Data portal

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.

    Network highlights at February 2017

    Networks are performing well for customers:

    • In 2015/16 all local electricity distribution network operators met or exceeded targets to reduce unplanned power cuts (for example reducing the time it takes to restore power supplies after storms damage the networks).
    • Customer service continues to improve with the majority of network companies meeting or beating customer service targets in 2015/16. 
    • Electricity distribution and electricity transmission network companies reduced the carbon footprint of their networks.
    • Gas distribution networks connected 40,000 more fuel poor homes to the gas grids since the start of the price control.  

    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

    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 2015-16.

    Information correct as of: February 2017

    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 three 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 1 stakeholder survey scoreYear 2 stakeholder survey scoreYear 3 stakeholder survey scoreYear 1 customer survey score (NGET only)Year 2 customer survey scoreYear 3 customer survey score
    National Grid Electricity Transmission5.7566.257.537.747.537.417.47.54
    Scottish Power Transmission4.95.56.257.47.16.9
    Scottish Hydro Electricity Transmission5.4666.57.78.2

    More information

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

    • The stakeholder survey score for Scottish Hydro Electricity Transmission was up from the value reported last year. 
    • Scottish Power Transmission and National Grid Electricity Transmission's stakeholder survey scores are slightly lower than 2014/15 levels. 
    • National Grid Electricity Transmission reported a strong customer survey score in 2015/16, its highest customer score to date.

    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.

    close

    Chart

    Source: RIIO electricity transmission annual report 2015-16.

    Information correct as of: February 2017

    This chart is an indicator of company performance on network connections delivered on time under the three 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 time
    National Grid Electricity Transmission013902350280
    Scottish Power Transmission2502860116
    Scottish Hydro Electricity Transmission047098088

    More information

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

    In 2015/16 a total of 484 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.

    close

    Chart

    Source: RIIO electricity transmission annual report 2015-16.

    Information correct as of: February 2017

    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 target
    National Grid Electricity Transmission1353168.73164.5316
    Scottish Power Transmission42.22252.822513.9225
    Scottish Hydro Electricity Transmission35.6120106.11200120

    More information

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

    • All three transmission operators have significantly outperformed their targets in year three (2015-16) of the RIIO-T1 price control.
    • Scottish Hydro Electricity Transmission, in particular, delivered a major improvement to the volume reported in 2014/15.

    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 2015-16.

    Information correct as of: February 2017

    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.

    Policy Areas:

    • Electricity - transmission

    Data Table

    Sulphur Hexafluoride (SF6) emissions: Electricity transmission (RIIO-T1)
    Year 1 actual emissionsYear 1 target emissionsYear 2 actual emissionsYear 2 target emissionsYear 3 actual emissionsYear 3 target emissions
    National Grid Electricity Transmission1011011,933954412,035950212,097
    Scottish Power Transmission729.5573.3494.6591.8441618.9
    Scottish Hydro Electricity Transmission335.27150.7339.2173.1272.26223.6

    More information

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

    • In 2015/16, both National Grid Electricity Transmission and Scottish Power Transmission outperformed against their target emissions levels for SF6.
    • Scottish Hydro Electricity  Transmission's leakage rate is above the target figure and will therefore be penalised under the incentive mechanism. 
    • All three electricity transmission companies 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 2015-16.

    Information correct as of: February 2017

    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 Transmission9.76%
    National Grid Electricity Transmission (excl. System Operator)9.37%
    Scottish Hydro Electricity Transmission11.53%
    Scottish Power Transmission9.83%

    More information

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

    • RoRE across the sector is 10.1%
    • It ranges from 11.5% for Scottish Hydro Electricity Transmission to 9.8% for National Grid Electricity Transmission.
    • The baseline is 7.0%.

    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.

    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 is potential clawbacks for non-delivery of outputs.
    • Our 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: Electricity transmission (RIIO-T1).

    Source: RIIO electricity transmission annual report 2015-16.

