Realising the Isle of Wight’s aspirations for renewable energy power generation and local consumption

Abstract

Transitioning to net-zero carbon emissions will necessitate the use of many low-carbon technologies such as electric vehicles (EV), heat pumps (HP), micro- and utility-scale low-carbon electricity generation– such as solar photovoltaics. All such systems are likely to be rapidly deployed and connected to the electrical network at varying voltage levels. This is predicted to have a fundamental change to net-demand and substation load through transformers, which the current network infrastructure was not originally designed for. Hence, there is risk of faults occurring within the network, one of which is exceeding thermal limits due to high demand. This provides a threat to energy security and reliability as outages may occur due to such faults. To facilitate this transition, there is a need for high-resolution net-demand and constraint forecasting to assist Distribution Network Operators (DNO) with effective network planning.

Within the context of the Isle of Wight (IoW), an island off the south-coast of the UK in the English Channel, this research proposes a methodology to determine the areas at greatest risk of constraints arising and when they may occur, and how these can be effectively managed to assist the IoW Council’s energy aspirations. The IoW Council wishes to transition to net-zero by 2040 and become self-sufficient in electricity from local renewable sources. By using actual half-hourly scaled EV charging and HP demand data, and weather data for the IoW in conjunction with technology penetration projections, potential constraint events were forecasted for different technologies rate of uptake. It was found that network constraints could arise as soon as 2030 with regular faults occurring soon after, which shows the urgency for immediate intervention.

There are a range of interventions that can be considered by the DNO to manage and alleviate network constraints. The traditional method is to reinforce the network which increases the connectable capacity however, this is often time-consuming and expensive. This research proposes alternative interventions that the DNO should consider including utility- and micro-scale battery storage systems (BSS), time-of-use tariffs, private wire connections, an increase in the connected low-carbon generation capacity, and combinations of all these interventions. It was found that a combination of interventions is most beneficial to the DNO and can provide effective protection to the network against power constraints. This will also assist with the IoW Council’s aspirations as well as ensure energy security during the transition to net-zero.

A business case for the DNO was created by completing economic analysis to protect the network from constraints arising across the IoW. This analysis compares the Capital Expenditure (Capex) of reinforcing the network to that of the utility-scale BSS capacity required to protect the network on its own, and as a combination of other interventions. An incentive scheme is also proposed in the research to incentivise the purchase of micro-scale BSS, which can absorb micro-scale low-carbon generation (e.g. rooftop solar photovoltaic systems) on site to be used during times when demand increases and provide protection to the network by reducing power flows through it. The incentivisation scheme proposed found that by subsidising the Capex of a micro-scale BSS by less than 40% provides the DNO with financial benefits as opposed to solely deploying utility-scale BSS to protect the network.

The proposed methods applied are generalisable and can be replicated in other areas of the UK, globally, and should provide advice to other local authorities and DNO who are likely to experience similar challenges as they make their net-zero transition.

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Identifiers

ORCID for Ellis Ridett: orcid.org/0000-0002-1903-7175

ORCID for Abubakr Bahaj: orcid.org/0000-0002-0043-6045

ORCID for Patrick James: orcid.org/0000-0002-2694-7054

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