WASHINGTON, D.C. – A new report from ACORE presents survey data from leading investors about the performance of tax equity structures and how they continue to play a significant role in financing clean energy projects.  

For more than two decades, tax equity has provided a stable private financing mechanism and an important source of capital for new clean energy projects in the United States. The U.S. clean energy industry now attracts over $45 billion in tax credit investments annually, of which more than $20 billion is provided by banks through tax equity arrangements. The report provides an expert look into how tax equity financing transactions are structured and the risks and returns associated with these deals.

Key takeaways from the report include:

• Overwhelmingly Positive Returns: An ACORE survey representing over 75% of the tax equity market showed that these investors typically receive a median 8.4% return on current investments.

• Minimal Downside Risk: Risks associated with recapture, foreclosure, and bankruptcy have been exceptionally low for tax equity investors.  

• Demand for Tax Equity Exceeds Supply: Tax equity is responsible for between one third and two thirds of a clean energy project’s overall financing, and about 45% of tax equity is provided by banks through tax equity arrangements. Demand for tax equity will accelerate as investors look to finance energy storage and other eligible technologies that continue to qualify for tax credits.

“This report reflects ACORE’s commitment to delivering solid, impartial insights from the entire span of the clean energy industry,” said Ray Long, President and CEO of ACORE. “Getting clean energy tax policy right is the key to ensuring the United States is ready to deliver the power needed for tomorrow’s economy.”

The Risk Profile of Tax Equity Investments: 2026 Edition, is available in full on the ACORE website.  

###

About ACORE
ACORE is a nonpartisan nonprofit organization that operates at the intersection of affordability, reliability, and clean energy deployment. Our work is focused on stabilizing energy prices, strengthening the electric grid, and driving investment in cost-effective technologies to ensure that clean energy delivers for people, businesses, and the U.S. economy.

ACORE’s membership includes clean energy investors, developers, energy buyers, power generators, manufacturers, and energy providers. In 2024, nearly 80% of the booming utility-scale domestic clean energy growth was financed, developed, owned, equipped, or contracted by ACORE members. For more information, visit www.acore.org.  

Media Contacts:

Chris Higginbotham
higginbotham@acore.org

The post New ACORE Resource Breaks Down the Complexities of Energy Tax Equity Structures   appeared first on ACORE.

https://acore.org/news/new-acore-resource-breaks-down-the-complexities-of-energy-tax-equity-structures/

Right-wingers, like the fellow shown here, tend to make broad and unfair generalizations about the left.

Progressives would like to see an economy that works for everyone, not just the uber-rich.  We want wealth creation for the people who need it most.

The best way to make this happen is strong, high-quality public education and universal healthcare.

These are not radical concepts; this is the way the vast majority of the developed world operates.

An Economy that Works for Everyone

Weather Guard Lightning Tech

Blade Breaks at He Dreiht, Suzlon Posts Record Quarter

A V236 blade fails during construction at He Dreiht. Plus a 53 GW US wind forecast, Suzlon’s record quarter, and what turbine noise really measures.

Sign up now for Uptime Tech News, our weekly newsletter on all things wind technology. This episode is sponsored by Weather Guard Lightning Tech. Learn more about Weather Guard’s StrikeTape Wind Turbine LPS retrofit. Follow the show on YouTube, Linkedin and visit Weather Guard on the web. And subscribe to Rosemary’s “Engineering with Rosie” YouTube channel here. Have a question we can answer on the show? Email us!

The Uptime Wind Energy podcast, brought to you by StrikeTape. Protecting thousands of wind turbines from lightning damage worldwide. Visit striketape.com. And now your hosts

Allen Hall: Welcome to the “Uptime Wind Energy” podcast. I’m your host, Allen Hall, and I’m here with Matthew Stead, Yolanda Padron, and Rosemary Barnes. And to lead off this week, s- there’s been some trouble in the North Sea. On July 22nd, a blade failed on one of the turbines at EnBW’s 960-megawatt He Dreiht offshore wind farm.

Uh, EnBW spokesperson said there were no injuries, thank goodness, and that the authorities were notified immediately, which is generally the case in Europe. They’re very safety conscious, of course. But the machine was a Vestas V236, which is a– that 15-megawatt offshore turbine that Vestas is offering. And He Dreiht is where the platform [00:01:00] has made its debut.

