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SDG&E Volt Charging costs per month at the highest tier

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We live in the country and consequently use a lot of electricity. We have a deep well and pressure pump that, combined with our regular usage, puts us in tier 4 energy. This is the highest rate at 28 cent a kwh. Anyway we just got our first full electric bill after buying the Volts. Yes, that is Volts. We have two. Both Volts added $100 a month to our bill at the highest rate. That $100 cost replaced ~$700/month is fuel bills. My old fuel bill was $900 a month, but half of my charging is done at work for free so I only accounted for $450 for me and the $250 my wife was paying for her old car.

People keep asking how much our electric bill went up. Because we went on vacation and never had a full month to go on, I could never give a firm answer. Now I have one. At the highest tier, $50 a month. I run Clipper Creek chargers.

In the next few weeks, my solar panels come online. It will put charging the cars back in free, tier 1 or 2. Tier 1 will cost us $6 a month to charge each car. If we are in tier 2, it will cost $24 a month to charge the car. My calculations tell me that we will mostly in tier 1.

People keep telling me that the car doesn't make financial sense. Saving me $400 a month until the car is paid off and then saving me $900 a month there after, I think the car make a whole lot of sense.

The net for my wife is a negative $200 a month she makes for her car payment. But for $200 a month, she drives a pretty nice car. After her car is paid off, she will save $200 a month in fuel.
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The cost per kWh is very variable and depends on your individual situation and your electric utility. The two points I'd make is that the cost of a kWh for charging the Volt is your average cost per kWh, and, if you install solar, the cost per kWh depends on how much it cost to install the solar system. For this calculation I'd take the cost after all rebates and credits, toss in the cost of another inverter, and depreciate the system over 20 years.
 

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the cost of a kWh for charging the Volt is your average cost per kW
This again? For his application, that is absolutely incorrect. He was clearly trying to take into consideration the cost of charging his Volts vs the cost of running non-EVs, and for that it all gets billed at the latter tiers (probably some 3 and some 4 in his scenario). Assuming his previous load always put him in Tier4 as he said, the answer to his "how much did my bill go up" its going to be VoltKWHUsed * Tier4CostPerKWH. Simple as that. VoltKWHUsed * AvgKWHCost is totally the incorrect answer for what he was solving for.
 

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This again? For his application, that is absolutely incorrect. He was clearly trying to take into consideration the cost of charging his Volts vs the cost of running non-EVs, and for that it all gets billed at the latter tiers (probably some 3 and some 4 in his scenario). Assuming his previous load always put him in Tier4 as he said, the answer to his "how much did my bill go up" its going to be VoltKWHUsed * Tier4CostPerKWH. Simple as that. VoltKWHUsed * AvgKWHCost is totally the incorrect answer for what he was solving for.
And this again? By your logic, if he now goes out and buys a replacement refrigerator that uses 100 kWh/month, that refrigerator is now costing him the highest possible rate because it was the last thing added to the power bill. Now, because the old refrigerator is out, and the new one is in, the Volts move down to a Tier 2 rate instead of a Tier 3 rate? Arbitrarily determining which Tier an electronic device falls under based solely on the point in time in which it was added to the system is illogical.

If he wants to know how much his power bill will go up after buying a Volt, that answer is simple. Old bill subtracted from new bill. The rates of the various Tiers do not and should not be considered.

If he wants to know how much it is costing him to charge the Volt, he can either track specific rates, times, and usages of the Volt, or he can simply take the average rate he is paying for electricity and multiply that by the number of kWh the Volt uses.

In my opinion, the simplest solution, though possibly hard for many non-EV owners to fathom, would be to total all energy expenditures. Pre Volts, his power bill was X + $700 (gasoline). Post Volts, his power bill is (X + $200) - $700.

The trick is figuring out what you are solving for, and he, specifically, wants to know how much it costs to charge the Volt. So in his case, Don is right: He should be using his average rate. Sure, that makes all of his other electronics more expensive to operate, but you can't, arbitrarily, assign all of those increased expenses to one electronic device.
 

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the answer to his "how much did my bill go up" its going to be VoltKWHUsed * Tier4CostPerKWH. Simple as that. VoltKWHUsed * AvgKWHCost is totally the incorrect answer for what he was solving for.
In reality it's not so simple because people are forever confusing "How much did my bill go up?" with "How much does it cost to charge my Volt?". These are entirely different questions and I was just pointing that (a) it's best to understand the distinctions and that (b) the answer to the first is not the answer to the second.

