Electric vehicle sales will be largely influenced by advances in battery technology and the rollout of charging infrastructure. But these technologies will become even more intertwined going forward as the proliferation of electric vehicles may foster demand for batteries as local energy storage.
Many consumers who park a Volt, Leaf or other plug-in EV in their garage will notice a bump in their overall electricity cost because EVs can increase monthly consumption by 50% to 100%. This will lead many consumers to closely scrutinize their utility bills and look for ways to reduce their cost per kWh. Several utilities are launching EV-specific time of use rates to encourage consumers to charge off-peak.
Also drawing consumers’ attention to energy use will be the new applications from EV charging station vendors that enable consumers to track consumption, cost and carbon emissions reductions either online or via their mobile phones. As consumers realize that they can save money by charging off peak and get comfortable with lithium batteries, they will be primed to consider purchasing energy storage in the home.
Two charging equipment companies, AeroVironment and Eaton, are developing products that incorporate energy storage. In some areas with high energy rates and time of use pricing (such as California), electricity can cost 80% less overnight than at peak times. With even a small battery pack (say 1-2 kWh), consumers in these areas can greatly reduce their peak energy costs for their households.
Putting storage into the charger rather than using the vehicle for power to the home will preserve the life of the EV’s batteries and can capture cheaper energy even if the vehicle is not plugged in. (EV manufacturers have so far largely frowned upon V2G applications because of the potential impact on battery life.) Also, any surplus in solar power generated at home could also be captured. Storage batteries could be lithium ion (in the future from the vehicles after their useful life), as well as less costly nickel metal hydride or advanced lead acid batteries.
For commercial fast DC chargers, incorporating battery storage could be a way around impacting peak demand. In addition to also storing excess solar power, commercial customers could use the charger/storage system as emergency power and to similarly purchase energy when it is the cheapest and quick charge their fleets on demand without worrying about cost or impact on the grid.
Charging just one vehicle at this rate is equal to approximately 43 vehicles being charged via Level 1 (aka standard household current) or 9-18 vehicles at Level 2 using charging equipment. Complicating matters is that DC charging is by necessity immediate – delaying a 15-30 charge defeats the entire purpose. Plus, these charge locations are likely to be at truck stops, gas stations, or mini-marts, which aren’t places that most folks plan on spending a lot of time.