    Information correct as of: February 2017

    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 allowance
    National Grid Electricity Transmission1.41.91.11.71.21.4
    Scottish Power Transmission0.20.40.30.50.40.4
    Scottish Hydro Electricity Transmission0.20.20.30.40.50.8

    More information

    Expenditure vs allowance: At-a-glance summary

    • National Grid Electricity Transmission and Scottish Hydro Electricity Transmission both report total expenditure below the annual revenue allowance in 2015-16. National Grid Electricity Transmission reported an underspend of £216 million (16%) and Scottish Hydro Electricity Transmission reported an underspend of £287 million (35%).
    • Scottish Power Transmission reported a total expenditure of £358 million, which was £6.6 million (or 1.8%) above their annual revenue allowance in 2015-16. Scottish Power Transmission explains that this largely reflects changes in project delivery profiles and also the changes to the timing of windfarm connections.

    Relevance and further information

    • This chart is an indicator of company financial performance against cost allowances for the first three 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.
    • The values do not include some areas of expenditure, such as areas under Excluded Services which will be brought in at the end of RIIO-T1. They also do not reflect the Mid-period Review, which will have a small impact on the figures for National Grid Electricity Transmission.

    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: 1 February 2017

    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-1323.3091.308.90115.00
    May-1323.3091.308.90115.00
    Jun-1323.3091.308.90115.00
    Jul-1323.3091.308.90115.00
    Aug-1323.3091.308.90115.00
    Sep-1323.3091.308.90115.00
    Oct-1323.3091.309.90114.60
    Nov-1323.3091.309.90114.60
    Dec-1323.3091.309.90114.60
    Jan-1423.3091.309.90114.60
    Feb-1423.3091.309.90114.60
    Mar-1423.3091.309.90114.60
    Apr-1426.8094.3010.10115.00
    May-1426.8094.3010.10115.00
    Jun-1426.8094.3010.10115.00
    Jul-1426.8094.3010.10115.00
    Aug-1426.8094.3010.10115.00
    Sep-1426.8094.3010.10115.00
    Oct-1426.8094.3010.30115.10
    Nov-1426.8094.3010.30115.10
    Dec-1426.8094.3010.30115.10
    Jan-1526.8094.3010.30115.10
    Feb-1526.8094.3010.30115.10
    Mar-1526.8094.3010.30115.10
    Apr-1531.7087.209.70118.40
    May-1531.7087.209.70118.40
    Jun-1531.7087.209.70118.40
    Jul-1531.7087.209.70118.40
    Aug-1531.7087.209.70118.40
    Sep-1531.7087.209.70118.40
    Oct-1531.7087.209.60119.20
    Nov-1531.7087.209.60119.20
    Dec-1531.7087.209.60119.20
    Jan-1631.7087.209.60119.20
    Feb-1631.7087.209.60119.20
    Mar-1631.7087.209.60119.20
    Apr-1638.3092.9010.00119.70
    May-1638.3092.9010.00119.70
    Jun-1638.3092.9010.00119.70
    Jul-1638.3092.9010.00119.70
    Aug-1638.3092.9010.00119.70
    Sep-1638.3092.9010.00119.70
    Oct-1638.3092.909.70121.70
    Nov-1638.3092.909.70121.70
    Dec-1638.3092.909.70121.70
    Jan-1738.3092.909.70121.70
    Feb-1738.3092.909.70121.70
    Mar-1738.3092.909.70121.70
    Apr-1737.8085.809.60118.20
    May-1737.8085.809.60118.20
    Jun-1737.8085.809.60118.20
    Jul-1737.8085.809.60118.20
    Aug-1737.8085.809.60118.20
    Sep-1737.8085.809.60118.20
    Oct-1737.8085.809.60118.20
    Nov-1737.8085.809.60118.20
    Dec-1737.8085.809.60118.20
    Jan-1837.8085.809.60118.20
    Feb-1837.8085.809.60118.20
    Mar-1837.8085.809.60118.20

    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 we expect a reduction in all categories of network costs in 2017/18 compared to the previous charging year.
    • 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 quarter of a dual fuel bill in 2015.