So Vestas and EnBW are working together on an investigation, an RCA, a- along, uh, looking at the environmental impact because parts of the blade landed in the water. And the, the images I saw online were like a sheer web that was being pulled in onto a ship, so big pieces of blade. Uh, there’s gonna be 64 of these turbines going into that wind farm, but this is probably a little bit of a weird thing because it does seem like that the wind farm is under construction when the blade broke, which is not the first time this has happened, right?

That we’ve seen blade breaks at, uh, Vineyard Wind and at Dogger Bank on the GE side. Is this just a construction issue, Yolanda, you think? Or is it some sort of, uh, vibration that’s happening during construction that’s putting extra stress on the blades?

Yolanda Padron: We were talking about it a little bit offline and how it might be a loading [00:02:00] issue because it’s not, uh, it’s not in the optimal operating, uh, conditions, right?

Uh, but this is– It’s– I don’t like that it’s becoming a trend more than an anomaly from what we’ve seen on this podcast. Uh, Matt, I know you work a lot in solutions, right? What, what would you recommend people start doing?

Matthew Stead: Yeah. I think, um, more and more there’s ways of just checking out, you know, pre-construction, um, you know, some of the vibration modes, some of the unusual, um, wind loading when it’s in standstill, you know, different yaw angles and so forth.

So there, there’s more and more ways of, um, checking out what the blade is doing when it’s in those unusual, um, sort of pre-con, pre-operation phases. So, um, you know, for instance, um, we do know that there is some sort of sometimes edgewise or flatwise vibration, which, um, you know, maybe is not normal, um, and maybe could be, be [00:03:00] thought about in a bit more detail.

Um, certainly I know there are some research organizations which are looking into this and also, you know, things like blade twists. Um, so what is actually happening in terms of the, um, the twisting of the blade along, along its axis.

Allen Hall: I think the last time this happened, I remember going back and looking at patents about how to protect the blades during this construction phase.

So you wanna prevent the blade from generating lift from sideways winds pretty much. So the designs that I saw were like putting like a, a netting across the blade to disrupt the airflow so that it wouldn’t generate lift. But I haven’t really seen that implemented. Maybe it is being implemented, but these loads are a little odd, right?

I, I, I’m wondering if there’s any IEC certification test that looks into them, uh, just because it’s, it’s happened a couple of times now, more than a handful.

Matthew Stead: We, we saw, um, we saw that picture of some blades on the ground. [00:04:00] You remember they were in storage. Um, there was a, a strong wind that came across them when they were in storage, and there was some, some flutter and, you know, some, some damage it caused, uh, even when they were on the ground.

Um, yeah, I think just thinking out loud, you know how on some, you know, wind stacks and, or, you know, turbine stacks and, um, you know, poles, you know, exhaust stacks. Sorry, that’s the word I’m looking for. Exhaust stacks. They have the, the spiral around it. You know, it’s for around vortex shedding. So maybe it’s an opportunity for, for Rosie to jump in here and, uh, and comment.

But, um, maybe we can put like vortex, uh, spiral vortex, um, you know, dissipators on the, on the blades before they’re fully commissioned.

Rosemary Barnes: So it’s cer- certainly not a, a matter of the design just being a little bit wrong, right? That would mean that it would last for a, for a while and then And then break. But it, it also, it could be several things.

It could [00:05:00] have been a manufacturing defect, a bad one. It could have been transport damage. Tho- those are two other things. It could have been, yeah, you know, like a, a new design feature or material that performed massively differently under real loads than what it did, um, you know, in their computer models and in their coupon tests and in their, um, static tests, fatigue tests that they did.

It could be any of those things. Sometimes you do see problems where technically you’re not supposed to leave the rotor locked out for any period of time because it is not designed for the off, off-axis weird loads that you can get when the blade is oriented in a suboptimal way compared to the wind.

And there have been instances where it’s like technically, you know, that was in the instruction manual, however, nobody ever followed it, and it’s only under extreme circumstances where that actually is severe enough to break it. There, there can be instances like that [00:06:00] where I would say that it- it’s pretty difficult/impossible to actually design s- for safety during any conceivable series of events during installation.

The way that you would do it would be to make sure that the blade can handle any wind load and, you know, up to the maximum gust at any, at any time in any position. But having, you know, done a little bit of work, um, on blade design in my past, it is massive. That is just a massive, massive load that is y- it will never see in its lifetime.

