Integration into the electricity system
The integration of electric road transport into an electricity system needs to be considered at multiple levels. In this section, we will assess the energy needed for electrification of road transport and how this compares with the electricity system as a whole, the potential integration with variable renewable electricity generation, integration with regard to the capacity of the electricity network, and finally integration with public charging.
The electric capacity needed for electric road transport
The first question that needs to be answered is whether the electricity system can cope with the increase of volume of energy that is required to electrify road transport, especially considering that other sectors also need to electrify. Taking the EU as an example: at present, the entire transport sector represents about 2% of Europe’s electricity use, and most of that is for rail transport. By 2050, the extensive electrification of road transport will see the share of transport, in what will then be a much larger electricity mix, rise to 17%.
By mid-century, transport electricity demand will be marginally less than that from manufacturing and less than half the electricity demand from buildings. Accommodating this substantial rise in electricity demand across Europe will be challenging, but in our view is not unrealistic.
Electrification has significant efficiency advantages compared with internal combustion engines. Thus, despite the comprehensive transition of the road vehicle fleet to electricity, transport electricity demand will only rise by some 35–40% by 2050 compared with today. In fact, a much larger increase in electricity demand will come from the replacement of natural gas for heating with electrical heating, even considering the high efficiencies of modern heat pumps for space heating.
The transport sector represents about 2% of Europe's electricity use. This will rise to 17% by 2050.
Renewable integration
The energy transition requires a huge increase in renewable generation from wind and sun. Because these sources are variable and follow weather patterns instead of demand profiles, electricity storage, connectivity, demand-response and demand-following renewable generation (like biomass-based electricity generation) are required to make optimal use of these variable renewable energy sources.
EVs have the potential to provide a major and relatively cost-effective contribution to generation-following demand and electricity storage because of the inherent storage capacity of on-board batteries. This requires coordination with the electricity system to ensure that their charging — and possible discharging — will happen at times that are beneficial to the system.
Discharging into the grid (vehicle-to-grid orV2G) is interesting, because it drastically increases the available storage capacity for the electricity system. Most EVs currently do not support V2G, and what is presently termed ‘smart charging’ only replenishes the energy that has been used for driving flexibly. With V2G, the whole capacity of the battery is available for the electricity system (considering energy reserved for driving and a safety margin to avoid excessive battery degradation). Properly configured for V2G, the storage volume EVs can offer to the electricity system is multiplied by a factor 4 to 5.
