How much do you pay in electricity to charge your car

[BernardJenkins]

FYI, we went with Solarcity to install our leased solar power system and we definitely paid less on our lease than we did in electricity before it was installed. However, we are relatively high power users, and our roof is ideally situated for solar panels (virtually no trees shading it). I should also note that last I heard Solarcity was VERY backed up with installs and it was taking 2-3 months before they could get the panels up.

The question is how charging the car will affect those rates, and we are not sure yet. We have switched to EV-A as of last week and if I understand correctly, given that we sell electricity back during the day when rates are highest, and charge the car at night when rates are low, the net effect on our bill should be very small. However, if I also understand correctly, that is averaged across the whole year before they figure your final bill. (People with solar pay PG&E once a year.) In other words, they add up all your usage during peak hours, all during partial peak, and all during off peak (for the whole year) and then multiply it by the rates for those times and figure your bill. From what I can see, it sure looks like we are net energy producers during peak hours, so that net positive will be balanced by our off peak usage at less than a third of that rate. Someone please correct me if I am wrong, but it seems like if we are careful about daytime usage, we could easily come out ahead...

Month by month PG&E will send you a separate statement that will calculate your energy charges for that month. You will be able to see a positive or negative kWh number for each TOU period - Peak, Part-Peak, and off Off-Peak and a total energy charge for that month. Those energy charges will be accumulated until your anniversary date, when it will be transferred to your regular PG&E bill. If your final net dollars are negative but your net energy usage is positive, the small negative dollars will be wiped out. If your net dollars and net energy is negative, meaning that you over-generated, you will be paid something less than 4 cents/kWh for the surplus energy. PG&E has some approved formula for how to calculate that.

My understanding is that Solar City Power Purchase Agreements also settle up at the end of the year. They estimate a monthly payment and then at the end of the year if the system produced more than they estimated, you pay more. If it under-produced, they refund some money. I think your agreement has a fixed price per kWh that you pay them.

I think it is the ideal way of reducing the cost of electricity generation for car..I am thinking of getting solar panels for my car and I will be able to achieve continuous charging with ease.

 

[miimura]

I did some analysis of the incremental cost of home EV charging. I posted earlier results in other threads, but I think this one is more appropriate for the comparison between the two homes. In order to make it simple for people, these two cases do not involve solar and are based on real PG&E data from my relatives' homes. All EV charging is assumed to take place in the Off-Peak time window of 11pm-7am.

The first case is a detached single story townhouse in Cupertino - 2BR 2BA ~1700sf which is occupied by a retired couple. This is what I consider to be a small home and their average electric usage is about 425kWh/month with only December and January over 500kWh.

Choosing the best rate plan, Schedule EV, would result in an increase of about $60 per month to the electric bill at the townhouse. This comes to approximately 6 cents per mile. Staying on the same rate plan that most people use, E-1, would result in a bill increase of more than $120 per month, doubling the incremental cost of EV charging.

The second case is a single family home in Los Altos with 5BR 4.5BA ~4,800sf in two stories. A family of 4 including two elementary school children lives there. The average usage is about 700kWh/month for most of the year, with Nov-Jan over 800kWh and peaking at just over 1,000kWh in December.

You can see that the average monthly bill without an EV is MUCH larger for the larger home. This is primarily due to the tiered rate system that penalizes high usage. The larger house is already paying over $160/mo for electricity, so adding EV charging and using a non-tiered rate adds less than $25/mo to the bill. That's only 2.5 cents per mile!

The details of the Townhouse analysis can be found in a PDF here. That PDF contains the actual usage and the projected usage with EV charging calculated on E-1, E-6, E-9A, EV month by month.
The single family analysis can be found in a PDF here. The spreadsheet that I used to do these calculations is here. It uses SmartMeter data downloaded from PG&E to do all the calculations. Rates in the Excel workbook are from the Tariffs effective 5/1/2014.

