Impact case study database

Context

ENWL supply electricity to over 5,000,000 customers in the North West of England, and are the largest electrical distribution network operator (DNO) in the UK. To help meet the UK government’s 2050 net zero carbon emissions target, an increasing number of low-carbon and renewable technologies are being connected to the network. However, renewable energies can cause fluctuations in voltage and power flow, which affect the overall stability and security of the network. The regulator Ofgem will also require DNOs to take a more active role in carbon reduction in the next price control period (RIIO-ED2) beginning in 2023. ENWL identified that they needed to significantly invest in and enhance their network capacity (e.g., bigger lines, substations, and other infrastructures) in order to manage the voltage and thermal fluctuations that result from these additional connections. However, new investments are costly and have a significant carbon and material consumption penalty. Actively managing these voltage and power fluctuations can avoid specific costly infrastructure investments whilst improving and enhancing existing infrastructure assets. UoM collaborated with ENWL to support a strategic approach to enhancing network performance and minimising investment needs.

Pathways to impact

In 2012, ENWL commissioned UoM to undertake a series of research projects to inform more effective network investment. The C₂C project assessed the capability of ENWL’s distribution networks to cope with both an increasing number of customers as well as integrating renewable power generation. Building on the subsequent project reports, ENWL identified the need to explore new ideas to further increase network capacity, which led to the CLASS (2014-2016) and Smart Street (2015-2019) projects.

As part of these projects, UoM developed a range of models and planning tools that facilitated ENWL to implement flexible demand-side response controls to increasing network capacity. Trials run by ENWL identified the success of these projects to provide improved network capacity and flexibility, whilst substantially reducing the financial investment (and embedded carbon) in new assets.

Reach and significance of the impact

Improved network capacity through connection management

Spare capacity in the distribution network is vital to ensure a reliable electricity supply to customers. As we transition to a net-zero economy, the demands placed upon local electricity networks are changing (e.g., solar photovoltaics feeding in, increased demand due to electric vehicles and heating): in some areas any previous spare capacity will no longer be sufficient to ensure reliability of supply. Given investments to add capacity are costly, UoM research developed a planning tool – RO-CBA – to demonstrate where investment savings can be made across a network [1].

Using RO-CBA, this research [1] identified that ‘managed connections’ reduce the need for new infrastructure by effectively obtaining spare capacity from customers who reduce their consumption when contingencies occur (such as the failure of a line). In 2016, as a result of the UoM research [1], ENWL fundamentally changed their policy making and investment process, and rolled out managed connections across their entire network. This approach, and the RO-CBA tool, are now integrated into their business-as-usual assessment of network upgrade options. [Text removed for publication]. This tool [1] has led to improved management of network connections for an increasing number of customers whilst maximising the integration of renewable power generation [1]: through maximising spare capacity in the existing network, the network is better able to cope with increased demands from renewable technology. Overall this has increased the confidence in which ENWL can safely connect a greater level of (intermittent) renewables to the network. [Text removed for publication].

Flexible demand response management techniques improve network stability

i) CLASS

Responding to the power and voltage fluctuations described above, ENWL applied the learnings from the CLASS and Smart Streets projects to improve network stability. Following CLASS, ENWL installed new monitoring equipment and ‘voltage controllers’ on over 60 primary substations at tactical points on the distribution network, as recommended through the UoM research [2-5]. Evaluation by ENWL has confirmed this can save its customers around GBP100,000,000 over the next 25 years [B]. The CLASS method can be implemented at a primary substation 57 times faster and 12 times more cheaply than traditional network reinforcement [C].

The CLASS research [2-5], successfully applied in the North-West, has also been approved for national use. The National Grid Electricity System Operator (NGESO) is responsible for managing the electricity system across the UK. NGESO has confirmed that the ENWL CLASS passed testing for the low frequency static response service in 2018, and the fast reserve service in 2019 [D]. This allows CLASS to participate in the Firm Frequency Response (FFR) and Fast Reserve (FR) tendered markets – essentially enabling the National Grid to ‘buy’ load from DNOs. CLASS provides a more cost-effective service than previously available: according to NGESO [E][F], the accepted ENWL2 method (i.e. ENWL CLASS), offers the lowest firm energy fee (GBP80 per MWh) in the tendered market. [Text removed for publication].

Since March 2019, the CLASS method has been successfully activated [G] [Text removed for publication].

The CLASS programme has allowed DNO/DSOs to optimise the effectiveness of their infrastructure investment by taking a strategic approach to the assessment of managed connections and flexible demand response. These approaches have made significant savings for both the network operators and consumers and allow the decarbonisation of electricity networks to be delivered more rapidly and with lower levels of investment and disruption.

ii) Smart Streets

Smart Streets was the first UK demonstration of a fully centralised low voltage network management and automation system [H]. Smart Streets stabilises voltage by using new controllable switching devices integrated into the ENWL network management system. Subsequently, the supply voltage to customers is reduced to an optimum level – known as conservation voltage reduction – enabling both the network and customer appliances to work more efficiently [I].

Smart Streets uses assets deployed as part of the CLASS and C₂C projects, and additional HV and LV network models developed by UoM, to analyse the impact and benefits of the Smart Streets trials, as well as undertaking a carbon impact assessment (based on the methodologies in [6]) [G]. ENWL used these findings to support their application for GBP18,000,000 as part of the Innovation Rollout Mechanism (IRM) from Ofgem and the UK Government Department for Business, Energy and Industrial Strategy (BEIS), to roll out voltage optimisation across the LV networks. [Text removed for publication].

The Smart Streets method enables customer appliances to operate more efficiently which can extend the life of the equipment as well as the more immediate benefit in reduced operating cost [J]. Further, the carbon impact assessment demonstrated Smart Street could provide carbon savings of up to 17 MtCO₂e in the North West by 2060 [K]. By controlling voltage on ENWL’s LV network, Smart Streets can reduce customer electricity bills by up to GBP60 to GBP70 a year, reduce carbon emissions and provide more flexible solutions to connect low-carbon technologies into the network, all without reducing power quality [G][H]. Given the direct financial benefit to customers, ENWL have prioritised the selection of substations that overlap with customers identified as living in fuel poverty. Once fully integrated into ENWL’s network management system, this will create the UK’s first actively optimised network [H].