You would have such heavy, expensive blades if you actually designed it like that. Um, and so yeah, the That, that would be probably the most charitable reason for a failure where nobody really did their job wrong. It’s just kind of like some bad luck that happens every now and then.

Allen Hall: Well, it does seem like there’s a trend there between Dogger Bank, Vineyard Wind, [00:07:00] some of the things we’ve seen in China.

During the construction phase, those turbines are very vulnerable and the, the blades can break. Aren’t there extra precautions that could be put in place? Like, you, you could obviously do weather forecasting, and I know that that’s done, but it does seem like it’s, uh, such a consequential problem to have a blade break on a turbine in the North Sea, near Germany.

Like, that, that’s just bad PR. Even if you have all the engineering precautions in the world there, you would still maybe play it a little bit safer so this wouldn’t happen?

Rosemary Barnes: It’s really hard. Like I said, if you want to design it so that a blade won’t break under these, like, really unusual set of operating conditions that happen during construction, not during– Like, during operation it has to be able to handle whatever is thrown at it, like, no doubt.

Um, everybody agrees on that, including, you know, certification bodies. But during installation, yeah, if you want your blade to be able to handle anything that [00:08:00] that area can throw at it, even, you know, one in 50, one in 100 year storm that comes up unexpectedly, I personally think I haven’t done the optimization.

I wouldn’t be surprised if people had. In fact, I would be surprised if they hadn’t. But I bet that it will cost more to design every blade to withstand that than it would to lose the occasional one, you know, one out of What is it? Like one out of 500 blades or something this happens to, one out of 1,000?

I, I, I don’t know, maybe even less, less than that. Um, you know, so it’s, I don’t know how much these blades cost new, but, you know, say a few hundred thousand. Uh, it’s just, it’s gonna be it, it’ll be more cost-effective to lose the odd one every now and then. And like you say, it’s bad PR, but, um, I don’t know.

Is it that, like- It- … things, things happen, things break sometimes. Um, yeah, I don’t know. Is the PR that bad? I’m not sure.

Matthew Stead: So [00:09:00] I, I’ve got a question and, um, you know, on LinkedIn, you know, you see whenever there’s a, um, whenever there’s a failure on L- um, e- everyone posts about it.

Rosemary Barnes: Condition monitoring would’ve stopped this.

If there had only been condition monitoring that, that turbine, then they wouldn’t have had a blade break during construction. That’s why I’m so hesitant to, to, you know, make any calls now ’cause I don’t wanna sound like one of those

Allen Hall: LinkedIn losers. LinkedIn loser.

Rosemary Barnes: I learned that the last, um, root cause analysis, like, you know, catastrophic blade failure, um, the last one that I, uh, yeah, got approached to work on, I was told y- you know, like half a dozen different companies have approached us after they saw this in the news.

So people are ambulance chasing. I’m like, “Oh my goodness, should I, should I be ambulance chasing? Is this a new, a new thing that I should be doing?”

Allen Hall: Let’s take a quick break and when we come back, a fresh forecast says the United States is building more wind than anyone expected As wind energy professionals, staying [00:10:00] informed is crucial, and let’s face it, difficult.

That’s why the Uptime podcast recommends PES Wind magazine. PES Wind offers a diverse range of in-depth articles and expert insights that dive into the most pressing issues facing our energy future. Whether you’re an industry veteran or new to wind, PES Wind has the high-quality content you need. Don’t miss out.

Visit peswind.com today. Well, here’s a number that runs against the mood of the industry. Wood Mackenzie now expects the United States wind industry to add more than 53 gigawatts of capacity by 2030. That is a 5% increase over the previous quarter’s five-year forecast, and the reason is really straightforward.

Shovels are in the ground. Developers pushed to start construction ahead of the July safe harbor deadline, and firm turbine orders reached 1.1 gigawatts, five times the level of a year earlier. So demand is holding up too, [00:11:00] led by a 1.9 gigawatt deal between Google and Xcel Energy. So the One Big Beautiful Bill, or OB3 as I’ve heard it called more recently, is driving wind energy installations up for the time being.

This is somewhat of a positive measure. Does it demonstrate in, in sort of uncertain terms that wind is still a choice for a lot of energy developers?

