An unprecedented opportunity for change

Why short interruptions will matter in RIIO-ED2 and how to address them.

An unprecedented opportunity for change

The combination of the UK’s net zero commitment and the upcoming price control provides a momentous opportunity for improving power network reliability, says Chris Watts, director of regulatory affairs, S&C Electric Company.

Over the past year, there has been renewed urgency to move to a low carbon energy system. Last May, the Committee on Climate Change published its report on net zero. Moreover, last summer the UK government made a legally binding commitment to a net zero carbon emissions target for 2050 and the Scottish government set an earlier target of 2045.

Also, Ofgem recently published its Decarbonisation Plan, which establishes nine key actions for driving changes to the energy system.

All sectors must play their part in achieving decarbonisation. For one, the electrification of transport is quickly emerging and will place much greater demand on the electricity system. National Grid’s 2019 Future Energy Scenarios (FES) report estimates there could be 10 million electric vehicles by 2030 and more than 35 million by 2050. This will require the increased load on electricity distribution networks to be carefully managed with smart charging.

Perhaps even more challenging, decarbonisation of heat will place increasing strain on electricity distribution networks. National Grid’s 2019 FES report estimates more than 23 million homes will need low carbon heating by 2050.


So, what does this mean for RIIO-ED2? The price control should be ambitious, incentivising and funding anticipatory investment to support the rollout of electric vehicles and decarbonisation of heat, while including uncertainty mechanisms to allow for change.

We’ve seen major developments with distribution network operators (DNOs) procuring flexibility services such as peak sharing. Ofgem must consider how these opportunities are reflected in determining allowed revenues.  Companies will need incentives to make effective use of existing capacity and have the flexibility to consider all options where new capacity is required. Importantly, these changes will depend on increasingly reliable electricity distribution networks.

All interruptions matter

It isn’t enough to just address customer interruptions (CIs) and customer minutes lost (CML). There was a 32 per cent reduction in CIs and a 42 per cent reduction in CML from 2010 to 2019. However, over the same period there was a 16 per cent increase in short interruptions, which are an increasing part of customers’ overall experience.

Strategies used to manage CIs and CML are causing short interruptions. Some 70-80 per cent of faults affecting overhead lines are transient. Replacing fuses on spurs with autosectionalisers has improved CIs and CML because there aren’t transient faults blowing fuses.

However, using sectionalisers with upline reclosers increases short interruptions significantly because it doesn’t contain the faults to the spurs on which they occur. This worked well previously but isn’t well-suited to a modern grid having large volumes of distributed generation and distributed energy resources.

While there aren’t incentives on short interruptions in RIIO-ED1, there is a good opportunity for them to be introduced in RIIO-ED2 as part of the move to a low carbon energy system. Incentives have already been implemented in Victoria (Australia), Norway, Finland, and Italy. Since the Italian regulator extended incentives to short interruptions in 2008, short interruptions have fallen by 46 per cent. There are proven technologies such as single-phase reclosers that can drive major improvements in short interruptions.


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