Tag Archives: PV

March 2020 Solar Production and EV Efficiency

My solar monitoring platform was available for an entire month and all of the panels on my solar system were fully functional.  This led to a pretty good March for solar production:

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Just under 578 kWh for the month.  This compares with ~316 kWh in 2019 and ~424 kWh in 2018 or an increase of ~83% and ~36% over each of those years respectively.  My guess is that the average year-over-year production increase will fall somewhere in the middle of those two on average over the course of the next year.  Only time will tell.

For the month, my household ended up “net positive” ~67 kWh.  My household was also “net positive” in March.  It is my assumption that the next couple of months will be big “net positive” months in terms of electricity consumption versus production since the period before the hot summer months is generally light on consumption.

One factor driving a lower level of electricity consumption is the fact that we are not driving much, if at all, as a household due to COVID-19.  All of my children’s activities have been cancelled and we are working from home.  I cannot remember if I have charged my Nissan Leaf in the two weeks we have been home from an aborted spring ski trip to Colorado.

For the month, I drove my Nissan Leaf ~652 miles at an average efficiency of 5.3 miles per kWh.  Almost all of those miles were in the two weeks before we locked down at home.  I “saved” ~746 pounds of carbon dioxide emissions compared to driving my truck assuming that I pulled all of the electricity from the grid at my utility’s average carbon intensity.  In the first quarter I have “saved” ~2,785 ponds of carbon dioxide emissions.  Given that I am now producing more electricity via my solar panels than my household is consuming, including EV charging, those carbon dioxide savings are even greater.  The same logic goes for the fuel cost savings.

April is going to be a weird month for sure.

Back to Full Strength

At least in terms of solar photovoltaic production.  Last week I wrote about my solar array having a single panel that seemed to be out of commission for some reason.  I was able to diagnose this via the monitoring platform that is part of my system from Moxie Solar.

Here is what things look like today:

Physical Layour Fixed

You will notice the formerly inoperable panel in the top right corner is producing electricity like a good boy.  The problem was a loose connection that took about five minutes for a tech to diagnose and repair.

Now I can put a few more clean, green electrons back into the grid.

The Importance of Solar System Monitoring

Once a solar system is installed, the local utility has signed off, and the city inspectors give the go-ahead there is a moment of relief as the lever is finally pushed into place.  Once operational, your photovoltaic array sends clean and green electrons through your home’s electrical system and out into the world.  Hopefully.

A lot of monitoring systems give you a picture of the total photovoltaic system.  You can usually see how much the system is producing in aggregate and maybe you get a picture of your production versus consumption.  However, there is a level of system monitoring below this aggregate level that is critically important.

Take a look at the following system layout:

Solar Physical Layout

Notice anything odd?  Look at the top left corner.  Notice the panel producing 0 kWh of electricity?  Something is wrong.  It could be a bad panel.  It could be a bad connection.

Had I not had access to a panel by panel breakdown of production I would never know that one of my panels was not producing.  Now it is easy to request service and it should be a quick fix rather than a laborious process of diagnosing the malfunctioning part of the system.

February 2020 Solar Production and EV Efficiency

The monitoring platform for my expanded photovoltaic array is back online:

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It was only turned on for the last few days of the month, so I do not know how the system performed for the entirety of February.  However, in just four days the system recorded more production than the entire month of February last year.  Granted, the array was under ten inches or more of snow for most of that time last year.

Overall, I ended up nearly even in terms of production versus consumption.  The actual number was approximately 4 kWh “ahead.”  I am figuring that I will end up “ahead” of consumption for most months here on out until January rolls around again.

The crazy thing was that if I had driven a normal amount this month I would have been even more in the black.  Due to a work commitment out of town for an entire week I drove approximately 50% more miles per day on average in the month of February.  Those highway miles added up to a lot of extra driving at a not so efficient clip.

For the month of February I drove ~973 miles at an average efficiency of 4.6 miles per kilowatt hour.  That driving used ~212 kWh of electricity and saved ~1,086 pounds of CO2 being emitted, assuming all electricity was pulled from the grid at an average carbon intensity for my region of the country, versus if those same miles were driven in my truck.

January 2020 Solar Production and EV Efficiency

Okay, January kind of sucks if you are living the electrified life.  On average, January and/or February are the worst months for solar production and EV efficiency.  Why?

For my solar photovoltaic array the answer is in two parts: snow and clouds.  For part of the month, it is common for my panels to be covered with snow.  I have tried my best to knock the snow free with a foam roof rake, but this is really just scratching at the surface of the problem.

