28 January Production Report

28 January 2014

Production Review

It has been a weird winter of 2013-2014.  Some people claim that it is the coldest since 1942.  Normally cold means clear but not so this month.

I knew that the 27th was going to be a good day when I saw Venus shining extremely brightly in the SE before sunrise.

We produced 54.54 kW or around $21.59 for the day. Here is the production curve.

This is almost a perfect bell curve or histogram. With a system maximum output of 8.3 kW (max possible 10 kW with microfit).  The day was sunny, with clear blue skies and -23 C.  Solar noon is at 12:30 here.

We had had a peak earlier in the month that was around 9.2 kW.  That was closer to perihelia of 3 January when the earth's orbit is closest to the sun and we get 7% more solar energy.  In December we were peaking at 7 kW so we are slowly improving as we once again move towards summer solstice.   Remember, our roof is a 5/12 pitch or 22.6 degree and the optimum solar angle is much closer to 60 degrees at this time of year.  That is a 18.6% improvement in just over one month.  The amount of sunlight per day has also gotten longer from about 8 hours to about 8 hours 50 minutes.  

What is the expected January Solar Harvesting Amount?

Records are scarce.  One location reported 0.775 MW for 2013 but they have a 40 degree roof.  I expect that we will harvest around 0.6 MW having missed about 0.1 MW when our panels were under snow and the sun was shinning brightly.

 Since that time I have learnt that if you want production, then you must remove the snow that does not blow off from the panels.

I also have optimized this procedure making for safe, easy access to the panels.  Some people just can't do this.  I blogged earlier about our 18 ft extension pole with a broom head for doing this and ladder safety.  It has not been normal for us to do this here in Lakeshore, Ontario, so some people haven't been doing snow removal.  As a result, we have 50-100% more production then they did.  Once removed, you normally don't have to do any more removal until the next storm.

When it is this cold (-15C), I have learnt that the snow/ice normally does not melt much.

Snow removal does not take a lot of time.  Most days, you might just find that the wind has done most of the work for you.  You must try to completely clear the panel.  As soon as you have removed some snow from a panel it will immediately reward you by producing energy.  You can write off the ladder's cost as a production expense.  Always buy a class 1A ladder with a wide base.  See my earlier post.

I have had one panel with about 10% fouling and the snow is still there after two bright solar days. This small amount of fouling REDUCED the output by up to 80% of its rating.    Here is the output at 12:00 noon. Click the image to make enlarge.

NORTH is at the Top and South at the bottom  Panel 1.0.12 is fouled with snow.  Panel 1.0.19 has a problem and will be replaced in March when I can get on the roof to replace it.  It will reduce the total annual income by $50 per year but not too much money at this time of year.

Why you must avoid systems with Straight String Inverters

Anyone promoting string inverters alone should be ashamed of them selves. 

Our system employs SolarEdge Inverters with Optimizers installed by Flexible Solar southern Ontario's best solar panel installers.

Look at the wild range of power being collected from each panel. Now pick the LOWEST one on each string and that is what each panel would produce. UGG.  Who would sell someone a system like that?

This is why optimizers are the best and IMHO the ONLY system to employ.

The panel monitoring system with SolarEdge also showed me that panel 1.0.19 should be replaced (I bought two spares).  Panel 2.010 also produces typically 10% less but due to its location and difficulty to replace, will remain there.

Without optimizers, I would have LOST 30% or $1800 per year or $36000 over the life of the contract.  But wait a moment.  That is what we paid for everything.

People who sell straight string inverter systems simply don't have any respect for the customer.

Which panel orientation is Best?

We can see that by noon time, West Facing panels looking east via our dynamic positioning system have harvested the same amount of energy as South Facing Panels.  At this time of year, West and East do not produce well around noon and South Facing Panels peak at this time.  South Facing Panels are still out producing the array but the difference has been cut in half.

The array is harvesting 75% more energy than statically positioned East or West panels.

South Facing Panels are the best orientation for solar panels.

