penalising underperformance and rewarding those who beat their targets.

    Methodology

    We set annual targets for customer interruptions and customer minutes lost.  Each year distribution network operators must report on their performance under the RIIO-ED1 price control. This allows us to assess if targets have been met and to reward or penalise network operators appropriately. 

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    Chart

    Source: RIIO Electricity Distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of network operator performance on connections to the electricity distribution network. It shows the average time to connect (TTC) for single service low voltage (LVSSA) connections and small project demand (LVSSB) connections. It compares these to the targets set in 2013.

    We update this chart on an annual basis. Click the ‘more information’ tab above for details of how to interpret the figures and for information on methodology 

    Policy Areas:

    • Electricity - distribution

    Data Table

    Average time to connect to the network: Electricity distribution (RIIO-ED1)
    Distribution network operatorsLVSSA targetLVSSA (2017/18)LVSSB targetLVSSB (2017/18)
    Electricity North West42.0831.7252.7034.28
    Northern Powergrid42.0850.4152.7059.26
    Western Power Distribution42.0827.5852.7036.03
    UK Power Networks42.0840.2452.7046.69
    SP Energy Networks42.0851.8352.7067.73
    Scottish & Southern Electricity Networks42.0836.7752.7046.38

    More information

     Average time to connect to the distribution network: At-a-glance summary

    • Since last year, the average time to connect (TTC) has improved; however, in 2017-18 six out of the fourteen DNOs did not meet the TTC targets we set.
    • Average TTC across LVSSA (Single service LV connection) was lowest for Western Power Distribution and was lowest for Electricity North West Ltd across LVSSB (Small project demand connection (LV)). The average TTC across both connections types was highest for Scottish Power Energy Networks.

    Relevance and further info

    Under RIIO, each company has to deliver a range of outputs, which they are required to report on each year. This chart provides us with an indicator of network performance against connections.

    Methodology

    Each year, network companies must report on their performance under the RIIO-ED1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

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    Chart

    Source: RIIO Electricity Distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of environmental impact. It shows the length of overhead lines removed in National Parks, Areas of Outstanding Natural Beauty and National Scenic Areas. In RIIO-ED1, each distribution network operator is able to recover a defined amount of funding to pay for undergrounding of network cables in these designated areas.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Electricity - distribution

    Data Table

    Undergrounding of overhead lines: Electricity distribution (RIIO-ED1)
    Distribution network operatorsLength of installations (km)Total expenditure (GBP £ million)
    Electricity North West4.461.08
    Northern Powergrid15.622.41
    Western Power Distribution9.451.27
    UK Power Networks3.450.23
    SP Energy Networks5.460.49
    Scottish & Southern Electricity Networks2.511.02

    More information

    Undergrounding of overhead lines: At-a-glance summary

    In 2017-18 approximately 34km of overhead lines were removed and approximately 41km of underground lines installed by the distribution network operators at a cost of £6.5 million.

    Relevance and further information

    Undergrounding reduces the visual impact of overhead lines on the environment. This contributes towards the environment output the distribution network operators must deliver for customers.  

    Methodology

    Allowances are calculated to reflect stakeholder interest in visual amenity and each network operator’s funding is based on the amount of its network in Areas of Outstanding Natural Beauty and National Parks.

    Each year, distribution network operators must report on expenditure and activity related to undergrounding. This allows us to determine if they are meeting stakeholder requirements.

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    Chart

    Source: RIIO electricity distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of financial performance. It shows our estimates of electricity distribution network operators’ return on regulatory equity (RoRE). It is our current view of an eight-year average RoRE over RIIO-ED1.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Electricity - distribution

    Data Table

    Return on regulatory equity: Electricity distribution (RIIO-ED1)
    Distribution OperatorsCurrent eight year view
    ENWL6.51%
    NPg8.21%
    WPD9.05%
    UKPN11.63%
    SPEN8.45%
    SSEN8.04%

    More information

    Return on regulatory equity (RoRE): At-a-glance summary

    • RoRE across the sector is 9.1%,
    • It ranges from 6.5% for Electricity North West Ltd to 11.6% for UK Power Networks.

    Relevance and further information

    • RoRE helps us monitor the financial performance of distribution network operators under the price control.
    • RoRE should be compared to the cost of equity allowed at the start of the price control. The Western Power Distribution group was allowed 6.4% and the remaining five groups 6.0%.
    • No distribution network operators are forecast to earn returns below their cost of equity.