 

[smkettner]

For once I am semi glad to have SCE. Calculation is easy for the EV whole house super off peak rate. 9 cents in summer, 10 cents per kWh in winter. 12a to 6a
Air conditioner runs a lot at night also

 

[miimura]

For once I am semi glad to have SCE. Calculation is easy for the EV whole house super off peak rate. 9 cents in summer, 10 cents per kWh in winter. 12a to 6a
Air conditioner runs a lot at night also

PG&E is the same way. Schedule EV Off-Peak is 9.83c/kWh Summer, 10.1c/kWh Winter. The gotcha is that the rest of your house changes from non-TOU to TOU. How much does THAT cost? I was trying to capture the change to TOU and the addition of EV energy in a complete scenario.

 

[drmanny3]

FYI, we went with Solarcity to install our leased solar power system and we definitely paid less on our lease than we did in electricity before it was installed. However, we are relatively high power users, and our roof is ideally situated for solar (virtually no trees shading it). I should also note that last I heard Solarcity was VERY backed up with installs and it was taking 2-3 months before they could get the panels up.

The question is how charging the car will affect those rates, and we are not sure yet. We have switched to EV-A as of last week and if I understand correctly, given that we sell electricity back during the day when rates are highest, and charge the car at night when rates are low, the net effect on our bill should be very small. However, if I also understand correctly, that is averaged across the whole year before they figure your final bill. (People with solar pay PG&E once a year.) In other words, they add up all your usage during peak hours, all during partial peak, and all during off peak (for the whole year) and then multiply it by the rates for those times and figure your bill. From what I can see, it sure looks like we are net energy producers during peak hours, so that net positive will be balanced by our off peak usage at less than a third of that rate. Someone please correct me if I am wrong, but it seems like if we are careful about daytime usage, we could easily come out ahead...

I posted this response in another section of the forum, however I think it addresses your question. While we are with SCE and they probably price things differently, there may be some commonality. If you are frugal during the day and your system is large enough to produce electricity beyond the first tier then you will indeed come up with a surplus. This surplus will offset your charging of the car during the super off peak time. We use a lot of electricity are our home as well. I have tons of electronics going at all times. Even though our net electric use is up the credit often exceeds the actual usage. For SCE it is not the net amount of kwhs consumed because the money is not evenly distributed. So even though we might end up with a net of 350 kwh for the month our bill might be a negative $15 because the credits far exceed the debits. A kwh during peak time can be worth $0.35 versus only $0.09 during super off peak.


We originally sized our solar panels to cover about 70% of our electric usage. The idea was to stay in tier one or two at most. That actually worked initially. I think we also cut back on electricity use by changing out old electric bulbs for the newer types like Leds. When we added the LEAF we ended up consuming a lot more electricity. In May of 2011 we paid $318 for the previous year plus the typical $1 to $2 monthly service charge. We got the LEAF in May of 2011. In May of 2012 we paid $350 for the year. In May of 2013 we paid $525 for the year. In May of 2014 we paid $230 for the year. In the last year we had both the 2011 LEAF and the Rav4EV (purchased on Jan 24th 2014). So when you look at our electric bill over the last few years we managed to almost charge the cars for free. Our first year bill without any electric vehicle cost us $318. When we got our 2011 LEAF later that month we immediately shifted to the TOU (Time of Use). I think our super off peak usage was about 300 to 350 kwh each month. We often would get a credit during the day because of the solar panels. As was mentioned above you need to keep electric use to a minimum during the day up to 6pm. Otherwise instead of a big credit you will get a big bill. I can tell you there were a number of days where we suffered until 6 pm when we could then turn on the air conditioner. I also should mention that we upgraded the insulation in the attic as well as upgraded our forced air/air conditioning systems. Everything is pretty energy efficient and that makes a big difference. The Rav4EV uses more juice for the same mileage than our LEAF delivered, but it is still working out nicely. So to recap we went from about $2400 per year in electricity to about $200 to $500. The solar panels from SolarCity cost us a one time lease payment of $10,414. We were one of the last homes that used thin film technology panels. They tend to be lower in efficiency but work even when the day is cloudy. Our system consists of 68 panels in three sections. Our solar system is rated at 4.6 kw AC or 5.1 kw DC. I had originally estimated our payback at 4 1/2 to 5 years. If you add the use of an electric car then our payback occurred probably in the 4th year. I could figure out exactly what the LEAF cost us each month with and without the panels but this is seat of the pants guess. This does not cover the savings in gas as we went from $160 month for the Prius to about $40 a month. I also considered a second meter but found the requirements of adding the second panel and connections a real pain and high cost. In the end the current 12 midnight to 6 am is almost as cheap as the second meter, just not as much charging time. Hope this helps.
Manny

