EV+PV - Who Has It?

[Dsinned]

DSinned, . . . On the metering, have you perhaps considered a whole house electric usage meter? Milholland was suggesting that I look into the G-Meter (http://www.greennet.com/consumer/gmeter/), which taps into the house at the panel, and allows you to monitor all circuits live via a web portal. Actually, they proposed that they will install one for me as a beta trail for their company so long as share access to the portal.

Yes. I have tried several. There are two that I'd recommend.

The first is a 10 channel capable home energy monitor made by Current Cost (UK), called the "EnviR". The second one is almost the same thing, but only can monitor the whole house on a single channel and corrects for power factor variations. It is made by Eferegy (also in the UK) and is called the True Power Meter. They are both under $150 (Amazon.com) for basically "everything you need" kits.

The EnviR is by far the most versatile of the two, because it can monitor the whole house and nine additional load circuits (120V or 240V) all in one monitoring device. It also has subscription based local and remote web monitoring capabilities at additional cost. Efergy has a similar web based monitoring solution as well, also for about $150, but not for their True Power Meter monitoring device.

Here's a link to "Enerati" the EnviR's web portal: https://www.enerati.com/Electricity/ConfigDashboard.aspx?param1=Ng==&param2=Ng==&param3=ZGZhZmI1ZjVmOGJlNDFiZGI2MDA1MmY2YjVjM2JhNGE=

And here's a link to the Efergy Elite "TPM" webpage for additional info: http://www.efergy.us/index.php/usa/products-usa/electricity-monitors/elitetpm-monitor-usa.html

 

[TeCKis300]

Something told me that you'd have some good input on the whole house monitoring.

Thanks for that, I'll look into those a bit more. While I wasn't particularly curious about this originally, my interest has definitely been piqued after Milholland recommended it. I think they are also curious how the EV+PV combination works together and they wanted further data. Other than thatn, I'm also curious as to how much power certain things use in my house - like my 'command center' desktop computer, and laundry machines that are always running for the little kids. Granted, I can use a kill-a-watt type meter for instantaneous draw, but it'd be more interesting to profile them for how much they use over time.

 

[Dsinned]

. . . my interest has definitely been piqued after Milholland recommended it. I think they are also curious how the EV+PV combination works together and they wanted further data. Other than that, I'm also curious as to how much power certain things use in my house - like my 'command center' desktop computer, and laundry machines that are always running for the little kids. Granted, I can use a kill-a-watt type meter for instantaneous draw, but it'd be more interesting to profile them for how much they use over time.

Who is "Milholland", your solar installer?

With EnviR HEM, I have the capability of monitoring "10" different load circuits including plug-ins at various 120V outlet (similar to Kill-o-watt). In addition to the whole house from the AC Mains, I am also monitoring my HVAC, L2 EVSE Leviton charger, and PV system, all 240V. The rest are 120V outlets for things like my refrigerator, microwave oven, dishwasher, washing machine, and H2O Cooler. Except for my central HVAC blower motor, the latter are all being remotely monitored with a plug-in wall outlet devices called, IAMs (Individual Appliance Monitors). The 240V loads (and PV system) require multiple sensor transmitters and clamp-on transformers on L1 and L2 for each of those dedicated AC branch circuits. These devices can be quite a chore to fit in a load center distribution circuit breaker panel, so some are installed at the input wiring to the equipment being monitored if space permits in those equipment enclosures. For example, I was able to fit a pair of CTs inside the enclosure for my Leviton charger, and associated transmitter for those current sensors via the sensor wires to a local mounting location external to that enclosure. Of course, doing something like this, may void your OEM warranty, but everything can be restored exactly as it was if necessary.

Monitoring the solar system with EnviR is kind of tricky, because the current sensors are really not monitoring a load, but rather an AC "generating" source. I haven't yet quite figured out how to get Enerati to incorporate the whole house load with the PV source to net out the difference. By doing this I'll have the independent means to do my own local net metering instead of relying solely on PG&E billings.

 

[miimura]

I just got my utility bill from PG&E for the 30 day period ending April 24th. My PV system wasn't even operating for 12 days during that period, but my electic bill was only $4.67!!!

