Our solar production

[turbo2ltr]

Well I can finally post in this thread..
24 Yingli 230W panels (5.5 kW DC)
5kw Fronius inverter
Solar City one payment lease
The peak of my roof runs almost north-south. So there are 12 panels on the east side and 12 on the west.
http://solarguard.solarcity.com/kiosk/solarguard.aspx?share=1&ID=E9D64A94-BA71-41F7-84C0-5B646EF92CAF" onclick="window.open(this.href);return false;

I'm curious how you made over 20kW hs on Oct. 1st. Here, it was heavily clouded over almost all day.

We don't get the weather up here that people in central phoenix and the east valley get. It always seems to pass south of us. It was sunny until noon, it started getting a little cloudy, but didn't get fully overcast until later in the afternoon.

 

[TonyWilliams]

That is a very large residential system. Was your regular use of electricity that high per month? Otherwise why so large. How many panels?
Thanks,

Why so large? I have a big house.

My solar PV system matches about 105% of my household use, and my LEAF is on a separate meter at 7.7 cents/kWh.

35 Sunpower 228watt panels, with 35 Enphase M190 microinverters.

 

[batzman]

Love the feeding the Leaf concept by Solar....

My solar is:

9.46 kW solar PV
44 SunPower 215 watt panels
Approx. 1149 kWh per month

however, also have a KVAR system to assist in electric savings.

I tend to over produce and since my solar install 1.7 years ago, I have about 5 months of electricity saved (my average spend of it) through my utility (net metering).

 

[turbo2ltr]

A little spreadsheet I made..
Still need to automate the meter reading.
https://docs.google.com/spreadsheet/ccc?key=0AinhvyBxwd-IdGMtX2VuSE8wTXdNajh1WEpTQWFtc3c&hl=en_US" onclick="window.open(this.href);return false;

 

[drmanny3]

I wanted a larger system but because mine is utilizing thin film technology I had a lot of panels, 64 and one large inverter. With all that it is still only a 5.2 kwh. This is about 80% of our usage. However in switching to the TOU (Time Of Use). We are now producing more electricity credit then we did in the past. So thus far the Leaf has been free to charge at night. That is something that I did not expect. Our home is about 3800 sqft. Not big but not small either.
Manny

 

[wsbca]

We just got prompted by our solar installer to consider registering with "www.theleafexchange.com" (no relation to Nissan LEAF), an aggregator of Distributed Generator (ie residential solar) Renewable Energy Credits. It seems like a potentially prudent thing to do. We apparently aren't yet able to sell our credits, but if/when we are, there will apparently be some retroactive window, but only if you've logged the credits in some official way. Anybody else been prompted by their installer or other info/research to pursue something like this? Apparently you can do it yourself (register with wregis.org, the record keeper and perhaps market maker for RECs), but there's a fee...the flip side is this aggregator will take a cut of any REC you end up selling on the not-yet-established market, but they'll take care of the details.

I wonder how this might relate, or not, to the Utilities at some point raising their AB920 rate in order to buy our RECs...that doesn't quite seem plausible though, because according to what I've read, RECs are on gross generation, not net surplus. Even a smart net meter doesn't record gross generation, so presumably the validation of credits would have to come from inverter data, which begs the question of the utility-grade-ness of that data...

Anyway - anybody know anything about this?

 

[Yanquetino]

"Good day, sunshine!" Despite shorter days and lower angle, my solar again generated more kWh than I used last month:

So far this year:

The gray slice is the electricity the home has pulled from the grid at night. The yellow is the solar that goes into the home during the day. And the orange is the solar that gets fed into the grid during the day. As long as the orange is a bigger slice than the gray, I'm in good shape. I'm just not sure if that difference will be big enough to cover all my miles when I (finally) get my LEAF someday.

 

[SilverLeaf]

Well I can finally post in this thread..

24 Yingli 230W panels (5.5 kW DC)
5kw Fronius inverter
Solar City one payment lease

The peak of my roof runs almost north-south. So there are 12 panels on the east side and 12 on the west.

http://solarguard.solarcity.com/kiosk/solarguard.aspx?share=1&ID=E9D64A94-BA71-41F7-84C0-5B646EF92CAF" onclick="window.open(this.href);return false;

You may want to compare your system to mine. I have a 5.52 Kw Sunpower system with 24 230 watt panels.

Here is the link to my production: http://www.tigoenergy.com/site.php?PVPwrEv" onclick="window.open(this.href);return false;

 

[ERG4ALL]

Yanquetino wrote:

I'm just not sure if that difference will be big enough to cover all my miles when I (finally) get my LEAF someday.

