As the project team began disaggregating the range of issues and decision-making factors informing the business challenge posed to utilities, it became obvious that two tiers of decisionmaking needed addressing.
The first decision point is defined by the current state of the market and utility strategy needs. The EV market adoption is already underway, but options for Vehicle-to-Grid (V2G) tactics are limited by the lack of commercial availability of bidirectional charging equipment. Specifically, outside of pilot projects, most consumers only have cost-effective access to unidirectional charging equipment; they cannot export power from their vehicles to the grid yet. This means that utilities witnessing significant EV growth in their distribution territories are limited to grid-support tactics that rely more on behavior change. Until bi-directional chargers become widely available, utilities must find ways to incentivize their customers to avoid charging during summer peak hours, especially during heat waves. At present, there is a viable solution: dynamic pricing tariffs that vary the cost for power during peak and offpeak hours, respectively. Today, utilities in twenty states (including Oregon and California) have made dynamic pricing programs available to customers with EVs.
Having determined that applying the hierarchical decisionmaking methodology would be unnecessary to address the first decision-point, this research team decided to focus its efforts on supporting a near-future decision point that will emerge with the commercial availability of bi-directional chargers. Additionally, while there are many potential services that could be provided through V2G approaches, our team focused on one use case: the summer peak grid support.
1.2.Problem definition
Research problem: What are the most opportune behind-the-meter transportation technologies/products to use for future summer peak V2G programs in California, Oregon and/or Washington?
To explore this question, we investigated a range of potential EV applications (see Table 1) and challenged ourselves to view the availability of these options over time (as they might emerge in the market place as viable resources for future V2G programs). For this evaluation, we defined summer peak periods as those generally experienced in Washington, Oregon and California, that is, from 1 June to 30 September, between 4 pm and 9 pm. Of course, while there is a daily evening peak, there are typically only about 20 days per year where utilities need additional resources to successfully serve peak loads (most often during summer heat waves or days of highest summer temperatures).
Table 1.Potential V2G applications.
Note: An “X” means that the technology/product is not a good fit; a “
1.3.Gap analysis
Following brainstorming potential options, the research team identified a total of eleven EV products/technologies that could potentially provide exports to distribution grids during periods of summer peak stress. The initial eleven options identified included eight fleet options and three non-fleet options. Municipal buses, municipal non-bus vehicles, school buses, police vehicles, taxis, military vehicles, garbage vehicles and delivery vehicles made up the fleet options, while individual electric vehicles, off-road vehicles and Electrical Vehicle Supply Equipment (EVSE) comprised the non-fleet options.
As pointed out, these technologies/products were considered with the assumption that bi-directional charging equipment will become available to EV owners in the near-future. With this first enabling capability in mind, the next task required us to evaluate those options to determine which option, if any, would likely be available and capable enough to participate in a summer peak V2G program. Key gaps that needed to be filled, included: availability during summer peak periods, commercial availability, the likelihood of having sufficient export capability (determined by the State of Charge (SoC) available in the battery system during peak hours) and the capability of the EV owners (that is, their ability to participate without negatively impacting their primary use requirements/needs). Table 1 summarizes our findings; the prioritized options are shaded.
1.4.Perspectives and criteria
The Transportation Technology Assessment conducted for this report considered three overarching perspectives: Availability, Readiness Status, and the Likelihood of Owner Participation. These three perspectives are important for analyzing the adoption rate of Vehicle Grid Integration (VGI) technology in the near future. Each perspective includes criteria that inform the decision-making model and the options it provides.
1.Availability essentially considers potential EV types as options based on time and power. There are three criterions that build out this perspective:
i.The likelihood of being connected to a charger during the summer peak. Certain types of EVs, such as those that are individually owned, may be used more during peak times than others, e.g., garbage truck fleets.
ii.Whether the existing SoC is high enough to provide exportable power during peak hours, which depends on an EV’s charging load and speed. The key factor is whether an EV can be charged fast enough during prepeak or current peak times, so that it can export power to help support the grid during such peak times.
iii.Whether EVs are capable of being scheduled for precharging prior to peak times. Some EVs, such as school buses, are not constantly in use and may be scheduled more easily than other EVs that are regularly in use, such as police vehicles.
2.The Readiness Status is the product of a combination of two elements—technology and market.
i.Technological readiness, the first criterion, is a measure of product maturation. What this means for the EVs considered for connecting to and supporting the electrical grid, is the level to which VGI EV technology is ready for but may differ between EV types.
ii.Technological readiness measures the technology in its current capabilities, while the second criterion—market adoption and existing market conditions—measures it based on the market. This criterion seeks to measure the existing adoption of EV types and the potential for their market growth. This takes into consideration existing market conditions, more specifically, consumer interest and demand for VGI EVs.
3.The last perspective is the Likelihood of Owner Participation, which is influenced by two criterions.
i.The first criterion analyzes the incentives and benefits for owners who participate in bi-directional grid support programs, as well as existing and planned incentives for transmission and distribution construction.
ii.The second criterion is the likelihood of an owner’s willingness to invest in bi-directional charging equipment that is likely needed to implement wide-scale VGI EV infrastructure.
1.5.Relevant application alternatives
As we assessed the technologies/products in question, certain options were deemed unlikely to help utilities serve summer peak needs, although we did see opportunities for these options to serve other service requirements, for example, ancillary services, renewables integration, volt/VAR support, etc. Municipal buses, for example, were likely to be in use during summer peak hours, but they could also be very helpful in integrating wind power at night (off-peak hours). Police fleets were cut from the list because emergency responders would likely need to keep their SoCs as high as possible, but they could also support ancillary services while plugged in. Taxi fleets were a mismatch in the same way as municipal buses, but could also help with renewables integration. Delivery fleets were cut from the list for the same reason, although some