    Methodology

    • Our RoRE calculation measures companies’ performance for the RIIO-ED1 period, this includes the first three years actual return and their forecast performance for the remaining five years of RIIO-ED1.
    • We report RoRE values for the companies compared against the assumptions we set for RIIO-ED1. Our RoRE now includes their actual and forecast financing (cost of debt) and tax performance. This is a new way of reporting RoRE, and values may not be comparable with the values we have published in the past.
    • Our calculation assumes all outputs will be delivered.
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    Chart

    Source: RIIO Electricity Distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of financial performance. It compares electricity distribution operators’ realised total expenditure for their regulated business activities against their allowance for the first year of the RIIO-ED1 network price control.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Electricity - distribution

    Data Table

    Expenditure vs allowance: Electricity distribution (RIIO-ED1)
    Distribution network operatorsYear 1 expenditureYear 1 allowanceYear 2 expenditureYear 2 allowanceYear 3 expenditureYear 3 allowance
    Electricity North West259265220254255256
    Northern Powergrid464477424457398440
    Western Power Distribution1044101910861015942958
    UK Power Networks681902749933795883
    SP Energy Networks456495487504496485
    Scottish & Southern Electricity Networks458524500533530523

    More information

    Expenditure vs allowance: At-a-glance summary

    • Four of the six distribution network operator groups underspent their allowances in 2017/18.
    • Underspend was greatest for UK Power Networks.
    • Scottish Power Energy Networks and Scottish and Southern Electricity Networks overspent on its allowances.

    Relevance and further information

    • This chart is an indicator of company financial performance against cost allowances for the first and second years of the RIIO-ED1 price control period.
    • We set the total amount each company can spend ahead of the price control (company ‘allowances’) and monitor their actual spend (‘total expenditure’) against these amounts annually.
    • Network companies are allowed to retain a part of any savings achieved, with the rest being passed on to consumers.

    Methodology

    Each year, distribution network operators must report on their performance under the RIIO-ED1 price control. Our review of their submissions and supporting information informs our annual publications on distribution network operator financial performance. 

    close

    Chart

    Javascript is required to render chart Estimated network costs per domestic customer (GB average).

    Source: Ofgem analysis of network companies’ cost information .

    Information correct as of: March 2019

    This chart shows our estimate of trends in the annual cost of the different components of network charges for a domestic customer with a fixed amount of consumption. Balancing Services Use of System charges are not included in the chart.

    Click the ‘more information’ tab above for a summary of the latest trends, an explanation of network costs and for further detail on how we calculate the costs.

    Policy Areas:

    • Electricity - distribution
    • Electricity - transmission
    • Gas - distribution
    • Gas - transmission

    Data Table

    Estimated network costs per domestic customer (GB average)
    Annualised network costsElectricity (transmission)Electricity (distribution)Gas (transmission)Gas (distribution)
    Apr-1532969120
    May-1532969120
    Jun-1532969120
    Jul-1532969120
    Aug-1532969120
    Sep-1532969120
    Oct-1532969120
    Nov-1532969120
    Dec-1532969120
    Jan-1632969120
    Feb-1632969120
    Mar-1632969120
    Apr-16391019120
    May-16391019120
    Jun-16391019120
    Jul-16391019120
    Aug-16391019120
    Sep-16391019120
    Oct-16391019120
    Nov-16391019120
    Dec-16391019120
    Jan-17391019120
    Feb-17391019120
    Mar-17391019120
    Apr-1737909114
    May-1737909114
    Jun-1737909114
    Jul-1737909114
    Aug-1737909114
    Sep-1737909114
    Oct-1737909114
    Nov-1737909114
    Dec-1737909114
    Jan-1837909114
    Feb-1837909114
    Mar-1837909114
    Apr-1835859113
    May-1835859113
    Jun-1835859113
    Jul-1835859113
    Aug-1835859113
    Sep-1835859113
    Oct-1835859113
    Nov-1835859113
    Dec-1835859113
    Jan-1935859113
    Feb-1935859113
    Mar-1935859113
    Apr-19358710114
    May-19358710114
    Jun-19358710114
    Jul-19358710114
    Aug-19358710114
    Sep-19358710114
    Oct-19358710114
    Nov-19358710114
    Dec-19358710114
    Jan-20358710114
    Feb-20358710114
    Mar-20358710114

    More information

    Estimated network costs per domestic customer: At-a-glance summary

    • The majority of network costs for a domestic customer are for the use of the gas and electricity distribution networks.
    • For a household whose consumption does not change, on average across GB network costs in 2019/20 will increase for gas distribution, electricity distribution, and gas transmission. For electricity transmission, costs compared to the previous charging year will rise broadly in line with inflation.
    • Actual costs will vary depending on where a customer lives, how much energy they use, and what type of meter they have.

    What are network costs?

    Suppliers are charged for the costs to build, maintain, improve and operate the energy networks. Most of the networks are owned by monopoly businesses. Therefore through regulation, we limit the revenue that these companies can recover from customer charges to run the networks.

    The network charges paid by suppliers vary depending on where their customers live, what type of meter they have, when energy is used and how much energy they use. In total, these charges accounted for approximately a fifth of a dual fuel bill in 2019.

    Different charges apply for the high voltage/pressure transmission networks (which take electricity and gas around Great Britain) and the lower voltage/pressure distribution networks, which connect customers to the overall networks.

    As well as the charges to suppliers that are considered here, electricity generators and gas producers are also charged for their use of the networks. It is important to note that trends in network costs will therefore also affect supplier costs indirectly through wholesale prices.

