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Reliability

Performance summary 2020/2021

Network performance
48%
reduction of customer minutes lost
87%
of customers had their power restored within one hour of a high voltage fault
Overview of outputs
11
Improve network performance by the end of RIIO-ED1 so that, on average, customers will have 16% fewer power cuts and have their electricity supplies restored 23% quicker.(See note 1 below).
Customer interruptions have reduced by 38% and customer minutes lost have reduced by 48% from the underlying performance benchmark.
12
Make sure that at least 85% of customers have their power restored within an hour of a high voltage fault happening.(See note 2 below)
87% of customers had their power restored within one hour of a high voltage fault.

Guaranteed Standards of Performance (GSOPs)
98.5%
reduction of the number of customers left without electricity for more than 12 hours
Overview of outputs
13
Reduce by 20% the number of customers experiencing a power cut which lasts for 12 hours or more.(See note 1 below).
The number of customers without electricity for more than 12 hours (where the GSOP applied) was 155, an improvement of over 98.56% on our 2012/13 benchmark performance. Customers received a set payment where we failed to achieve the GSOP.
14
Achieve no failures on all other GSOPs.(See note 2)
We had no failures against most GSOP categories. However, we did not meet the standard for restoring supply following a main fuse failure for 3 customers and failed to notify 8 customers of planned interruptions to their electricity supply. There was 14 failures in total.

Worst served customers
13,495
customers have been helped by projects to reduce the number of worst served customers
Overview of outputs
15
Reduce by 20% the number of customers classified as worst served.(See note 1 below).
To date, projects to reduce the number of worst served customers have been put in place for 13,495 customers. Our target for the whole of RIIO-ED1 was 6,812 customers.

Making our network more resilient
78
substations have had flood defences installed
78%
of the tree clearance programme completed
Overview of outputs
16
Apply flood defences to 75 substations, reducing the risk of both damage to equipment and power cuts due to flooding.(See note 1 below).
We are on track to achieve our RIIO-ED1 targets. To date, we have installed flood defences at 78 substations.
17
Speed up the programme of tree clearance (specifically related to storm resilience) by 40%, with the aim of clearing 700km of overhead lines per year (delivering the programme five years earlier than suggested by Government guidelines).(See note 1 below)
The programme on track to meet the RIIO-ED1 target. We have completed 78% of the programme of tree clearance for resilience that we committed to for the whole of RIIO- ED1.
18
Improve substation battery life to last for 72 hours if there is a major, network-wide power loss.(See note 1 below)
All programmes are ahead of plan.
Protection batteries – 92% of eight-year programme complete.
SCADA batteries – 86% of eight-year programme complete.
Telecommunications sites – 92% of eight-year programme complete.

Note 1: This target is for the full eight-year RIIO-ED1 period, not for each separate year.

Note 2: This target is for each year of RIIO-ED1.

Full summary report

RIIO-ED1 Business Plan Commitments summary report