The system is not optimized for winter.  It is optimized for the period between March to September when the days are longest and you produce 70% of your total yearly harvesting.  It is fun for me to watch the dynamic array slowly catch up in production to South Facing Panels.  I can track the panels output in Watts on 15 minutes intervals throughout the day.

Stop Paying for your Electrical Energy Bill:

We expect to earn $6500-7500 per year depending on the weather for 20 years.  That should work out to us having an extra $100,000.00 income for our retirement over and above your system costs.  At that point we grid tie and earn the going rate of power which just might be very close to what we are currently being paid.

We expect to earn around an extra $500 per month on average for one year or $100,000.00 for the 20 year contract (over and above system costs).  If that interest you, then call Steve and tell him that Kirk sent you.

 Steve at Flexible Solar Serving Southern Ontario 519-962-9218

Which Type of Solar Panel is best: Mono-crystalline or Poly-crystalline?

Which type of Solar Panels to use- Mono or Poly-crystalline?

This is always an interesting choice that people have to make.  I will discuss the pro's and con's of each type of solar panel for a location in Southern Ontario. I compare my installation - Poly-crystalline Panels with some one 265 W Silfab MONO panel.  I updated this review in May 2014 after installing the test Silfab panel.

Introduction:

I have spoken about getting the highest ROI on your investment before in my opening blog (see Dec 2013). If you have a very limited roof area, then you may get a higher ROI and income by using higher capacity panels which are the mono type.  With no roof area limitation, then poly might be your best choice. Presently, poly-crystalline panels appear to be the best choice for me.  You will pay a high penalty for little benefit to get 10-20 Watt more per panel.  I believe that in the past, there was a bigger difference between the two.

Simply put, both work.  Mono crystalline cells use more expensive refined silica.  Polycrystalline panels use a lower cost silica and look a bit different than mono.

You can check on line what is a mono and what is a poly-crystalline solar panel and what is the physical differences.  It is believed that Poly-crystalline panels work better in low light situations, off axis production and in hotter climates.  Though-out the winter months you will experience at least 30-40% over cast days with some intermittent sun light.  Panel orientation is not relevant when the day is over cast.  The clouds act as a big soft-box and spread the light every where evenly.

I am gathering data on how and when the east and south facing panels turn on in the am as the sun slowly moves to an easterly rising location from its 21 December position. This helps to show how a south facing panel with the sun coming from the SSE to East reacts to the early morning sun compared to an east facing panel.  I can see a small but important improvement in the east's panel output over that of the south facing panels.  As of 21 January, south still out performs east by about 40%.  I move the east panels to track to the west and it is about 18% less than south at this time of year.  This changes to neutral and then to + 20% as we enter March.  Unless you move your panels, south is almost always the best orientation to use.

Discussion:

Poly-crystalline panels are increasing in output as the years progress.  You can get 260 W poly's verse 280 W mono's.  Because Mono panels can cost 20-25% more than Poly, Poly will win on the best ROI.  That makes the cost of that small incremental difference of 10 or so watts very high. Panel orientation, south or the angle of the sun of your roof is of much more importance.  Unfortunately we can not change the angle of our roofs. There is another consideration for mono.  You just might like the look of mono panels better.  You might also like the look of black panels better.  Black panel backing is a great thing to have in winter but gets hotter in summer.  Over all I stuck with the blue panels but it is a personal thing.  My wife likes the blue. Getting a quality installation is extremely important as it will add  significant value to your property at re-sale due to the income generating ability of the panels.  The Flexible Solar people did a great looking job for us. They don't cut corners and use or offer the best materials for long life project.

Comparison:

Update: Mayv2014 preliminary

We remove one of our poly panels and installed a 265 W mono from Silfab.  So far I have learnt this:

1. Low light and early morning light:  Winner goes to poly panels.  I have 250 W making more than the mono who should be making the most as it is rated 6% higher

2.0 Overcast and over head:  Goes to polycrystalline.

3.0  Bright sun both do well.  Mono does perform well under bright sunlight.  Problem is that this May we have had very few days with full sunlight.  On the 19 May 2014 we had a very good solar day.  No visible clouds at solar noon. Temperature around 20 C with a small wind. reported 13 kph.  System would not peak showing that we have high level light scattering occurring.  The angle of the sun hitting the panel nearly a perfect 90 degress.  Solar harvesting in AM 46 kW hr and 88 kW hr total for the day.  That is best for May to date.  Based on these very sunny conditions, all of my Poly-crystalline panels worked better than the mono when adjusted to equal rating.  We are comparing 250 W poly, 300 W poly and 265 W mono.