We are experiencing about 4.7 miles per kWh over the last six months with our LEAF. We have some 65 mph and some hills on the way in to town. Thus, I calculate that for 12,000 miles per year we will use about 2,553 kWh. You may be able to work up a similar calculation to see how much you will power your LEAF by the sun.

 

[Yanquetino]

We are experiencing about 4.7 miles per kWh over the last six months with our LEAF. We have some 65 mph and some hills on the way in to town. Thus, I calculate that for 12,000 miles per year we will use about 2,553 kWh. You may be able to work up a similar calculation to see how much you will power your LEAF by the sun.

Yup, that's what I plan to do, once I know how many surplus kWhs my solar array generates year round, averaging out both "fat" and "lean" months. I have to say that 4.7 miles per kWh is very good! Sure puts the EPA's numbers to shame: a mere 2.94 miles per kWh (combined city/highway). :?

 

[TonyWilliams]

Yanquetino wrote:

I'm just not sure if that difference will be big enough to cover all my miles when I (finally) get my LEAF someday.

We are experiencing about 4.7 miles per kWh over the last six months with our LEAF. We have some 65 mph and some hills on the way in to town. Thus, I calculate that for 12,000 miles per year we will use about 2,553 kWh. You may be able to work up a similar calculation to see how much you will power your LEAF by the sun.

First, your 4.7m/kWh is probably not a good average to suggest (congrats to you), and secondly, you need to calculate 85% charger efficiency.

So, a more typical 3.9 miles/kWh from the dash will get 3.3 from the wall, therefore 4524 kWh for 15,000 annual miles.

 

[ERG4ALL]

Our system was empirically driven. By adding all the things we use electricity for we were able to get a reasonable estimate of the size of the solar system necessary. The amount of adjustments made between the meter and the wheel are insignificant in the overall scope of generating all of our electricity which was our goal. Each item that we added would have an amount of tolerance associated with it for the amount of electricity and how the device is used. And, if we erred on the side of too little, with Enphase micro inverters it is easy to add on to the system. I am just suggesting that using the car dash figures is a reasonable way to start. There are so many other factors when sizing the system depending on your goals and your lifestyle and the type of house you live in etc. etc.

If Yanquetino wants solar solely for the purpose of charging a LEAF, Tony, your accuracy is probably warranted but even then Yanquetino's as yet undetermined driving habits may negate the precision with which the wall-to-wheel accuracy was used.
When I designed the capacity of our solar system, I treated our entire house as a system with many component parts. Each has an impact on the size of the system. In each case I tried to present worst case which is what I think you provided with you sharper figures. With that in mind and the pluses and minuses from each component, I am pleased that we have been very happy with the system and are generating enough power to offset our electricity purchases and still send some to the grid and get paid with a little check from the utility each year.

If anyone is interested, I've written an 18 page outline of all the things that we considered when designing our system. All things would not be appropriate for all areas of the country, but it may be a useful stimulus to take into account all of the items that make a difference in the total electrical usage of your house (and car). If interested, send me a PM.

 

[Yanquetino]

Yanquetino's as yet undetermined driving habits may negate the precision with which the wall-to-wheel accuracy was used.

Well... to clarify, my intent was to install sufficient solar to power our home as well as an EV someday. Whether or not my 'guess'timates prove accurate remains to be seen.

There were many unknown variables at the time. We had just built this new home, and had thus never yet been able to determine our average kWh per day. We had averaged about 31 kWh per day in our other home for the last 6 years, but it is in a colder climate, so I assumed we'd run more air conditioning in this slightly larger home in the desert. On the other hand, the other home was not as well built and insulated, with many more windows, so perhaps the difference would be a wash...?

And happily, I have learned so far that, in fact, we have, indeed, been averaging 31 kWh per day. That average will likely continue to drop as we finish off the year, since we now are past the air conditioning season. Of course, we'll also be burning more lights at night, with fewer hours of sunlight. As for the solar production, our average so far is about 39 kWh per day.

If those averages hold steady, that's about 8 kWh surplus x 365 days = 2,920 extra kWh per year beyond what we need for the home. That might allow me to drive...

At 4.7 miles/kWh = 13,724 miles per year.
At 3.9 miles/kWh = 11,388 miles per year.
At 2.9 miles/kWh = 8,468 miles per year.

I seriously doubt we will be driving our Leaf that many miles per year, as we now work at home and only drive for errands, shopping, etc. We'll keep our "workhorse" Subaru for any long distance trips and towing our small sailboat.

