How much will my electric bill increase with an electric car?

How do you get utility customers to conserve electricity? Convince them to buy a plugin electric car!

Sounds counter intuitive, I know. Let me explain.

Most people have no clue how to read their electricity bill.  I surely had no idea, nor did I really care.  That, of course, all changed after I purchased my first plug-in electric vehicle (PEV) in March of this year.

When I first decided to purchase my PEV, it did not cross my mind how my electricity bill was going to be impacted.  The car salesman even pitched a very neat feature on the car where you could specify what time of day the car charges.  I politely smiled and said “cool”, but had no idea what was so “cool” about it.

Within a week of purchasing my electric car, I soon realized how my new “major appliance” was going to start drawing a massive amount of electricity on a regular basis.  It was a sobering moment.  I started worrying about how much my monthly electricity bill was going to cost for both my home electricity and new electric car charging needs.  It was time to take a closer look at my electricity bill.

As I dug deeper into my past monthly utility bills (I looked back over 2 years worth of bills!), I found out that I was frequently going over my electricity baseline, the amount of electricity specified in kilowatt hours (kWh), that each customer in a given service area is allocated for a monthly billing cycle.  Then I learned that the rate that I pay for any usage over my baseline increases exponentially in a tiered pricing system as I consume more and more electricity.

It is not too different from your cell phone bill, where you are charged a premium rate if you go over your “included” plan minutes in a given month.  But with electricity plans, you get penalized more severely the more you go over your “included” monthly kWh.  Sticking with the cell phone plan analogy, instead of paying a flat cost per minute fee, like $0.40 per minute for any overages, imagine paying more like $0.45 per minute for going 30% over, $0.92 per minute for going anywhere from 30% to 100% over, and $1.05 per minute for anything above 100%.  To get a better idea of how this applies to electricity rates, you can take a look at the different cost tiers for PG&E’s electric rates and a explanation of how to understand your PG&E electric charges.

Doing a few back of the envelope calculations based on my projected amount of daily driving, I figured out that I was going to double my electricity usage!  But the question still remained “How much more would my electricity bill increase?” (especially given the exponentially tiered rates for overages)  That is when I started getting a serious bout of buyer’s remorse, wondering why I did not do more homework beforehand.  Then, I remembered that “cool” little feature the salesman had mentioned before I purchased the car, and decided to look into what was so cool about it.

I called my local utility company, PG&E, and learned I was currently on the E-1 residential rate plan (flat rate), but was eligible for a special time-of-use rate plan for electric vehicle owners that would allow me to pay different rates based on when I used electricity.  I was surprised to find out that I could even select from many different utility rate plans (once every 12 months).  With the new electric vehicle rate plan called the E-9 rate, I would be offered a significantly discounted cost per kWh for using electricity during “off-peak” hours, and a higher cost per kWh during “peak” hours when compared to the E-1 rate plan.  There was also something called “mid-peak” time which was a slightly discounted price from the standard E-1 rates, but not nearly as cheap as “off-peak” rates.  Below is a $/kWh cost comparison between the E-1 and E-9 rate plan for the first cost tier (i.e. – up to my baseline usage).

E-1 E-9
Off-peak $0.12845 $0.30178
Mid-peak $0.12845 $0.09876
Peak $0.12845 $0.03743

The E-9 plan sounded great, however, my biggest concern with the E-9 rate was I had no idea how much electricity I normally consumed during peak hours and if my monthly bill would end up costing more or less if I changed rate plans.  This was especially concerning given I have a toddler and stay at home parent who are usually home during peak hours.  That is what inspired the creation of the PEV calculator, which utilizes Green Button data, a downloadable file that details your actual energy consumption on an hourly basis. The PEV calculator takes that historical data and computes a projected cost of electricity for various rate plans.  After using the calculator, I found out that the E-9 rate was going to be the more cost effective plan and immediately changed my rate plan.

And I did not stop there (much to the chagrin of my wife, but she came around when she saw how much electricity we were wasting pre-PEV).  I wanted to minimize my home electricity consumption as much as possible, especially during peak hours.  So below is a list of a few simple things I did to try to conserve electricity:

  • Used fewer light bulbs, but enough to light up a room.  For example, our bathroom was using eight 100-watt light bulbs. I unscrewed half of them and could barely tell the difference in room brightness, but saved 400 watts per use
  • Opened up windows and blinds to use more natural sunlight throughout the day instead of turning on lights
  • Unplugged all unused appliances, like small appliances with digital clocks
  • Attached a power strip to rarely used appliances, like the TV and printer to be turned on only when needed
  • Hand washed dishes whenever possible
  • Used time delays on the washing machine and dishwasher to consume electricity during off-peak hours

The results of these energy conservation efforts were surprising.  I reduced my average daily kWh usage by 20% when compared to the previous year (see table below), and also reduced my electricity cost per kWh to an average of $0.08 per kWh compared to the $0.13 per kWh I paid before.  What amazed me the most was my electricity consumption now included both my electric vehicle charging and home electricity needs, and I was using less electricity compared to the same time frame the year before.  Essentially, all of that previously wasted electricity was now being put into my electric car for my personal auto fuel needs.  (Oh, and did I mention that I haven’t filled up my PEV with gas since I purchased it almost 5 months ago?)

(in kWh) April May June Average
2012 8.85 9.49 12.55 10.30
2011 10.83 11.43 16.37 12.88
Difference -18% -17% -23% -20%

Probably the funniest thing that has come out of this whole experience is that I never thought I would look forward to receiving a monthly bill, but for the first time ever, I actually look forward to getting my utility bill to find out how much electricity and money I save each month… all thanks to my new electric vehicle!  Although, I’m not sure my wife is as thankful as I am given that we sit in the dark every night until after 9:00 pm (off-peak hours).  But I’ll leave that topic for another post… :)

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Posted in EV Costs
One comment on “How much will my electric bill increase with an electric car?
  1. tom lyons says:

    John’s experience represents something that motivates us all- the challenge to improve ourselves, our family’s well being, and ‘do no harm’ along the way. There’s a lot of satisfaction reducing your utility bill to save, while knowing you’re practicing energy conservation whose benefits extend beyond ourselves.

    I wonder though, would it be easier to understand our usage and to change as John did, if the utilities were incented to EV adoption? I mean, do they earn a carbon credit for replacing gasoline emissions with a kwh?

    If they are, California’s utilities could use their marketing programs to really help. If they aren’t, we [as individuals and EV advocate communities]ought to spread our knowledge far and wide.
    -TL

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