Several of my poly panels harvested the same as the 265 W mono with no adjustment based on there STC ratings.  All panels were performing closer to their PTC rating and not their STC rating.  Winner goes to polycrystalline hands down.   All of Heline's 72 cell polycrystalline 300 W panels exceeded the 265 W Mono. Several of our 250 W CG poly panels equalled the Mono panel.  In addition, the mono panel had not yet had time to burn in.

4.0 Comparison between Silfab's mono and our 60 cell CG panels and our 72 cell Heliene panels.  Panel monitoring is a bit addictive.  You must resist using the instantaneous number and wait for the Solar Edge monitoring system to fully report at the end of the day.  The 265 W mono Silfab would be a  good 250- 255 W panel.  It is a very poor 265 W panel.  That is because some manufactures and Silfab is not the only one over rate the performance of their panels.  I have had days where our 250 W CG poly panels produce more than the mono or very close to the mono.  We hope to try the Heliene's mono panels rated at 17.5% efficiency.  My heart skips a beat when you see the power rating of their 72 cell poly panel.  It is a bit unfair as it does have 20% more cells but the numbers do speak for themselves.  The performed on a watt by watt comparison a bit better than the 265 W mono.

5.0  Mono offers higher outputs and better efficiency and the chance to have the backing in Black.  As temperature does effect performance significantly, we keep to the white backing.  You many choose mono over poly if you have a limited roof area as you can get more watts per square foot or you just like the look of mono over poly.  All in all, poly panels are the better choice in a warmer environment for max ROI.  I am not including the SunPower panels in this discussion as it is something you have to pay too much for and most of us can not even get them.

6.0  Silfab also use the lower cost PET backing material verse the better backing material used by Heliene and CG.  You can see my posts on suitable panel backing materials.  Personally I would stay away from PET and request Tedlar or Kynar backing be used.  I got the Silfab to replace a panel that was producing 30% lower than expected.  Heliene suggested (it is a CG panel) that perhaps one of the diodes was not working.  I tried to check the diode and found what appears to be a loose connection.  I need to replace the battery in my Multi Meter to check the diode.  The connection may have been all that was wrong.  I will re-install the panel to check it out in the near future. I took the panel outside in the sun and it read 37 V DC showing that all cells are now working.

FYI the backing of the panel is critical to ensure long life of the panel and to seal it from moisture and oxygen attack.  There is a link on one of my posts showing cracking problems with someone's (?) PET backing panels.  People understandably are using lower cost materials to help them save money.  This is important: Solar Harvesting is a long term investment and you must use the best materials available so that you don't have to replace your panels early.

This chart show the daily output of 3 different solar panels. 300 W  Poly- from Heliene, 265 W Mono from Silfab, and 250 W CG Poly panels.  Can you find the 265 W Mono Panel?  A 265 W panel should produce 6% more than the 250 W Poly panels.  Likewise, the 300 W Poly panel should produce 13 % more than the Mono Panel.

What you see then, all the 250 W poly panels should have produced 1.69 kW hrs.  All except 2.20.11 which has a known problem are exceeding that value.  Accordingly, based on the 265 W Mono, all of the 300 W Heliene Poly panels should be less than  2.03 kW hrs.The fact is they are producing 2.125 kW hrs, much more than an equivalent Silfab 72 cell Mono based on this testing.  Also the Mono panel is not yet burnt in, so we are seeing the good side of this panel.  The Silfab panel is 2;20;19  These results were taken on a good sunny day without visible clouds when the sunlight was perpendicular to the panels based on the time of the year.  The Heliene 72 cell panels are 5% over and above this 265 W  Mono panel.  It is all about ROI and Poly is winning here.