Yolanda Padron: I mean, we’ve still seen a lot of wind developers continue on, right? And just maybe put something further back down the timeline than they initially would for, for a new project.

Uh, but I, I don’t know. I kind of equate this to, like, you know when there’s, like, a massive sale or something on a, at a store where it’s like, “Everything must go”? And I feel like everybody was just kind of leaning towards that in the short term, and then there’s probably gonna be a lull, [00:12:00] and then just go back to, things will probably just go back to normal, I think.

Matthew Stead: My, my take is that if I had a spare few billion dollars, um, and I was in the energy market I would be building wind solar and battery. And so I would see it continuing

Allen Hall: The existing Department of War review, this is that are not being completed, so it’s holding up a number of projects. That’s gonna eventually hit the courts.

I know it’s in the courts right now. I’m– At least that seems to be some of the news about it, and my guess is based on previous history in the courts is that they’re gonna force the Department of War to either finish the analyses and make some sort of proclamation or to allow them all to pass through.

Uh, just put a stay on the, in the Department of War. I’m not sure how that works because I’ve never heard of that happening in the past, but w- you know, we’re in new times [00:13:00] obviously. But if they, if the courts were able to tell the Department of War to stand down and let the developers go, that would be very interesting.

I think you may see some more activity in wind and that was, you know, off the table just a couple of weeks ago. Is, is that the feeling? I, I know that there’s also some larger discussions. I was listening to this discussion from an MIT analysis about how wind is gonna suffer because solar is so cool and battery is the hot thing.

But in reality, good luck, right? I think you have to have all of the above scenario to get your projects done. If you can’t rely on gas turbines, you better be looking for every possible electricity-generating piece of equipment you can get your hands on right now.

Yolanda Padron: Do you guys think it’s gonna be one of those things where the US kind of turns away from its traditional cowboy-like way of approaching wind [00:14:00] turbines?

Or at least like blades, you know? Because there’s gonna– there seems to be a lot more I, I don’t know if a lot more restrictions, but a lot more implementation of those restrictions on the operation of wind turbines, um, just like from bird monitoring and just a lot of issues that you might see on a wind site that maybe people didn’t care too much to look at before.

Allen Hall: Well, the argument that MIT was making was operating wind turbines is harder than running a solar farm, which generically is true early on. I think that’s probably true. But from what I see from solar farms and hear from operators, solar farms are not easy either. They have their own problems like fire, hail, uh, yeah, bad inverters, electrical problems, animals eating the wires.

Like, everything comes with this set of issues that it has to work through. But wind’s been going a little bit longer. I feel [00:15:00] like there’s an infrastructure there that solar is just now developing, and the history from large solar developments like in, in Spain has not been great over time. And Australia’s sort of a little bit of a different case, Rosemary, where most of the solar in Australia is put on top of people’s roofs.

But is there a real advantage to solar and battery over wind?

Rosemary Barnes: I think yes. I think it’s, it, like, it’s not The scale is, yeah, there, it, there is maintenance and management to be done on a solar farm, but it’s not like on a wind farm, uh, in my opinion.

Allen Hall: Why? Why do you say that?

Rosemary Barnes: So when I talk with asset managers for solar farms, their number one challenge, at least in Australia, is, is grass, managing the grass.

And in fact, there were some solar farms in Victoria that got shut down briefly by the safety regulator because the grass levels were not s- not safe in terms of, you know, being a fire hazard. You know, like basically it’s mowing the grass, and it’s once a year driving some drones around that are doing [00:16:00]thermal imaging and seeing if there’s any faults there, and then replacing them.

So there’s stuff to do, but it’s not like as much stuff as there is in a wind farm. I’ve always thought that it’s wrong to have wind and solar competing against each other, and it’ll be, you know, like one renewable generation to rule them all. I think it’s definitely true that solar is cheaper and simpler than wind energy.

It had a big disadvantage up until recently because it turns out that the sun sets every single night. I’m not sure if you guys were all aware of that, but, um, yeah, people, people have gotten in touch with me on LinkedIn comments to let me know that that’s true, that the sun sets every night, and sometimes it’s not windy.

Are these two… You know, mind absolutely blown from the, um, YouTube commenters.

Matthew Stead: LinkedIn losers. Yeah.

