Transforming Mobility Into Grid Assets via VPPs

Combined with the continued development of advanced battery chemistries, government vehicle fuel efficiency regulations are likely to make EVs cheaper to purchase than gaseous fuel-powered vehicles by 2030. For the electric power sector, this load growth (each EV is nearly the equivalent of a single house) is a boon, but one that requires smart and active energy management. 

While basic load growth is good for the sector, uneven distribution of growth within a specific location or at a specific time could prove burdensome for utilities, perhaps leading to power outages due to overloading circuits. Actively managing and spreading the EV charging load across infrastructure assets and time could not only prevent infrastructure upgrade costs but also may decrease grid balancing costs. This is important as more intermittent renewable resources, such as solar and wind, are added to wholesale generation portfolios.

Support for the Larger Grid

Vehicle-grid integration (VGI) enables EVs to participate in grid balancing schemes as generation or demand assets for grid operators. Yet these EVs can perform similar balancing options for smaller subsets of the grid, including inward facing microgrids and outward facing virtual power plants (VPPs). Focus will be on the latter of these two platforms for now, since VPPs are more focused on supporting the larger grid, opening the door to new transactive energy revenue streams.

Batteries in EVs can potentially respond more quickly and accurately to grid signals than other utility grid service assets (such as natural gas-powered peaking plants). This speed and accuracy could boost grid efficiency, however, in most markets these grid service performance advantages are not compensated accordingly, since such markets are immature.

Shifting VPP Market

The entire VPP market is shifting in the direction of mixed-asset VPPs, aggregations of diverse assets that span load, generation, and energy storage. A new Guidehouse Insights report notes that EVs will increasingly be added to these VPPs (and microgrids), offering the following distributed energy resources options: 

• Reduction of negative impacts of EV charging loads on overall grid stability 
• Provision of frequency regulation and voltage support for power grids 
• Enabling of mobile energy storage devices in EVs as a grid balancing resource, especially when aggregated as fleets in campus or military base settings 

Successful integration of EVs into VPPs hinges on control technologies advancing in parallel with open and organized grid service markets. Some utilities, such as Alectra, are integrating EVs into VPPs already; however, there is still considerable work that needs to be done. 

Candidates for VPP Usage

In the near-term, EV fleets are the best candidates for early adoption of VGI for VPPs. VGI investments in fleets realize a speedier return than investments in individually owned EVs. Fleets have better potential to use vehicle-to-grid-based systems (which increases EV availability) and less overhead tied to customer contract management on a per-vehicle basis. Additionally, fleets often have regimented drive schedules, which can make aggregation easier.

But opportunities also exist within the residential sector. For example, Enel X’s subsidiary, eMotorWerks, is using a fleet of 6,000 primarily residential EV chargers in California to participate as a demand response resource for the California Independent System Operator. The EV chargers offered by Enel connect to its cloud-based JuiceNet software to create a 30 MW/70 MWh VPP. The cloud-based software can manage the charging loads as a way of balancing grid demand, reducing wholesale energy costs, and mitigating the intermittency of variable renewables. VPP software trend setters such as Enbala are working to include EV charging infrastructure from ChargePoint and a list of others into their growing mixed asset VPP portfolios.