Showing posts with label Dom EV Rates Series. Show all posts
Showing posts with label Dom EV Rates Series. Show all posts

Friday, October 21, 2011

Dominion Virginia Power EV Rates Revealed (Part 3)

Calling Dominion

During the Canadian Thanksgiving Day weekend I called Dominion's Electric Vehicle information and sign up line to discuss which pilot project I should choose: Schedule EV or Schedule 1EV, below.  I found out that if I signed up then I'd be getting my new meter before my EV arrived which wouldn't be useful for the program.  We thus decided to punt the decision until after my next meter reading on the 17th of October.  That way, the new meter would be installed during the subsequent meter reading in November, which should be after my LEAF arrives.

Not So Smart Meter

The other thing I found out was that the Smart Meters Dominion installs are an earlier design.  These units are only capable of sampling electrical usage at fixed intervals which allow them to calculate for each of the prescribed Time-Of-Use intervals under the given rate plan.  They don't have the advanced technology of having 3 lines to the house, where, for instance, one has a household line, an EV line and potentially a line to a Solar or Wind generator.

In fact, the Schedule EV program installs 2 meters on your home.  You keep your original meter for your household, ticking off net electrical usage under the standard Residential Schedule 1 rate.  Typically next to this, they add a second meter to the mains which is the smart meter monitoring the EV usage under Schedule EV.  However, if they find it convenient, they may place the meter anywhere where an electrical line in can be tapped, though the location of the current meter seems the most logical.

The other new Smart Meter technology is the ability to create a mesh network, as they're doing in Austin, TX.  This technology allows the customer to monitor their current and historical electrical usage via a wireless network that sends information to Austin Energy.  What's more, these new Smart Meters can communicate with smart household appliances to regulate appliances like a refrigerator or central air conditioning, allowing the power company to reduce household electrical usage during peak hours.  On the surface this may sound like big business controlling we the consumers, but it benefits us too.  After all, throttling our appliances during the most expensive, peak demand will save us money, especially if we're under a Time-Of-Use rate.

Second Meter?

As stated above, folks interested in the Schedule EV plan will be getting a second meter to monitor the EV electrical usage.  Because this is a second meter, it needs to have its own line into the house which must be provided by an accredited electrical contractor.  Dominion's responsibility is only to the meter.  They'll hook up the meter if and only if there's already a line into the house with a empty mounting for a that meter, as would be for Schedule 1EV (household Time-Of-Use).  If your electrician hasn't yet run the line out for the second meter and installed the meter mounting, Dominion can't connect the meter to your EV.

So today I spoke with my favorite Electrical Contractor, Joe from Cullen Electric, Inc..  Unfortunately, for most of the conversation I had him confused with a representative from Dominion, much to my chagrin.  I'm waiting for a call from the Net Metering folks at Dominion to answer a question I still have about hooking up solar panels under one of the EV schedules.  So unfortunately I dragged Joe into a long and only partially productive debate about installing Photovoltaic panels on my home.  My plan is still to consider installing Solar Panels on my home, especially if I can get the guidelines of my HOA overturned this week, but obviously that's not why I asked Joe to call me.  Sorry about that Joe!

Anyway, Joe estimates the job to be about three-quarters of a day's work and estimates about $700 – $800.  Basically, since there's already a circuit breaker panel in the garage for the EV, Joe just needs to pull the 125A 1/0 SER cable out of the main breaker, hook it into a new cut-off switch and then run a wire out from the cutoff to the new meter mounting.  The cutoff switch is for safety since it needs to be within a minimum number of feet from the meter, but is convenient since it doesn't require the current 125A wire to be extended.  As of the time of this writing, I'm still checking with Joe on whether he knows which meter mounting to get but if I do go with Schedule EV, it looks like he can install it pretty close to the Smart Meter installation date, assuming it's 17 November as Dominion indicated to me when I first called.

