Consumption data for one year with a solar power system that was standing still
As I was browsing through some photos recently, I was reminded of a very expensive saga where free solar monitoring would have saved thousands of dollars in electricity. Read on as we detail episode one of several costly mistakes.
I sometimes regret spending many hours in nursing homes, and I visited one in particular too many times. I’m sure the quality of care is good, but the quality of the solar system has undoubtedly proven to be questionable.
I’m proud that I had nothing to do with the installation. However, I was the repairman sent to diagnose errors and resolve problems. I shouldn’t complain since it was a quaint little town that was closer to my house than the office, and so I often left home and went straight there to spend a day…frustrated.
Solar energy is just reliable, isn’t it?
Conceptually, you can’t go wrong with a solar system. The panels are solid state and the wiring is simple. There is a lot of electronics inside an inverter, but it is generally very reliable because there are hardly any moving parts.
However, in this particular case it was a commercial system that required a Network Protection Unit (NPU). The fatal flaw was inside the NPU, a motor-driven circuit breaker. It carried all the power out of the system and was designed to isolate everything when errors were detected by the controller.
One could easily argue that each of these green pillars is worth $2,000
When a small component in the circuit breaker failed, the entire 100kW system was offline for months. Eventually, the accountants noticed that the electric bill looked suspiciously high, but not after losing an entire summer of production.
The worst? They had lost ⅓ I commissioned the system 18 months ago and did not notice this error when it occurred.
Something so simple
Diagnosing this system was fairly easy. DC voltage came from the roof, but no AC voltage to the three 27 kW inverters.
To find out the exact error, follow the bouncing ball with the multimeter.
How an NPU works is not complex, but this box can cost more than an inverter.
The fancy tripping mechanism inside the circuit breaker was about half the size of a matchbox, but the complexity of the entire motor drive assembly made me realize that the combination of features was not a refinement.
Later NPU models used a simple contactor and separate circuit breaker for reliability.
Another month late
You cannot purchase spare parts for Terasaki industrial equipment at your local Hammerbarn. So by the time we ordered them, shipped them, and assembled them, another month’s worth of production was wasted.
Even though it wasn’t ideal, if the plant had been monitored and someone had been assigned to monitor it, all of the revenue lost in the previous months could have been saved.
This trigger mechanism, colored by the heat of an internal solenoid valve, operates in a “fail safe” manner and shuts down the system.
Automatic notifications are invaluable
Solar inverters offer their own native monitoring, alerts and email notifications that you can customize to suit your needs.
Use them.
With Fronius Solar Web I can program it to ignore surge alarms from my uncle’s1 SWER line system because it’s the boy who cried wolf!
However, the message “Error 457 – No production for 24 hours” lands directly in my primary email inbox.
Independent services like Solar Analytics can offer even more granular performance comparisons. I highly recommend them because they know what the weather is like in your area even if they can’t detect a DC insulation or ground fault. For such an electrical fault, you still need the monitoring that your inverter is equipped with.
Don’t rely on your solar dealer
As mentioned, solar retail companies have a fleet monitoring portal that allows them to see your power system in action.
Rest assured that this poses no privacy risk because no one at your solar company will bother to look at your system until you call and ask.
Unimportant alerts clog the system and drown out real problems in the noise. In any case, it’s best to monitor your own system.
When You If you raise concerns, remote monitoring will likely save you a trip fee. Your installer can log in and check the system remotely.
They may be able to allay fears, identify faults, or even bring appropriate parts to troubleshoot problems during a visit.
Support is essential
A reliable installer will show you his monitoring and interest in using it. What you don’t want is a sales company that goes bankrupt and disappears with your warranty and your monitoring.
If your installer is down or you just can’t stand the sight of him anymore, moving your system to another company isn’t a problem. Manufacturers usually have a process listed on their website that you can follow yourself without having to seek technical support.
Less than 40% of this 1,070-strong installer fleet is visible online
Make sure you are connected
In my favorite nursing home, Wi-Fi access was problematic. It was annoying to find the right signal with sufficient strength, be whitelisted by the IT security team and still not be allowed to trust the password.
Then, after half a day on the phone with tech support, it was finally proven that the communications card was defective. A replacement was ordered for another day. Luckily, my iPad remembers passwords, so I didn’t have to deal with thoughtful coworkers entering all the network details over and over again.
Remember when software came on CDs? This survives in a forgotten storage room in the dementia department.
If you have changed your internet tariff, router, dealer or NBN connection since your solar system was completed, there is a chance that the inverter is no longer connected. WiFi works, but the best way to ensure reliable coverage is to use a data cable from your inverter directly into your internet router.
Make sure that emails coming from your monitoring platform (such as Solar Web, iSolar Cloud, PV Master, Aurora Vision, SEMS) are received and do not end up in spam filters.
Unless your system is equipped with a flash light or buzzer, These email notifications are considered a legal obligation So that you as a system operator know whether a ground fault has occurred in your solar system.
As modern solar energy moves toward flexible export, demand response, and emergency backstop control through networks, Wi-Fi connectivity becomes an economic necessity, not just a mere security rule.
Late payments cost real money
With electricity accounts now transitioning to utility rates, solar energy has a secondary benefit; Reduction of consumption peaks. Generating energy behind the meter can avoid exceeding demand thresholds and reduce your bills in ways that were not previously possible.
In our nursing home example, operators lost solar kilowatt-hours for months, ultimately leading them to import thousands of dollars of electricity instead.
I’d like to report that they learned their lesson, but in our next update I’ll explain that that simply didn’t happen. There will be more stories of suffering to come.
In the meantime, you should check if the app is installed on your phone and then check your own solar monitoring; It could save you thousands.
Footnotes
- A single wire earth return (SWER) line system is a rural power distribution method that often results in voltage irregularities ↩
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