    Methodology

    • Network costs are calculated by combining charging information published by the network companies with assumptions about consumption and losses for domestic customers.
    • All costs are calculated for medium annual typical domestic consumption values of 12,000kWh for gas and 3,100kWh of electricity, which is held fixed across the charging years. The actual network costs a supplier incurs to serve a customer will depend on how much energy is used, the timing of its use as well as the charges that apply from one year to the next.
    • The costs shown are GB averages, calculated by taking a simple unweighted average of the tariffs that apply in different regions of the country.
    • The costs are expressed in nominal money (i.e. the amount of money a customer ‘pays over the counter’), rather than in real terms (i.e. after adjusting for inflation). For electricity, the costs reported are for a standard unrestricted meter.
    • Balancing Services Use of System charges are not included on the chart. These charges cover the cost of services used to balance the electricity system and internal system operator operating costs.

    The methodology we use to calculate these charges is consistent with our methodology for the Default Tariff Cap. Further details on the calculations are available in our Default Tariff Cap publications.

    Further information

    You can find further information on the different components making up an energy bill at Understand your gas and electricity bill.

    To see how the network fits together, visit The energy network: How it works for you.

    close

    All gas transmission charts and data (RIIO-T1)

    National Grid Gas Transmissionopen key term pop-up is responsible for operating the high pressure transmission of gas across GB.

    The RIIO-T1 price control runs from 1 April 2013 to 31 March 2021. The data presented here gives a snapshot of their financial performance and performance against key outputs for consumers.

    Chart

    Javascript is required to render chart Customer satisfaction: Gas transmission (RIIO-T1).

    Source: RIIO gas transmission annual report 2017-18.

    Information correct as of: December 2018

    This chart is an indicator of customer satisfaction with National Grid Gas Transmission.  It shows three scores comprising customer satisfaction over the five completed years of the price control.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Gas - transmission

    Data Table

    Customer satisfaction: Gas transmission (RIIO-T1)
    YearStakeholder engagement incentive scoreStakeholder survey scoreCustomer survey score
    2013/145.757.87.2
    2014/156.257.97.6
    2015/166.1587.6
    2016/176.57.9828.027
    2017/184.2587.6

    More information

    Customer satisfaction: At-a-glance summary

    National Grid Gas Transmission outperformed their targets for both customer and stakeholder satisfaction surveys in 2017-18.

    Relevance and further information

    • We want transmission owners to understand consumers’ needs and proactively engage with them to make sure these are met.
    • National Grid Gas Transmission receive an annual financial reward or penalty based on their customer survey scores. Rewards can be up to 0.5% of their annual revenue.
    • There is also a stakeholder engagement incentive discretionary reward, which is an annual panel assessment of stakeholder engagement.

    Methodology

    For the customer and stakeholder satisfaction surveys incentive, companies may be rewarded or penalised depending on their performance against the targets set.

    Ofgem and an independent panel of experts conduct the assessment for the stakeholder engagement incentive.

    close

    Chart

    Javascript is required to render chart Network reliability: Gas transmission (RIIO-T1).

    Source: National Grid's annual report 2017-18 (opens an external website).

    Information correct as of: December 2018

    This chart is an indicator of the reliability and availability of the gas National Transmission System over the five completed years of the RIIO-T1 price control.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Gas - transmission

    Data Table

    Network reliability: Gas transmission (RIIO-T1)
    YearTargetActual
    213/14100%100%
    2014/15100%100%
    2015/16100%100%
    2016/17100%99.75%
    2017/18100%99.90%

    More information

    Network reliability: At-a-glance summary

    National Grid Gas Transmission achieved 99.90% reliability on its network during 2017-18.

    Relevance and further information

    Network availability is the time that the network is available.

    Methodology

    National Grid reports this information on their website each year.

    close

    Chart

    Javascript is required to render chart Network connections: Gas transmission (RIIO-T1).

    Source: RIIO gas transmission annual report 2017-18.

    Information correct as of: December 2018

    This chart is an indicator of National Grid Gas Transmission’s performance on network connections. It shows applications received and offers made by National Grid Gas Transmission over the five completed years of the RIIO-T1 price control.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Gas - transmission

    Data Table

    Network connections: Gas transmission (RIIO-T1)
    YearConnection Offers ReceivedOffers made or processing within timescale
    2013/1466
    2014/1586
    2015/1666
    2016/1788
    2017/1898

    More information

    Network connections: At-a-glance summary

    In 2017/18 a total of nine applications were submitted from parties seeking to connect to the National Transmission System.

    Eight offers were made within the required timescales.

    Relevance and further information

    • National Grid Gas Transmission is required to deliver timely and effective connections for customers applying to connect to the network.
    • We expect companies to provide a good service for customers wanting to connect to the network. 

    Methodology

    Each year, network companies must report on their performance under the RIIO-T1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

    close

    Chart

    Javascript is required to render chart Business carbon footprint: Gas transmission (RIIO-T1).

    Source: RIIO gas transmission annual report 2017-18.

