Potential PHEV, EV Issues

David Mulder, Capgemini America

Although recent announcements have generated interest and validation that public charging infrastructure will be available to support plug-in hybrid electric vehicles (PHEVs) and electric vehicles (EVs), there is less focus on how customers will adapt their infrastructure and usage at home to accommodate them. For customers, two major value tenets to owning a PHEV or EV—cost savings and convenience—are directly affected by customers’ ability to charge vehicles at home. Several components exist that directly impact the ability for customers to achieve this value.

The Home PHEV Charger. While most of the recent activity has focused on building commercial charging infrastructure, experts are predicting that PHEVs and EVs will spend most time at homes. A Level 2 charger—assumed to be the customer option—can charge an EV in about three hours. The major issues with the Level 2 charger, however, are cost of installation; whether a customer’s electric service can support the additional 7 kW-plus load that comes from use; and the local permitting process, because a permit may be required to install a Level 2 charger and dedicated circuit breaker.

Customer Coincident Peak. A loose definition of coincident peak is the point during the day when the demand for electricity is highest. This event also occurs for each customer, and it may vary significantly based on demographics, usage characteristics and other factors. Adding a PHEV or EV charger to a household may change when this peak occurs for a customer and could overload the customer’s service if all appliances are on at the same time. In short, PHEV and EV owners must become proactive in managing their electricity consumption.

The Meter. Many discussions about PHEVs and EVs center on their impact on the utility grid. The solution is usually to charge the vehicle off peak, and introduce time-of-use (TOU) rates and demand response programs. Unless the customer has a smart meter, neither the customer nor the utility has the knowledge required to successfully manage load. A smart meter will provide internal data (as granular as every 15 minutes) that will allow the utility to deploy—and the customer to react to—TOU rates.

Home Energy Management System (HEMS). Utilities are exploring the feasibility of HEMS as a way for customers (and utilities with permission) to remotely manage their appliances to curtail electric load when the electric grid is constrained. HEMS will play an increasingly important role in allowing customers to manage their electric demand to accommodate the addition of a PHEV—and not solely for the benefit of the utility. Alternatively, some utilities have begun offering customer energy portals as a value-added service. Customers will need a mechanism to monitor their energy usage at the least—and control their usage at the most—to gain the most value from adding a PHEV or EV to their home load.

Time-of-use Rates. TOU rates have been repeatedly touted as the silver bullet to convince customers to charge their PHEVs off-peak. Experience with TOU rates, however, has been limited in the U.S., where most utilities still use fixed-rate tariffs. Furthermore, unless the PHEV is metered separately, TOU rates would affect the total customer electric load. As a result, the customer might have to alter his or her lifestyle and move additional load off peak to avoid electric bill increases from the adoption of a TOU rate required for the PHEV.

As the PHEV and EV market begins to ramp up, a significant number of activities must be completed to allow for successful, widespread adoption. While it is impressive to see attention—and stimulus funding—being funneled toward commercial infrastructure, it is time to start working on the customer issues as well. In many respects, the critical path for completion of these issues may be longer than the commercial infrastructure activities.

David Mulder is the director of Green Grid Initiatives at Capgemini. He focuses on the integration and operation of renewable resources and demand response programs on the utility’s smart grid.


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