Snow and Cold ( I mean really cold (at least for Toronto))

The weather for the last month in the Toronto region has been unseasonably cold due to an air mass originating in the far north. Therefore the snow has not melted but built up on the solar panels. I have from 6" to 12" of snow on most panels with a few partially covered. When viewing my Solaredge web portal, it shows how little sun is actually penetrating down to the actually panel. Remember, my review was with bright sunlight at approx 3:10 pm Feb 27, 2015. Obviously this illustration shows the limitation of using panels without removing the snow. In my case I can't get up on my roof so I have to grin and bear it. However, compared to last year I have lost at least $80 in sunlight revenue due to the snow covering.

How Temperature Affects Solar Modules

Here is an explanation I found on the web that is very helpful.  This helps explain why Toronto, Ontario, Canada can produce reasonable solar power when compared to Miami, Florida which is further south and one would expect have greater solar power generation potential.  This is a bit technical but worth the read.

A 300 W– rated module at 25°C and an irradiance of 1,000 W/m2  generates 300 W of power. If irradiance is constant but ambient temperature increases, causing cell temperatures to reach

50°C, the same module (assuming a -0.43%/°C temperature coefficient) now produces only 268 W of power (300 W x [1 + (50°C - 25°C) x -0.43%/°C] = 268 W).

 Modules using standard crystalline PV cells have a temperaturecoefficient of about -0.45%/C, meaning that a 1°C increase in operating cell temperature decreases power output by 0.45%. Use of these advanced cells can reduce the coefficient to -0.43%/°C, or even -0.41%/°C.

A One Year Update

It has not been a little over a year that I have been operating ShefmanSolar.  Although my stats are not 100% accurate because of internet outages (generally my fault with a faulty UPC's) and power outages etc, I think I am pretty close and it certainly gives one a pretty good idea of what power I have generated over the period. 

 I am pretty close to both my installers estimate and my estimate of power production and that is with a black ( no power) module for most of the year...I haven't missed it and probably didn't need it to begin with as it would have added maybe 4% or 1 kW a day to my production during the summer- not worth the cost of of the labour to replace.  The optimizer (hardware) was under warranty and can be replaced for free.

The Numbers

Solar for one year-info taken at 12:04 August 11, 2013 (August 10, 2102 to August 10, 2013)

5.86 Mwh generated to 12 noon 

Approx $4699 for the year based on Solaredge (Optimizer)  data which is incomplete due to router and internet issues.

Based upon Powerstream (LDC) billing: (approx info but close)

Total power generated:  6173.64 Kw 

Total Gross revenue : $5170.00.  My installer  Enviro-Energy Technology estimated last year that my gross revenue would be $4941.66.  Pretty good estimate considering where my modules are ( 3 side of the house and that I am using the Solaredge Optimizers)!

Total Net revenue (minus Customer Charge):$4951.26

Variance from Powerstream data vs. Solaredgedge date : 368 Kw (Solaredge reading is 368 Kw less than Powerstream) I attribute this to data loss over the year due to Power failures, router or internet connection failures.

Highest hourly power generated: 5100.72 watts

Most daily power generated: 39.2 kW

WTO Ruling

It seems that Ontario has lost its case at the WTO and now must respond.  This has huge implications for individuals and companies who intend to install FIT and microFIT projects in Ontario in 2013.  What this means is that the Ontario content rules, which require 60% Made in Ontario content and labour in your installation will be altered.  The question is how?     At this point I would suggest that anyone looking to install solar to be very careful and follow the news.  If the government removes this requirement that would mean your install cost would go down and your potential profit would be higher with the present tariff regime.  For an excellent article discussing the implications and the various alternatives that may be selected visti this link:

http://www.renewableenergyworld.com/rea/news/article/2013/05/ontario-loses-wto-appeal-what-happens-next?cmpid=WNL-Friday-May17-2013

Overcast and Rain Equals Limited Solar Power Generation

Today was a grey and overcast day.  I thought it might be interesting to post my power production for my 6.24 Kw rooftop solar system.  The screenshots were taken around 4:15 pm so we've had a day of .....sun?

Energy production today-compared to previous days production

Weather for today and the next few days

There's snow on my modules!

Ahh winter!  Cold, snowy and diffenetly less sun.

In December the most power I had generated was 9.39 Kw, while the worse day was .106..just enough to light a 100 watt light bulb for 1 hour.  Toronto winters can be dull!.

Power generation was not great but considering it is winter and there is less light up here in the northern hemisphere; I can’t complain.  It has been less sunny than last year, but then again last year we had an exceptional winter; in fact I can’t really remember it as winter so much as a prolonged slightly colder fall with lots of sunlight. Yes this is Canada, but our weather in Toronto is moderated by Lake Ontario. The lake retains the heat from the summer for quite some time.  We don’t get much snow up on our side of the lake unlike Buffalo N.Y or Niagara Falls.  This is called the lake effect....and of course there is climate change to blame as well.  But what does this have to do with generating solar electricity?  Not much really aside from the fact that when it does snow, the snow can sit on the modules for some time, especially when it is very cold outside.  Some electricity will be generated depending upon the coverage, depth of snow and the amount of sun hitting the panels.  The cold temperatures also make the generation of power from the modules more efficient than at much warmer termperatures.  

The other aspect which is a factor to consider, is what happens when the panel is only partially covered with snow.  If you have a an Optimizer that would help because that panel will not affect the rest of the string, however if you do not, the snow on just the one panel will affect your entire string and reduce your total energy harvest.  

Random patches of snow covering the panels

I have noticed that my Solaredge installation is doing quite a bit better in some cases than a 10 kw Powerone install a few kilometres away.  For example today (Jan 2 at approx. 4 pm) the 10 Kw install has generated a total of 398 Whr of electricity while my 6.24 Kw system has generated 2.42 Kw. I really don't have an explanation except possible there is a lot of snow on the panels.   I have also compared my system to a 5.5 Kw system in the neighborhood and during sunny summertime it is generating more power.  Remember, I have an “inefficient” install. That is, I have panels on the West, South and East gables of my house.  But the inefficient approach works efficiently in this instance for a number of reasons I suspect.  Some of my panels are facing sunlight at some point in the day when there is sun or intermittent cloud. Panels that are partially covered in snow don’t bring the whole string down because of the Optimizer, so I produce power most of the time. My roof has different angles so while one side may have snow on the panels that other side doesn’t.  So I get a benefit.  Mind you it is a small benefit compared to having a completely south facing system but at least over the 20 year contract, there is some payback.

Meanwhile, up here in Canada, in the wintertime you would not want to depend upon solar to handle all of your energy needs.

Fall and Early Winter Power Generation

Web view of my solar generation in October

December 2012 solar generation

November and December in Vaughan, Ontario, just north of Toronto has been pretty sad when it comes to solar power generation.  I would imagine it was the same for the whole eastern seaboard of North America to the Great Lakes. Check out my numbers above for October and December.  The beginning of January was similar, however we did get a few sunny days.  One thing I have found when comparing the amount of sun at noon time to summertime is that the intensity is a lot less.  You don't notice it when the sun is out...the day seems as bright as any, but when you compare the figures you can see just how much less sun radiance we have in the winter in the Greater Toronto Area than we have in the summertime.