    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 12,500kWh 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 customer number weighted 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 Supplier Cost Index, and that used to set the value of the prepayment meter price cap. Further details on the calculations are available in our Supplier Cost Index methodology.

    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 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 2015-16.

    Information correct as of: February 2017

    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 enagement and complaints handling. This chart shows performance against two of those scores over the three completed years 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 West6.98.12
    Northern Powergrid6.58.51
    Western Power Distribution8.758.98
    UK Power Networks7.538.64
    SP Energy Networks6.788.75
    Scottish & Southern Electricity Networks5.738.52

    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 improved since the DPCR5 price control.
    • 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 2015-16.

    Information correct as of: February 2017

    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)
    Distribution network operatorsTarget 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 West48.3736.6647.3732.5
    Northern Powergrid66.1755.4464.4945.97
    Western Power Distribution64.1352.143.8129.39
    UK Power Networks54.3137.8248.7730.13
    SP Energy Networks45.1739.3145.9334.19
    Scottish and Southern Electricity Networks67.2257.1259.3448.2

    More information

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

    • All distribution network operator groups exceeded their targets for customer interruptions and customer minutes lost in 2015-16.
    • 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.
    • These results are a further improvement on 2014/15.

    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 2015-16..

    Information correct as of: February 2017

    This chart is an indicator of electricity distribution companies’ performance on connections. Electricity distribution companies are required to deliver timely and effective connections to the network through their licences. This chart provides information on the average time to connect (TTC) for single service low voltage (LVSSA) connections and small project demand (LVSSB) connections in 2015-16. It compares these to the targets set in 2013.

    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

    Average time to connect to the network: Electricity distribution (RIIO-ED1)
    Distribution network operatorsLVSSA targetLVSSA (2015/16)LVSSB targetLVSSB (2015/16)
    Electricity North West42.0830.3652.7036.88
    Northern Powergrid42.0841.7752.7047.52
    Western Power Distribution42.0832.1252.7039.57
    UK Power Networks42.0840.5752.7047.70
    SP Energy Networks42.0835.6552.7042.94
    Scottish & Southern Electricity Networks42.0832.3452.7042.53

    More information

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

    • All distribution network groups reduced their TTC since the targets were set. 
    • Average TTC across both connection types was lowest for Electricity North West and highest for Northern Powergrid.

    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 2015-16.

    Information correct as of: February 2017

    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 West3.410.86
    Northern Powergrid16.911.22
    Western Power Distribution5.030.76
    UK Power Networks8.020.82
    SP Energy Networks0.000.09
    Scottish & Southern Electricity Networks0.800.25

    More information

    Undergrounding of overhead lines: At-a-glance summary

    In 2015-16 approximately 32km of overhead lines were removed by the distribution network operators at a cost of £4 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 2015-16.

    Information correct as of: February 2017

    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 network operatorsCurrent eight-year view
    Electricity North West9.22%
    Northern Powergrid8.06%
    Western Power Distribution8.10%
    UK Power Networks11.50%
    SP Energy Networks7.26%
    Scottish & Southern Electricity Networks 9.42%

    More information

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

    • RoRE across the sector is 9.03%,
    • It ranges from 11.50% for UK Power Networks to 7.26% for Scottish Power Energy 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 is based on a mix of first year 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.
    • Our calculation assumes all outputs will be delivered.
    • Returns may not equal the actual returns seen by shareholders.
    close

    Chart

    Source: RIIO electricity distribution annual report 2015-16.

