Operational flexibility in power systems to integrate EVs

Even though EV smart charging can add valuable flexibility to the power system, many EVs may still charge quickly and uncontrollably, causing voltage instability, congestion at transformers or on lines, or other issues.

However, system operators can use already installed assets of their own to provide flexibility and resolve such issues. Such assets include tap-changer transformers (which can change voltage), capacitors and similar devices providing reactive control, and inverter-based generators.

System operators can also ask for contributions from other flexibility service providers, such as generators or aggregated demand-response providers. Using market-based mechanisms would help ensure the fair and competitive provision of flexibility services.

Using power systems’ flexibility resources and encouraging assets to participate in flexibility markets or demand-response programmes will enable system operators to prevent uncoordinated integration of EVs or uncontrolled charging from causing problems on the grid. Doing so will avoid technical and financial losses and allow power systems to operate optimally. It will also be important to co-ordinate EV charging with the use of system flexibility resources to maximise system-level flexibility.