GAWD, I love this going "green" stuff!!! :mrgreen:

Don't forget, that is only the interconnection fee. You will have to pay for your annual net usage when your Annual True-Up bill comes just after the anniversary of your installation. Did you get your first True-Up statement yet? It's a separately mailed statement on letter-size paper. I installed during the winter, so I accumulated some amount that I owe them. We will see how the annual total goes now that the peak production months are coming and now that I actually have an EV. Once the monthly usage goes positive again in the Fall, I will probably start paying some of the accumulated charge so that I don't have a big bill due at the same time as my Christmas shopping credit card payments.

Oh, and here's my solar install...

The array to the left faces south-west and the other faces south-east. The top 3 SE panels have generated the most energy due to winter shading. The shading due to trees is less now, but I can't escape the fact that the sun goes behind the hills pretty early in the evening. Milpitas and East San Jose are much better in that regard because they will get more generation during PG&E's Peak times.

 

[jspearman]

I'm near the end of my first year of production, and if the sun stays out for the next few days I'll hit 28,000kWh. That's about 3,500 more than they estimated, so I'm ecstatic. I'll try to post some pics one of these days.

 

[TonyWilliams]

Link to my solar production

...Date......Monthly......Daily Peak

Jan 2012: 937 kWh..... 39.79 kWh
Feb 2012: 970 kWh.... 43.57 kWh
Mar 2012: 1210 kWh.. 50.72 kWh
Apr 2012: 1267 kWh.. 54.18 kWh
May 2012: 1390 kWh.. 53.6 kWh
Jun 2012: 1455 kWh.. 55.1 kWh
July 2012: 1402 kWh.. 52.4 kWh
Aug 2012: 1318 kWh.. 50.0 kWh
Sep 2012: 1.25 MWh
Oct 2012: 1.12 MWh
Nov 2012: 0.91 MWh
Dec 2012: 0.716 MWh

2012 Year to Date: 13.9 MWh


Jan 2013: 0.955 MWh
Feb 2013: 0.999 MWh
Mar 2013: 1.252 MWh 48.8kW peak
Apr 2013: 1.241 MWh 54.08kW peak
May 2013: ?.??? MWh


Lifetime: 25.1 MWh



Estimated Production

Month Solar Radiation
(kWh/m²/day) AC Energy (kWh)
Jan: 4.10 913.0
Feb: 4.70 937.0
Mar: 5.41 1191.0
Apr: 6.08 1276.0
May: 6.49 1400.0
Jun: 6.67 1376.0
Jul: 6.74 1403.0
Aug: 6.57 1356.0
Sep: 6.01 1213.0
Oct: 4.99 1072.0
Nov: 4.45 946.0
Dec: 3.78 839.0

 

[Dsinned]

I just got my utility bill from PG&E for the 30 day period ending April 24th. My PV system wasn't even operating for 12 days during that period, but my electic bill was only $4.67!!!

GAWD, I love this going "green" stuff!!! :mrgreen:

Don't forget, that is only the interconnection fee. You will have to pay for your annual net usage when your Annual True-Up bill comes just after the anniversary of your installation. Did you get your first True-Up statement yet? It's a separately mailed statement on letter-size paper. I installed during the winter, so I accumulated some amount that I owe them. We will see how the annual total goes now that the peak production months are coming and now that I actually have an EV. Once the monthly usage goes positive again in the Fall, I will probably start paying some of the accumulated charge so that I don't have a big bill due at the same time as my Christmas shopping credit card payments.

Miimura, I just realized you are correct. However, after reconciling my bill, weighing E-9A TOU Partial Peak vs. Off Peak consumption, it looks like I zeroed out my bill for the last 30 days. This is because I got a few dollars towards a "credit". I just started working toward a 12 month "true up" period. The next several months are the best solar generators of the year, so I should be in good shape with a lot more credits by next April.

Btw, I just finished adding 3 more 250W panels to my existing array. "Over" generating now should be a piece of cake!

 

[miimura]

I've posted my spreadsheet for calculating usage and costs based on SmartMeter data. See the thread Understanding PG&E E9A Electric Vehicle Electric Rates for the link.

