Are EVs an Energy System Concern or Savior?

The expected growth in plug-in EVs (PEVs) threatens the stability of electrical grids. Yet, proactive action by utilities in developing vehicle-to-grid (V2G) capabilities can mitigate these risks and lead to a range of benefits, including greater utilization of transmission and distribution resources and reduced grid investment costs.

V2G applications can be classified into four categories: transmission system services, distribution system services, wholesale market arbitrage, and behind-the-meter (BTM) solutions. Among these applications, grid ancillary services are currently best suited for V2G from technological, economic, and regulatory viewpoints.

In the UK, the grid services that would benefit from V2G solutions include firm frequency response (FFR), short-term operating reserve, demand turn-up, and imbalance management. Out of these, FFR currently offers the best business case, though there is a risk that FFR market saturation and falling prices could soon lead to a loss of grid service revenue for V2G. As of September 2019, estimates of annual revenue through grid services have ranged from £400 ($493) to £1,300 ($1,603) per vehicle per year depending on PEV plug-in rates and charger capacity assumptions.

Shifting Toward Location-Dependent Distribution System Services

Beyond transmission system services, V2G solutions show strong potential for application in distribution networks. V2G’s geographical flexibility makes it well-suited to providing location-dependent services to improve transformer operating conditions, including constraint management, reactive power support, and voltage regulation.

These distribution system services, also known as distributed energy resource (DER) management systems are especially valuable in regions with high renewable penetration. V2G is a source of flexible load and energy storage and can be a more cost-effective and resourceful solution for managing intermittent renewables over prevailing curtailment methods.

Though promising, distribution system operator (DSO) services is a nascent market, and regulatory changes are needed before this technology can become a viable option for V2G. The DSO market requires greater coordination between the transmission system operator and the DSO given that both actors will be competing for the same commodity. The Power Potential project, a 3-year pilot study in the UK ran by National Grid ESO, is investigating how to tackle this challenge by considering a new reactive power market for DER.

The Future of Vehicle-to-X Applications

The more straightforward case for V2G for everyday PEV drivers is in BTM solutions. Active BTM energy management techniques such as load shifting, peak price avoidance, and arbitrage can result in significant cost-savings, especially if the drivers have predictable mobility patterns. Open Energi’s analysis suggests that this kind of demand optimization could be worth up to £1,500 ($1,852) per EV annually.

V2G technology is not restricted to the use cases that are being adopted in ongoing pilot projects. There are conceptualized uses of PEVs for peer-to-peer trading, vehicle-to-building, vehicle-to-home, and vehicle-to-X (V2X). V2X, a catchall phrase for future applications beyond current V2G interfaces, includes using PEVs to power telescopes, barbecue grills, or as a source of power while camping. These applications reflect the flexibility of bidirectional PEVs beyond current imagination. The future of V2G looks promising with the right set of policies and regulations in place.