    Information correct as of: February 2017

    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 allowance
    Electricity North West244251
    Northern Powergrid436450
    Western Power Distribution985961
    UK Power Networks643851
    SP Energy Networks431467
    Scottish & Southern Electricity Networks427495

    More information

    Expenditure vs allowance: At-a-glance summary

    • Five of the six distribution network operator groups underspent their allowances.
    • Underspend was greatest for UK Power Networks.
    • Only Western Power Distribution overspent on its allowances.

    Relevance and further information

    • This chart is an indicator of company financial performance against cost allowances for the first year 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: 1 February 2017

    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-1323.3091.308.90115.00
    May-1323.3091.308.90115.00
    Jun-1323.3091.308.90115.00
    Jul-1323.3091.308.90115.00
    Aug-1323.3091.308.90115.00
    Sep-1323.3091.308.90115.00
    Oct-1323.3091.309.90114.60
    Nov-1323.3091.309.90114.60
    Dec-1323.3091.309.90114.60
    Jan-1423.3091.309.90114.60
    Feb-1423.3091.309.90114.60
    Mar-1423.3091.309.90114.60
    Apr-1426.8094.3010.10115.00
    May-1426.8094.3010.10115.00
    Jun-1426.8094.3010.10115.00
    Jul-1426.8094.3010.10115.00
    Aug-1426.8094.3010.10115.00
    Sep-1426.8094.3010.10115.00
    Oct-1426.8094.3010.30115.10
    Nov-1426.8094.3010.30115.10
    Dec-1426.8094.3010.30115.10
    Jan-1526.8094.3010.30115.10
    Feb-1526.8094.3010.30115.10
    Mar-1526.8094.3010.30115.10
    Apr-1531.7087.209.70118.40
    May-1531.7087.209.70118.40
    Jun-1531.7087.209.70118.40
    Jul-1531.7087.209.70118.40
    Aug-1531.7087.209.70118.40
    Sep-1531.7087.209.70118.40
    Oct-1531.7087.209.60119.20
    Nov-1531.7087.209.60119.20
    Dec-1531.7087.209.60119.20
    Jan-1631.7087.209.60119.20
    Feb-1631.7087.209.60119.20
    Mar-1631.7087.209.60119.20
    Apr-1638.3092.9010.00119.70
    May-1638.3092.9010.00119.70
    Jun-1638.3092.9010.00119.70
    Jul-1638.3092.9010.00119.70
    Aug-1638.3092.9010.00119.70
    Sep-1638.3092.9010.00119.70
    Oct-1638.3092.909.70121.70
    Nov-1638.3092.909.70121.70
    Dec-1638.3092.909.70121.70
    Jan-1738.3092.909.70121.70
    Feb-1738.3092.909.70121.70
    Mar-1738.3092.909.70121.70
    Apr-1737.8085.809.60118.20
    May-1737.8085.809.60118.20
    Jun-1737.8085.809.60118.20
    Jul-1737.8085.809.60118.20
    Aug-1737.8085.809.60118.20
    Sep-1737.8085.809.60118.20
    Oct-1737.8085.809.60118.20
    Nov-1737.8085.809.60118.20
    Dec-1737.8085.809.60118.20
    Jan-1837.8085.809.60118.20
    Feb-1837.8085.809.60118.20
    Mar-1837.8085.809.60118.20

    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 we expect a reduction in all categories of network costs in 2017/18 compared to the previous charging year.
    • 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 quarter of a dual fuel bill in 2015.

    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 12,500kWh 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 customer number weighted 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 Supplier Cost Index, and that used to set the value of the prepayment meter price cap. Further details on the calculations are available in our Supplier Cost Index methodology.

    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 2015-16.

    Information correct as of: February 2017

    This chart is an indicator of customer satisfaction with National Grid Gas Transmission.  It shows three scores comprising customer satisfaction over the three 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)
    Network companyYear 1 stakeholder engagement incentive reward scoreYear 2 stakeholder engagement incentive reward scoreYear 3 stakeholder engagement incentive reward scoreYear 1 stakeholder survey scoreYear 2 stakeholder survey scoreYear 3 stakeholder survey scoreYear 1 customer survey scoreYear 2 customer survey scoreYear 3 customer survey score
    National Grid Gas Transmission5.756.256.157.797.948.027.157.597.55

    More information

    Customer satisfaction: At-a-glance summary

    National Grid Gas Transmission outperformed their targets for both customer and stakeholder satisfaction surveys in 2015-16.

