Lets look at an Electric Vehicle Tariff

Energy Tariff Experts (ETE) was founded by a guy who loves cars and utility tariffs. In kindergarten, ETE's founder gave a presentation on Chrysler's 1985 model year line up for show and tell and his interest in cars hasn't abated since. As a result, analyzing Electric Vehicle (EV) tariffs is about the most fun we can have over here at ETE. In this post, we are going to take a close look at Baltimore Gas & Electric's (BGE) Residential EV pilot tariff and discuss how it is different from the standard residential rate.

Many utilities see EVs as a way to improve the load factor of their systems and tariffs that incentivize off-peak charging are one way for utilities to encourage consumers to charge their EVs at night or during low load periods (e.g., weekends, holidays, etc.). Often, utilities are constrained in their tariff design options by the capabilities of their billing systems so they are rarely able to make up a rate design that is totally different from existing rates. The graphic below shows the Time of Use (TOU) periods for BGE's standard TOU rates and the residential EV pilot rate. The EV pilot rate is available to residential consumers who own and charge an EV at their residence. The big difference in the EV Pilot rate is that the intermediate period is treated as an off-peak period.

The BGE residential EV rate distribution charges for usage and the monthly customer charge are actually identical to those for the non-TOU standard residential rate. BGE uses the supply portion of the bill to provide the off-peak discount in the energy charges. You can check out BGE's current supply rates at this link. The table below compares the standard residential rate structure with the residential EV pilot rate. For simplicity, the table leaves out many of the Riders that are used to adjust the distribution base rates so this table may not match an invoice perfectly.

As you can see, the off-peak charging rate on the EV pilot tariff represents at discount of approximately $0.03415/kWh off the standard non-TOU residential rate, but the peak charges are significantly elevated. This rate requires the customer take supply service from BGE, so it precludes competitive supply (which may or may not be less expensive than BGE per market conditions). For a consumer to make an educated decision regarding opting into the EV pilot rate, they would need to evaluate their current domestic electric usage (e.g., appliances, water heater, HVAC, TV, etc.) that occurs during the peak period relative to their off-peak consumption and expected EV charging needs. For someone who is a heavy EV charger, this rate may offer savings, but for the casual EV charger with significant household electric consumption during the peak periods, this rate could end up being a wash or a money loser. Consumer behavior and consumption patterns will determine the savings opportunity from this rate.

In summary, BGE's residential pilot EV rate is fairly typical of utility EV rates in that it conforms to the limitations of the utility's billing system and provides a discount for off-peak consumption. If you have a project related to EV tariffs and need some help, please call us. We'd love to give you a proposal.