    Information correct as of: December 2018

    This chart is an indicator of environmental impact. It shows National Grid Gas Transmission’s business carbon footprint for emissions in tonnes of carbon dioxide equivalent (tCO2e) for the five completed years of the RIIO-T1 price control. Click on Scopes 1 and 2 in the chart legend to view the column data for Scope 3.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Gas - transmission

    Data Table

    Business carbon footprint: Gas transmission (RIIO-T1)
    YearScope 1Scope 2Scope 3
    2013-1433204528253627
    2014-1526902435593747
    2015-1636553861325630
    2016-17568808118784942.3954922
    2017-185845451011472435

    More information

    Business carbon footprint: At-a-glance summary

    There has been a general increase in emissions figures during 2017-18 with a slight decrease for Scope 2 emissions.

    Relevance and further information

    National Grid Gas Transmission reports annually on their business carbon footprint to allow interested stakeholders to monitor its performance. There are no financial incentives linked to this output.

    The business carbon footprint measure includes:

    • Scope 1 - emissions directly related to the day-to-day business activities of network business.
    • Scope 2 - emissions which arise from operating the network, including the CO2 emissions from losses of electricity or shrinkage of gas that occur as a result of transporting energy on the network.
    • Scope 3 - emissions due to third party contractors carrying out business activities on behalf of the network.

    Emissions from natural gas fuel combustion to run gas-powered compressor units are included in the Scope 1 emissions figures. 

    Methodology

    Each year, network companies must report on their performance under the RIIO-T1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

    close

    Chart

    Javascript is required to render chart Return on regulatory equity: Gas transmission (RIIO-T1).

    Source: RIIO gas transmission annual report 2017-18.

    Information correct as of: December 2018

    This chart is an indicator of financial performance. It shows our estimates of National Grid Gas Transmission’s return on regulatory equity (RoRE). It is our current view of an eight-year average RoRE over the RIIO-T1 period.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Gas - transmission

    Data Table

    Return on regulatory equity: Gas transmission (RIIO-T1)
    NetworkCurrent eight-year view
    National Grid Gas Transmission7%

    More information

    Return on regulatory equity: At-a-glance summary

    • National Grid Gas Transmission’s RoRE is 7%.

    Relevance and further information

    • RoRE helps us monitor the financial performance of network companies under the price control.
    • RoRE should be compared to the cost of equity allowed at the start of the price control. For National Grid Gas Transmission this was 6.8%. 
    • National Grid Gas Transmission’s numbers include the impact of the Mid-Period Review.

    Methodology

    • Our RoRE calculation is based on a mix of the first three years’ performance, company forecasts and simple averages.
    • There are a number of factors not reflected in our RoRE calculations which may impact the return realised by shareholders. The largest being potential clawbacks for non-delivery of outputs.
    • The calculation assumes all outputs will be delivered.
    • Returns may not equal the actual returns seen by shareholders.
    close

    Chart

    Javascript is required to render chart Expenditure vs allowance: Gas transmission (RIIO-T1).

    Source: RIIO gas transmission annual report 2017-18.

    Information correct as of: December 2018

    This chart compares National Grid Gas Transmission’s total expenditure for their regulated business activities against their allowance for each year under the RIIO-T1 price control. 

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Gas - transmission

    Data Table

    Expenditure vs allowance: Gas transmission (RIIO-T1)
    YearAllowance Expenditure
    2013-14383.7585174316.3399907
    2014-15355.8741183326.6537432
    2015-16351.0954932344.8563811
    2016-17378.9167393380.283819
    2017-18428.2551545474.3580518

    More information

    Expenditure vs allowance: At-a-glance summary

    Network companies are allowed to retain a part of any savings achieved, and the rest is passed on to consumers. 

    Relevance and further information

    This chart is an indicator of company RIIO-T1 financial performance against cost allowances so far.

    The allowances reflect NGGT view. They are lower than anticipated at the start of the price control due to the forecast effect of reopener mechanisms.

    Methodology

    Each year, network companies must report on their performance under the RIIO-T1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

    close

    Chart

    Javascript is required to render chart Estimated network costs per domestic customer (GB average).

    Source: Ofgem analysis of network companies’ cost information .

    Information correct as of: March 2019

    This chart shows our estimate of trends in the annual cost of the different components of network charges for a domestic customer with a fixed amount of consumption. Balancing Services Use of System charges are not included in the chart.

    Click the ‘more information’ tab above for a summary of the latest trends, an explanation of network costs and for further detail on how we calculate the costs.

    Policy Areas:

    • Electricity - distribution
    • Electricity - transmission
    • Gas - distribution
    • Gas - transmission