I'm considering just going for the Schedule 1EV to simplify the work by Dominion and not have to run a new wire out of my house, though I certainly could budget the extra electrical work.  I certainly have always preferred the EV-Only Schedule EV, but it's looking more and more like I'll be going with Schedule 1EV.  But each day this changes and Joe is still trying to track down information on the correct mounting…

Schedule 1EV

Finally, we come to the long sought after description of Schedule 1EV — it's only taken me 8 months to write!  Recall from Part 2 that we start with 4.417¢kWh for fuel, transmission, taxes and other various fixed costs.  We then need to add in the base Distribution and Support rates for Schedule 1EV; these rates are summarized in the following two tables:

Schedule 1EV Rate 16 April – 15 October
Hours Distribution rate in ¢kWh Supply rate in ¢kWh Net Cost (EV) Net Cost (House)
01–05 (Super Off-Peak) 0.000 0.444 $10.32 $0.73
05–10 (Off-Peak) 2.053 1.652 $0.17 $164.49
10–13 (Intermediate) 2.053 3.818 $0.16 $57.92
13–19 (Peak) 2.053 9.501 $0.63 $398.98
19–22 (Intermediate) 2.053 3.818 $0.16 $193.08
22–01 (Off-Peak) 2.053 1.652 $46.59 $56.35
Totals $58.04 $871.56
Schedule 1EV Rate 16 October – 15 April
Hours Distribution rate in ¢kWh Supply rate in ¢kWh Net Cost (EV) Net Cost (House)
01–05 (Super Off-Peak) 0.000 1.388 $32.14 $1.25
05–06 (Off-Peak) 2.053 2.106 $0.04 $11.24
06–11 (Peak) 2.053 4.605 $0.30 $155.89
11–17 (Off-Peak) 2.053 2.106 $0.23 $56.18
17–22 (Peak) 2.053 4.605 $0.30 $179.88
22–01 (Off-Peak) 2.053 2.106 $52.08 $34.65
Totals $85.10 $439.09

This by far is the most complicated rate of all that I've analysed.  Not only is it a Time-Of-Use rate, like Schedule EV, Schedule 1T (The old Time-Of-Use household rate) and Schedule 1S (The Time-Of-Use rate used for houses with Solar Net-Metering), but its seasonal periods break mid-month so it means I have to compute complete months then prorated, partial months in during the summer schedule and add that to prorated, partial months in the winter schedule.  Thus, my sheet does 3 look-ups for each month and each hour, making it bulky, slow, hard to maintain and from which it's hard to get specific details.

What's more, Schedule 1EV is an alternate rate, not an additional rate.  You use Schedule 1EV instead of Schedule 1, not in additional to it like with Schedule EV.  This means that your entire household rate could be effected by the change, not just by the addition of the EV, but now your usage and time of usage matters for everything.  When you run your A/C or Electric Heater, when your Refrigerator cycles or when you watch Television or Browse the Internet can all effect your total electricity rate.

Since my home is currently on the 2-tiered, fixed-rate Schedule 1 plan, I don't have any information about how many kWh of electricity I use at say 10 am (hour 10) or 10 pm (hour 22), or when I may be my peak usage and when do I use the least.  The EV is easy to estimate because I know when I plan to charge it, how long it takes to charge and thus when the charging will typically stop, not so with the whole household.  All I know for sure is the total electricity usage in my one month billing cycle.  Any more detail than that, and I have to guess.

Estimating Home Electricity Usage

I've literally wanted to post this since I wrote the first part of this article back in February.  Indeed, it's the entire inspiration for this series I've made about explaining the electric rate.  Of all the things I've discussed thus far, I can show evidence, trace steps, and point to solid sources of information to back up my claims.  When it comes to estimating household electrical usage, however, things reduce to an educated guess.

Daily Electrical Usage Curve

To start with, I decided to assign an arbitrary point system to my daily electrical usage.  The points don't correspond to any real-life value, they just follow the rule that if hour x value is greater than that for hour y, then that hour is estimated to use more electricity and if the value at x is twice y then x used twice as much electricity as y,  The following table details the numbers I used and some of my reasoning.

