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  • Writer's pictureAPD

Adding Some Irradiance Capture

Updated: Feb 17, 2023

Following on from last week’s excitement, which saw us switch on our 7.5kW wind turbine, it was the turn of our 30kW solar system.

Our Solar Array

Atop the APD building, we have 75 Perlight Delta solar panels, installed on custom built mounting frames.

Each frame holds two 400W panels in landscape format pitched at 35 degrees and weighted down to our flat roof with no drilling required.

The panels are arranged to face due south, in rows that maximise the available space but are far apart enough to avoid casting shadows on each other.

Capturing Solar Irradiance

Naturally solar panels will always work best in the full glare of the sun, however the panels will start producing with any solar irradiance, even through cloud, which is essential when you are relying on the infamous Scottish weather!

Solar irradiance is the measure of solar power at a location. It quantifies the amount of solar energy that arrives in a particular area at a given moment.

The panels pick up the UV wavelengths and turn them into DC voltage which we harvest and convert to AC.

The Solaredge Inverter

Each solar panel has its own power optimiser, with a unique barcode. During our commissioning this week we scanned each optimiser barcode into the Solaredge Inverter which then provides it with the real-time data to control and monitor each panel individually.

Although this step is not required to enable a PV system to function, using this barcode system does allow for a safer installation with a higher output and more accessible on-going monitoring and maintenance.

Without it, a solar panel is just a simple generator connected in series to the next. If any panel in that string fails then the whole string would fail to produce. The same would happen if any of the panels were obscured by cloud or other shadow.

Using an optimiser eliminates this risk by turning each panel into an individual generator, continually informing the inverter of how it is performing and capable of bypassing itself automatically on failure or obstruction and without hampering the generating capabilities of the other panels. It also means we can pin point faulty panels quickly.

After the team spent the day completing all the connections to the inverter, ensuring the system was commissioned correctly and checking G99 compliance, the isolator was enabled and the panels began generating, just in time to benefit from the lengthening, and hopefully, sunnier spring days.

Energy Insights System

In tandem to the commissioning of both our solar array and our wind turbine, we’ve also been busy fitting an innovative energy insights system. So far we’ve fitted ten sensors, two of which are now monitoring our renewable energy generation.

We’ve already seen some pretty promising results despite the less-than-optimal, calm and cloudy weather conditions of late.

Since the sensors were fitted last Friday, we’ve seen several periods of time where we’ve been generating more than we are consuming.

The other eight sensors are busy monitoring the energy consumption of the APD building – another key factor in the bigger energy generation picture - but more on that another day!

What’s Next?

APD’s “Journey to Net Zero” feels like it has really picked up the pace since the new year and we’re not planning to slow it down anytime soon.

Next on our to-do list is the incorporation of the battery storage system. We’ve briefly mentioned The Pixii PowerShaper previously, but until now it’s been waiting on the arrival of a bi-directional energy meter. This specialist kit will allow us to detect when the batteries are being charged and when they are expending power. Not only will this supply us with key information, the addition of the meter will also give our system full G99 compliance.

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