    Data Table

    Estimated network costs per domestic customer (GB average)
    Annualised network costsElectricity (transmission)Electricity (distribution)Gas (transmission)Gas (distribution)
    Apr-1532969120
    May-1532969120
    Jun-1532969120
    Jul-1532969120
    Aug-1532969120
    Sep-1532969120
    Oct-1532969120
    Nov-1532969120
    Dec-1532969120
    Jan-1632969120
    Feb-1632969120
    Mar-1632969120
    Apr-16391019120
    May-16391019120
    Jun-16391019120
    Jul-16391019120
    Aug-16391019120
    Sep-16391019120
    Oct-16391019120
    Nov-16391019120
    Dec-16391019120
    Jan-17391019120
    Feb-17391019120
    Mar-17391019120
    Apr-1737909114
    May-1737909114
    Jun-1737909114
    Jul-1737909114
    Aug-1737909114
    Sep-1737909114
    Oct-1737909114
    Nov-1737909114
    Dec-1737909114
    Jan-1837909114
    Feb-1837909114
    Mar-1837909114
    Apr-1835859113
    May-1835859113
    Jun-1835859113
    Jul-1835859113
    Aug-1835859113
    Sep-1835859113
    Oct-1835859113
    Nov-1835859113
    Dec-1835859113
    Jan-1935859113
    Feb-1935859113
    Mar-1935859113
    Apr-19358710114
    May-19358710114
    Jun-19358710114
    Jul-19358710114
    Aug-19358710114
    Sep-19358710114
    Oct-19358710114
    Nov-19358710114
    Dec-19358710114
    Jan-20358710114
    Feb-20358710114
    Mar-20358710114

    More information

    Estimated network costs per domestic customer: At-a-glance summary

    • The majority of network costs for a domestic customer are for the use of the gas and electricity distribution networks.
    • For a household whose consumption does not change, on average across GB network costs in 2019/20 will increase for gas distribution, electricity distribution, and gas transmission. For electricity transmission, costs compared to the previous charging year will rise broadly in line with inflation.
    • Actual costs will vary depending on where a customer lives, how much energy they use, and what type of meter they have.

    What are network costs?

    Suppliers are charged for the costs to build, maintain, improve and operate the energy networks. Most of the networks are owned by monopoly businesses. Therefore through regulation, we limit the revenue that these companies can recover from customer charges to run the networks.

    The network charges paid by suppliers vary depending on where their customers live, what type of meter they have, when energy is used and how much energy they use. In total, these charges accounted for approximately a fifth of a dual fuel bill in 2019.

    Different charges apply for the high voltage/pressure transmission networks (which take electricity and gas around Great Britain) and the lower voltage/pressure distribution networks, which connect customers to the overall networks.

    As well as the charges to suppliers that are considered here, electricity generators and gas producers are also charged for their use of the networks. It is important to note that trends in network costs will therefore also affect supplier costs indirectly through wholesale prices.

    Methodology

    • Network costs are calculated by combining charging information published by the network companies with assumptions about consumption and losses for domestic customers.
    • All costs are calculated for medium annual typical domestic consumption values of 12,000kWh for gas and 3,100kWh of electricity, which is held fixed across the charging years. The actual network costs a supplier incurs to serve a customer will depend on how much energy is used, the timing of its use as well as the charges that apply from one year to the next.
    • The costs shown are GB averages, calculated by taking a simple unweighted average of the tariffs that apply in different regions of the country.
    • The costs are expressed in nominal money (i.e. the amount of money a customer ‘pays over the counter’), rather than in real terms (i.e. after adjusting for inflation). For electricity, the costs reported are for a standard unrestricted meter.
    • Balancing Services Use of System charges are not included on the chart. These charges cover the cost of services used to balance the electricity system and internal system operator operating costs.

    The methodology we use to calculate these charges is consistent with our methodology for the Default Tariff Cap. Further details on the calculations are available in our Default Tariff Cap publications.

    Further information

    You can find further information on the different components making up an energy bill at Understand your gas and electricity bill.

    To see how the network fits together, visit The energy network: How it works for you.

    close

    All gas distribution charts and data (RIIO-GD1)

    There are eight gas distribution network operatorsopen key term pop-up, owned by four ownership groups. They operate the local gas networks, taking energy from the gas transmission system to homes and businesses.

    The RIIO-GD1 price control runs from 1 April 2013 to 31 March 2021. The data presented here gives a snapshot of the network owners' financial performance and their performance against key outputs for consumers.

    Chart

    Source: RIIO gas distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of customer satisfaction with gas distribution companies under the RIIO-GD1 price control. It shows three scores comprising customer satisfaction over the five completed years of the price control.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Gas - distribution

    Data Table

    Customer satisfaction with network owners: Gas distribution (RIIO-GD1)
    SEIRS 2013/14SEIRS 2014/15SEIRS 2015/16SEIRS 2016/17SEIRS 2017/18AVCSC 2013/14AVCSC 2014/15AVCSC 2015/16AVCSC 2016/17AVCSC 2017/18
    Cadent7.15.96.96.968.158.238.368.398.49
    NGN6.755.56.87.256.158.759.019.179.179.14
    SGN5.956.45.7576.258.648.728.989.139.12
    WWU6.27.056.05658.699.049.059.119.15

    More information

    At-a-glance summary

    In most cases gas distribution networks are achieving high levels of customer satisfaction, but there are some pockets of poorer performance.

    All GDNs met their annual targets for 2017-18 except Cadent. Cadent North London missed its target for the connections survey, and Cadent West Midlands missed its target for the connections and planned interruptions surveys.