Daily Electrical Usage (Estimated)
Hour Value Percent Reasoning
00 0.25 0.30% Sleeping, for the most part
01 0.25 0.30%
02 0.25 0.30%
03 0.25 0.30%
04 0.25 0.30%
05 3 3.56% Wakie, wakie!
06 6 7.12% Get ready for work (or sleep in on weekends)
07 6 7.12%
08 6 7.12%
09 6 7.12%
10 2 2.37% At work with alarm active or relaxing in front of the Television or Computer
11 2 2.37%
12 2 2.37%
13 2 2.37%
14 2 2.37%
15 2 2.37%
16 5 5.93% Chillin after work
17 5 5.93%
18 5 5.93%
19 7 8.31% Primetime: The height of activity
20 7 8.31%
21 6 7.12% Evening slowdown
22 6 7.12%
23 3 3.56% Getting ready for bed

Phew!  So, that's what I estimated.  I took those numbers, summed them to get a total points used, then divided each by that number to get a percent usage, which you can see next to the raw values above.  I take these percents and multiply the total monthly usage by them to get the estimated total monthly electrical usage for that hour of the day.

Because I've never been on a Time-Of-Use rate before and I'm no-where near confident with these numbers, I would be happy to hear from one of my readers to show my my mistakes.  Barring that, I could just go with the Schedule 1EV rate and see what happens.  They won't break out my usage in hours for me, as I explained above, but I could at least see if my estimates were near the mark.

Rate to Rate: Who's cheaper for a household?

Up until now, I've only been talking about EV rates.  The amount of money it costs to run the household electricity is different than that for an EV because the costs for an EV already assume some electricity usage so the electricity is never metered from zero.  For instance, under Schedule 1, there are 2 tiers of electrical usage for the base Distribution and Supply rates: the first 800 kWh are charged charged at one rate and anything above that at another.  As such, since my home already uses more than 800 kWh per month, my EV would always be charged the abouve 800 kWh rate.

In addition to this, there are taxes like the State Consumption Tax, the Special Regulatory Tax and the Local Consumption Tax, as well as the Fairfax County tax.  In the case of the three Commonwealth taxes, they are each 3-tired taxes.  In Part 2 I estimated that most of my EV's electricity would be in the in the first Tier, with a little less than ⅓ in Tier 2.  With the household, we're counting from zero so all again most usage is at Tier 1 with a bit in Tier 2 with the above 2,500 kWh usages over Summer.  Also, where as the Fairfax County Tax has already reached its $4 cap by the time we start to count the EV, that entire $4 is paid at the household level.

Household Rate Fixed Costs

Fortunately, the only thing different between the Schedule 1 rate household and the Schedule 1EV rate household is the Distribution and Supply usage rates.  Even the monthly rate of $7 is the same under both schedules.  These invariant values a summarized in the next table:

Name cost in ¢kWh Annual Cost
Schedule 1 & 1EV: Distribution (Monthly cost, $7.00) $84.00
Rider C1: Peak Shaving 0.009 $1.93
Rider C2: Energy Efficiency 0.044 $9.43
Rider S: Virginia City Hybrid Energy Center 0.280 $60.03
Rider R: Bear Garden Generating Station 0.117 $25.09
Rider BRC: Base Rate Credit -0.132 -$28.30
Rider T: Transmission 0.616 $132.08
Fuel Charge Rider A 3.289 $705.19
Sales and Use Surcharge 0.056 $12.01
Consumption Taxes (Tier 1) (< 2.5 MWh) 0.155 $31.08
Consumption Taxes (Tier 2) (2.5 MWh ≤ x < 50 MWh) 0.099 $1.38
Consumption Taxes (Tier 3) (≥ 50 MWh) 0.075 $0.00
Fairfax County Tax (Min 56¢; Max $4) 0.605 $48.00
Totals 4.430 $1,081.92

As before, we need to explain the base rate calculation here.  I currently estimate about 21,441 kWh per year of electrical usage in my household given the pattern of data I have going back almost two years.  How this breaks down in terms of the Consumption Taxes is 20,051½ kWh of that is under the Tier 1 level and only 1,389½ kWh falls under Tier 2.  I again use these estimates to calculate the last 0.151¢ of the tax total.

