DC Share

Project Description

This project will assist with the facilitation of rapid EV charging equipment by providing appropriate network connections where they are needed, whilst making optimal use of the available network capacity.

The connection costs for rapid EV charging facilities are a critical consideration for developers. Provision of rapid charging facilities is key to the uptake of electric vehicles (particularly for fleets and urban delivery services) and hence high connection costs in some areas could be seen as a potential barrier to the uptake of EVs. Users must be able to charge their EVs in a manner that is at least as convenient as current refuelling methods, which means minimum dwell time, or opportunity charging where vehicles may stop.

DC share is a smart DC network solution that facilitates rapid charging in constrained areas by using the available latent capacity across a number of substations. The solution will mesh a number of distribution substations, with DC converters and high capacity DC links. The DC system will then determine the best point to draw power from for the charger and it will also support heavily loaded transformers.

Problem(s)

The Government’s Clean Growth Strategy sets out the importance of accelerating the shift to Low Carbon Transport with one of its key aims being to “Develop one of the best electric vehicle (EV) charging networks in the world” alongside the policy of ending the sale of new conventional petrol and diesel engine cars and vans by 2040. The Net Zero – Technical Committee on Climate Change report published in May 2019 observes that cars, vans and heavy goods vehicles are the most significant sources of greenhouse gas emissions in the transport sector. The Committee are calling for the 2040 date to be bought forward to 2035, and to include ending the sale of hybrid and plug-in-hybrid vehicles. They also call for an end to the use of petrol and diesel vehicles (including hybrid and plug-in-hybrid vehicles) by 2050. In June 2019 parliament amended the Climate Change Act to legislate for net zero carbon emissions by 2050.

There are currently just over 200,000 EVs in GB. National Grid’s “two degrees” Future Energy Scenario is based upon 7.3 million EVs (30% of vehicles) by 2030. The majority of these are expected to be battery EVs with substantial battery capacity and rapid charge capability Rapid Charging Hubs will be one of the enablers for mass EV uptake, in particular in town centres and along major road routes. Charging hubs will not only serve those on longer journeys with a convenient to-up, but will also be used by the 40% of the population who do not have off-street parking.

Key to user confidence for the uptake of EVs will be the availability of a range of offerings for EV charging; each having an impact on the power system and serving different charging use cases. Currently there are no large-scale availability of EV charging points in GB, however, there are several possible scenarios to be considered to provide the necessary infrastructure. DC Share provides an approach to delivering rapid (>50 kW) charging facilities in short stay destinations such as town centres, taxi ranks, commercial vehicle and car club charging hubs.

Recent projects (for example My Electric Avenue and Electric Nation) have demonstrated that slow (7 kW and below) chargers can be largely accommodated by managed charging solutions. However, the provision of rapid (50 - 100 kW) chargers at any scale in urban environments (where users charge for short periods of time rather than hours), will be required to allow:

1. Destination charging – for those without access to domestic or workplace slow charging, or during a longer journey/prior to a return journey, and
2. High utilisation commercial individual or fleet charging – for use by taxi drivers, delivery vans etc. where vehicle downtime should be minimised.

These rapid chargers will be a necessary part of the charging ecosystem that will enable longer and irregular journeys, as well as facilitating the adoption of EVs in high utilisation fleets. Furthermore, the provision of rapid chargers in cities and urban environments is particularly important to support these fleets and maximise improvements to local air quality.

In Ofgem’s Future Insights Series, “Implications of the transition to Electric Vehicles” it is noted that given the speed of recent improvements in battery size and vehicle range, the need for rapid charge points could change significantly in the near term. Ricardo’s own analysis shows that up to 11,000 rapid chargers may be needed for cars and vans by 2030 and 300,000 depot rapid chargers could be required in the UK to electrify the HGV fleet by 2050. To combat range anxiety, blocked and non-functioning chargers it is anticipated that an oversupply of rapid chargers will be necessary.

Rapid chargers will likely be deployed in hubs (multiple chargers in one location) to minimise the cost of civil works and grid connections, and to ensure charger availability for multiple users. Rapid chargers that have been installed to date have often been deployed in small clusters (typically between two and four, meaning that chargers are likely to be busy during peak periods) and in locations where a cost-effective grid connection could be secured.

The location of the rapid chargers will be an important factor in the successful widespread uptake of EVs and should therefore be dictated by user requirements rather than network capacity and space constraints.

Rapid charging facilities are likely to require network reinforcement, due to the power requirements of each charger and the fact that these are likely to be deployed as charging hubs. A recent charging hub in Milton Keynes3 houses 8 x 50 kW chargers and required installation of a new secondary substation and HV cables. In this case there was space available for the charging points and the substation.