    In 2017-18, Cadent was penalised £1.16 million under the Broad Measure of Customer Satisfaction incentive for failing to meet the customer satisfaction targets in these areas (although Cadent achieved a net overall reward for this incentive based on its performance in other component parts, such as in other customer satisfaction surveys).

    WWU achieved the highest average score in 2017-18 and has recorded the highest average customer satisfaction in RIIO-GD1 so far.

    Relevance and further information

    We want gas distribution companies to understand consumers’ needs and proactively engage with them to make sure these are met.

    Customer satisfaction is measured annually across three categories:

    • planned work
    • unplanned work and
    • connections work.

    GDNs can be rewarded or penalised annually by up to 0.5% of their base revenue, depending on how well they perform against their target.

    Methodology

    Each year, gas distribution network owners must report on their performance under the RIIO-GD1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

     

    close

    Chart

    Javascript is required to render chart Fuel poor connections: Gas distribution (RIIO-GD1).

    Source: RIIO gas distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of gas distribution companies’ performance on fuel poor connections. It shows the number of fuel poor connections made by each gas distribution company over the five completed years of the RIIO-GD1 price control.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology. 

    Policy Areas:

    • Gas - distribution

    Data Table

    Fuel poor connections: Gas distribution (RIIO-GD1)
    Commitment (5 year cumulative)Actual (5 year cumulative)
    EoE71137888
    Lon17601646
    NW84008593
    WM52505335
    NGN875010066
    Sc1026516776
    So60695390
    WWU80958499

    More information

    At-a-glance summary

    So far in RIIO-GD1, GDNs have connected 64,100 households under this scheme, which is just over 70% of the eight-year industry target.

    Cadent’s London SGN Southern networks are currently behind schedule compared to the five-year target, but are forecasting to meet to meet their eight-year target.

    Relevance and further information

    The Fuel Poor Network Extension Scheme helps vulnerable and fuel poor households that are off the gas grid to switch to natural gas by offering funding towards the cost of connecting to the gas network.

    We increased Fuel Poor network extension targets by 20%  following a public consultation in 2015.

    Methodology

    Each year, network companies must report on their performance under the RIIO-GD1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

    close

    Chart

    Javascript is required to render chart Network availability: Gas distribution (RIIO-GD1).

    Source: RIIO gas distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of network availability. It shows the gas distribution network availability as a percentage over the five completed years of the RIIO-GD1 price control. Availability for 2017/18 has been consistently 99.998 for GB customers. You can see how this breaks down by network owner in the table below.

     

    Year 1

    Year 2

    Year 3

    Year 4

    Year 5

    Cadent

    99.997%

    99.997%

    99.996%

    99.996%

    99.996%

    NGN

    99.998%

    99.998%

    99.998%

    99.998%

    99.998%

    SGN

    99.997%

    99.998%

    99.998%

    99.998%

    99.998%

    WWU

    99.999%

    99.998%

    99.999%

    99.999%

    99.999%

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Gas - distribution

    Data Table

    Network availability: Gas distribution (RIIO-GD1)
    Year 1 (2013-14)Year 2 (2014-15)Year 3 (2015-16)Year 4 (2016-17)Year 5 (2017-18)
    Cadent99.997%99.997%99.996%99.996%99.996%
    NGN99.998%99.998%99.998%99.998%99.998%
    SGN99.997%99.998%99.998%99.998%99.998%
    WWU99.999%99.998%99.999%99.999%99.999%

    More information

    At-a-glance summary

    Network availability (availability of supply) to GB consumers was 99.998% in 2017-18 and has been consistent over the RIIO-GD1 period so far.  

    Relevance and further information

    Network availability is the time (as a % of total time during that period) that the GD network is available to consumers.

    Network availability accounts for both planned and unplanned interruptions.

    Methodology

    Each year, network companies must report on their performance under the RIIO-GD1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

    close

    Chart

    Javascript is required to render chart Risk removed from the network: Gas distribution (RIIO-GD1).

    Source: RIIO gas distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of network safety. Due to their nature, gas networks pose a safety risk. We set targets for gas distribution network owners to reduce the safety risk on their networks. The chart shows the level of safety risk network owners have removed by replacing or abandoning iron gas mains over the three completed years of the RIIO-GD1 price control.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Gas - distribution

    Data Table

    Risk removed from the network: Gas distribution (RIIO-GD1)
    Proportionate risk reductionActual Risk reduction
    Cadent362,919467,620
    NGN69,494164,391
    SGN113,478216,653
    WWU61,70489,144

    More information

    At-a-glance summary

    In 2017-18, five out of the eight networks have now exceeded their total GD1 primary output target of risk removed. The remaining three networks have yet to achieve their total output target but have still removed more risk than expected at this point in the price control.

    Relevance and further information

    Gas distribution companies undertake long-term programme of replacing risky iron mains on their networks as mandated by the Health and Safety Executive. Under RIIO-GD1, the ‘iron mains risk reduction’ primary output target sets the level of iron mains risk that GDNs must remove from their networks.

    Methodology

    Each year, network companies must report on their performance under the RIIO-GD1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

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    Chart

    Javascript is required to render chart Volume of gas lost from the distribution network (RIIO-GD1).