 

[smkettner]

For once I am semi glad to have SCE. Calculation is easy for the EV whole house super off peak rate. 9 cents in summer, 10 cents per kWh in winter. 12a to 6a
Air conditioner runs a lot at night also

PG&E is the same way. Schedule EV Off-Peak is 9.83c/kWh Summer, 10.1c/kWh Winter. The gotcha is that the rest of your house changes from non-TOU to TOU. How much does THAT cost? I was trying to capture the change to TOU and the addition of EV energy in a complete scenario.

When I switched the total kWh was about the same and the bill was $50 lower on EV-TOU. Now solar takes care of the on peak so it comes out very favorable.

 

[longschlng22]

San Diego rates are ridiculous in comparison to US average. For super off peak from 12 am to 5 am it is 0.16/kWh, off peak is 0.20/kWh and 0.44/kWh during peak hours. These are the summer time rates.

Due to these rates I typically spend around a hundred dollars a month to charge the RAV4ev. It was around three hundred per month in gas with the g37 that just sits there now.

 

[buickanddeere]

Before the Ontario Green Energy Act between 7-9 cents per Kwhr. Now after f.i.t. solar, wind and gas turbines to replace coal. 17.6 cents per Kw hr average last month.

 

[Surfitall]

San Diego rates are ridiculous in comparison to US average. For super off peak from 12 am to 5 am it is 0.16/kWh, off peak is 0.20/kWh and 0.44/kWh during peak hours. These are the summer time rates.

Due to these rates I typically spend around a hundred dollars a month to charge the RAV4ev. It was around three hundred per month in gas with the g37 that just sits there now.

Your post made me look up average rates in the US. I had no idea SDGE rates were so high relative to everywhere else. Makes me want to get solar panels.

 

[drmanny3]

Well lets face it, the truth is that we will pay more for clean energy in the near term. A gallon of gas contains a significant amount of energy in comparison to our current technology in solar, wind, and battery technology. Never the less, most can agree that waiting is not a good strategy. Even though 2600 Rav4EVs is but a drop in the bucket it does represent forward movement. As various technologies improve in their efficiency so will our dependence on fossil fuels diminish. I'm sorry but for a lot of people money is a motivator. If the price of gas, electricity, and other fossil fuels goes up so will the motivation to find alternatives. As was once said everything is local when it comes to politics. People in general focus on their immediate lives and how they can survive and prosper.

I have often heard it said that once we have sufficient domestic oil available we will be free of foreign oil and the nations that supply it. Nothing could be further from the truth. Oil is a commodity that has a pricing structure that is elastic in nature. When it goes up in one place everywhere else adjusts. The businesses that harvest the oil are mostly international organizations and they will not want to lose a penny if they can help it. I know this from having worked for Atlantic Richfield way back in the 70s. While we controlled about 20% of the Alaskan North Slope we always adjusted our pricing structure to reflect world prices. Why? Because we would sell to anyone who had the money. We did this even with our own subsidiaries. So if oil is worth $125 to the Chinese and we domestically sell it at $100 you can bet in short order the price will become what the market will bear $125.

I am old enough to remember coming in from grammar school recess in Los Angeles where I lived and experiencing all the results of smog. The kids would all have to lay their heads down on their desks in an attempt to again breath freely. Air quality was terrible. You could see the soot in the air. Back then we did a lot of things like burn our trash in old concrete ovens in the backyard. This was a common practice. Eventually burning trash was outlawed and a whole industry of trash hauling trucks came into being. It cost money to have your trash collected but the alternative was killing us. Unfortunately, cars multiplied and easily made up for the difference.