    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 (opens an external website).

    Information correct as of: February 2017

    This chart is an indicator of the reliability and availability of the gas National Transmission System over the three 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)
    National Grid Gas TransmissionTargetActual
    Year 1 (2013/14)100%100%
    Year 2 (2014/15)100%100%
    Year 3 (2015/16)100%100%

    More information

    Network reliability: At-a-glance summary

    • National Grid Gas Transmission achieved almost 100% reliability on its network during 2015-16.
    • There was a short interruption to supply at one National Transmission System location during 2015-16. Due to rounding, the reliability still shows as 100%.

    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 2015-16.

    Information correct as of: February 2017

    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 three 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)
    Connection offers receivedOffers made or processing within timescale
    Year 1 (2013/14)66
    Year 2 (2014/15)86
    Year 3 (2015/16)66

    More information

    Network connections: At-a-glance summary

    • In 2015/16 a total of six applications were submitted from parties seeking to connect to the National Transmission System.
    • All connection offers were provided 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 2015-16.

    Information correct as of: February 2017

    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 three 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)
    Scope 1Scope 2Scope 3
    Year 1 (2013-14) 321,346 28,253 627
    Year 2 (2014-15) 260,219 35,593 747
    Year 3 (2015-16) 356,245 61,325 630

    More information

    Business carbon footprint: At-a-glance summary

    • The increase in emissions figures during 2015-16, compared to the previous year, is due to increased compressor usage.
    • Scope 2 emissions figures are driven by the increased amount of electricity needed to power the electric-driven compressor units. 

    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 2015-16.

    Information correct as of: February 2017

    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)
    Current eight-year view
    National Grid Gas Transmission7.84%

    More information

    Return on regulatory equity: At-a-glance summary

    • National Grid Gas Transmission’s RoRE is 7.84%.
    • The baseline is 6.8%.

    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 2015-16.

    Information correct as of: February 2017

    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)
    Network companyYear 1 expenditureYear 1 allowanceYear 2 expenditureYear 2 allowanceYear 3 expenditureYear 3 allowance
    National Grid Gas Transmission226.1249218.8244.5224.1242.1

    More information

    Expenditure vs allowance: At-a-glance summary

    • We set a total expenditure allowance of £2.4 billion for the full RIIO-T1 period.
    • National Grid Gas Transmission is currently underspending against their allowances by 13% for the first three years of RIIO-T1.
    • Network companies are allowed to retain a part of any savings achieved, and the rest is passed on to consumers. 
    • These numbers include the impact of the Mid-Period Review.

    Relevance and further information

    • This chart is an indicator of company financial performance against cost allowances for the first three years of RIIO-T1.
    • We set a total expenditure allowance of £2.2 billion for the full RIIO-T1 period. National Grid Gas Transmission is currently underspending against their allowances by 9% for the first three years of RIIO-T1.

