[ad#post_ad]In a few weeks I will be taking delivery of a Chevrolet Volt test car to live with for three months as a member of GM’s consumer advisory board. Sooner than that I will have the official GM 240-v Volt charger installed in my garage. This level 2 charger allows the car to be fully recharged in about 4 hours as opposed to the 8 to 10 hours it would take at conventional 120-v household current.
The Volt has a programmable interface that allows owners to delay charging. This function allows one to take advantage of overnight off-peak utility rates, which are generally significantly less expensive. Utilities meet peak daytime demand by trading off excess nighttime capacity. The utilities would love the chance to sell that capacity, and by offering a lower rate can encourage people to buy it.
Electric cars are the perfect application for this off-peak power because mostly people will want to charge them at night while they are sleeping. In some cases rates are less than 2 cents per kwh off-peak, though they can be more than 10 times that during the day. To refill the Volts 8 kwh, or 40 miles range, of battery capacity could cost as little as 10 or 15 cents off-peak. In comparison, gas costs about $3.50 to $4.50 per 40 miles even at today’s rates.
Most homes have a fixed electric meter that simply records overall kwh usage and doesn’t tell the utility company when that power is being drawn. Customers are simply charged a fixed rate for all power consumed regardless of when it is used. To take advantage of off-peak rates one has to have the utility company install a time-of-use meter (TOU) that records specifically when power is consumed.
The problem with this, however, is that the utility company may offer stellar rates off-peak, but in exchange will inflate the peak rate to far above the standard, negating or even inverting any benefit for charging your car.
Le’ts take my case in point, as I have studied it to see if a TOU meter makes sense.
Currently my electric charges billed by Orange and Rockland (O&R; a subsidiary of Con Edison) in New York has two components; delivery charges and supplier charges.
O&R currently charges 8.6 cents per kwh for delivering the electricity I use. They do not profit off the electric power itself, as that is sold by a third party, in my case Coned Solutions. This provider is charging 10.5 cents per kwh. Thus my overall charge is 19.1 cents per kwh.
If I switch to TOU metering, O&R is offering an amazingly low 1.3 cents per kwh delivery charge for 9PM through 10AM. However, in that case the 12PM to 7PM rate balloons to 20.4 cents per kwh. Its 7.3 cents per kwh at all other times.
Let’s say in the average month I use 1000 kwh of energy, and 50% is during peak times. My bill would come to $191.00.
If I added 240 kwh per month charging my Volt six days per week, my bill would rise to $236.84.
Now let’s say I switched to TOU metering. My regular charges would be $155 (500 kw peak rate) + 79.50 (500 kw regular rate) +28.32 (240 kw off-peak rate) = $262.82
Thus though these differences are small, switching to TOU would wind up costing more. The less the percent of electricity drawn during peak the less the disadvantage, and at some lower level of peak usage a benefit will begin, this benefit will also be larger the larger the car battery. However it is hard to know how much peak electricity one uses unless the switch to TOU has already been made.
This situation is unfortunate and really doesn’t help promote electric car adoption. I suggested my utility company simply offer the 1.3 cents per kwh 9PM to 10AM rate for validated EV owners without changing their daytime rates.
My response so far from an O&R expert by the name of Paul Koretz is “the existing tariffs do not have an incentive for EV owners beyond the TOU rate at this time.”
Asked if that could change he said, “I will see if we have something in the works specifically for EV.” Paul advises that he is continuing to check on that.
“You’ve hit the nail on the head regarding TOU rates,” says GM’s director of infrastructure Britta Gross. “It is really going to depend on a customer by customer basis how much electricity you really use during the peak hours of the day (and what the rate differential is).”
“If nobody is home during the day, then the TOU can make a lot of sense – but if there is a lot of activity at home during the day the lower evening rate just to charge the vehicle may not make it worth it (because of the daytime higher rate),” she said.
“Some utilities have put rate calculators on their websites to let a customer play with the various options,” she added.
There is some hope this situation will change over time if more of us complain.
“Some utilities (just a few) do offer a special EV rate – and it is separately metered from the normal household energy use – and this is a low evening rate,” said Gross. “Maybe this will catch on – though there is the upfront cost of the separate ‘submeter’”
So if you can, call your utility provider and find out if they offer a special EV off-peak rate, if not see whether switching to TOU makes sense for you.