What noise does a tracking solar panel make?

Solar panels are admittedly somewhat new to us all. Some of the team here have a few on their rooftops, but when it comes to an industrial sized version they are few and far between in Suffolk. For good reason. And none of these are tracking solar panels.

A tracking solar panel is one that follows the sun in the sky from east to west. And they reset back to east when the sun has set ready for the morning (we think as Enso Energy haven’t answered this question yet). The panels are linked to a motor that moves the horizontal bar that the panels are mounted on.

One of the most common concerns is around the sound of the tracking solar panels. These are very new to the UK, with only a handful of tracking sites built. And not anywhere near Suffolk. So what noise does a tracking solar panel make?

What have Enso Energy said?

Not a whole lot. Enso Energy had an assessment of the baseline noise (i.e. what it is now) done during 15th – 21st July 2020.

The baseline measurements came in with a continuous background noise at 39dB-48dB during the daytime, and 35db-45db at night. The maximum recorded noise was 75dB during the day, and 67dB at night. We’d like to note that there were 4 noise recorders and these were all next to (or as close to) the nearest properties. Not one recorder was placed along a public footpath or near woodland. These quite and serene areas would have given a more realistic picture of the entire site.

According to their own guideline table, the continuous range of sound is comparable to a living room during the day to a typical office. If you’ve walked the paths around here you’d know that’s not really the level of sound we have in the countryside. Except maybe when the military helicopters are flying overhead or you hear a badger crunching on a snail.

Based on their concept plan the assessment indicated a “predominantly low impact during the day, and a potential adverse to significantly adverse impact during the night-time.” However with better design this can be reduced to a low impact that is “not considered to be significant in the context of the EIA regulations.” It’ll be interesting to see how their concept design changes and the impact this has on noise levels, and presumably a new noise assessment.

We’re also curious about the “occasional passing trains” they recorded and the failure to mention overhead helicopters! We’re not near a railway line but we are under the flight path of Wattisham RAF helicopters…

So what does a solar panel actually sound like?

With permission to share from a friend who recorded this herself, we have a video so you can hear the continuous background hum.

Note that the speakers in some devices are tuned to reduce the deeper tones. We recommend listening with head/earphones.

This is from a 10 acre solar farm in Greensburg, Indiana, USA. Enso Energy is 242 acres.

Enso Energy have supplied no data to their noise experts (inacoustic) on the sound of the solar panels themselves.

In the video you can hear some rather loud crickets as general background noise. But the solar panel hum can still be heard.

And when the motors start moving the solar panels?

Courtesy of our friend again, she has allowed us to share this video. You can hear when the motors kick in.

Enso Energy have supplied their noise experts (inacoustic) with the sound data of this equipment. Apparently there will be approximately 2000 PC Tracker Motors, and when standing 10m from them you will hear a sound level at 29dB. Apparently this is the equivalent of a “quiet bedroom at night”.

Conclusion

The most interesting part of all this is that Enso Energy have supplied noise level data on the technology to their expert. Yet during the public webinar Enso Energy explicitly stated that they can’t tell us what technology they will be using because even they don’t know what technology they will be using yet. How can they supply the noise data of the technology to an expert if they don’t know what technology they are going to use?? Hmm…

We’ve also asked for a less obscure sound level map, (they’ve blacked out the site area) but so far nothing has been received. Maybe we’ll have to do it for them.

Overall we find that the noise assessment is not a true reflection of the full site area, and quite showing of their lack of respect for residential areas. Only putting the 4 sound recorders near to the site boundary’s closest houses is not truly reflective of the full site area. If you’ve ever walked the footpaths you’ll know that on some occasions there is almost zero noise, aside from your own breath and footsteps. You can hear the gentle rustle of a bird or a mouse scurry away because there is nothing else to hear. It’s blissfully quiet. And if the closest points are recording sound levels akin to a “typical office” then their site is just a bit too close for comfort. How close to your home would those recorders need to be to get that level of sound?

We also appreciate that the videos are not necessarily of the same panels and motors that Enso Energy will use. But we hope this has given you an idea of what the noise may be like. After all, Enso Energy certainly won’t be giving you a video like this because they don’t know what technology they are going to use(!) and they’ve never built a solar farm either.

As for the conclusion, you’ve heard the videos. Do you think a “quiet bedroom at night” is an accurate representation of the noise a tracking solar panel makes?

4 thoughts on “What noise does a tracking solar panel make?”

  1. Mention is made of several portacabins with electrical equipment and (I guess) transformers within same. It would be good to get some noise levels adjacent to these as well.

    1. Yes there are currently 11 shipping containers proposed to house electrical equipment such as transformers and inverters. This is an excellent point and we will look at finding something for you.

  2. Pingback: What noise does an inverter make? – CARE Suffolk

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