More or less the same for the solar. Electricity generated by your solar system is not "free". In fact it may or may not cost him more to charge the Volt after getting solar. You'd have to compare the AVERAGE cost per kWh before and after the solar to know. Part of that computation is deriving the cost per kWh of electricity generated by the solar system.
 

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What I'm worried about is how much the [email protected]#$% Xmas lights are going to make the bill go up, LOL. I'm on a TOU meter and mostly charge the Volt on the "super off peak" rate and NEVER on the peak rate so I figure it based on that. Plus it really encourages me to run the dishwasher and other appliances late at night. Now that it's gotten colder I'm getting up at 5:30 to run he bathroom heater before 6:00, hahaha.

Anyway, I just don't sweat it. The Volt is totally cool and I HATE to buy gas, so what's not to like? For sure my neighbors with their big Benzes, BMWs and Lexi aren't sitting around doing the sums on the cost of their gas.
 

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We live in the country and consequently use a lot of electricity. We have a deep well and pressure pump that, combined with our regular usage, puts us in tier 4 energy. This is the highest rate at 28 cent a kwh. Anyway we just got our first full electric bill after buying the Volts. Yes, that is Volts. We have two.
Congratulations on the two new cars, Michael! I am curious... how far do you and your wife commute?

Since you are pumping your own water, that reminds me... People here in Central CA with their own well are permitted to have TWO electric meters and therefore two baseline allocations of electricity, if they wire their pump to the new meter. The same is possible with an electric vehicle (I am looking into that option). So you have your own pump and TWO electrics. I would think SDGE likely has the same rules. With all those extra electrical units, I would think it would be worth checking if you qualify for an extra meter, and I'd certainly ask about adding more than one meter.
 

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Discussion Starter · #8 ·
This again? For his application, that is absolutely incorrect. He was clearly trying to take into consideration the cost of charging his Volts vs the cost of running non-EVs, and for that it all gets billed at the latter tiers (probably some 3 and some 4 in his scenario). Assuming his previous load always put him in Tier4 as he said, the answer to his "how much did my bill go up" its going to be VoltKWHUsed * Tier4CostPerKWH. Simple as that. VoltKWHUsed * AvgKWHCost is totally the incorrect answer for what he was solving for.
I feel like I've committed a Faux Pax of some sort here. jmX is correct, the Volt is charging with Tier 4 power. I am often asked how much does it cost to charge my Volt. I have a definitive answer, for me! $50 a month at SDG&E Tier 4. I am putting in solar. It has nothing to do with the Volts. I purchased the system months before my wife convinced me to look at the Volts. The system was designed to cover 100% of our power needs when it was purchased, with the idea we had a few project that would require more energy. When I bought the Volts, I was certain how much my power bill would go up. No I do. My purpose is posting is to let others know that, even though I am paying for the MOST expensive electricity, it is still MUCH cheaper than gasoline.

I have to admit that this constant need to "justify" owning a Volt perplexes me. I haven't gone through a cost analysis of ANY car that I bought. I probably should have with the Yukon XL; the gas and maintenance was horrendous for the miles I was driving. Why do people here even bother with cost benefit analysis for the car?

The take away from this was intended to be, when someone asks you how much it costs to charge the car, your answer is, "It depends on your rates, but I know this guy how drives 1000 miles a month for $50 and he is paying for expensive electricity.
 

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Discussion Starter · #9 ·
Thank you Steve. I drive 2000+ miles a month. My wife drives 800 miles a month. We have chargers at work so I only foot the bill for half that. Work has solar panels for the chargers. It is a perk for working here. My wife's work is putting in charges as well. They are a international solar panel manufacturer so they want to showcase green. When that happens, she will never burn gas.

I looked into a second meter and I do qualify. The cost per kwh is .11 cents. That is certainly cheaper than tier 3 and 4. The solar panels however will put the EV charging at Tier 1 (.02 cents) and Tier 2 (.08) cents so it will be cheaper not getting the second meter.

Because we are rural, SDG&E has decided to cut power off when ever we have a Santa Ana (winds for non Californians). No power, no water. So the solar system I put in is a grid tied battery backup system. One of the chargers is tied to that sub panel so that we will be able to charge a car even when power is cut off to our home.
 

