How do you assess system performance?
Solar systems can be confusing to look at. There are tons of different panels, locations, wiring, let alone the graphs or charts provided by your solar monitoring company. To assess your solar system’s performance, we need to define what exactly “performance” is, and what it means for that to be “good” for YOU.
By solar system performance, we mean:
“The ability of your solar system to hold up to its original estimated production on a yearly basis - without major errors”
How do we define this as “good” or “bad” in your situation?
Well, it all comes down to expectations set forth by your solar agreement (estimate solar production in kilowatt hours) vs your homes electrical usage. If you simply compare what was listed as the estimated yearly production number in your contract (kwh’s), to what the system has done year over year in your monitoring portal, you can get a great look at overall system performance.
Essentially, did your system perform exactly how it said it would in the contract? This production number might be 8,550 kwh’s, did your system hit 8,550 kwhs? Did it go over, or is it slightly under? If it is really close to that estimated number, say within 150 kwhs plus or minus, that is great! That means your system so far IS holding up to it’s performance estimate.
All you have to do to assess your systems performance then is be familiar with your monitoring portal, and check on it every year to compare. You can also check month to month to ensure there are no major errors showing. This is where Solar Reveal comes in, we can get you a general quick answer on this if you reach out to us here.
HOWEVER this does NOT mean that you automatically will be saving just as much money as you originally thought. You very well might, but there’s more to that equation when it comes to saving money.
How does the saving money side work then?
Saving money in New Jersey, comes down to comparing how much electricity you used from your solar system VS the grid (PSEG/JCPL/ACE etc). In the very best case scenario, your solar system produced 100% or more of your electrical needs ALL year, and you did not pull ANY power from the utility grid to use. This would mean your utility bill is basically zeroed out, and you only paid the amount owed to the solar company/loan (depending which agreement you got). This therefore saves you the MOST money because you are likely getting the discounted rate from solar, and NOT paying anything to the utility company, which typically is a higher rate. This slightly changes depending on which agreement you have, but the general principle is the same. The LESS you have to pull from the grid (because your solar generated it) the more you overall save.
Solar Production + Home Energy Efficiency
S.P. = Solar Production
Opt H.E. = Optimized Home Efficiency
The numbers on the chart are a bit arbitrary, but it proves the point.
Therefore it’s a simple equation we can use. Think of “x” as your solar generation and “y” as your homes electrical usage. g is the payment owed to the utility.
x - y = g
If g is positive, you get extra net metering credits stored on the grid (saving you additional money)! If g is negative, you OWE money to the utility (just like before solar) at their usual rates.
Therefore, saving money (on a base level) comes down to comparing how much electricity you use vs the solar production. You homes usage is JUST AS IMPORTANT as how much power your system produces. This is the biggest MISTAKE I see solar companies forget to mention, because in theory they can sell you larger solar systems and make more money. The LESS power you use in your home, the more efficient you are, has just as much weight and importance on savings than the amount your system produces. Solar production AND home energy efficiency is the double whammy to savings. So BE efficient if you can! Check out blog 2 where we give helpful tips and tricks on that.
One thing to keep in mind, is older solar systems, say over 10 years, may inevitably encounter issues. This may be simple fixes, like a wire going bad due to weathering. It could also be a big fix, like replacing an inverter. It’s good to get a FULL report on how every aspect of your system is working if you are in this boat. We are partnered with local solar companies in NJ that can do this assessment for you at a fair cost. This is something we highly recommend IF you notice errors on your system, or any kind of drop in production over time. If you’re someone who JUST bought the house and want a full report, this is also a good option then too. Click here to learn more.
