While the falling price of gasoline is welcome news for many drivers, it undercuts the financial argument for driving a plug-in electric vehicle (PEV). On a per-mile basis, electricity in the United States is between 20% to 35% of the cost of driving a gasoline-powered car, depending on the utility rates and gas taxes. Avoiding paying $50 or more for a weekly fill-up on gas compared to around $40 per month for charging an EV gives EV drivers financial satisfaction.
Gas has dipped below $2 in some states, and U.S. sales of plug-in hybrids have simultaneously slumped, falling 26% in November 2014 versus a year ago, according to HybridCars.com. However, EV economics can be further improved by charging off-peak, and recent studies show that not only are significant savings possible, but also that consumers will adjust their charging to take advantage of the lower rates.
Time to Charge
A recent demonstration that provided EV owners with timely information about the cost of electricity and grid health indicates that the cost of charging can be reduced by up to 60% through smart charging. Customers in the study had access to hourly utility rates through a connection to the Siemens energy cloud, and charging power levels were alternated based on the needs of the grid. The study was performed by Duke Energy and Siemens and delivered charging information to mobile phones, tablets, and computers, enabling EV drivers to schedule charging based on the anticipated costs given the varying rates at different times of the day.
Siemens delivered electricity rate information via its computing cloud using the OpenADR demand response protocol, which enables energy-consuming devices (including charging stations) to respond to grid conditions. The Society of Automotive Engineers (SAE) has established many standards for communications between charging stations and EVs; others, including the CEA-2045 modular communications interface standard, enable communications between charging stations with smart meters and home networking devices.
A Bad Connection
Meanwhile, in December, the U.S. Department of Energy published a report summarizing six projects related to EV charging that were funded in 2009 as part of the American Recovery and Reinvestment Act. Entitled Evaluating Electric Vehicle Charging Impacts and Customer Charging Behaviors, the report states that when provided with discounted overnight rates for EV charging, consumers will adapt their charging habits. “Customers took advantage of time-based rates to save on overnight residential charging” when they were able to pre-program charging, according to the report. Convenience in managing charging is viewed as essential to minimize the cost of EV charging.
The report also points out that work needs to continue on connecting EV chargers with smart grid devices. The Sacramento Municipal Utility District (SMUD), which was one of the six utilities managing the projects, found that charging equipment “successfully connected to SMUD meters about 50% of the time for several reasons, including poor ZigBee radio signal quality (often range related), problems with power supply circuits in the EVSE [electric vehicle supply equipment] communications module packet loss recovery, and environmental interference.”
Simplifying and reducing the cost of EV charging is critical to convincing more consumers to opt for EVs over conventional vehicles – especially when prices at the pump are low.
Tags: Clean Transportation, Electric Vehicles, EV Charging, Oil & Gas, Transportation Efficiencies
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