For us, Poly-crystalline panels win over mono-crystalline because we have a good roof area and are most interested in ROI.  If we didn't have a 10 kW limitation, then it is quite likely that high output mono would be the way to go.  The best would be SunPower Mono but you can't get them or the price is way too high.  All of these things can change over night.  Many times products are prices not on cost but on how much one can get.  That is why we must always look at ROI.  Pay strict attention to quality build and quality long life components.  Look at the type of backing being used.  Stay away from PET backing and stick with Tedlar and or Kynar.

Based on our one day test, I calculate that we would lose the output of two panels over twenty years using the Silfab panel verse our Polycrystalline panels.  There is no reason to believe that the panel will produce more power and it is likely to produce less power as it burns in.  All of the poly panels have been burnt in for months.  We harvest about $150-160 per panel per year.  Losing two panels because some one wanted to make more money would have cost us over $6000 over 20 years.  IMHO, panel manufacturers need to under rate and not over rate their panels.  They need to make money so charge accordingly.  Panels will lose about 10% over 20 years, so starting at +3-4% is a good way to rate the panel.  You will sell more panels under the 10 kW microfit limitation any way.

Our recommendation:  Heliene 60 or 72 Cell polycrystalline panels.

Kirk is a retired Professional Engineer with experience in the Electrical Utility sector.

More information:

If you are interested in installing a Microfit or Fit solar panel system, I strongly recommend giving Steve a call at Flexible Solar Solutions in Windsor, Ontario serving Southern Ontario.  They are the best and most honest microfit solar panel installers that I have had the pleasure of working with.  They will give you a straight analysis of your roof and what you can expect to earn.  Don't forget to tell them that Kirk sent you.  See my first post for more information on going Solar.

We expect to earn $6500-7500 per year depending on the weather for 20 years.  That should work out to us having an extra $100,000.00 income for our retirement over and above your system costs.  At that point we grid tie and earn the going rate of power which just might be very close to what we are currently being paid.

 Steve at Flexible Solar Serving Southern Ontario 519-962-9218

19 January 2014

Monitoring Your System

Introduction

Once you get a solar panel system installed with a panel level monitoring system, you become more aware of the solar cycle that that interested man kind for the past 20,000 years.  You can visually see the Sun low on the horizon on 21 December and quickly rise up at the end of December and early in January.  This continues of course until 21 June when the cycle starts to go backwards.  I can even see this effect on the instantaneous output of the South and East panels early in the morning.

Discussion: 

What I would like to see in a monitoring system is instantaneous, peak production, daily production, hourly, daily, weekly and monthly output per individual panels.  One of the first limitations that you see with all panel monitoring systems is that they are internet based.  That is so that they can sell you the monitoring system at some time.  Ours is included with the system for 20 years.  What I want to see overall is if any panels are not working up to stuff or are there shading issues that I am not aware of.  Being Internet based, the panel information is only captured and shown every 15 min.  Therefore it is an approximation of what is happening. With clouds moving in and out across the Sun, you can miss the any peak values that may occur in the system.  For example, our peak values showed up a few days ago as around 6.6 kW but I was able to observe a peak value of around 8.4 kW via the DC/AC  Inverter panel display.

I am speaking about an overall system monitoring program.  You revenue meter insures that all power produced is shown and paid for regardless of what you may monitor.

SolarEdge does a good job in showing the output of every panel and highlighting low production panels for easy identification.  It also helps me to see that the way the snow is left on the panel can have a major impact on the panels output.  If 3-4 inches wide of snow is left longitudinally on the panel and 90% or so of the panel is left clear, the snow will reduce the panel's output by about 80%.  That helps to highlight how important it is to clear all the snow off of the panel.  The same effect occurs with early morning Sun and any shading caused by buildings and roofs, structures or trees. 