    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: 1 February 2017

    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-1323.3091.308.90115.00
    May-1323.3091.308.90115.00
    Jun-1323.3091.308.90115.00
    Jul-1323.3091.308.90115.00
    Aug-1323.3091.308.90115.00
    Sep-1323.3091.308.90115.00
    Oct-1323.3091.309.90114.60
    Nov-1323.3091.309.90114.60
    Dec-1323.3091.309.90114.60
    Jan-1423.3091.309.90114.60
    Feb-1423.3091.309.90114.60
    Mar-1423.3091.309.90114.60
    Apr-1426.8094.3010.10115.00
    May-1426.8094.3010.10115.00
    Jun-1426.8094.3010.10115.00
    Jul-1426.8094.3010.10115.00
    Aug-1426.8094.3010.10115.00
    Sep-1426.8094.3010.10115.00
    Oct-1426.8094.3010.30115.10
    Nov-1426.8094.3010.30115.10
    Dec-1426.8094.3010.30115.10
    Jan-1526.8094.3010.30115.10
    Feb-1526.8094.3010.30115.10
    Mar-1526.8094.3010.30115.10
    Apr-1531.7087.209.70118.40
    May-1531.7087.209.70118.40
    Jun-1531.7087.209.70118.40
    Jul-1531.7087.209.70118.40
    Aug-1531.7087.209.70118.40
    Sep-1531.7087.209.70118.40
    Oct-1531.7087.209.60119.20
    Nov-1531.7087.209.60119.20
    Dec-1531.7087.209.60119.20
    Jan-1631.7087.209.60119.20
    Feb-1631.7087.209.60119.20
    Mar-1631.7087.209.60119.20
    Apr-1638.3092.9010.00119.70
    May-1638.3092.9010.00119.70
    Jun-1638.3092.9010.00119.70
    Jul-1638.3092.9010.00119.70
    Aug-1638.3092.9010.00119.70
    Sep-1638.3092.9010.00119.70
    Oct-1638.3092.909.70121.70
    Nov-1638.3092.909.70121.70
    Dec-1638.3092.909.70121.70
    Jan-1738.3092.909.70121.70
    Feb-1738.3092.909.70121.70
    Mar-1738.3092.909.70121.70
    Apr-1737.8085.809.60118.20
    May-1737.8085.809.60118.20
    Jun-1737.8085.809.60118.20
    Jul-1737.8085.809.60118.20
    Aug-1737.8085.809.60118.20
    Sep-1737.8085.809.60118.20
    Oct-1737.8085.809.60118.20
    Nov-1737.8085.809.60118.20
    Dec-1737.8085.809.60118.20
    Jan-1837.8085.809.60118.20
    Feb-1837.8085.809.60118.20
    Mar-1837.8085.809.60118.20

    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 we expect a reduction in all categories of network costs in 2017/18 compared to the previous charging year.
    • 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 quarter of a dual fuel bill in 2015.

    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 12,500kWh 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 customer number weighted 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 Supplier Cost Index, and that used to set the value of the prepayment meter price cap. Further details on the calculations are available in our Supplier Cost Index methodology.

    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 2015-16.

    Information correct as of: February 2017

    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 three 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)
    Year 1 stakeholder engagement incentive reward scoreYear 2 stakeholder engagement incentive reward scoreYear 3 stakeholder engagement incentive reward scoreYear 1 average customer survey scoreYear 2 average customer survey scoreYear 3 average customer survey score
    National Grid Gas Distribution7.155.96.98.158.238.36
    Northern Gas Networks6.755.56.88.759.019.17
    SGN6.056.45.758.648.728.98
    Wales & West Utilities6.37.056.058.699.049.05

    More information

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

    • Average industry performance for customer satisfaction has continued to increase and most gas distribution network owners improved on their average score from last year.
    • Northern Gas Networks achieved the highest average score in 2015-16 and has the highest average customer satisfaction in RIIO-GD1 so far.
    • National Grid Gas Distribution has been penalised for failure to meet their targets in two of the three satisfaction scoring categories (planned work and connections). All other companies are meeting targets and earning financial rewards.

    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.

    We set targets for customer satisfaction, with associated penalties and rewards, based on how well gas distribution owners perform in each category.

    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 2015-16.

    Information correct as of: February 2017

    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 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

    Fuel poor connections: Gas distribution (RIIO-GD1)
    Commitment (3 year cumulative)Actual (3 year cumulative)
    EoE38184414
    Lon1020742
    NW50205053
    WM31303170
    NGN49175329
    Sc552211418
    So33233543
    WWU47985852

    More information

    Fuel poor connections: At-a-glance summary

    • So far in RIIO-GD1, gas distribution companies have connected 39,521 fuel poor households, just over 43% of their eight-year target of 91,203.
    • National Grid Gas Distribution’s London network is currently behind schedule compared to the three-year linear forecast, but it still expects to meet the 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.