 

[root710]

I'm contemplating Solar PV system and would like to know how to calculate the actual amount of power my car uses including charging losses. I know it takes more to charge than the car actually uses for driving. There are losses from AC to DV conversion, loss of energy thru heat as the battery is charging etc. Does anyone have a figure for how many miles per kwh of house current being devoted to the car. I've only had my car a couple weeks so I don't have any electric bills to go by and I don't have seperate metering anyway.

I'm trying to figure how much more power I will need the PV system designed for how that I have an EV.

 

[fooljoe]

Charging is ~80% efficient on 240V and 66% efficient on 120V. However, that doesn't really help you if you don't yet know how efficiently you drive the car. A conservative approach would be to just take the sticker efficiency of 76 MPGe, or 2.25 miles/kWh. Note that those sticker numbers are already "at the wall", so you don't need to factor in charging efficiency. Then, assuming you have an idea of how many miles you'll drive, you can divide to see how much electricity you'll consume. For example, 12,000 miles/year would translate to 5333 kWh consumed.

To better refine your estimate you might also want to factor in whether you'll do a significant amount of charging away from home, and you'll want to adjust that efficiency assumption as you get better acquainted with your car. Using the aforementioned 80% efficiency, the sticker 2.25 miles/kWh translates to about 2.8 miles/kWh at the dash, so adjust accordingly if your long-term efficiency is under or (hopefully) over that number.

 

[Dsinned]

Have you got a L2 EVSE yet? If not, I recommend a JuiceBox Premium (or Basic with LCD and Remote options). If you can wait a couple months there will be a newer version that replaces the current Premium version or may perhaps replace both versions. JuiceBoxes (w/LCD) keeps track of all your EV charging electric power consumption (at the EVSE as the "source" of AC power) and displays this value in "kWh". This value is continually updated and kept in non-volatile memory. This sounds like the type of EVSE feature you could use to help plan your PV requirements with respect to charging your EV(s) at home. The display also tells you the amount of power consumed by each individual charging session.

 

[root710]

Yes, I do have a level 2 EVSE. Sounds like some useful features coming to the juice box. I might want to put in a permanently mounted EVSE in the future. Thanks FoolJoe for those numbers, that's exactly what I needed to get started with estimating my electric usage..

Does everyone switch to a TOU rate plan when they go solar? Without solar the TOU plan does not appear beneficial. Charging the car in the middle of the night is cheap but running a refrigerator and freezer during the day at peak time will cost a whopping $.46 kWh. It doesn't seem like it would balance out very well.

With solar and TOU it sounds like you can sell the kWh during expensive peak hours and buy them at night when you need them at the cheap rate. If this is the case it seems like a straight comparison to my current usage would not be accurate for determining solar capacity needs. I might need to produce less than I currently use because I can sell high and buy low. Of course in either case I have to add in my projected needs for the EV.

Has anyone else found useful ways of determining what size system you need? The solar sales people don't strike me as the most trustworthy sources for determining the size PV system I would need. They all strike me as used car salesmen types. Seems like it might be more in their interest to sell you more than needed.

 

[kiwiguy]

Here's a panorama of my 13.8kW ground mount. 60 230W panels with SolarEdge power optimizers.
The system has been in for just about a year, but it took PG&E 4 months to approve the net metering as they "lost" the paper work multiple times! Was over producing until we got the EV and now we are burning through the credits. The NEM for August was $3.50 with a full month of EV charging (~2000 miles) and 3 AC units. For some reason it looks like September will be a large positive bill, probably because it was hotter than August and the solar is dropping off.

True-up isn't until February. Having the solar definitely helped make the EV decision. Didn't want to give away surplus generation at 4c/kWh!

For those interested, here are some stats:

Month	  Total kWh	Peak kWh
Oct 2013		1992		75
Nov 2013		1008		64
Dec 2013		1350		52
Jan 2014		1420		61
Feb 2014		1200		74
Mar 2014		1870		83
Apr 2014		2358		98
May 2014		2811		102
Jun 2014		2827		99
Jul 2014		2682		95
Aug 2014		2478		92
Sep 2014		2066		82

Year Total	24062

 

[ggodman]

Impressive Mi/Kwh

 

[n3ckf]

Ive had a 6KW solar system up in the mountains for almost exactly a year now (well about 15 months in reality, but PG&E only has about 11 months of tracking on it. I'm coming up to my first year reconciliation date in about a month.