I've also eliminated the County Tax from the calculation but not because it isn't paid, but because it's always always $4.00 per month for me, regardless of how much electricity I use.  For this rate to be relevant, I'd have to use less than 661.157 025 kWh of electricity in a given month and that is no-where near happening.  After all, I'm never even going below 800 kWh to stay within the Schedule 1 Tier 1 Base rate.  Thus, the County Tax and Monthly Distribution rate are not counted in the total cost per kWh, but are included in the annual totals.

I spend about $1,081.92 each year … on all secondary items

In summary, I spend about $1,081.92 each year in electricity regardless of rate schedule on all the secondary items, riders and taxes.  This value is without the Base Rate, which turns out to be the lion's share of the calculation.

Comparison of Rate Schedules

As I stated before, Schedule 1 is a 2-Tiered system.  It's also a seasonal schedule, with different rates depending on the time of year.  These rates are summarized in the following table.

Rate Category Non-Summer Rate, 1 October – 31 May, in ¢kWh Summer Rate, 1 June – 30 September, in ¢kWh Net Cost (EV) Net Cost (House)
Distribution ≤ 800 kWh 2.233 2.233 $0.00 $214.37
Distribution > 800 kWh 1.260 1.260 $90.49 $149.20
Supply ≤ 800 kWh 3.795 3.795 $0.00 $364.32
Supply > 800 kWh 2.927 5.773 $278.48 $574.71
Totals $368.97 $1,302.59

Putting it all together

Compare this to the results from the Schedule 1EV rate above.  In the tables describing the Schedule 1EV rate, we have the totals for both the car and the household for the base Distribution and Supply rates.  The household rates are based on the estimated electricity usage from that section, and as such are only my best estimate for how much it would cost under Schedule 1EV: my own mileage may vary.  Summing together the values from that table and the one for Schedule 1 and finally pulling in the results for the Schedule EV in Part 2, we can finally compare each of the above rates:

Rate Schedule 1 Schedule 1 with Schedule EV Schedule 1EV
Distribution Cost per Year (EV) $90.49 $98.83 $52.17
Supply Cost per Year (EV) $278.48 $70.63 $90.97
Subtotal Cost (EV) $368.97 $169.47 $143.14
Total Cost (EV) $686.16 $486.66 $460.33
Distribution Cost per Year (House)1 $363.56 $363.56 $434.96
Supply Cost per Year (House) $939.03 $939.03 $875.69
Subtotal Cost (House) $1,302.59 $1,302.59 $1,310.65
Total Cost (House) $2,384.51 $2,384.51 $2,392.56

The Subtotal in the table above contains the sum of the Distribution and Supply costs and the Total adds this to the cost for everything else, including Taxes, Fuel, Transportation and the various other Riders.

The main take-away here is that if my estimates are correct, there's not much difference for the household electricity cost under Schedule 1 and Schedule 1EV; my calculations show less than $10 per year!  Stranger though is that the Distribution is about $70 higher under Schedule 1EV but about $60 lower than Schedule 1 for Supply.  Secondly, as you can see, the cost to run an EV under Schedule EV and Schedule 1EV doesn't differ much either.  Schedule 1EV looks to be about $25 cheaper than Schedule EV, but both are clearly less than half the rate under just Schedule 1.

What if the LEAF had a 6.6 kW charger?

I would be remiss if I didn't do the same analysis for the Schedule 1EV that I did for Schedule EV with respect to 6.6 kW charging.  Specifically, the $98.68 I pay per year for charging my LEAF from hour 22 to hour 1 (Off-Peak) could be reduced to a mere $0.22 cents and my Super-Off-Peak per year goes from $42.46 to $65.38 per year because of the greater overall electricity usage.  Thus, the cost to run the LEAF under Schedule 1EV goes down to $384.78 per year, about $75 in savings per year.

And that's all you need to know when you choose a new EV rate schedule.  So call Dominion right now: 1-866-566-6436 and join the EV Rate Revolution!


1Doesn't include the Monthly Charge since this is already assumed in the fixed cost independent of the rate program.

Monday, October 3, 2011

Dominion EV Pilot Program opens today!