We need to collectively think about not only what we do today but the consequences of those actions long term to the environment as well as to the health of the populace. I have a quote from W. Edwards Deming on my web site that says "We don't have to change, survival isn't mandatory". I think it is very telling. I know I am singing to the choir, but what we are doing is having an effect. Fossil fuels are really bad for us as a species.

So get that solar, add insulation to your attic, put film on your windows or replace them with double glazed glass, and change out all those energy inefficient appliances. You will be happy you did it.
Manny

 

[miimura]

I've updated the spreadsheet that I created to compare PG&E electric rate plans and usage scenarios with the rates effective August 1, 2014. It is on Google Drive here.

 

[jimbo69ny]

Well said Dr Manny. People wont change unless they are forced to. I wondered why CA electric was so expensive and it makes sense that it is because your state has spent so much money on alternative energy.

I only pay $.11/kwh in Ithaca NY.

 

[smkettner]

Well said Dr Manny. People wont change unless they are forced to. I wondered why CA electric was so expensive and it makes sense that it is because your state has spent so much money on alternative energy.

I only pay $.11/kwh in Ithaca NY.

Is NY municipal owned or regulated public business?
Municipal you pay for infrastructure once, investor owned you pay a rate of return indefinitely.
Electric has long been expensive in CA. Very poor planning IMO and drives business out.

 

[jimbo69ny]

I dont know the answer to that. In central NY we have NYSEG - New York State Electric and Gas

 

[fromport]

I am on SCE
I have no special rates or anything since we are in a rental and hope to move out soon.

month driven charger price price/mile
jun 1472 miles 431 kWh $108 $0.073/mile
jul 1477 miles 422 kWh $106 $0.072/mile
aug 1325 miles 388 kWh $91 $0.069/mile

In august I installed 1 solar panel with a micro inverter to offset the house load.
That way we didn't go as deep in tier4 as normal which helped to get the overal
cost per kWh down.

 

[dstjohn99]

Dusting off an old thread - SDGE rates are set to change. As a solar generator I've been on time of use for over 10 years. But starting in December TOU rates are changing from a 11am to 6pm peak, to a 4pm to 9pm peak. Also, TOU will be year-round and 7 days a week. No relaxed rates for winter or weekends. This means I'll be generating at lower rates than when I typically use power, and have a huge impact on my bill.

I have the option of going back to the tier structure until my 20 years are up, or an EV TOU schedule. Anyone have some insight here?

Tony, any chance of communicating with the Rav4 BMS / CANBUS system to create an interface with an inverter (substitute Rav4 battery for solar panels)? Where is the best place to start researching the data communication standards for the Rav?

 

[ehelmholtz]

I think you can sign up for EV-TOU2 until December and it would give you peak from 12-6pm. You'd be grandfathered into that rate for 5 years.

 

[dstjohn99]

I think you can sign up for EV-TOU2 until December and it would give you peak from 12-6pm. You'd be grandfathered into that rate for 5 years.

That's only for Net Metering 2.0 customers (less than 5 years). Since I'm already on TOU for more than 5 years, they require me to switch to the new structure. The EV TOU structure is changing in December also.

 

[ehelmholtz]

I think you can sign up for EV-TOU2 until December and it would give you peak from 12-6pm. You'd be grandfathered into that rate for 5 years.

That's only for Net Metering 2.0 customers (less than 5 years). Since I'm already on TOU for more than 5 years, they require me to switch to the new structure. The EV TOU structure is changing in December also.

I couldn't respond to this until now. I have had net metering 1.0 for 2 years (since January 2015) and I received the a letter that my plan is grandfathered in until January 2020. I also have net metering 2.0 in a different house and signed up for it in September 2017 and got a letter saying that it's grandfathered in until September 2022.