The second part of the problem is that the month of January is just not that sunny in eastern Iowa.  The sun came out on Saturday and everyone in the house sort of looked surprised.  It was a “Do you remember the last time you saw the sun” kind of moment.

The end result is that you do not make very much electricity.  For the month I am unsure of just how much my PV array produced because my monitoring setup is still not reporting correctly.  Needless to say, I know that I was in the hole ~400 kWh for the month.  Ugh.

The cold weather will also bit you on the rear end when you are driving an EV.  Granted, the cold weather will also impact the efficiency and performance of an ICE vehicle as well.

When you turn on the heat you watch your range and efficiency go into the tank.  On my 2015 Nissan Leaf which uses a resistive heater I can see the “guess o’ meter’s” range drop by at least 30% and more like 40% usually.

If it gets cold enough the “guess o’ meter” will also show less range because the batteries are chilly and cannot discharge as well.

To add insult to injury, regenerative braking is not as effective in the cold weather so more energy is lost to heat in the form of actually using the brake pedal.

However, given all of that downside I still managed to drive 850.5 miles at an average efficiency of 4.7 miles per kilowatt hour.  This compares with the same period last year where I averaged just 3.6 miles per kWh.  I chalk that up to the weather not being quite as harsh and me understanding how to wring more mileage out of my little Nissan Leaf.

For the month I saved ~953 pounds of CO2 from being emitted versus my prior vehicle assuming an average carbon intensity of electricity from the grid.

Like most people in eastern Iowa I am kind of excited to see February be here because it means an end to the ceaseless political ads and a potential break toward more electrified living amenable weather.

December 2019 Solar Production and EV Performance

The additional capacity for my solar photovoltaic array was finally turned on in the middle of December.  For some reason the monitoring software is screwed up—probably because it is tied to the old inverter that is now powering an array for a friend in northeast Iowa.  It is my hope that the issue is resolved in the next few days and I can start comparing total production of the array.

Regardless, I have a decent idea of how I am doing relative to total consumption versus total production using the readout from my bi-directional meter.  For December I ended up using ~208 kWh more than I produced.  Considering that my system was not operational for half of the month I am going to take this as a good sign that I should now produce more than I consume most months out of the year.  In the past December has been one of the worst for solar production.

Knowing my numbers at the beginning of the year it is my estimate that I will be net positive when it comes to total consumption versus total production even including my electricity usage for driving my Nissan Leaf.

For the month of December I drove my Nissan Lead 574.7 miles at an average efficiency of 5.0 miles per kWh.  This translates into a CO2 savings of ~651 pounds compared to driving my prior vehicle assuming an average carbon intensity of electricity from the grid.

For the entire year, I drove my Nissan Leaf ~7,987 miles at an average efficiency of 5.2 miles per kWh.  I think this is a pretty good average efficiency based on what I am seeing on forums and what not.  This represents a savings ~9,119 pounds of CO2 compared to driving my prior vehicle assuming an average carbon intensity of electricity from the grid.  It also represents ~$1,132 savings in fuel costs assuming I draw power from the grid at my residential rate.

The Downside of Snow

Unlike a lot of people I actually like snow.  I like snow so much that I spend my hard earned money to strap wooden sticks to my feet and fling myself down mountainsides covered with the stuff.  Come to think of it, when I describe my ski trips like that it does not sound so sane.  I digress.

The only problem that I have with snow is that it covers up my solar panels.  Like the two inches of snow that fell overnight:

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After last year’s snowy and cold January and February left my panels snow covered and non-productive I decided to come into this winter prepared.  Enter the SnoBroom:

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Okay, the SnoBroom is just the blue foam blade atop the extendable pole.  The extendable pole might be the true star of this story.  It extends to a maximum of 24’ which seemed like a lot right up until I was clearing snow for real:

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With the pole alone I was able to clear the first row of panels and a portion of the second row.  You can see on the closest panels that I spent some time with a step stool to get additional height.  Yes, I was able to nearly clear the panels.  No, I did not fully clear my array.

In the interest of full disclosure I need to come up with a better approach to clearing the array.  Snow, aluminum steps, and a little liquid moisture make for a precarious endeavor.  Practice makes perfect, right?

The other reason I did not push the issue this afternoon is that the temperature is supposed to be nearly 40 degrees with sunny skies tomorrow.  The snow will take care of itself this time.