Dominion Virginia Power Electric Vehicle Charging Pilot Program Begins

As I've indicated numerous times before, I'm very keen to make my Power Utility, Dominion Virginia Power, aware of my intent to use an Electric Vehicle so that they can better prepare for the load I would be drawing and be able to provide sufficient power at times optimal for charging.  Fortunately, like most EV drivers, my intention is to charge my car overnight, when the demand for electricity is already at its lowest, which allows my PU to balance generation between the peak daylight hours and the nighttime hours when my car draws energy.

In return for this, I've asked my PU to set me up to be charged a Time-Of-Use rate which would reduce the cost to charge the EV when it's charged over night versus during the daylight hours.  Back in February, I reported that Dominion Virginia Power was proposing two new pilot program rates specifically for electric vehicles which would use new smart meters and allow the calculation of rates based on Time-Of-Use.  Excited, I sought more information and was able to calculate a $200 savings by switching over to either of the new EV-based TOU rates.

Dominion Virginia Power EV Rates Revealed (Part 2)

I explained how rates are calculated back on Valentine's Day because I ♥ calculating this kind of stuff.1  And although the rate for Fuel has gone up slightly since I wrote Part 1 — it's now 3.289¢kWh — all the calculations remain the same.

So take for example the Nissan LEAF with its 24 kWh battery pack.  If we estimate the LEAF's wall-to-wheel efficiency to be 3⅓ mi⁄kWh (5.364 kmkWh), with a 38 mi (61 km) commute each way, this represents 22.8 kWh (2 × 38 mi ÷ 3⅓ mi⁄kWh) or 95% of the 24 kWh pack on the LEAF.  I then assume the weekend driving consists of more local, around town driving equivalent to exactly half of the weekday driving or about 38 mi (61 km) per day or 11.4 kWh.

In addition to each of these, it's important to remember that the EVSE also draws power to maintain its status and remain in a ready state.  My EVSE only draws 5 Watts to maintain its ready state — EVSEs with more Internet connectivity and wireless capabilities will draw more power than a plan nuts and bolts EVSE like my Clipper Creek CS-100.

Since I plan to only charge my vehicle over night and be out of the house around 5:00 am, I set my calculations to assume I can finish charging by that time.  This would be different if I could charge my car at work, but with a 3.3 kW charger on the Nissan LEAF, it will take 6.09 hours (22.8 kWh ÷ 3.3 kW) to charge the LEAF during the weekdays and 3.45 hours (11.4 kWh ÷ 3.3 kW) on the weekend.

The Missing 4 cents revisited

Once the total electrical energy required for charging the EV is known, we can calculate the cost for Transmission and Fuel rates and Use, Consumption and County Tax, as well as the various Distribution and Supply riders to get the base price for charging our EV.  These rates are summarized in the following table:

Name cost in ¢kWh Annual Cost
Rider C1: Peak Shaving 0.009 $0.65
Rider C2: Energy Efficiency 0.044 $3.16
Rider S: Virginia City Hybrid Energy Center 0.280 $20.11
Rider R: Bear Garden Generating Station 0.117 $8.40
Rider BRC: Base Rate Credit -0.1322 -$9.48
Rider T: Transmission 0.616 $44.24
Fuel Charge Rider A 3.289 $236.21
Sales and Use Surcharge 0.056 $4.02
Consumption Taxes (Tier 1) (< 2.5 MWh) 0.155 $7.68
Consumption Taxes (Tier 2) (2.5 MWh ≤ x < 50 MWh) 0.099 $2.20
Consumption Taxes (Tier 3) (≥ 50 MWh) 0.075 $0.00
Fairfax County Tax (Min 56¢; Max $4) 0.605 $0.00
Totals 4.417 $317.19

Now, the Fairfax County Tax will typically hit the $4 maximum without the EV so the EV won't add to that tax.  Also, for the Consumption Taxes, many months my household never goes over 2.5 MWh.  Generally, I still do come close to if not going over in the warmer months of June, July, August and September, even after going to R-49 attic insulation but not in the winter since I have methane-based (natural gas) heating.  In my calculations, I use my actual historical household data to compute the Consumption Taxes, so in months where the usage does go over 2.5 MWh, I calculate my EV's electricity rate accordingly using the Tier 1 or Tier 2 Pricing as necessary.

