2020 Solar PV Performance

[jebatty]

2020 set near record-breaking kWh production of 16,007 kWh, just missing the all-time record of 16,073 kWh in 2014. Factors that might have contributed may be reduced pollution from transportation and industrial sectors due to Covid-19, favorable winds which reduced smoke from western US and Canada forest fires, or just more sunny days. The average annual production for the first five years following installation is 15,435 kWh. The lowest production year was 2019 at 14,520 kWh.

 

[stoveliker]

Installed in October '18 so only two full years, but for me, despite the nice surprise in May, 2020 got me the exact same amount (6.3 MWh) as 2019...

 

[jebatty]

What size is your system? In our area of northern MN, latitude 46.9N, in a near shade free location, annual kWh production is easily computed as being system size in kW x 1.2 to 1.3 = MWh annual. For me, size is 12.3kW x 1.2 = 14.7 MWh or x 1.3 = 16.0MWh. annual.

To get that production it also is necessary to clear snow from the panels, which I do and is easily done on a ground mount system. If snow is not cleared, Dec - Apr could have panels mostly snow covered, and production loss could be as high as about 5.6MWh.

 

[stoveliker]

7.2 kWh. Half facing East, half facing West. And I'm in a place with a hill on the East, West, and South sides - all topped with large trees. So the sun comes up late and settles relatively early.

So far snow slides off in a day or two as it's not been cold long enough - if there's one place where a piece of the panel is exposed, it'll warm up in the sun and starts exposing neighboring areas.

But this covers all my electric needs including heating with a minisplit when it's 35+ F, with 1-1.5 MWh to spare. Net metering is great...

 

[DuaeGuttae]

2020 set near record-breaking kWh production of 16,007 kWh, just missing the all-time record of 16,073 kWh in 2014. Factors that might have contributed may be reduced pollution from transportation and industrial sectors due to Covid-19, favorable winds which reduced smoke from western US and Canada forest fires, or just more sunny days. The average annual production for the first five years following installation is 15,435 kWh. The lowest production year was 2019 at 14,520 kWh.

View attachment 270900

Thanks, jebatty, for another update. I've read (and reread) your threads over the years as we've considered having a solar system installed. We were finally able to do so this year with the system becoming active in mid-November. Our latitude is about 29 degrees, so we're still able to produce a good amount of electricity in winter. I don't have any fancy graphs to share, but we are thrilled to have produced 2.5 MWh in the last month and a half of 2020. Our system is a ground mount 13.475 kW array.

 

[jebatty]

Very true that the panels normally clear of snow quickly as soon as a patch or two of snow free area appears. The problem is a wet snowfall or rain changing to snow and the consequent freezing of the snow to solid ice. Can't rake that off the panels. And winter temps where I live are frequently in the -10 to -30F range, sometimes for up to several weeks. It can take a long time to get rid of that ice. So, I try to get the snow off the panels before it has a chance to freeze to ice. It's the solar addict in me listening for the ching, ching, ching of net meter $ flowing and eliminating uses of fossil fuels.

 

[DBoon]

Nice to hear from you, jebatty.

In October 2019 we added 10 kW total additional solar PV using two 5kW single-axis ground mounts (each oriented 25 degrees from direct south, in opposite directions) to our 5.3 kW fixed-tilt (south-oriented) ground mount.

I got pretty tired of brushing snow off my fixed-tilt ground-mounted array, which is why I went to the single-axis mounts for the new panels. The original PV array was equipped with Suniva panels with a fairly substantial edge that held the snow in place pretty well. I have definitely felt the pain of an ice storm followed by 10 days of subzero weather pretty much eliminating my production for two weeks or so.

The new arrays have less of an edge on the panel so they snow slides off them better, and I put them at a 50 degree (from vertical) angle in the snow season, so snow slides off pretty quickly.

I get yearly production in MWh at about a 1.15 or 1.2 factor to my panels PV kW rating. This past full year they produced about 18 MWh. The lower production factor than most is mostly due to a pretty bad lake-effect driven climate that results in a lot of cloudy weather, including the odd effect of clouds during sub-zero weather. November and December can be pretty tough for production in Central NY. Many days in a row I get 5 kWh/day production total from 15.3 kW of panels. Still, it's a pretty good testament that the technology can work anywhere if it can work in Central NY. I still get a lot of questions from people in the area asking me "do they really work here?".

I change the panel tilt about 4 or 5 times a year, and by doing so, I get enough extra production to offset the orientation from due south. FWIW, I oriented away from due south on the new arrays with the knowledge that someday net metering will be taken away (I think I have 18 years left on this in NY State) and wanted to produce a flatter hourly yield curve throughout the day and year looking ahead to when I might dispense with power line hookups and go completely off-grid (been a dream of mine for 30 years or so).

