Costs for charging electronic vehicles are a balancing act

Ken Pruitt, energy manager for the Town of Arlington, explains the costs for charging electronic vehicles in town:

Ken Pruitt, town energy manager, at HeatSmart kickoff. / Susan Gilbert photo

Regarding the cost of charging electronic vehicles (EV) at town-owned charging stations, the issue basically comes down to this: Setting rates that recover the town's costs to provide EV charging makes those rates a bit pricey for those wishing to use the charging stations.

It's a question of balancing the town's desire to promote electric vehicles with the need to be fair to all taxpayers. Here's a detailed breakdown:

The rates for public EV charging at the Russell Common lot and Gibbs School parking lots are as follows:

Russell Common: 30 cents per kilowatt hour for electricity plus a 50-cents-per-hour parking fee (parking fee applies only 8 a.m. to 8 p.m. Monday through Saturday);

Gibbs: 30 cents per kilowatt hour for electricity (no separate parking charge);

Planned at the Railroad lot (behind Not Your Average Joe's): 30 cents per kilowatt hour plus a 50-cents-per-hour parking fee (parking fee applies only 8 a.m. to 8 p.m. Monday through Saturday); and

Planned at the new Park Avenue location (in front of ACMi): 30 cents per kilowatt hour (no separate parking charge).

The parking rate at Russell Common is separate from the electricity charge, but is charged directly by ChargePoint on top of the electricity fee, which makes charging at this lot more expensive than at Gibbs (at least 8 a.m. to 8 p.m. Monday through Saturday).

However, this rate would be in effect regardless of whether a charging station were there, so it is really only fair to count the 30 cents per kilowatt hour as the EV charging fee.

Town's best estimate

It is true that 30 cents is higher than what the town typically pays for electricity (average town cost is about 21 to 22 cents per kilowatt hour. However, 30 cents is the town’s best estimate for the actual cost for providing electricity through ChargePoint stations.

That is because ChargePoint has added fees. They include 10 percent of electricity sold (so, about 2.2 cents per kilowatt hour), a $560 annual networking fee to pay for Internet connectivity and related services (that’s how a user can determine where the station is, whether it is occupied or unoccupied and other details about the station from the ChargePoint app) and a service plan that fully covers hardware and software problems with the station ($500 per year).

We don’t have enough data yet to have ground-truthed the 30 cents-per-kilowatt figure, but again, it was the town’s best guess and continues to be. We plan to periodically revisit the rate charged at town-owned charging stations.

Compared to gas

Even at 30 cents per kilowatt, charging an electronic vehicles is a better deal than paying for gas, mile-for-mile.

A typical EV uses about 30 kilowatt hours to travel 100 miles (the Chevy Bolt is slightly better: 28 kilowatt hours per 100 miles). At 30 kilowatt hours, it would cost $9 to go 100 miles.

At the current average gasoline price in Massachusetts -- $2.70 per gallon -- and assuming a vehicle that gets 25 MPG (I rounded up from the 23.6 MPG, the U.S. average for all cars and trucks in 2018), it would take four gallons of gas to drive 100 miles. Four gallons times $2.70 equals $10, or $1.80 more per 100 miles driven than the same miles driven with 30 kilowatt hours of electricity.

The town wants to promote EV adoption and to make EV charging as convenient and affordable as possible. Input from residents will help inform our efforts going forward. 

March 31, 2019: Town eyes adding 2 electric-vehicle charging stations

This informative explanation, which includes opinion, was published Wednesday, April 3, 2019.