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    Chart

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

    Source: RIIO gas distribution annual report 2015-16.

    Information correct as of: February 2017

    This chart is an indicator of network availability. It shows the gas distribution network availability as a percentage over the three completed years of the RIIO-GD1 price control. Availability for 2015/16 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

    National Grid Gas Distribution

    99.997%

    99.997%

    99.996%

    Northern Gas Networks

    99.998%

    99.998%

    99.998%

    Scotia Gas Networks

    99.997%

    99.998%

    99.998%

    Wales & West Utilities

    99.999%

    99.998%

    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)
    NGGD99.997%99.997%99.996%
    NGN99.998%99.998%99.998%
    SGN99.997%99.998%99.998%
    WWU99.999%99.998%99.999%

    More information

    Network availability: At-a-glance summary

    Network availability (availability of supply) to GB consumers was 99.998% in 2015-16 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.

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    Chart

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

    Source: RIIO gas distribution annual report 2015-16.

    Information correct as of: February 2017

    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)
    Expected risk reductionActual risk reduction
    National Grid Gas (Distribution)217751318763
    Northern Gas Networks41697114225
    Scotia Gas Networks68087152364
    Wales & West Utilities3702365756

    More information

    Risk removed from the network: At-a-glance summary

    At this stage of the price control, all four gas distribution companies expect to exceed their targets and are currently removing more risk than might be expected. 

    Relevance and further information

    Network risk is the risk of an incident occurring on the gas distribution network. Gas distribution networks must remove a certain level of risk from their networks in RIIO-GD1 and they use a model to identify this risk.  

    ll network owners explain that they are targeting higher risk mains first as a way to achieve this output early. As a consequence, since the start of the RIIO-GD1 price control, the iron mains risk across the distribution networks has reduced by 0.69 incidents per year from the original start position of 2.52 incidents per year. 

    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 2015-16.

    Information correct as of: February 2017

    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)
    Year 1 target (2013/14)Year 1 actual (2013/14)Year 2 target (2014/15)Year 2 actual (2014/15)Year 3 target (2015/16)Year 3 actual (2015/16)
    National Grid Gas Distribution162814181498137414601374
    Northern Gas Networks459417445397432382
    Scotia Gas Networks884825848785826766
    Wales & West Utilities440417429414421381

    More information

    Volume of gas lost from the distribution network: 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 RIIO-GD1 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
    • 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 2015-16.

    Information correct as of: February 2017

    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
    National Grid Gas Distribution9.78%
    Northern Gas Networks11.23%
    Scotia Gas Networks11.61%
    Wales & West Utilities11.31%

    More information

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

    • RoRE across the gas distribution sector is 10.64%
    • It ranges from 11.61% for Scotia Gas Networks to 9.78% for National Grid Gas Distribution.
    • The baseline is 6.7%.

    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 all gas distribution owners, this was 6.7%
    • No gas distribution owners are forecast to earn returns below their cost of equity.

    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.
    • Our calculation assumes all outputs will be delivered. Returns may not equal the actual returns seen by shareholders.
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    Chart

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

    Source: RIIO gas distribution annual report 2015-16.