    Source: RIIO gas distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of company performance on environmental impact. It shows the annual volume of gas lost (referred to as ‘shrinkage’)  by gas distribution network owners. Shrinkage is the dominant element of network owners’ business carbon footprint.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Gas - distribution

    Data Table

    Volume of gas lost from the distribution network (RIIO-GD1)
    Target 13/14Actual 13/14Target 14/15Actual 14/15Target 15/16Actual 15/16Target 16/17Actual 16/17Target 17/18Actual 17/18
    Cadent1540141714981374146013241422130713861269
    NGN455417445397433382423354412352
    SGN884839848796826766802733780715
    WWU440417429395421381413378405372

    More information

    At-a-glance summary

    All gas distribution network owners are meeting their annual volume of gas lost (‘shrinkage‘) targets and forecast to meet them for the rest of the RIIO-GD1 price control period.

    Relevance and further information

    Under the price control, we expect companies to reduce their environmental impact, including reducing the amount of shrinkage from their networks.

    We incentivise gas distribution companies to minimise shrinkage through two mechanisms:

    • the Environmental Emissions Incentive and
    • the Shrinkage Incentive.

    Shrinkage targets were updated in 2014/15 following an update of the model used. We have therefore revised the 2013/14 figures to make them relative to the new targets.

    Methodology

    Each year, network companies must report on their performance under the RIIO-GD1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance.

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    Chart

    Javascript is required to render chart Return on regulatory equity: Gas distribution (RIIO-GD1).

    Source: RIIO gas distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart is an indicator of financial performance. It shows our estimates of gas distribution network owners’ return on regulatory equity (RoRE). It is our current view of an eight-year average RoRE over RIIO-GD1.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Electricity - distribution
    • Gas - distribution

    Data Table

    Return on regulatory equity: Gas distribution (RIIO-GD1)
    Current eight-year view
    Cadent12.59%
    NGN12.73%
    SGN11.18%
    WWU9.39%

    More information

    At-a-glance summary

    • RoRE (inclusive of financing and tax) across the gas distribution sector is 11.5%,
    • It ranges from 9.4% for WWU and 12.7% for NGN.

    Relevance and further information

    • RoRE helps us assess the financial performance of gas distribution networks under the price control.
    • RoRE should be compared to the cost of equity allowed at the start of the price control which was 6.7% for all of the gas distribution networks.
    • No gas distribution owners are forecast to earn returns below their cost of equity.

    Methodology

    • Our RoRE calculation measures companies’ performance for the RIIO-1 period, this includes the first five years’ actual return and their forecast performance for the remaining three years of RIIO-GD1.
    • We report RoRE values for the companies compared against the assumptions we set for RIIO-1. Our RoRE now includes their actual and forecast financing (cost of debt) and tax performance. This is a new way of reporting RoRE, and values may not be comparable with the values we have published in the past.
    • Our calculation assumes all outputs will be delivered.
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    Chart

    Javascript is required to render chart Expenditure vs allowance: Gas distribution (RIIO-GD1).

    Source: RIIO gas distribution annual report 2017-18.

    Information correct as of: March 2019

    This chart compares gas distribution companies’ realised total expenditure for their regulated business activities against their allowance for the five years of RIIO-GD1 network price control.

    We update this chart on an annual basis. Click the ‘more information’ tab above for a summary of the latest trends, details of how to interpret the figures and for information on methodology.

    Policy Areas:

    • Gas - distribution

    Data Table

    Expenditure vs allowance: Gas distribution (RIIO-GD1)
    CompanyY1 ExpenditureY1 AllowanceY2 ExpenditureY2 AllowanceY3 ExpenditureY3 AllowanceY4 ExpenditureY4 AllowanceY5 ExpenditureY5 Allowance
    Cadent-EoE327354321340318336317339319351
    Cadent-Lon258301237302254321268313267310
    Cadent-NW241274273259242251216253214259
    Cadent-WM176204164204185197178195164201
    NGN228266243273241277235274227257
    SGN-Sc157223180214175210177232163221
    SGN-So341457358431356432373443383446
    WWU236282225275221271219268195266

    More information

    At-a-glance summary

    • Gas distribution network owners forecast that they will outperform their cost allowances over the eight years of RIIO-GD1 by 11.4%.
    • Cost savings are shared with consumers, which help keep down the network costs part of an energy bill.

    Relevance and further information

    • This chart is an indicator of company financial performance against cost allowances for the four completed years of the RIIO-GD1 price control period.
    • We set the total amount each company can spend ahead of the price control (company ‘allowances’) and monitor their actual spend (‘total expenditure’) against these amounts annually.
    • The expenditure shown only accounts for controllable total expenditure.
    • Network companies are allowed to retain a part of any savings they achieve, with the rest being passed on to consumers.

    Methodology

    • Each year, network companies must report on their performance under the RIIO-GD1 price control. Our review of their submissions and supporting information informs our annual publications on network company performance. 
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    Chart

    Javascript is required to render chart Estimated network costs per domestic customer (GB average).