Accommodating the new charging demand within networks is key to enabling the decarbonisation of transport. Rapid chargers represent a significant load to distribution networks.

Solution

DC Share will make best use of existing assets to provide rapid EV charging facilities and network equalisation.

DC Share will obtain greater utilisation of substation assets through equalisation and load management. DC Share will use the latent capacity between adjacent substations with different load profiles (i.e. some with commercial profiles and some domestic profiles) to provide capacity for EV charging from the most appropriate location.

DC Share will facilitate the fast and flexible connection of high-power charging points for

EVs and support future Low Carbon Technology (LCT) demands, and the network design makes use of the diversity of charging load to provide greater capacity than BaU equivalent solutions.

Method(s)

DC Share will trial a DC ring that will be fed via multiple in feeds from secondary substations, allowing it to:

1. Draw power from those locations with capacity available;

2. Transfer power between substations to allow those with spare capacity to support those that are heavily loaded, deferring the need for reinforcement.

The DC ring will have fifteen rapid (50-100 kW) chargers directly connected, allowing the method to make use of charging demand diversity.

The DC network can be expanded to accommodate additional in feeds when required, and in future could incorporate connection of other Low Carbon Technologies.

• Benefits

  There are significant benefits to implementing power systems with more flexibility, enabling dynamic optimisation of use of existing assets, and providing capacity where it is needed. Once implemented, the DC Share solution will result in:

  • Significant financial, capacity, and carbon benefits associated with the EV charging network and optimisation over multiple substations – These financial, capacity, and carbon benefits have been quantified through business case modelling, as described below:
    • £162m in direct financial benefits up to 2050 across GB, which will benefit the customer though network savings resulting in lower customer bills, and through enabling access to more infrastructure at a lower cost.
    • 1,800 MVA capacity released up to 2050 across GB
    • 26,000 tCO2e of direct savings up to 2050 across GB
  • Substantial indirect carbon and environmental benefits through supporting the uptake of EVs and the connection of LCTs – The availability of charging is a significant enabler of the uptake of EVs, and the release of capacity through real-time active management can enable the connection of LCTs at a lower cost. There are substantial environmental benefits, including 21 tCO2e carbon savings through electrification of each passenger car and 67 tCO2e through electrification of each taxi (based on average mileage and fuel/energy consumption figures). This reduction in carbon emissions will have substantial impact on air quality in the GB as the vehicle part transfers, and DC share will facilitate this through provision of rapid charging facilities.
  • Minimise the impact of significant clusters of rapid charge points on the network - As part of the DC Share solution, rapid charging points can be managed and optimised as part of the wider DC solution, taking advantage of flexibility in charging time and minimising the peak demand on the network.
  • Increased network flexibility – The provision of flexible methods enables increasing uncertainty to be managed more effectively, optimising power flow in real time to react to changing network demands and providing real-time controllable support to the wider AC network.
  • Future-proofing of the network infrastructure and avoidance of stranded assets – The solution can provide future-proofing through enabling the connection of future DC loads, generation and storage to established DC Share solutions. The topology of a DC Share solution can expand and adapt over time to meet the changing future needs of the customers. Under-utilised substations can be connected to the DC network, allowing them to provide additional capacity to the system and enabling avoidance of stranded assets.
  • Network control benefits – Additional network control benefits using Power Electronics may be enabled through the solution, such as the ability to actively manage network voltage and power flows, which can offer customers improved quality of supply which can be maintained through changing network conditions.
  • Reduced Losses – Charger losses are lower in DC Fed EV Charge points, by virtue of the simplified architecture of the devices. System losses are also lower in the DC Share case than in the “Soft Open Point” and “Solid State Transformer” cases, due to the reduction in conversions between AC and DC. Losses can also be minimised on the DC Share system, by actively managing power flows (when possible) to minimise current in the parts of the network most susceptible to losses, and by switching off converters when not required for use.

  DC Share is well aligned to the Western Power Distribution, Electricity North West and overarching ENA innovation strategy, of facilitating change. DC Share will provide a coordinated approach to the deployment of EV charging points, whilst also using smart technologies to maximise capacity within the power system.

• Documents and links

  FSP

  Project Progress Report: Jan 20 – Jun 20

  Project Progress Report: Jul 20 – Dec 20

  Project Progress Report: Jan 21 – Jun 21

  Site Selection Report

  Final Design Report

  Project Close Down Report

• Monthly updates

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