Learnings

Outcomes

Take Charge was delivered in four work packages as detailed in Section 5 of this report. The following sections outline the outcomes from each of the work packages.

Work Package 1 – System Capacity Optimisation

The first work package in Take Charge determined the optimal trial location for the CCS and the required capacity for the trial site.

The Site Selection Methodology report was produced as an output from this work package and explained the process created for determining the optimal location for the trial site. 

This report provides a clear and concise method for selecting suitable trial sites for such installations and could easily be tailored for future innovation projects. In addition, the report also captures a number of lessons learnt that would be attributable to other projects that involve establishing new substation infrastructure.

With the CCS now installed at the trial site, we are content that the process followed to determine the trial site was the correct one and no changes are required should it be implemented again for a different project.

The second key output from Take Charge was the System Capacity Optimisation report. This report considered the required power capacity of the CCS (peak MW) to provide for the needs of customers for charging at MSA locations up to 2050. We believe that the solution developed in this project will be essential bearing in mind that 

electrical plant has a service life of around fifty years and there is a need to ensure multiple network reinforcement is avoided in line with the Committee for Climate Change view of “touch it once till 2050”.

In a similar approach to the Site Selection Methodology, the System Capacity Optimisation report presented the process created for calculating the optimum capacity for EV charging across MSAs. The report considered two separate approaches and after analysis, recommended the optimum one for calculation of the capacity.

The report provides a replicable approach for calculating EV capacity and has been used to calculate the capacity across all sites in NGED’s licence area. The approach can also be updated for new information when available, such as visitor numbers, new FES data and traffic movements.

Work Package 2 – Develop and Design the Connection Solution

The main outcome from work package 2 is the specification documentation which provides sufficient detail to allow others to replicate the CCS for use in other locations and applications.

The specification documentation was prepared in conjunction with policy engineers, equipment manufacturers and consultants and covers all the main elements of the CCS. It is recognised that some parts of the specification will have to be tailored to the specific arrangements of the network owner/operator. These arrangements generally focus on the interface of the CCS with existing infrastructure (for example, the Supervisory Control and Data Acquisition (SCADA) requirements) and preferences in relation to equipment manufacturers. However, the CCS is very well aligned with the requirements of UK distribution networks having been prepared based on Electricity Network Association (ENA) Technical Specifications and British Standards.

An initial functional specification was prepared at the start of the project and was used for contract purposes. However, as part of the project learning, we have updated this specification and produced an “as-built version”. This version captures the subtle changes that were integrated during the design and build phases and provides an accurate representation of what was installed on site.

Work Package 3 – Build and Install the Connection Solution

The main outcome of this work package was the successful build and installation of the CCS at Exeter MSA. Although there were some minor design challenges and delays with gaining planning permission, the overall installation went very well with minimal changes on site and with no safety incidents.

Close coordination with all parties helped ensure that the impact on customers visiting the MSA was minimal, despite the site being very busy throughout the day. Including traffic calming and protection measures at the entrance to the site helped manage traffic flow and potential dangers from large, fast moving vehicles.

In addition, the chosen substation location on the Exeter MSA site corresponded well with the existing and future EV infrastructure. Both Gridserve and Tesla have established new high capacity chargers and these are located in the parking areas immediately adjacent to the CCS reducing cabling costs and disruption.

Finally, the delivery and offloading of the equipment for the CCS was carried out on schedule without any issues. The offloading process only took a matter of hours for all components.

Throughout the design phase we ensured that offloading was a critical part of the strategy knowing the complications of such a busy site.

Work Package 4 – Trial and Evaluation

Following delivery and offloading of the CCS equipment work began on making the preparations for energising the substation and beginning the trial. In parallel, we were also consolidating the information, data and learning that had been gathered throughout the course of the project.

The energisation of the CCS went as planned following the final installation and commissioning activities. The pre-booked outages ensured that we had sufficient time to test the connections and equipment prior to the final energisation on to the 33 kV network fed from Sowton 132/33 kV substation.

We were pleased to note that there have been no issues following energisation, with the CCS remaining connected to the network and supplying the 11 kV network. As further new EV infrastructure is connected to the CCS we will continue to monitor the operational data, however, we are confident that there will be no issues in the performance.

We have also been sharing the learning generated by the project as part of the trial and evaluation work package. In particular, we have disseminated and engaged with stakeholders at a number of industry conferences, through social media platforms and through our defined project progress updates (monthly website updates, six monthly reports and annual NIA reports).

In addition, Take Charge was shortlisted in the “Disruptor Award” category in the Utility Week Awards 2022. Despite very strong competition from other utilities, Take Charge won the award, helping highlight how important the project was in delivering a new approach that challenges traditional engineering solutions.

Lessons Learnt

Lessons learnt for future projects can be found in Section 9 of the closedown report.

Some of the key learning points in relation to network studies are; 

·       Choosing an MSA located with access to both sides of a motorway (and near to large town or city) will provide more space and footfall that should result in greater participation in the trial (i.e. more EVs).