So... it just might be that I projected correctly by installing in an 8,280 watt solar array. Hope so!

 

[Yanquetino]

The numbers are in for my solar production in November. It turned out to be the lowest month of the year --although my bet is that December will dip down even further. Still, the panels managed to put more kWh into the grid than we took out of it. I have uploaded the results to my solar array web page.

You'll see that I have added the following table, which tallies and averages the stats. I included a range of 'guess'timates of how many miles I could have driven on the surplus kWh generated. I am not sure if this is accurate, but I figured that my EVSE would be 93% efficient :?: when charging a Leaf with the surplus. Please correct me if I'm off base with that assumption, and I'll adjust the table accordingly. [EDIT: I have since updated the efficiency to 85% in the table, as suggested below. Thanks, Boomer23!]

Now if I only had my Leaf...!

 

[Boomer23]

I am not sure if this is accurate, but I figured that my EVSE would be 93% efficient :?: when charging a Leaf with the surplus. Please correct me if I'm off base with that assumption, and I'll adjust the table accordingly.

I'm averaging 3.2 miles driven per kWh measured at the power panel. This is with an average of about 3.8 miles/kWh displayed on the LEAF dashboard. So I'm getting perhaps 85% efficiency in the charging process.

Also, I'm kind of puzzled by the part of your table that shows "utility kWh used to power home". If your total solar generation exceeds your total usage, then wouldn't the net amount coming from the utility be zero? I may be getting caught up in semantics or perhaps I'm not taking the time to compare your numbers with mine, so please correct my misunderstanding if that's the case.

 

[TonyWilliams]

July - 1,086.3 (first month, since 9 July... 1463 projected for month)
Aug - 1,484.6
Sep - 1,185.3
Oct - 1,142.9
Nov - 871.1

 

[Yanquetino]

I'm averaging 3.2 miles driven per kWh measured at the power panel. This is with an average of about 3.8 miles/kWh displayed on the LEAF dashboard. So I'm getting perhaps 85% efficiency in the charging process.

I ought to change the percentage, then, but I'll let others chime in first. I was using an estimate of EVSE efficiency that I've seen on a few different web pages, but had no idea how truly accurate it was.

Also, I'm kind of puzzled by the part of your table that shows "utility kWh used to power home". If your total solar generation exceeds your total usage, then wouldn't the net amount coming from the utility be zero? I may be getting caught up in semantics or perhaps I'm not taking the time to compare your numbers with mine, so please correct my misunderstanding if that's the case.

Yeah, I can understand your confusion. That line is for the kWh that come into the home from the grid at night, when the solar array isn't working. My utility bill separates the amounts into two "meters" (programmed in one meter, actually): Meter 14 (how many kWh Rocky Mountain Power sells me at night), and Meter 24 (how many kWh I sell to Rocky Mountain Power in the day). This pie chart shows the amounts so far according to my last bill on November 21:

As long as the orange slice (Meter 24) is larger than the grey slice (Meter 14), I am in good shape. The difference between the two is my "surplus" solar kWh, i.e., I subtract the kWhs used to power the home (grey + yellow slices) from the TOTAL solar kWhs produced (orange + yellow slices). Because the total is greater than my use, Rocky Mountain Power owes me that surplus. In the future... it will power my Leaf. Hopefully with a few kWh to spare.

Have I confused you even more? Probably. :?

 

[Boomer23]

Have I confused you even more? Probably. :?

Nope, clear as mud, now.

Congrats on your great solar performance. You'll LOVE seeing that excess solar power your LEAF when it comes.

 

[N952JL]

My 10kW system went online 2 July 2010. Since then I've produced over 21mWh Yes that's megawatt. Nov ended with 1007+ kWh. My two biggest months were April & May both over 1600 kWh with highest days being over 76 kWh. I have shading issues with the neigbor's trees. So after all the leave are fully out by the end of May, I lose the morning sun till the next Feb/March time frame.

By the way, I live in Warner Robins GA and my adv for the year is just over 1200 kWh per month. But with my mother's addition I have over 4500 sq feet and a pool so I don't normally run a surplus. I'm looking into ground based heatpumps when the heaters need to be replaced. (I'm total electric here). Leaf still hasn't come in even though I have the lowest (earliest) reservation in GA. Atlanta area seems to get theirs first.

pear SL
reserved 4/20/10
Order confirmed 8/11/11
still pending.

 

[mwalsh]

One year anniversary as of today. Total production for the last 365 days - 10,213kWh.