    Information correct as of: February 2017

    This chart compares gas distribution companies’ realised total expenditure for their regulated business activities against their allowance for the three completed years of the 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)
    Network companyYear 1 expenditureYear 1 allowanceYear 2 expenditureYear 2 allowanceYear 3 expenditureYear 3 allowance
    National Grid Gas Distribution (East of England)308.8333.8303.4320.5300.4316.3
    National Grid Gas Distribution) (London)243.4284224285240.1302.6
    National Grid Gas Distribution (North West)227.1256.9257.5243.1228.2235.2
    National Grid Gas Distribution (West Midlands)165.8191.5154.6191.4174.3184.7
    Northern Gas Networks215.6250.8229.7258.1227.3261.3
    Scotia Gas Networks (Scotland)148.2210.1170.3202.3165196.4
    Scotia Gas Networks (Southern)322.4431.1338410.8336.4410.6
    Wales & West Utilities223.1263.3212.7258.2208.9254.5

    More information

    Expenditure vs allowance: At-a-glance summary

    • Gas distribution network owners forecast that they will outperform their cost allowances over the eight years of RIIO-GD1 by 12.3%.
    • 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 three 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: 1 February 2017

    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-1323.3091.308.90115.00
    May-1323.3091.308.90115.00
    Jun-1323.3091.308.90115.00
    Jul-1323.3091.308.90115.00
    Aug-1323.3091.308.90115.00
    Sep-1323.3091.308.90115.00
    Oct-1323.3091.309.90114.60
    Nov-1323.3091.309.90114.60
    Dec-1323.3091.309.90114.60
    Jan-1423.3091.309.90114.60
    Feb-1423.3091.309.90114.60
    Mar-1423.3091.309.90114.60
    Apr-1426.8094.3010.10115.00
    May-1426.8094.3010.10115.00
    Jun-1426.8094.3010.10115.00
    Jul-1426.8094.3010.10115.00
    Aug-1426.8094.3010.10115.00
    Sep-1426.8094.3010.10115.00
    Oct-1426.8094.3010.30115.10
    Nov-1426.8094.3010.30115.10
    Dec-1426.8094.3010.30115.10
    Jan-1526.8094.3010.30115.10
    Feb-1526.8094.3010.30115.10
    Mar-1526.8094.3010.30115.10
    Apr-1531.7087.209.70118.40
    May-1531.7087.209.70118.40
    Jun-1531.7087.209.70118.40
    Jul-1531.7087.209.70118.40
    Aug-1531.7087.209.70118.40
    Sep-1531.7087.209.70118.40
    Oct-1531.7087.209.60119.20
    Nov-1531.7087.209.60119.20
    Dec-1531.7087.209.60119.20
    Jan-1631.7087.209.60119.20
    Feb-1631.7087.209.60119.20
    Mar-1631.7087.209.60119.20
    Apr-1638.3092.9010.00119.70
    May-1638.3092.9010.00119.70
    Jun-1638.3092.9010.00119.70
    Jul-1638.3092.9010.00119.70
    Aug-1638.3092.9010.00119.70
    Sep-1638.3092.9010.00119.70
    Oct-1638.3092.909.70121.70
    Nov-1638.3092.909.70121.70
    Dec-1638.3092.909.70121.70
    Jan-1738.3092.909.70121.70
    Feb-1738.3092.909.70121.70
    Mar-1738.3092.909.70121.70
    Apr-1737.8085.809.60118.20
    May-1737.8085.809.60118.20
    Jun-1737.8085.809.60118.20
    Jul-1737.8085.809.60118.20
    Aug-1737.8085.809.60118.20
    Sep-1737.8085.809.60118.20
    Oct-1737.8085.809.60118.20
    Nov-1737.8085.809.60118.20
    Dec-1737.8085.809.60118.20
    Jan-1837.8085.809.60118.20
    Feb-1837.8085.809.60118.20
    Mar-1837.8085.809.60118.20

    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 we expect a reduction in all categories of network costs in 2017/18 compared to the previous charging year.
    • 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 quarter of a dual fuel bill in 2015.

    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 12,500kWh 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 customer number weighted 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 Supplier Cost Index, and that used to set the value of the prepayment meter price cap. Further details on the calculations are available in our Supplier Cost Index methodology.

    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 2015-16

    RIIO electricity distribution annual report 2015-16

    RIIO gas transmission annual report 2015-16

    RIIO gas distribution annual report 2015-16

    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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