·       For a variety of reasons, charging profiles at motorway services will be different to those seen for home or on-street charging. These profiles will correlate with the volumes of traffic visiting the MSA

·       The configuration of rapid charging infrastructure on site is limited by interfacing with existing NGED standard assets (such as distribution transformers). For example, 350 kW rapid chargers are currently connected at LV and therefore only a maximum of three can be connected at one distribution substation if they are planned to be fully utilised. There are possibilities to connect more, however, control systems would be required to limit the output from chargers at peak times (the current approach by charge point operators).

·       Having a “modular” approach to adding capacity is preferred and also allows for greater security of supply in the future.

In terms of the design, some of the key learning points are; 

·       The configuration of the switchroom enclosure for the new package substation has to be limited to 3.4m wide to allow for transportation without the need for special permits. The layout of the enclosure should also seek to provide space all around the switchgear to ensure that operatives can easily exit in an emergency.

·       In some instances the CCS may be connected to the local 11 kV network to provide additional security of supply. To provide this facility an 11 kV busbar VT is required on the CCS switchboard to provide a voltage reference in the event of the incoming primary transformer VT being disconnected

·       The standard 11 kV feeder circuit breaker rating of 630 A was used as the alternative, 1250 A, would require a cable larger than 3x300mm² and this would not be able to be terminated into a standard distribution Ring Main Unit(RMU).

·       The CCS should be located somewhere that is easy for personnel to access, requires minimal civil works and adjacent to the existing network infrastructure.

·       Due to the configuration of the CCS and the existing protection arrangements at Exeter Science Park, the 33 kV circuits to the CCS will need to be run open to prevent losing both circuits for a cable fault.

·       Any new substations over 29m3 require planning permission, therefore, a full planning application had to be developed for the CCS at Exeter.

·       11 kV switchgear was originally planned to have metering Voltage and Current Transformers (VTs and CTs). However, customers have indicated that they would like to be metered at HV RMUs further downstream. Removing the metering requirement from the CCS helped reduce the cost and complexity.

·       Following initial discussions with Exeter City Council we discovered that all trees around the Motorway Service Area were covered by Tree Preservation Orders (TPOs). The trees are not a species of particular interest, however, it was apparent that the council want to retain as much green space as possible. In future for such sites, we would look to carry out a search of TPOs before starting with the design.

·       The cable contractors have proposed the use of a vacuum excavator to remove soil and material from around trees protected by TPOs. The use of this technique helps to protect tree roots and prevents the need to remove or disturb trees.

·       The fit-out of the switchroom container took much longer than originally planned. This is due to long-lead time materials and issues with contractor interpreting the design. For any new installation the following should be considered: i) changing Steel Wire Armour cables to those with standard insulation, ii) repositioning the Remote Terminal Unit (RTU) to provide bottom-entry access, iii) reducing the size of the marshalling cabinet to avoid all switchgear wiring being routed through it.

·       A percolation test was required on site to understand whether a soakaway would be a suitable system to manage the drainage for the new substation. The test was delayed during mobilisation and performed after the construction started. This delay resulted in percolation test initially being performed in less than ideal conditions (after heavy rain). It is recommended that this survey should be completed in advance of any construction work to avoid any possible issues for future installations.

·       The offload of equipment was successful, however, some updates to the design would have helped to improve the offloading procedure. The main update would be to increase the size of the crane pad area (only marginally) and swap the position of the transformer and switchroom such that the heaviest item was closest to the crane.

·       The 33 kV switchgear was fully tested after being delivered to the contractors for fit-out (56 kV insulation test). After the secondary wiring and equipment was installed, the switchroom was then shipped to site and it was important to test that the integrity of the switchgear had not been compromised during transport. However, the manufacturer were averse to performing further tests as it may stress the switchgear. After consultation, another 56 kV test was performed and no defects were found. For future installations it is recommended that the final tests are performed on-site rather than at the contractor’s location.

·       Following energisation a point was raised regarding the parking area and restrictions for the new substation. We have a dedicated layby for the substation, however, as the substation is located within the Moto site itself, parking is nominally restricted to 2 hours (otherwise staff have to report to the main Moto building to log their details). For future sites it would be worth considering where the site can be located external to the Moto Automatic Number Plate Recognition) ANPR area to avoid potential confusion.

For project management, the learning highlights are; 

·       The timescales originally proposed for the project were extremely tight and did not allow for sufficient time to complete the various surveys and designs for a new primary substation. For future installations or projects, actual timescales for Take Charge can be used as a basis to develop a project programme.

·       The planning application process for Take Charge has delayed the project for many months. As part of the dissemination activities we have highlighted to various stakeholders the need for improved planning processes to help accelerate applications that are required to help deliver net zero.

·       The original business case for Take Charge had been prepared using estimates that were not fully up to date. For new projects, the latest estimating costs from CROWN should be used to ensure the business case is as accurate as possible. In addition, the business case should be prepared in conjunction with Network Services to ensure that the costs are realistic and accurate.

·       There have been numerous activities relating to surveys and searches for wayleave purposes. These include further ecological surveys and land owner searches to ensure the route of the 33 kV cable can proceed as planned. These have been “ad-hoc” and were only highlighted to the project team at short notice. For future projects, any new asset installations should consider these aspects at the very start of the project.