Electric Vehicles (EVs), with their potential for gasoline savings and emissions reductions, are generating significant consumer and political interest, particularly in the wake of the recent Gulf of Mexico oil leak. However, given the sizable amount of electricity they require for charging, EVs are also generating concern among utilities tasked with supplying that electricity on the nation’s aging grid. The next two years are expected to bring a significant shift in the electrification of transportation as nearly 20 automakers introduce battery-powered EVs or plug-in hybrid EVs. With consumer pre-orders for the vehicles already in the tens of thousands and researchers expecting millions of EVs to be on the road by 2020, utilities must act now to develop a strategy on integrating EVs.
Scott Lang
Chairman, President & CEO
SilverSpring Networks
The most serious concern for utilities is controlling when EV charging stations (known as EVSE, or Electric Vehicle Supply Equipment) will apply load to the grid. A high percentage of consumers will instinctively charge their EVs when they get home from work, likely having a serious impact on peak demand on the grid. With EV home charging stations typically drawing an electricity load of 6.6kW (240V and 30 amps) - roughly the equivalent to the load of an entire house at 7kW – a single EV can double a home’s peak load, and even low levels of EV adoption in a particular neighborhood can strain existing power infrastructure. In fact, data released by the Electric Power Research Institute (EPRI) suggests that if two customers on the same transformer plugged in 6.6 kW charging stations during a peak time, their charging load, in addition to existing load, may exceed the emergency rating of roughly 40 percent of today’s distribution transformers.
However, the growing EV trend will not necessarily require utilities to add new generation capacity or make extreme infrastructure upgrades. According to the Pacific Northwest National Laboratory (PNNL), approximately 160 million vehicles in the U.S. could be powered solely from existing off-peak generating capacity. This means that many utilities could initially support EV charging by better managing existing generation.
The Smart Grid is the key to smart EV charging. The Smart Grid provides the visibility and control needed to mitigate the load impacts and protect components of the distribution network from being overloaded by EVs thus ensuring electricity generating capacity is used most efficiently. With a Smart Grid, utilities can manage when and how EV charging occurs while still adhering to customer preferences.
Smart Grid integration of EVs also enables utilities to provide consumers with greater insights into their EV experience – allowing their customers to better understand cost of “fueling”, positive impact on the environment and ability to set charging preferences. A Smart Grid also allows utilities to collect EV-specific meter data, offer specific rates for EV charging, engage consumers with information on energy transmission, and collect data for greenhouse gas abatement credits.
Because of the robust communications infrastructure offered by the Smart Grid, utilities can remotely monitor charging stations and allow for the comprehensive management of EV charging. Utilities can also troubleshoot charging issues without unnecessary on-site service calls and manage when connected EVs are charged.
With the Smart Grid, utility back offices will be able to support, integrate and optimize EV charge management as part of an integrated Demand Side Management (DSM) operation. This approach requires systems that not only manage EV charging, but also optimize it with respect to other Demand Response (DR) programs, such as A/C Cycling.
The Smart Grid also allows utilities to seamlessly integrate an EVSE meter with the Advanced Metering Infrastructure (AMI) system. This allows a utility to break out EV charging from the primary meter and bill for EV charging at a separate rate. AMI integration can also make it easy for utilities to track and report EV charging usage for greenhouse gas credits and use data to predict local reliability issues.
While EV integration poses numerous challenges, it also presents utilities with a significant opportunity: by planning now, utilities can maximize their existing infrastructure, create closer relationships with customers and leverage communications investments to enable the adoption of EVs. Those that don’t prepare to integrate EVs risk being perceived as bottlenecks and will find themselves with an over-taxed grid and the potential for reliability issues.
About the Author
Scott Lang is the Chairman, President and CEO of Silver Spring Networks, a leading Smart Grid solutions provider. Silver Spring is working with EV charging station manufacturers to integrate communications and metering into EVSEs, and developing software to enable load management, helping utilities better manage EV-related demands.