I will be very close to net-energy-zero. (becuase of TOU metering, i'm *way* ahead on $ right now, about a $250 credit) but i'm actually just catching up on net KWH (with solar you drop your bill faster than you actually generate power because during-the-day power is so much more expensive).

My system is handicapped (esp in winter) by a lot of 150' trees around my property, however i get about 80% of the available "summer" solar power.

This includes charging the car (just about totally) each weekend i visit the house since i use about 95% of the battery capacity getting there.
(but i don't do that every weekend, average of every other weekend). So less use than i would have if i actually lived at that site full time.

If i lived there, i'd probably expand the solar to 8-10kw. The 6KW would get almost all the "expensive" power paid for though.

 

[miimura]

Yes, I do have a level 2 EVSE. Sounds like some useful features coming to the juice box. I might want to put in a permanently mounted EVSE in the future. Thanks FoolJoe for those numbers, that's exactly what I needed to get started with estimating my electric usage..

Does everyone switch to a TOU rate plan when they go solar? Without solar the TOU plan does not appear beneficial. Charging the car in the middle of the night is cheap but running a refrigerator and freezer during the day at peak time will cost a whopping $.46 kWh. It doesn't seem like it would balance out very well.

With solar and TOU it sounds like you can sell the kWh during expensive peak hours and buy them at night when you need them at the cheap rate. If this is the case it seems like a straight comparison to my current usage would not be accurate for determining solar capacity needs. I might need to produce less than I currently use because I can sell high and buy low. Of course in either case I have to add in my projected needs for the EV.

Has anyone else found useful ways of determining what size system you need? The solar sales people don't strike me as the most trustworthy sources for determining the size PV system I would need. They all strike me as used car salesmen types. Seems like it might be more in their interest to sell you more than needed.

Strangely, a lot of solar installers don't know how to properly size a solar system with an electric car and calculate with EV rate plans. For simplicity, I would ask for a quote to offset 100% of your historical household kWh use. With overnight EV charging, you should come out about right and not too big. The tendency is for those guys to over-size the system. My humble opinion is that it does not make economic sense to get a solar system so big that it completely offsets your kWh (net zero energy) because you will have a significant negative bill that just gets tossed out at the end of the year. Aiming for zero billable dollars is much better.

Also, you didn't mention where you are located and how much A/C you use. That makes a huge difference in whether you should do TOU without solar. With solar, you should do TOU regardless of A/C use. If you want to save a little money, cool the house more in the morning and set the temp higher after the peak time period starts. A/C system efficiency is higher when the outside temp is lower too.

 

[kiwiguy]

The really simple rule of thumb for calculating your system size is to divide your annual usage by 365*average sun per day, which is about 5 hours for most of California. For my system spec'd above you get 365*5*13.8 = 25185 kWh, which is pretty close to what I generated (24062).

To maximize your ROI you don't want to over produce as you only get 4c/kW. If you can't afford or even fit a large system that zeros your costs, just calculate your total usage for Tiers 2, 3, and 4. Your payback will be faster, and you only pay the cheap baseline rates.

Once your get solar you will likely use more electricity! We actually turn on the A/C more in the summer rather than sweating it out. Also looking as using a heat pump instead of just propane for heat. And then there is that second EV...

 

[root710]

I'm in Coronado so we get a lot of May Grey and June gloom type or marine layer weather. Supposedly the San Diego area gets avg of 5 hours usable sunlight per day but I think that would be a stretch for coastal communities. My roof is also not ideal because it faces SE. So it will be situated best for morning light but that is when we have clouds. I think my roof is about a 5-12 slope. Was thinking about getting some kind of rack system to angle the panels in a more favorable direction but don't know how significant an implact that is on the overall cost and if it's worth the cost.

It makes sense that overproducing is bad because the power company pays pennies on the dollar for the excess power. What a rip off.

The good thing is we don't have A/C except a little 5,000 BTU window unit that we use for 1-2 weeks a year at night. No forced air heat either. Gas floor furnace that we hardly ever use and sometimes some small portable electric heaters. Nice thing about the coast is you don't need much heat or A/C, windows open almost year round.

I guess I'll kind of shoot for something that will produce about what I've been using without the EV and the TOU will make up the difference or close to it anyway.

 

[jimbo69ny]