Rosemary Barnes: Not so much LinkedIn losers, like YouTube, YouTube, um, I don’t know, Y- YouTube enthusiasts. But then batteries came along and started getting cheap enough that you can quite easily cover, you know, at least the evening peak with, um, by adding [00:17:00] batteries to a solar farm.

So I think that that together has reduced how much wind energy we need by a bit. But what it hasn’t touched is, um, the times when there isn’t solar available. So wind can step in for that, wind can step in for cloudy weeks and, you know, that’s somewhere like Australia, which is, you know, the most favorable place for solar plus batteries.

But then when you head to somewhere more northern, somewhere with a more severe winter, less sun, uh, and more, you know, demand for heating, et cetera, then y- you know, you just can’t do without wind. It’s, it’s, it’s doing a different thing than what solar is. So I do think that it’s wrong to think solar or wind.

We have to be better than solar. Um, we need to be better for sure. We being wind energy. Wind energy does need to be better, but not because it’s in a competition with solar, but because it’s in a competition with, you know, fossil fuels and y- just being able to [00:18:00] do the transition, energy transition at all.

Allen Hall: We’ll be right back after a short break, and when we return, a turbine maker having a very good year, and it may not be one that you would guess

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CIC NDT maps every critical defect, delivers actionable reports, and provides support to get your blades back in service. So visit cicndt.com because catching blade problems early will save you millions.

Well, not [00:19:00] every wind turbine maker is having a hard year. Suzlon Energy has posted its highest ever first quarter deliveries, 506 megawatts of wind turbine generators. Revenue for the first quarter of the fiscal year came in at 3– 38.19 billion rupees, or roughly $398 million. That is up 22 and a half percent from a year ago.

506 megawatts delivered in a single first quarter says the machines are not just being ordered, they are going up. So there’s a, a big demand in India. India is trying to get into a lot of solar and wind and some battery storage to improve the electricity grid there. S-Suzlon is gonna be a, a winner in that race.

At least there’s just a handful of companies that can really participate because of the way that India has structured the market there. But the Suzlon stock dropped, uh, a couple of percentage points on this news as the net profit was a little tighter than analysts would have [00:20:00] preferred, so there was a lot of profit-taking earlier in the day.

But the long-term forecasts have to be very positive for Suzlon, right? It, it’s just been a long-term player in India and elsewhere even, United States being one of those places, um, Australia being another Is it a positive sign that they’re just seeing more orders, more deliveries, that eventually the profit margin will jump up and that Suzlon will be extremely profitable, kinda like Vestas is now?

Matthew Stead: Yeah, I mean, they’re a, you know, great, great company. They’ve got great product. Um, they’ve got a great market in India. You know, India is growing. Um, I think they’ll continue to improve. I, I would’ve thought it’d be a great stock.

Allen Hall: It’s, it does seem to be a little bit of a rough ride just because there’s now a lot of competitors within India, Adani being one of them.

There’s o- other wind turbine manufacturers in India. Uh, not a lot of European participation. And was it GE Vernova is essentially out. [00:21:00] Is that right, Rosemary? GE Vernova is out of India altogether at the moment.

Matthew Stead: And Siemens Gamesa as well?

Allen Hall: Oh, that would be Omtera. I’m not sure if Omtera is in India at the minute.

Yeah.

Matthew Stead: Thanks for the reminder.

Allen Hall: Do you think it’s gonna be a little bit of a rough ride? I think that’s my take on it. And even though the demand will be there and the, the government is making a huge push for it, it, it… Nothing is easy in wind is when you’re trying to scale up because it’s such a huge industry.

Everything’s big. Everything’s expensive. You’re trying to expand your capacity. It doesn’t go smooth, and you’re gonna spend more than you would’ve spent because you gotta get new people in, and you need more equipment, you need more tooling. Everything gets more expensive as you’re doing it. I would expect the profits to drop down a little bit as you’re growing.

That’s normal.

Matthew Stead: I disagree. I, I think, you know, that they know what they’re doing. They’ve been doing it for a long time. You know, the market is growing, uh, but, you know, they’ve done it before. So I, you know, apart from their little wobble a while ago, um, I, I think it’s, it’s optimistic for [00:22:00] Suzlon.

Allen Hall: The growth of Suzlon and all the Indian wind turbine manufacturers internally allow them to, uh, do much more work outside of India.

