Does Solar Power Make Noise? - AVL Designs, Inc.

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So, let’s talk about solar power. Does solar power make noise, or doesn’t it?

We had someone approach us recently by email saying “Hey, we just need somebody to do a quick noise study. Shouldn’t be any big deal. Hopefully you can knock it off in a day or so.” My response was “For what?” I quickly learned that it was a solar farm that has 12 gazillion acres of panels going into an area which is rural and has a community noise code. Look at my previous video. This was a noise code that basically says, “make sure nobody is bothered.”

Power Supplies Always Make Noise

I didn’t know a whole lot about solar power, but I do know about electrical devices. I know that dimmers, inverters, and any kind of power supply always makes noise. The bigger the power supply, the bigger the noise. The frequencies are dependent on the voltage at which they operate – what load they’re operating at.

Most things, oddly enough, make more noise at half-load than they do at full load. So, I had to do some research before I even took the project. I went online and found that on YouTube there are some great videos when you search for “solar farm noise.” There are some good ones that were measured very close to, or video shot very close to, some of the solar farm equipment. The video revealed some really annoying 3 kilohertz and 6 kilohertz buzzing noises that came out of all this equipment. Now, knowing what we were dealing with, it seemed that we should be able to calculate where would be a problem. The town code didn’t really define proximity to the noise. Was the code referring to where people live or was it about the property lines because the properties people own there are farms and they are huge. Some of this equipment is operating let’s say 300 feet from a property line, but it’s 2000 feet from the nearest house.

For Sure, This Thing Was Going to Buzz

What we were starting with is that we do know is that this thing was going to buzz. We were told that there were a ton of these inverters going in and they also had fans in them so that, so when they start overheating, they would cool. But how do you figure out when this is occurring? Our next move was to contact the manufacturer and we got a number from them that is just a dBA number at a particular distance. Well, that wasn’t helpful. We needed more data. So, we sent them an email asking for FFT narrow band data and explained that we needed to know how they took levels on the other equipment. We needed measurements on all sides of the inverters to determine which side the noise was coming from. They denied our request.

Thinking that was kind of odd, we then went to their website and found that they have a white paper explaining how they are working to reduce the noise of inverters, which says to me they know they are noisy and that is why they didn’t want to give us the data. We explained to the people we were working for that with just dba we couldn’t know what frequencies are in it. We didn’t know if we were looking at fan noise in their number. Are we looking at fan noise with inverter noise, like buzzing? Are we looking at transformer noise from all the transformers on the site at lower frequencies? We didn’t know what we were looking at.

You want us to sign a what????

We found out that the only way they would provide this is if we signed an NDA, a non-disclosure agreement. What those mean is that any data they give you, you can’t disclose to anybody else. We couldn’t use it in our measurements, and we couldn’t use it in any of our reports and summaries. In my world, and I know that not everybody agrees with this, this means they are probably hiding something.

So, when people talk about solar power and how wonderful it is, it may be wonderful unless you live next door to it in the wrong orientation. In our final report we basically gave them lots of warnings. We explained frequency content and we gave them links to videos on YouTube where they could hear what we’re talking about. We added that we could not predict when and where it was going to be or at what level because we simply could not obtain that data. We did have the dBA numbers, though, and even those were higher than they should be at what we considered to be locations of concern.

Now let’s imagine we are talking about a neighborhood, and somebody wants to put a bunch of solar stuff on their roof with a small residential inverter. If they don’t put that inside their house and it ends up outdoors somewhere, we’ve seen some data online of some of the residential inverters where they rate them at say 50 dBA and they’re more like 80 under certain load conditions because of the buzzing noises. Some manufacturers are very good, some are very poor, so it is kind of a buyer beware thing.

Even if you are putting one in your house, if the inverter ends up inside your house and it’s making 3 kilohertz and 6 kilohertz of noises, go watch some of the videos online where they are installing it inside a house someplace. Obviously, the noise only happens when the sun is out. At night it is not going to be making noise, but during the daytime it can produce a significantly annoying noise if it’s loud relative to what else is going on in your house.

Again, we would say “buyer beware.” Solar does make noise and whether it’s a problem or not depends on where the equipment is placed, how loud it is, and a large number of other factors that are environmental. Just don’t commit to it without thinking your way through.