The original 5.3 kW array was sized to power the all-electric house. Half of the next 10 kW array more than satisfies 100% GSHP heating (estimated 4 MWh/year) and the other half of the 10 kW array is sized to power the first (and eventually) second EV. Right now, I'm not even putting 8,000 miles/year on my EV (estimated 2 MWh of total use), but this will probably increase again post-pandemic.

All this is for a house that is in the late stages of renovation that will become occupied in spring/summer of 2021. No electric bills for me, after that, aside from the $17 monthly hookup charge. I'm giving a lot of production back right now, but expect that in my next metering cycle I'll use about 70% of it, leaving me room for expansion into the second EV and/or more mileage on the first one.

 

[jebatty]

DBoon and others on this chain. I really like to hear the stories of solar PV. Each one reminds of how amazing it is that households and moving up even to countries, and finally the world, can have unlimited electric power which will be dependable, inexpensive, and clean. It's a joy in 2021 to be living part of that experience.

More power to everyone!

 

[jebatty]

Monthly kWh data to better understand the graph I posted. Notice the high level of performance in the winter/cold months of Feb-Apr

 

[kborndale]

My production for 2020 was 12.62 MWh. That's the best I've had since 2016 when I produced a tad over 13MWh.

 

[Brian26]

My production for 2020 was 12.62 MWh. That's the best I've had since 2016 when I produced a tad over 13MWh.

Same here over on the CT shoreline since my panels were put in on May 2017. May 2020 was my best production month ever.

I have a 5.4kw system.

 

[Brian26]

I have my panels on the PV Output website and just realized it tracks yearly panel efficiency. Here is the yearly data.

Cherry Hill Branford 5.400kW | Yearly

PVOutput.org - share, compare and monitor live solar photovoltaic output data

www.pvoutput.org

 

[Solarguy3500]

We had our system installed in late February - early March of 2020, but due to the utility invoking Force Majeure due to the pandemic, we didn't get the approval to operate the system until the end of April. So basically May - December of our first year we made 12.45 MWH of energy. The system is 15.2 kW DC and uses LG 400W 72 cell modules.


The panels are mounted on the east and west facing roofs of my 30' X 60' garage, and I spent the fall/winter of 2019 sistering the purlins and replacing the metal roof on the garage in preparation for the solar installation.




As a bit of background, I have worked in the solar industry since 2012 as an installer, project manager and in my current role of sales and system designer. I work for SunBug Solar, a certified B Corp with offices in Arlington and Westfield MA. I love my job, and the team of people that I work with are some of the best in the business.

 

[jebatty]

Good that you got your system up and operating during the high production summer months. Assuming a full year and E -W panels, what was your calculation on the amount ot kwh you can expect to produce in your location?

 

[Solarguy3500]

Good that you got your system up and operating during the high production summer months. Assuming a full year and E -W panels, what was your calculation on the amount ot kwh you can expect to produce in your location?

Yes, we were happy to get the system online in time to benefit from the late spring and summer production months. We banked a good amount of net metering credits and we still have some left at this point, but it might not be enough to get all the way through the winter so we may end up having a few small electric bills in late winter.

Given the E-W roofs and tilt angle of 15°, the system was projected to produce 14,361 kWh/yr. I have not been clearing snow off the panels so far this year because I've been so busy with other things so if we don't make the projection, that is probably why. There have been several zero production days in December due to snow on the panels. At our old house that we sold in 2019 we had panels and I was diligent about clearing the snow off the panels there because most of the panels were on a west facing dormer roof that only had a slope of 10° so if I didn't clear the snow off it took forever for them to clear and I would have lost a lot of production.

We also had a 3 collector solar hot water system installed in November which should reduce the electric usage quite a bit in the summer months since our DHW is an electric tank and accounts for between 1/2 - 2/3 of our current electric usage so by next winter we should have even more net metering credits for the winter since the water heater won't be working as hard.

 

[jebatty]

DHW is an electric tank and accounts for between 1/2 - 2/3 of our current electric usage

We have an electric DHW tank also. Quite a few years ago I raised the tank 3-1/2" on a 2x4 frame and insulated under the tank. I also wrapped the tank and top with 6" of insulation. Most of our DHW pipes were exposed in our basement, so I also insulated all the DHW pipes as much as possible. I also installed "U" shaped heat traps on both the cold and hot water pipes to/from the tank to prevent siphoning. Doing these things alone reduced our kWh for DHW electric by 50%. It's just my wife and myself, and our current electric usage for DHW averages 100 kWh/month. It used to be twice that.