Do you think that will help their order book, just because they’re successful in India and have that baseline of a marketplace that they can reach out to other parts of the world?

Matthew Stead: Yeah, I think that one’s– That’s gonna be harder , ’cause there’s a whole lot more competition.

Allen Hall: Right. That’s the real question.

How are they gonna compete against the Chinese in, in places where they don’t have a foothold yet?

Matthew Stead: Yeah, I mean, that one’s tricky. And, you know, I think, you know, while Suzlon has done well in Australia, they haven’t necessarily maintained their, their lead in Australia. So yeah, outside of India, it’s probably a different story.

Allen Hall: Isn’t Europe the next marketplace just because it won’t be banned like China has essentially been with- within Europe, the greater Europe? That Suzlon would be that one place, that one company that would be allowed in to, to make some onshore turbines?

Matthew Stead: I think we spoke about that probably about two months ago, and that was definitely in the news that, you know, Suzlon were looking at expanding into, into [00:23:00] Europe and, uh, exactly making the most of that.

Um, yeah. So that, maybe that’s their, their golden, um, export market.

Allen Hall: Well, a project in Queensland just got cut in half, and for two reasons at once. Alinta Energy has dropped the southern portion of its Mount Challenger wind farm in the Whitsunday Hinterlands. Six months of LiDAR monitoring showed that the wind resource at Kelsey Creek was not as strong enough to really to support the turbines, and the company also heard from residents opposed to turbines in that area, and a local action group gathered more than 6,000 signatures.

And for developers, it’s, it’s really a case study in wind data and the community arriving at the same result. But we’ve seen a lot of action up in Queensland more recently. Uh, I’m not sure what’s driving all the opposition to wind turbines, but I’ve seen news stories about it in the United States. [00:24:00] It’s great to have Matthew here because he’s an acoustician.

Uh, some of the discussion in the community, uh, event that I saw was just discussing 40 decibels of wind turbine noise, and which didn’t sound like a lot. And when I looked it up online, 40 decibels was like a library, which I think is being fairly quiet.

Rosemary Barnes: Yeah. Imagine if something got built near your property that was so noisy it was as bad as being inside a library or having a refrigerator in your home.

Easy to see how your life could be ruined.

Allen Hall: Matthew, what’s the, what’s the amount of noise from a, a road going by? Like a truck going by on a road, what is, roughly what is that?

Matthew Stead: I mean, that can quite easily get well above 60, 70, um, sometimes 80. I mean, the analogy, um, that I like to use is that each turbine has the sound emission which is similar to a truck.

[00:25:00] You know, a reasonable sized truck. Okay? So each– imagine each turbine is a truck. Um, but those trucks are a kilometer away. So, you know, the noise level decays in a logarithmic way. Um, and so by the time you’re a kilometer away, the noise from that truck is quite low. An individual turbine is gonna be way, way, way, way, way less than 40 But, you know, there’s more than one turbine, so you need to add them up and it’s n- it’s not a, it’s not a, you know, 20 plus 20 equals 40.

It’s a logarithmic addition. There are many, many, many people that live on busy roads with not 100 trucks, but thousands of trucks. So, you know, the noise exposure from a road can be way, way, way more than from a, you know, a wind farm.

Rosemary Barnes: That’s one of the things that strikes me when I have a, a look at, um, yeah, like Twitter comments for this particular post and everyone’s like, “Oh my God, that’s so terrible, 40 decibels.”

Like, yeah, I can see [00:26:00] why you’re ruining– that’s ruining your life. And yeah, I, um, I, you know, said that sarcastically at the start, but there’s, there’s plenty of, you know, hundreds of people that are, um, you know, thinking along the same lines, but the majority of them are like, “It should be legislated. You know, there should be rules around this.

They can just do whatever they want.” But, uh, the, it is legislated, right? Like, we all accept that wind turbines make noise. It is legislated. You can measure it, right? And so if you h- uh, have a property and you think it’s too noisy for the wind turbines two or three kilometers away, there’s something you can do, right, Matt?

Can you maybe tell us what is the process that, that happens when somebody thinks that a wind farm is too noisy?

Matthew Stead: So a few things. So, um, normally at a house, um, where you’re, say you’re a kilometer away, normally the ambient environment can be louder than the wind farm. The first challenge is to actually measure the noise from the wind farm and not from the ambient environment.