Total energy usage [is] about 7,138 kWh.

Now, to compute my total electricity usage, I take the average usage per day using a weighted average of 57 × 22.8 kWh each weekday and 27 × 11.4 kWh each weekend day for an average of 19 1935 kWh per day.  If we multiply that by the number of days in each month, we can get an estimate of how much energy we use per month and if we multiply by 365.2425 days per year, we have the total energy usage of about 7,138 kWh.  This is the value multiplied by each of the rates in the above table to get the total cost per year.

In the case of the Consumption Taxes, this further breaks down by my estimates to about 4,957 kWh taxed at Tier 1 and about 2,225 kWh taxed at Tier 2.  The Consumption Tax part of the Total in the table above is weighted using these estimates as a percent of the total electricity usage annually.

Taking these numbers, we can see a total cost of $317.19 to run my Nissan LEAF not including the base rate schedule.  Thus, no rate schedule can come to a total less than $317.19 per year.  However, depending on the Rate Schedule chosen, the additional cost could vary between $150 and $350.

The Base Rate Schedules

Dominion Virginia Power customers have 3 basic choices when it comes to their base electricity rate: Schedule 1, Schedule EV and Schedule 1EV.  Each of these is outlined below.

Schedule 1

Most Dominion Virginia Power residential customers are under this rate schedule.  Thus, these numbers represent no special EV rate and just plugging your car in under the normal rate schedule.  Since the monthly fee of $7 is already covered by your current electric bill, this can't count toward the cost to charge the EV since you have to pay it either way.  For Distribution and Supply, Dominion Virginia Power breaks the bill up into summer and off-summer months as well as usage under 800 kWh and usage beyond that.  In the case of the EV, my house never uses less than 800 kWh per month so I'll always be paying the above 800 kWh rate for my EV.  Thus, the rate for Distribution is 1.26¢kWh.  The rate for Supply varies throughout the year so from June to September it's 5.773¢kWh and 0.02927¢kWh the rest of the year.

Thus, the total base Distribution cost is $90.49 for the entire year and $138.49 for Supply for the Summer months and $139.99 for Supply the rest of the year.  The total Supply annually is therefore $278.48 for a total of $368.97 per year under Schedule 1.  Adding this to the fixed result, we get the total annual cost to run your EV under this rate schedule of $686.16.

Schedule EV

Technically, the Schedule EV rate plan isn't a primary rate schedule.  Instead, a dual meter is set up at your household with the main residence still under Schedule 1 and a dedicated line to EV metered using the Schedule EV rider instead.

Because Schedule EV is a Time-Of-Use rate, the time at which electrical energy is drawn becomes significant.  Fortunately, this is easy to calculate because we know from above how long it takes to charge the LEAF under my scenario, and thus how much power is required each hour.  When the EV is charging, since it's using a 3.3 kW charger, it will require that much power per hour and thus use 3.3 kWh per hour in use.  You also have the base EVSE power of 0.005 kW which comes to 0.005 kWh per hour, each hour.

In the case of Schedule EV, there is an additional Distribution charge for the second meter of $2.90 per month for a total of $34.80 per year.  The Distribution and Supply rates are then given by:

Hours Distribution rate in ¢kWh Supply rate in ¢kWh Net Cost
01–05 (Super-Off-Peak) 0.000 0.684 $31.74
05–06 (Off-Peak) 2.520 1.429 $0.07
06–22 (Peak) 2.520 10.256 $3.73
22–01 (Off-Peak) 2.520 1.429 $99.12

For simplicity, I've show the results for the entire period blocks, which generally fall into the following categories: 01–05 is full 3.3 kW charging, 05–06 is only the EVSE, as well as 06–22 and finally 22–01 is used to charge the EV during weekdays since at 3.3 kW the LEAF required more than 4 hours to charge to 95% from 0.  For that final block, it breaks down into no charging on weekends and 2.09 hours during the weekdays, where the rest of the charging occurs in 01–05 on both Weekdays and Weekends.

