I'd love some input on my electricity bill. Based upon other numbers I've seen - it appears extremely high. I'm not even sure where to start on fixing, but figured determining if it is indeed a problem might be a good first step. I've found a new supplier for the electric which should reduce our rate from 0.17 to 0.1cold in January in MA 0 per kWh, but it feels like the amount of electric being used is oddly high. I'd love any and all opinions. Thanks!
Last four months of bills:
Month Amount kWh kWh / Day Comment
11/17 $450.65 1,693 56.4 No EV charging
12/17 $446.70 1,678 62.1 No EV charging
01/18 $753.52 2,785 79.6 First full month of Model S - charging via 110v 15a circuit
02/18 $694.54 2,491 77.8 Second full month of Model S - charging via 220v 50a circuit
Rates:
-Total: 0.27605 / kWh
-Supply (NRG Retail Solutions): 0.16900 / kWh
-Delivery (Eversource): 0.10705 / kWh
Some context is needed:
-Located in suburb outside Boston, MA
-Provider is Eversource
-House is around 4,000 Sqft of finished space
-Rate of usage for past 12 months has varied from 56 - 62 kWh/Day in the winter and 75 - 80 kWh/Day in the summer due to AC
-Natural gas forced Hot Water / Radiant heating
-Three bathrooms have electric floor heating
-Three computers running
-1/2 of ceiling lights are LED other half are old school
-Electric Dryer
-Gas range
-Double electric ovens (not heavily used)
There are really two issues here, or maybe three -- How much energy is the car using, and is that reasonable? And is the cost of the electricity reasonable? I assume you were looking for us to help on the first question, because the answer to the second question is implied -- you are looking for a lower rate supplier (and well you should!).
As to the first question, regarding how much energy the car is using -- It would have been helpful if you had told us how many miles you drove in each period, and how many kWh the car tells you its used (as someone said above). Otherwise it is merely guessing to try to separate the car's usage from the rest of the house. You really can't guess at the amount being used by either the house or the car. As others have said, it was very, very cold in MA in January (I live in Dedham), the first month you charged at home. But February was warmer than normal. What I suggest is that you record your trip data each month on the same day as the meter is read. Each Eversource bill tells you when they expect to read it the following month, so you can put an item in your calendar to read it that day in the morning before you leave for work. It might be helpful to use one of your trip gauges for this. Maybe use Trip B and either reset it each month or just start it at zero when you first start tracking the energy usage. This way, you can get a good correlation among your miles driven, what the car says it consumed, and your electric bill. (If you charge elsewhere, such as at work or at a supercharger, you'd have to account for that energy, too.) Bear in mind that what Eversource supplies to charge your car will be somewhat more than what your car says it uses, because there are electrical losses from the meter to the car, and in the car's on-board AC to DC converter (aka "charger"). I have read that some people have estimated the conversion process uses about 10% of the energy fed to it. So what you might try to do is to develop a factor to account for that loss. use the Trip meter data and add 10% or maybe as much as 15% to it, and assume that is the amount of energy you are using for the car. What is left is used for the house.
As to the second question -- Yikes, you really had a bad deal on your energy supplier! I have Eversource, too. Their "default" rate for energy (if you do not choose your own supplier) is either a fixed rate or a variable rate. The fixed rate now for the first 6 months of 2018 is "only" 12.88 cents/kWh. If you were really paying 17 cents, you were paying much too much. The variable rate for Eversource varies by month, and will vary this year from 10.67 cents/kWh in June to 15.3 cents in February. So, definitely get a better deal if you can, or switch back to one of the Eversource default rates. (All this rate info is on the Eversource web site.)
In Dedham, we pay less than the default rate because Dedham is part of a consortium of towns that do a group purchase of power. Our energy supply rate will be 12.88 cents/kWh for the next 3 years, fixed by contract. i have tracked our costs and the savings is meaningful. There are consortiums being formed for Boston and some other communities, too. You might ask your town or city manager to look into this if they have not done so.
One other idea that might be helpful is to ask Eversource if you can get a second meter installed just for the car charging. or maybe ask your electrician if he can install a sub-meter that monitors just the power feed from the main panel to your car. That would make it easier to separate the car and the house. I have a separate meter for the car, and it definitely makes it easier to get an accurate picture of what is happening.
Hope these suggestions are helpful.
PS: One other thing that could have helped you, me and all of us in the Eversource territory is that the utility had a time of use rate for residential service, but they discontinued it on February 1 as part of their latest rate case. I was using the TOU rate and was saving about 10% on the delivery portion of my bill. SO, I was very disappointed and a bit angry that the DPU agreed that Eversource could drop it.
