Updated: 18th January 2021 – Enso Energy have changed their proposal from 11 inverters to 16.
We’ve looked at the noise that comes from a tracking solar panel, and we were asked about the inverters. So here goes…
What is an inverter?
When a solar panel produces electricity it is in a DC current. In order to convert it into an AC current (like we use in our homes) it must be inverted. And in it’s simplest form that is what an inverter does.
In utility-scale solar farms (like Enso Energy & EDF Renewables) these inverters are stored inside large shipping containers. And these shipping containers are dotted around the site, taking in the DC electricity from the solar panels.
What information do we have?
Neither Enso Energy nor EDF Renewables have released details on the inverter technology they will using. Enso Energy have stated that at this time they do not know what technology will be used. However interestingly, Enso Energy were able to submit noise ratings for their noise analysis(!) so we have a little information, even if it is completely bogus because they don’t know what technology they will be using.
In the Enso Energy noise report it states that at a distance of 10m from the inverter, the noise level during the day will be 59dB, and during the night it will 49dB. Inverters operate at a lower duty during the night time when the solar panels aren’t producing energy. According to their comparison chart this is similar to being “Inside a car” (we presume while it’s actually moving at speed), to a “Typical Office”.
And that sounds like….?
Yeah it doesn’t really give you much of an idea what it sounds like does it.
So we’ve found this video recording the sound of an inverter. We appreciate that this probably won’t be the exact same model that Enso Energy and EDF Renewables use, but they won’t tell us that, so this will have to do for now. We believe at the end the man talking says “but they don’t get too loud.”
Enso Energy have said there will be 16 inverters across the site, 6 of which will be adjacent to currently very tranquil public footpaths. EDF Renewables haven’t given this information yet.
The inverters will be working continuously throughout the life of the project. That is 40 years for Enso Energy, and 35 years for EDF Renewables.
The Enso Energy noise report states that the noise from the solar farm is “likely to have a low impact”, but the baseline* recordings weren’t taken across the full spectrum of the site. They were taken near the likely noisiest points of the site and used as a baseline across the whole site. The typical noise level along a public footpath (almost nothing) won’t be the same as that next to a house full of people. Especially on warm summer days like when the recordings were taken in July.
*The term “baseline” simply refers to the starting point. i.e. what the noise level is like now.
You may not be standing quite this close to an inverter, but we all know how far noise travels in these wide open landscapes.
How does the noise from this inverter compare to the noise you hear outside now? Would you agree with “low impact”?