Performance Issues

Last modified on April 6, 2020

My system just isn’t performing like it used to.  How do I get it back to its former glory?

Low output can be a big problem.  Reduced energy production means lower savings or lower revenues and translates to a poorer return on investment and reduced environmental benefit.  Here’s a list of the most common causes and what you can do: < ?SEPARATE INTO IMMEDIATE NO POWER OR REDUCED ENERGY OVER TIME?>

Snow cover

            Believe it or not one of the most common phone calls we get after a new snow fall is from clients who have just receive production alerts from their web based monitoring system saying the system, or part of the system, is under producing or offline.  When a solar array (or part of an array) gets covered in enough snow it can no longer generate enough power to ‘wake-up’ the solar inverter.  If a solar inverter doesn’t wake up it can’t communicate with the system monitor and this lack of communication often triggers an email alert.  If you get such an alert shortly after a fresh snow fall, check the array first.  If it’s covered in snow you’ll need to wait until it’s clear before further troubleshooting.  Most likely the issue will melt away with the snow.  If the array is clear and the error remains, call us with the error message and we’ll investigate.

New shade

As time marches on trees creep taller and taller.  Eventually that row of poplars that seemed so low and far away are now edging into the space between the sun and your array, causing shadows.  Partial shade can have noticeable effect, especially in the winter months when production is already low.  Even dappled shade from a deciduous tree with no leaves will cut into production.  Have a look on a sunny day.  If you are unsure, we can do a shade analysis to determine potential performance reductions.  We have some creative ways to deal with partial shade on your array (and they don’t always involve a chainsaw!).

Unseasonably overcast

Sometimes it is just a crummy sun month or sun year.  Traditionally, November was always the grayest month but, with our constantly changing climate, that’s no longer reliable.  A bad month or year for sun rarely accounts for variations greater than 10% though (and we can also get sunnier months than normal as well!).  If your output has changed by more than 10%, it could be something else.  We monitor many systems. If you suspect it’s more than just the weather, give us a call with your energy production numbers and we can compare with what we’re seeing elsewhere.

Inverter down/string down

Depending on your system design/details, even a partial loss of production could be the result of a system malfunction.  There are many electrical connections between the sun and the grid and we are intimately acquainted with all of them.  If you have a web-based monitoring system we can usually narrow down the problem in a matter of minutes.  If you have inverters with a display screen or indicator lights, call us while you’re in front of the inverter.  We may be able to zero in on the problem with you on the phone as our eyes and ears.  Though some issues, such as warranty claims, will still likely require a site visit.

Unhospitable host

Even the best solar generating system can underperform when connected to an unstable grid.  Your system is only allowed to generate power when the grid is stable and solid.  If the voltage on the grid is too high or too low or there are spikes created by irregular, large loads, your system will disconnect until stability returns.  Since it needs to see at least 5 minutes of stable grid, even if the issue happens only momentarily a dozen time per day, your system will be down for an hour or more.  Fortunately, we have the tools to do long term grid monitoring and if we see issues we can communicate them to the local distribution company (eg. Hydro One) and get them resolved.  The local distribution company is obligated to have a stable grid and are mandated by law to correct issues.  Often it’s just a case of them not being aware of the issue.  Once they are aware they can take action.