​e-heat & e-transport

e-heat & e-transport

With electricity becoming an increasingly low carbon fuel, the electrification of heat and transport will prove one of the most economic and practical ways to meet Irish decarbonisation targets.  

The Irish electricity distribution network has been installed over generations – greater use of these assets in substituting fossil fuels in transport and heat will prove societally cost effective. 

​Low Carbon Future

The Electrification of Heat & Transport innovation roadmap addresses network planning and operation, to meet these new demands without compromising our customers’ comfort, security or quality of supply, at an economic cost reflecting our customers’ needs and values.

 As we move towards a low carbon society, this innovation roadmap will help us to deliver the secure, reliable and efficient network our customers need, as they choose the heat and transport solutions that are right for their homes, businesses and lifestyles.

The concentrated uptake of electric vehicles (EVs) in clustered areas will require different solutions from a more dispersed, gradual uptake. Earlier research has suggested that, assuming a 3kW car charge point was installed at each residential premise, there was sufficient headroom in most locations to accommodate 20% EV penetration, albeit with the installation of tap changing transformers in particular areas of congestion to offset voltage drop. At penetration levels above 20% this approach may no longer be appropriate and a different approach could be required, including traditional reinforcement or demand side response schemes. 

These conclusions were informed by an assessment of the impact that clustered residential EV charging had on ESB Networks LV network during a trial in Dublin. In this trial, a cluster of EVs, charged in customers’ homes, were extensively monitored. This data was analysed and extrapolated to draw insight as to what impact EVs would have on residential urban LV networks. These insights were then used to assess what changes to LV design were required, and in what sequence, to accommodate different levels of EV penetration at different charging rates, taking into account the increased electrification of heat.   

ESB Networks’ investment planning standards provide for 16% voltage drop on the MV and LV systems. 10% of this is allocated upstream of the LV bar and the balance of 6-7% voltage drop is allowed for on the LV network.  Large extra domestic load due to installation of Air Source Heat Pumps (ASHP) and EVs, will cause the voltage drops on the LV network to increase. Ensuring that this does not impact customers’ quality of supply would normally require a more heavily engineered network in new estates and substantial conventional reinforcement in existing areas. 

ESB Networks is investigating alternatives which may provide more economic solutions. This particular approach is to regulate the sending LV voltage using MV/LV on-load tap changing transformers which have recently been developed . These would allow for larger voltage drops and greater voltage variation on the LV network without compromising customers received voltage. 

Short term pilots in Ireland will allow ESB Networks to evaluate the operational implications of their use, identify and design for the practical issues regarding their installation on the Irish system, and determine how best to integrate them with our existing network technologies and with Irish customers’ usage patterns. 

Their application will then facilitate lower cost of network design and reinforcement to facilitate greater electrification of heat and transport.

The electrification of heat and transport will lead to increased loads and potentially congestion on LV networks. Voltage drop limitations may be mitigated by MV/LV on-load tap changing transformers, however in other cases thermal capacity of LV Circuits may prove a limiting factor.


Thermal capacity limits can be effectively overcome with conventional reinforcement, upgrading cables/lines and upgrading or installing additional transformers to reduce the load on certain circuits sections. Installation of new transformers can often prove an economic long term solution, but practical issues, such as finding a site for a new secondary substation, can limit ESB Networks’ ability to deliver this solution in existing housing estates.


Miniature secondary substations, known as sidewalk transformers, are a solution to such spatial restrictions as they can be installed next to the congested circuits, on the sidewalk itself, and without the need for a large new site as would be required for a conventional installation. This technology is already in use in Tokyo, Japan for many years. ESB Networks now proposes to develop similar units suitable for use on the Irish network, and evaluate the practical implications of their deployment on the network.

The emergence and uptake patterns of new low carbon technologies such as EVs, ASHPs and micro-generation including PV, and demand response will drive significant changes in how we plan and operate the LV network.

The Future LV Design project will deliver consistent design approaches for new and existing LV networks supporting the economic integration of customers low carbon technology.

The LV design solutions being pursued through this project can be broadly segregated into new design solutions and retro fit solutions. They represent sensible and cost-effective proactive and reactive measures that can be deployed reasonably quickly in response to low carbon.

ESB Networks existing planning strategies employ evidence based, validated assumptions regarding customers’ use at different times of day, treating most domestic customers as a homogenous group. Emerging low carbon technologies such as electric vehicles (EVs), air source heat pumps (ASHPs) and domestic photovoltaic (PV) generation will increasingly challenge these assumptions, as will changes in how customers choose to manage their demand, for their own-use purposes (e.g. storing locally generated electricity) or coordinated with others (e.g. managed by aggregators).

The LV Planning Standards Review will consist of a comprehensive review and critique of our existing LV planning approaches. This will inform effective development of our LV design solutions so that we can effectively meet the demands of these new uses of the distribution system.

This project involves robust statistical analysis to derive new metrics, values and design tools. The analysis will leverage the results of past trials including the National Smart Meter Customer Behavioural Trial and ESB Networks EV impact assessments. It will also help ESB Networks identify gaps in knowledge, and also inform the development of other projects, including ESB Networks’ Winter Peak, Solar PV Trials and StoreNET projects.

The uptake of ASHPs in domestic dwellings will represent significant load growth, driving the development and update of our LV planning standards and designs. These changes must be evidence based, and as such, in this project ESB Networks is monitoring a number of new build locations with clustered ASHP installations. The data gathered will be analysed to develop robust models informing revised planning standards and designs.

ESB Networks has identified two new housing estates where ASHPs are currently being installed in each dwelling, one in Oranmore in Co. Galway and one in Killiney, Co. Dublin. Two new 400 kVA unit substations have been installed to supply both of the estates. Building on our current research work around MV/LV transformer monitoring, ESB Networks will install transformer monitoring devices in both unit substations.