The Distribution and Supply results together for each of the time blocks yields $134.67.  Add to that the monthly Distribution charge and we get $169.47, less than half the cost for base Distribution and Supply under Schedule 1.  Because the final bill is a combined bill between the household and the EV meters, the taxes are cumulative, so if under Schedule 1 the Tier 2 Consumption Tax threshold be reached for the household, it would also do so under Schedule EV.  The final result is a grand total of $486.66.

One final thing to note is the $99.12 spent from 22–01 could be avoided if the LEAF had a 6.6 kW charger instead of the cheap 3.3 kW charger it currently has.  With this charger, it wouldn't need to draw electricity in the more expensive off-peak period; all the needed energy could be added and metered during the Super-Off-Peak time for a mere $48.87 during that period and only $0.22 for the 22–01 Off-Peak.  Thus, the total cost with a 6.6 kW Charger would be $404.89, an over $80 per year in savings.

Schedule 1EV

Schedule 1EV is a household rate plan that replaces the Schedule 1 with a special Time-Of-Use rate specifically tailored to EV owners.  As such, it is far more complicated than anything I've discussed thus far and as such I shall hold off to discuss this in its own post.

Conclusion

As you can see, there's a lot of savings that can be made by just switching to one of the 2 experimental EV rate programs.  I'm personally looking very much forward to participating in the program; won't you join me?  Just sign up here and be a part of the future!


1Okay, technically the posting date was just a coincidence but sometimes I like to embellish to make these posts more readable.
2For Schedule 1, Schedule EV and Schedule 1EV.

Monday, February 14, 2011

Dominion Virginia Power EV Rates Revealed (Part 1)

You could save $200 or more by switching

You could save $200 or more by switching to one of Dominion Virginia Power's EV rates.  That's the result I get from over a week pouring through the complexities of Dominion's rate structure.  Of course, it's all contingent on Dominion's new EV Rate Proposal being accepted by the State Corporation Commission later this year.  Why, in a Commonwealth, we call it the State Corporation Commission, I'm stymied, but I digress.

Of course, that $200 is in addition to the $2,000 per year I could save by switching to an efficient EV since I estimate my annual petroleum fuel cost to be about $2,500.  I drive about 75 miles per day and with fuel at $2.99 910 and consuming 16 gallons per week, the costs add up quickly.  Compare this to an EV like the Nissan LEAF at only about $550 per year under current household electricity rates and you can see why I want to switch.

But that's under Dominion Virginia Power's Residential Schedule 1 rate, with all riders, taxes and fuel accounted for.  So why does this differ from my previous calculations of $300 or so under Schedule 1 where I deduced 7.033¢kWh in the Summer and 4.187¢kWh in the off-seasons?  As you can see from the official filing, those rates are correct under that schedule.  There's also the monthly distribution cost and the lower than 800 kWh rates, but I'm assuming those are taken up by my household's electricity costs.  Unfortunately, I never go under 800 kWh in even the lowest power months.

Yet I come up with a cost per kWh of 9.133¢, averaged over the entire year.  Remember, the off-season rate is valid for twice as only as the Summer rate so if anything, my costs should be less than 7¢ for every kWh, not 2.1¢ more.  In fact, if the cost were averaged over the entire year at those rates, the average cost per kWh would be just under 5.138¢, a nearly 4¢ difference.

The missing 4¢

The Dominion Virginia Power electricity rate schedule is actually broken up into 6 to 7 sections: Distribution, Supply, Transmission, Fuel, Sales and Use Surcharge, Consumption Taxes and occasionally Local / County Taxes.  Each of these are outlined below and then summarized.

Distribution

The distribution costs of your Dominion Virginia Power bill are broken into 4 parts:

What this comes down to is that the distribution line item of your bill is the sum of these 4 parts, the first 2 coming from the Schedule 1 or related rate schedule above, and the second two coming from additional riders on your bill for the purposes specified in the rider.  In the case of the Peak-Shaving rider, this comes out to 0.009¢kWh, and for the Energy Efficiency rider, there's an additional 0.044¢kWh.  That makes a total of 0.053¢kWh additional charges on your distribution.

