Retrofitting domestic customers to a three-phase supply will enable them to connect EVs and heat pumps to reduce their impact on the climate while delivering whole system benefits of reduced reinforcement and losses.

There are significant issues with upgrading using existing 3ph equipment, such as: resizing the meter cabinet to enable the connection; difficulty accessing service positions; drawing new 3ph service cables across existing properties and heat rise. This and more leads to increased costs and reduced customer acceptance, introducing more barriers to net zero.

Project OBELISC will aim to solve this problem by developing a new type of meter cabinet installed near the boundary edge of domestic properties to serve as the 3ph domestic connection point to the distribution network.

Benefits

Financial Benefits

The new solution is aimed at all customers who require an upgraded supply to connect LCTs, predominantly heat pumps and electrical vehicle charging points. The cost savings from the new solution would be passed down to all customers, as the reinforcement costs for this upgrade are socialised except for high capacity “red” rated heat pumps.

Benefit structure

The new solution for upgrading customers to three-phase supply on the boundary edge of their properties will create tangible benefits under two headings:

Avoided network costs. Creating a solution which connects at the boundary and reduces civil works will create value through:

Reduced costs for digging and reinstatement

• Eliminating costs for expanding meter cabinet recess
• Reduced installation time
• Reducing the volumes of three-phase service cable required to be purchased for upgrading customers

Avoided customer costs. A solution which integrates the existing service cable and connection will produce value to the customer directly through reduced need for in-house electrical remodelling.

As discussed in Section 3, there will be additional value to the customer due to the reduction in barriers to decarbonise their properties and reduction in stress and difficulty of the three-phase upgrade. These have not been quantified in this analysis.

Cost structure

Costs additional or alternative to the standard three-phase upgrade are derived from the development and rollout of the OBELISC solution. These costs fall under two categories:

Development costs. The costs to design and test the system such that it can be integrated into business as usual will come through:

• Delivery of the NIA project. This is aimed at being as cost-effective as possible as per NGED best practice, as described in Section 9
• Training of NGED and contractor staff in the techniques required to install the solution
• Dissemination to NGED planning and design staff when to use the OBELISC solution
• Integration of purchase and supply of the solution into procurement systems

Costs in perpetuity. Costs associated with using the OBELISC solution which occur for each installation will come through:

• Per-unit cost of the OBELISC solution
• Building any additional foundation or support structures for the OBELISC solution

Opportunity structure

The opportunity to produce benefits is derived from reducing the cost and disruption of upgrading domestic customers to three-phase supply. The likelihood this upgrade is triggered is influenced by a number of coincident factors:

• Connection of a heat pump at the property
• Connection of an electric vehicle charging point at the property
• Underlying electrical baseload

The trigger point for three-phase upgrade for NGED is when a supply of 80A is unachievable due to thermal or voltage limitations of the existing connection. Typically this is when demand exceeds the 80A rating of the cut-out fuse, which occurs when demand is around 18.4 kW. For most cases, this means that upgrade is triggered when a heat pump and an EV charging point is connected as neither is likely to exceed that demand on its own.

The opportunity to produce benefit derived is based upon the following assumptions:

• 75% of properties will connect both an EVCP and heat pump by 2050
• Around 45% of properties will be homes likely to have a large enough baseload demand to trigger the upgrade
• There is a 10% chance that the EVCP and heat pump size will coincide to exceed 18.4kW

Counterfactual

The counterfactual scenario is the cost of upgrading customers using a conventional three-phase upgrade, including civil works, capital costs and labour time. This typically ranges between £3,500 and £6,000 per installation, averaged to £4,750.

Expected financial benefits

Assuming a total project development and roll-out cost of £1.5m, even in the most pessimistic future energy scenario (Falling Short) an average cost reduction of 5% would be paid back by 2033 and deliver benefit between 2033 and 2050. Whereas in the most optimistic scenario (Customer Transformation), the project will have paid for itself four times over by 2033 even if only a 2.5% average cost reduction is achieved