Technical
About V2G
V2G is fundamentally different in nature to smart charging because energy can be cycled, whereas smart charging is limited to the amount of energy consumed by the EV, i.e. around 7-10KWh for a typical 28 mile a day vehicle. A vehicle charged with V2G could cycle up to 84KWh of energy in and out of the vehicle in more complex patterns trying to react to signals from the market actors. The strategies for using these services could vary significantly but also coincide, leading to unexpected peaks that could be more difficult to forecast. With the export feature this could lead to high voltage events should a national call for more energy coincide with low local load.
Electric Nation has shown that time of use tariffs may shift the evening peak and create a new peak later in the evening, leading to a need for management. Also, this would make it difficult to separate the shift in demand due to tariff or the call for Distribution Systems Operator (DSO) service – the Electric Nation Vehicle to Grid project will test a more integrated approach.
Also, when looking at the proposed services these are fairly simplistic, and they mirror how National Grid calls for flexibility – at the ends of the network with low diversity this approach is not likely to provide a complete solution. The Electric Nation Vehicle to Grid project will look to test alternative approaches with the DSO taking control only when energy supplier trading encroaches safe limits for the network.
The business case for the project
As electric vehicle numbers increase (by 2030 it is estimated that around 25% of households will have a plug-in vehicle) it is anticipated that around 5,601 substations will be running at between 100-110% capacity by 2030 at a potential reinforcement cost of around £84 million.
To maintain safe network limits, it is expected that 20% of the EV chargers would be contracted by the DSO to provide V2G balancing. This would cost £3.8 million per year, instead of an £84 million one-off reinforcement investment.
Forecasting precise impacts presents a challenge with so many changing parameters (e.g. varying uptake of EVs, domestic batteries, heat pumps, solar PV). The CrowdCharge smart service has many potential advantages:
- It offers huge flexibility. Compared to traditional reinforcement, it can be activated at shorter notice – and can be targeted very precisely. The number of chargers under control can be increased (or reduced) depending on how demand patterns evolve for each part of the network
- It will help to defer (or in some cases avoid entirely) significant amounts of reinforcement
- The solution can respond to new technology, for example can equally be applied via the same platform to utilise static domestic batteries, should they offer equivalent capacity by 2030
- The platform data will provide a broader insight to network activity, informing other network activities (for example it may support voltage monitoring)
- The £84 million estimate for traditional reinforcement assumes a planned replacement, however due to the highly distributed and unpredictable nature of EV growth (alongside equally unpredictable LCT uptake) it may require a significant percentage of emergency reinforcement as limits are breached earlier than forecasted, and therefore costs could rise significantly. In addition, emergency repairs cause greater customer impacts.
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