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Discussion Starter · #10 ·
In reality it's not so simple because people are forever confusing "How much did my bill go up?" with "How much does it cost to charge my Volt?". These are entirely different questions and I was just pointing that (a) it's best to understand the distinctions and that (b) the answer to the first is not the answer to the second.

More or less the same for the solar. Electricity generated by your solar system is not "free". In fact it may or may not cost him more to charge the Volt after getting solar. You'd have to compare the AVERAGE cost per kWh before and after the solar to know. Part of that computation is deriving the cost per kWh of electricity generated by the solar system.
We have a pretty consistent bill. We start charging the Volts and it increases a certain amount. I write a larger check for with that difference added. I'm extremely confident that my bill went up because of charging the Volts. So, THAT is what it costs to charge the Volts. Unless you think SDG&E is siphoning money out of my account.

As far a solar, people look for a break even there as well. I certainly think that is a factor when putting in a grid tied system. The only purpose for a system like that is bill reduction. But a battery backed grid system functions even if the power is turned off. We get the value of pumping water, charging the car, keeping food cold when everyone else is dark. I could put in a generator but then I could do a cost analysis of that and find it isn't worth it. A friend of mine, who just went through Sandy (lives in NJ) has a generator and a Volt. He was one of the few that was driving around while everyone else stood in line with gas cans. How do you factor that convenience in?

Electric rates are going up. Not an opinion but a fact. SDG&E asked for a 10% a year, for the next three years, rate increase. Big Bear Electric (I have a cabin up there) asked for and got an 8% rate increase for the next three years. I got the notice in the mail. How do you factor in the stability of your electric rate given the uncertainty of future electricity prices? What value to you assign to that?

We get semi annual bonuses at work. Many of my coworkers purchase cars, camera, high end Mac laptops...ect. None of those items went through a cost analysis before being purchased. A solar system can be purchased without a cost analysis as well. You can buy one merely because you want one.
 

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Discussion Starter · #11 ·
The trick is figuring out what you are solving for, and he, specifically, wants to know how much it costs to charge the Volt. So in his case, Don is right: He should be using his average rate. Sure, that makes all of his other electronics more expensive to operate, but you can't, arbitrarily, assign all of those increased expenses to one electronic device.
I disagree with you. The refrigerator replaces an existing appliance. The Volts didn't replace anything electric. They added to our load. And that additional load was all tier 4 power. We were in tier 4 before and we were in tier 4 after. So the cost to charge MY Volts is the difference between the old bill and the new bill. Micro analyzing the Volts charging and allocating those costs to other appliances to when they were run is a mental exercise that doesn't change the increased cost of my electric bill.
 

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For you people living in areas with tiered electricity rates, if you get bumped into a higher tier, does that mean ALL the electricity used during the billing period is billed at the higher tier rate?
For example, let's say tier 1 is 0-999 kWh @ 10 cents/kWh, tier 2 1000-1999 kWh @ 15 cents/kWh etc....
If you used 1,500 kWh during the month, would the entire amount be billed at 15 cents/kWh, or would it be prorated?
 

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Discussion Starter · #13 ·
For you people living in areas with tiered electricity rates, if you get bumped into a higher tier, does that mean ALL the electricity used during the billing period is billed at the higher tier rate?
For example, let's say tier 1 is 0-999 kWh @ 10 cents/kWh, tier 2 1000-1999 kWh @ 15 cents/kWh etc....
If you used 1,500 kWh during the month, would the entire amount be billed at 15 cents/kWh, or would it be prorated?
No, the first x hours is at tier 1, the next x hours is at tier 2, the next x.... (like income taxes)

They do tack on a generation fee on top of all the hours at a flat rate. Our rates are different than the rates our neighbors pay. The bill is literally on a house by house basis. It may have to do with the agriculture on our area.
 

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Micro analyzing the Volts charging and allocating those costs to other appliances to when they were run is a mental exercise that doesn't change the increased cost of my electric bill.
Which is technically a decreased electric bill because your overall energy costs are hundreds of dollars lower. So, essentially, sans mental exercise, your Volt is making everything you own that requires energy cheaper to run.

So again, all you are really calculating is how much your power bill went up, which is a moot point in the greater scheme of things.
 