Supply

The supply or generation costs of your Dominion Virginia bill are also broken into 4 parts as of this writing:

As before, the total supply charge is the sum of these 4 items.  The first part comes from the Schedule 1 or related schedule under the section labeled Generation.  The second and third are the Virginia City Hybrid Energy Center rider at 0.280¢kWh and the Bear Garden Generating Station at 0.117¢kWh.  Finally, you have the Base Rate Credit, which, as the name implies, is a rebate on the cost of the base rate schedule.  This credit is a new rider for 2011 and is different depending which base schedule is being used: -0.132¢kWh for Schedule 1, -0.128¢kWh for Schedule 1T and -0.101¢kWh for Schedule 1S; it's not clear at this time what Base Rate Credit, if any, will be received under the new Schedule 1EV rate, but more on that later…

So, under Schedule 1, the total cost of all 3 riders is 0.265¢kWh.

Transmission

The transmission costs of your bill come directly from Rider T: Transmission.  The cost for electricity transmission is therefore given by 0.616¢kWh.

Fuel

The cost of fuel for electricity generation is given by the Fuel Charge Rider A.  As would be expected, the cost of fuel is rather volatile; in the last 10 years, it's changed 8 times, though it's been steadily decreasing since July 2008.  As of this writing, it currently stands at 2.803¢kWh.  Thus, the cost of fuel is clearly the more than half of the additional 4¢ charge.

Sales and Use Surcharge

The Sales and Use Surcharge is a tax on electricity usage levied by the Commonwealth.  It's rated at 0.056¢kWh.

Consumption Taxes

The consumption taxes are by far the most complicated part of the Dominion Virginia Power bill to calculate.  First of all, this tax is actually made up of 3 different taxes: the State Consumption Tax, the Special Regulatory Tax and the Local Consumption Tax.  What complicates things is that, like the Schedule 1 rates, there's a tiered basis to these taxes.  If your total electricity usage in a given month is less than 2.5 MWh (remember, a Megawatt is 1,000 kilowatts), the tax summed over all 3 components comes in at 0.155¢kWh.  But, if you use more than 2.5 MWh, but less than 50 MWh, the summed rate reduces to 0.099¢kWh for all electricity usage above 2.5 MWh.  After 50 MWh, it goes even lower, but I doubt many homes are using 50 MWh in a month; I don't even use that much electricity in a year!

As it happens, last year I dipped into the 2.5 MWh range during all 4 of the Summer months, a total of 122 days under the Schedule 1 definition (June, July, August and September).  So in these months, my EV would have been taxed at the lower rate because of the large amount of electricity usage, but in the off-season months, it would be charged at the higher rate.  If one averages the two rates out, based on 122 days of the year for the lower rate and the 243.2425 off-season days (in the Gregorian Calendar) I therefore pay about 0.136¢kWh for the tax on average.

Local / County Taxes

Each county in Virginia has the option to apply an additional tax on top of the other taxes and surcharges.  For instance, in Fairfax County, where I live, the tax rate is 0.605¢kWh.  The difference with the county tax is that there's a minimum charge of $0.56 which effects any total usage under 93 kWh.  There is also a tax rate cap at $4.00, or about 661 kWh, so that there's no tax for any electricity usage above that limit.  As all of my current household monthly loads are in excess of 661 kWh (and even of the 800 kWh of Schedule 1), I don't expect my EV would incur any additional Fairfax County tax since I'm already paying the $4.00 on the base load.

The 4¢

By adding each of the 7 sections above, not including those already calculated as part of the Schedule 1 rate, you have a total of 3.929¢kWh, or just under 4¢

In the name of fairness, however, I should point out that there's a 0.066¢ discrepancy between the average result above and this result.  I assume this has to do with rounding errors because verifying against my internal calculations for each subsection, my numbers agree with those posted in the 7 sections above.

More to come…

In the second part of the Dominion Virginia Power Electric Vehicle rate proposal series, I'll be covering the details of the new Electric Vehicle rates and how they would effect a typical EV user like myself and what it's like to live under a Time-Of-Use rate.  All that and more, coming soon!