SolarEdge just recently (this week) changed the way that we can see the data that is collected.  By using the playback feature of the system, you can see the approximate output of each panel in Watt per sec.  That is what we would sometimes like to know.  We have 225 W panels and we can see the values rise from 10 to 180 W/s.  That is nice to know.  Being able to raise and lower my East and West panels, selecting the optimum angle is a bit tricky.  Now I am able to see just when the East panel outputs equal the South panels output or when the East and West panels should be raised or lowered to better optimize the system.  I have a 3 position switch for the panels, so there is not much room to optimize the daily output but it does help a lot because these panels can benefit form morning and afternoon Sun light equally.

Another great feature of this monitoring system is the histogram plotting of the system output.  I can see that if the weather is co-operating, I can get a very rapid rise in system output as the Sun rises early in the morning. This is showing how the South panels react to the sunlight early in the morning as it rises from the south-east. A slower response would mean that you would benefit from more East facing panels,  South panels do an amazing job here.  Currently in mid January, they equal the output of the East facing panels at around 10 AM.  East facing panels tend to peak at around 10:30 due to the fixed angle of the roof being as high an angle that I can go.  The West panels can exceed the angle of the East panels as they can be raised a bit higher in the morning to face the Sun.  That means that they will also stop peaking earlier and would benefit by a small change in the angle facing the Sun.

In the past, system owners would have to record the hourly output from each panel in order to determine the panels output power.  The recent inclusion of the play back recording now makes this a thing of the past.

Summary:

Over all I am very pleased with our panel monitoring system.  The biggest complaint is that it is internet based and not locally supported on my computer as it should be.  We can see and identify any panels not producing properly and see any unforeseen shading issues.  You can see the system charts and outputs by going to the SolarEdge website and  following the link located at the top of the page that says "Monitoring Portal Login".  Then go the the public sites and type in Lakeshore.  Select Lakeshore3 to see our results.

As a closing note, you will see the system panel layout, production summaries and all of the bells and whistles.  You will also see that almost every panel will have a slightly different output.  Remember, that without having panel optimizers, you would lose the power generated from each panel that is about the lowest value.  In my case that is very high as one panel is typically producing 10% lower and another panel which will be replaced, is producing about 30% lower than it should be.  That would rob us of over $40,000 if this situation was left un-noticed in a straight string inverter system as so many people tried to sell us.

Solar Production Update:

At or before the 15 January, overcast days are now producing 10 kW or more with next  to no observable sunshine.  It is not too dark but the sun normally isn't seen on these days.  This represents the break even day or point.  It is the minimum that you normally will earn even when the weather is "bad" or poor.  It covers you  monthly interest payment on your long term investment.  For example, today by 9:30 AM we were producing 2.25 kW and at 12:15 PM 8.0 kW (we can't exceed 10 kW).  This shows that you normally will produce 20-50% of your maximum output even with no sunshine.  The Sun did indeed just come out and we peaked at 9 kW (or $3.6 per hour)  On partially sunny days we are starting to produce about 30 kW or about $12 per day (or expressed $390 per month if every day were like this which it never normally is).  We have not yet seen a clear blue sky day in January, so that out put can only be estimate for this time of year to be around 50 kW ($20 per day or monthly rate of $620).  Unfortunately we never see that great of a solar day for many days in January, but we never expected to.  This varies from year to year.  The bottom line is that the system is starting to produce power at a return greater than the monthly interest charge.  This will only improve as the Sun moves or tracks higher in the sky.  We are doing very well as we have cleared the snow from the panels as I explained in an early post.  Having done so a few days ago, we only had a light dusting on most panels this AM.  I also removed snow this AM from two panels that I should have cleaned yesterday but forgot that I had installed a ladder support needed to safely do so.  I found the support this AM when clearing the snow. The wind is howling at around 30 mph or so gusts.  The light snow normally will just blow off the panels under these conditions.  The high wind will also really cool the panel improving its efficiency.  Solar panels produce heat and you can use the will chill temperature chart on them.  NOTE: Solar trackers lay flat when the wind exceeds 20 mph and the production goes down).   Extreme cold prevents snow from melting off the panels (-12 to -20 C).  One high producing panel remains with some fouling from snow that I couldn't reach.  Perhaps the high wind will help to remove the snow.