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No, the first x hours is at tier 1, the next x hours is at tier 2, the next x.... (like income taxes)

They do tack on a generation fee on top of all the hours at a flat rate. Our rates are different than the rates our neighbors pay. The bill is literally on a house by house basis. It may have to do with the agriculture on our area.
I see. In some countries, like South Korea, if you bump yourself into the next tier, even by 1 kWh, your rate for the entire month is whatever the higher tier rate is. So .01 kWh can potentially double your electric bill! It's no wonder people over there religiously unplug stuff from the outlets when not in use.
 

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all you are really calculating is how much your power bill went up
Yes, you're catching on now ;)

which is a moot point in the greater scheme of things.
How is that a moot point? To know how a Volt affects your total energy cost, you need to know how much more you pay for electricity and how much less you pay for gasoline. Solving one part of that equation is not a moot point, it's a necessity.
 

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Discussion Starter · #17 ·
When people ask me how much it cost me to charge my Volt, they are asking the question because they are thinking about purchasing one. If I were to tell them, it depends....and then give them all of the technical jargon, the question to the potential consumer goes unanswered. When I tell them, my bill went up $50 a month due to the Volt, and the electricity is from the highest tier, it puts it in language anyone can understand. I don't have to get into the gas not purchased. The person asking the question gets enough of an answer that they now know their electric bill isn't going to sky rocket.

When I was shopping around for a Volt, I asked the same question. Based on the answers I was getting, I would have passed on the Volt. I drove the Volt and liked it well enough and figured that my electric bill would be less than the amount I was spending on gas. Turns out my hunch was correct. My per mile cost is 1/10th of what I was spending with my previous car.

The question, "How much does it cost to charge my Volt" from a consumer does not necessitate the need to break out the current electrical metering equipment. There is no real need to say, "It depends." The answer I provide above is the sort of answer that many consumers are looking for when purchasing a vehicle such as a Volt. That a people here can't see that, does not negate the comment. Most people here are engineering their Volts and don't see the question from the average consumer's POV.
 

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When people ask me how much it cost me to charge my Volt, they are asking the question because they are thinking about purchasing one. If I were to tell them, it depends....and then give them all of the technical jargon, the question to the potential consumer goes unanswered.
But that is EXACTLY the right answer. When I am in Northern California, it costs me about $15 a month to charge my Volt. Many other Volt owners share a similar experience. Some pay less than that because they can charge free at work or at certain businesses. Some people were already in Tier 3 or Tier 4 rates when they got the Volt, so according to your math, they could be paying $100 a month (how much their power bill increased). There is a huge variance, but if your purpose is to inform a prospective buyer, you should always provide the caveat that your experiences aren't universal (i.e., it depends).

It works the same way with mpg. I had someone approach me and ask, "Does that car really get 80 mpg?" My answer: "Yeah, the average seems to be about 80 mpg. Some get a lot more. I only get about 50 mpg."
 

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What hours are you home? When is most of your energy consumed?

If the answer is mainly at night and in the mornings then you need to call SDGE right away and have them switch you to a Time of Use rate schedule. It will involve placing a Time of use meter (utility does this for "free"). You will then sell your energy at the highest possible retail rate, which is during the day when solar is cranking. Then at night you pay for the lower cost energy when you use it. Then, program your volt to charge at night and you should see signifigant savings.

The only new few you will incur is the $8 meter fee from SDGE. You should see a big drop in your bill this way.

Solar + Volt + TOU metering = BIG SAVINGS.
 

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Discussion Starter · #20 ·
But that is EXACTLY the right answer. When I am in Northern California, it costs me about $15 a month to charge my Volt. Many other Volt owners share a similar experience. Some pay less than that because they can charge free at work or at certain businesses. Some people were already in Tier 3 or Tier 4 rates when they got the Volt, so according to your math, they could be paying $100 a month (how much their power bill increased). There is a huge variance, but if your purpose is to inform a prospective buyer, you should always provide the caveat that your experiences aren't universal (i.e., it depends).

It works the same way with mpg. I had someone approach me and ask, "Does that car really get 80 mpg?" My answer: "Yeah, the average seems to be about 80 mpg. Some get a lot more. I only get about 50 mpg."
I am going to go out on a limb and guess that you are an engineer.
 
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