    Source: Ofgem analysis of network companies’ cost information .

    Information correct as of: March 2019

    This chart shows our estimate of trends in the annual cost of the different components of network charges for a domestic customer with a fixed amount of consumption. Balancing Services Use of System charges are not included in the chart.

    Click the ‘more information’ tab above for a summary of the latest trends, an explanation of network costs and for further detail on how we calculate the costs.

    Policy Areas:

    • Electricity - distribution
    • Electricity - transmission
    • Gas - distribution
    • Gas - transmission

    Data Table

    Estimated network costs per domestic customer (GB average)
    Annualised network costsElectricity (transmission)Electricity (distribution)Gas (transmission)Gas (distribution)
    Apr-1532969120
    May-1532969120
    Jun-1532969120
    Jul-1532969120
    Aug-1532969120
    Sep-1532969120
    Oct-1532969120
    Nov-1532969120
    Dec-1532969120
    Jan-1632969120
    Feb-1632969120
    Mar-1632969120
    Apr-16391019120
    May-16391019120
    Jun-16391019120
    Jul-16391019120
    Aug-16391019120
    Sep-16391019120
    Oct-16391019120
    Nov-16391019120
    Dec-16391019120
    Jan-17391019120
    Feb-17391019120
    Mar-17391019120
    Apr-1737909114
    May-1737909114
    Jun-1737909114
    Jul-1737909114
    Aug-1737909114
    Sep-1737909114
    Oct-1737909114
    Nov-1737909114
    Dec-1737909114
    Jan-1837909114
    Feb-1837909114
    Mar-1837909114
    Apr-1835859113
    May-1835859113
    Jun-1835859113
    Jul-1835859113
    Aug-1835859113
    Sep-1835859113
    Oct-1835859113
    Nov-1835859113
    Dec-1835859113
    Jan-1935859113
    Feb-1935859113
    Mar-1935859113
    Apr-19358710114
    May-19358710114
    Jun-19358710114
    Jul-19358710114
    Aug-19358710114
    Sep-19358710114
    Oct-19358710114
    Nov-19358710114
    Dec-19358710114
    Jan-20358710114
    Feb-20358710114
    Mar-20358710114

    More information

    Estimated network costs per domestic customer: At-a-glance summary

    • The majority of network costs for a domestic customer are for the use of the gas and electricity distribution networks.
    • For a household whose consumption does not change, on average across GB network costs in 2019/20 will increase for gas distribution, electricity distribution, and gas transmission. For electricity transmission, costs compared to the previous charging year will rise broadly in line with inflation.
    • Actual costs will vary depending on where a customer lives, how much energy they use, and what type of meter they have.

    What are network costs?

    Suppliers are charged for the costs to build, maintain, improve and operate the energy networks. Most of the networks are owned by monopoly businesses. Therefore through regulation, we limit the revenue that these companies can recover from customer charges to run the networks.

    The network charges paid by suppliers vary depending on where their customers live, what type of meter they have, when energy is used and how much energy they use. In total, these charges accounted for approximately a fifth of a dual fuel bill in 2019.

    Different charges apply for the high voltage/pressure transmission networks (which take electricity and gas around Great Britain) and the lower voltage/pressure distribution networks, which connect customers to the overall networks.

    As well as the charges to suppliers that are considered here, electricity generators and gas producers are also charged for their use of the networks. It is important to note that trends in network costs will therefore also affect supplier costs indirectly through wholesale prices.

    Methodology

    • Network costs are calculated by combining charging information published by the network companies with assumptions about consumption and losses for domestic customers.
    • All costs are calculated for medium annual typical domestic consumption values of 12,000kWh for gas and 3,100kWh of electricity, which is held fixed across the charging years. The actual network costs a supplier incurs to serve a customer will depend on how much energy is used, the timing of its use as well as the charges that apply from one year to the next.
    • The costs shown are GB averages, calculated by taking a simple unweighted average of the tariffs that apply in different regions of the country.
    • The costs are expressed in nominal money (i.e. the amount of money a customer ‘pays over the counter’), rather than in real terms (i.e. after adjusting for inflation). For electricity, the costs reported are for a standard unrestricted meter.
    • Balancing Services Use of System charges are not included on the chart. These charges cover the cost of services used to balance the electricity system and internal system operator operating costs.

    The methodology we use to calculate these charges is consistent with our methodology for the Default Tariff Cap. Further details on the calculations are available in our Default Tariff Cap publications.

    Further information

    You can find further information on the different components making up an energy bill at Understand your gas and electricity bill.

    To see how the network fits together, visit The energy network: How it works for you.

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    Related publications

    RIIO electricity transmission annual report 2017-18

    RIIO electricity distribution annual report 2017-18

    RIIO gas transmission annual report 2017-18

    RIIO gas distribution annual report 2017-18

    These market indicators and data are not intended for use or to be relied on for any commercial purposes. View copyright and disclaimer

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    Publications and updates

    • Published: 25th Jul 2019
    • Charts and data
    • 1 Associated documents
    Upcoming release dates for our market indicators and data on the Ofgem Data Portal.