 

[Solarguy3500]

We have an electric DHW tank also. Quite a few years ago I raised the tank 3-1/2" on a 2x4 frame and insulated under the tank. I also wrapped the tank and top with 6" of insulation. Most of our DHW pipes were exposed in our basement, so I also insulated all the DHW pipes as much as possible. I also installed "U" shaped heat traps on both the cold and hot water pipes to/from the tank to prevent siphoning. Doing these things alone reduced our kWh for DHW electric by 50%. It's just my wife and myself, and our current electric usage for DHW averages 100 kWh/month. It used to be twice that.

Those are great suggestions. I definitely need to insulate the pipes in the basement and wrap the tank with an insulation blanket. I hadn't thought of raising and insulating under the tank, but now that you mention it, that makes a lot of sense. Stop that thermal transfer of heat into the cold concrete floor.

 

[peakbagger]

While you are at it install heat traps on the outlet of the hot water heater. If you dont like heat traps, just put in loop of pipe on the outlet. If you do not, the heat from the tank will thermosyphon up into the unheated space.

 

[jebatty]

While you are at it install heat traps on the outlet of the hot water heater. If you dont like heat traps, just put in loop of pipe on the outlet. If you do not, the heat from the tank will thermosyphon up into the unheated space.

A heat trap on the cold water supply also will block siphoning of heat on the cold side. I think most if not all newer hot water heaters have a float-like heat trap on the fittings to the tank. I added the "U" heat traps because I noticed both the hot and cold pipes were still quite warm and obviously siphoning hot water.

As for a tank insulation wrap, 6" fiberglass is far better than the thin insulation blankets which can be purchased. Just wrap and tape the seams. Be sure to insulate the top and bottom too.

 

[sloeffle]

We also had a 3 collector solar hot water system installed in November which should reduce the electric usage quite a bit in the summer months since our DHW is an electric tank and accounts for between 1/2 - 2/3 of our current electric usage so by next winter we should have even more net metering credits for the winter since the water heater won't be working as hard.

I switched to a HPHW about 3 or 4 years ago and cut roughly 200 - 300 kWh of usage each month off of my electric bill. I also no longer have to run a dehumidifier in my basement in the summer. I figured the ROI to be around 2 years.

 

[ABMax24]

Here's my output for 2020. I have a 3kw roof mounted system, 10 panels total, 2 face east, 4 south, and 4 west. I split the panels like this to maximize the hours in a day that they generate power, at the summer solstice my panels start producing power at 6 am and stop at about 10pm. We don't get net metering here, it's "net billing" so every watt-second of electricity I have to import I pay transmission fees on, I don't get those fees back when I export, making self-consumption much more important.

I believe my roof is about 6/12 pitch, making it too shallow for ideal production in the winter months, but snow collects on them anyway. They do produce fairly well in the summer though. As shown by these charts:

 

[Rob711]

This is my full year. Last week I added a small electric 2.5 gallon hot water heater under kitchen sink. I’m strongly considering getting a 60 gallon HPHWH and plumbing it in after my 50 gallon natural gas heater.
My wife and three daughters use a lot of hot water. Last I checked after rebates the HPHWH would cost like 300 for a 60 gallon tank. Closer to 700 for the 80.

 

[Brian26]

This is my full year. Last week I added a small electric 2.5 gallon hot water heater under kitchen sink. I’m strongly considering getting a 60 gallon HPHWH and plumbing it in after my 50 gallon natural gas heater.
My wife and three daughters use a lot of hot water. Last I checked after rebates the HPHWH would cost like 300 for a 60 gallon tank. Closer to 700 for the 80.

I would just get rid of the gas heater and install a HPWH, especially since your on solar. With the big rebate there it makes even more sense.

A heat pump water heater will crush any natural gas water heater in efficiency. The AO Smith at Lowes has a COP (coefficient of performance) of 3.45 on the heat pump. That is an effective efficiency of 345%. I think most natural gas tanks are like 60-85% efficient.

 

[CaptSpiff]

Here's my output for 2020. I have a 3kw roof mounted system, 10 panels total, 2 face east, 4 south, and 4 west. I split the panels like this to maximize the hours in a day that they generate power, at the summer solstice my panels start producing power at 6 am and stop at about 10pm. We don't get net metering here, it's "net billing" so every watt-second of electricity I have to import I pay transmission fees on, I don't get those fees back when I export, making self-consumption much more important.

I believe my roof is about 6/12 pitch, making it too shallow for ideal production in the winter months, but snow collects on them anyway. They do produce fairly well in the summer though. As shown by these charts:
View attachment 271384 View attachment 271385

Can you explain how you are compensated when your Net goes negative?
Are you simply compensated for the Net negative at the Wholesale rate of power?

 

[jebatty]

I just received from the electric utility a summary of kWh usage for 2020 along with a calculation of average daily cost for electricity during 2020. The average daily cost was -$0.01.