So what that means is that normally, um, measurements are taken around a wind [00:27:00] farm before the wind farm’s even built, and so that way we actually know, well, how much is the ambient noise. Um, and you know, the ambient noise is probably above 40 for a good proportion of the time. So th- that’s the first thing.

You need to understand what the noise environment is like before the wind farm. And then, um, using highly sensitive, highly calibrated, um, sound level meters, which can be, you know, 0.1 decibel accuracy, um, you can then monitor the sound before and after And then compare the two. But what happens is, um, as I said, it’s normally very difficult to separate out the sound from the wind turbine from the general environment.

So then what, um, there are different methods then to, um, either measure in like, um, halfway. So if you measure halfway between the wind turbine and the house, then you can start to separate out the wind turbine noise from the general environment and then do a, you know, propagation or a [00:28:00] prediction or extrapolation of what it’d be at the house.

Um, the other way of doing it is actually measuring at the turbines. So you can measure the individual turbine sound and compare that to what was expected, um, and then sort of validate, um, the initial, you know, source levels. You know, is it really a truck or is it, um, quieter or, or louder than a truck?

Rosemary Barnes: And if they do, it, it– I mean, I’m sure on occasion that people do get it wrong in terms of the noise.

They are able to do stuff about that. That’s partly what the, um, serrations on a blade are, are there to make a, um, a blade quieter. And you can also just do something as simple as turning down the turbine when, um, wind conditions are such that you know that it’s gonna be particularly noisy. No one wants to do that because you get less power output, but certainly you can do something about it if it turns out to violate the conditions of the, um, y- you know, the noise that they promised it when the turbine was, when the wind farm was developed.

Matthew Stead: Yeah. And, um, you know, in the past, it’s [00:29:00]improved a lot, but in the past there were some unusual sounds that came from some turbines, which came from like the gearboxes and, you know, you know, the drivetrain and so forth. Um, but, you know, those things are– they’re, they’re mechanical machines as we spoke about, you know, and they can be addressed, and they can be dealt with through, through design and good engineering, and also, also fixed, you know, retrospectively as well.

And like you say, Rosie, um, if there’s too– if there’s more aerodynamic noise than expected, um, there are serrations and, and lower noise add-ons that can be added. Um, but also many of the turbines also have noise modes, uh, so it can be slightly derated y- with, with certain sectors of wind, um, wind direction and wind speeds to, you know, reduce the noise further.

It is an absolute science. It’s really well understood. It’s, it’s measurable. I mean, there is some uncertainty in the measurements, but it’s, it’s, yeah, there is a lot of knowledge about this topic.

Allen Hall: Well, I just had a math question. If they want to reduce the decibels by like three [00:30:00] dB, what kind of power reduction are we talking about?

Is it like a 5% decrease or 50% decrease in power output to achieve that three dB reduction in noise

Matthew Stead: Yeah. Uh, I don’t have the maths in front of me, but it would depend on the power curve and the actual make model, but I, I… It’s not, it’s not half the power. It’s, it’s, it’s, it’s, um, less tweaks to the power output than, than that much.

Allen Hall: So i- it’s not a massive number. It’s, it’s a reduction of course, but it’s not, you’re not losing a, a ton of revenue.

Matthew Stead: No, no. I mean, obviously it depends, but yeah, it’s not necessarily a ton of revenue loss.

Rosemary Barnes: But I think it’s a real shame, ’cause like when I look at, you know, social media posts where, um, people are up- upset about noise, like they are clearly not aware that there is a very mundane process to go through.

Like, you know, it is not… You don’t, you don’t have to get so worked up. If you’ve got noise at your house and, um, you know, it’s upsetting you, [00:31:00]there is a very established process that you can go through and it can be, it can be fixed. And I know from, you know, the asset managers that I, I work with, um, that are some of my friends, like I, I know that they want to help you.

They do not want people living around the wind farm to hate the wind farm. So y- you need to get in touch and let them know, and, and I… They’re gonna be able to fix your problem. If it’s, if it’s detectable y- you know, with the methods that Matt said, then they are gonna be able to, um, fix it. I know that sometimes people say that they can hear noise, and you just cannot find any evidence of it, and therefore you cannot, there is nothing you can do to that wind farm operation to be able to solve that problem.

So I’m not saying in every case if you think you’ve got a problem they’re gonna be able to solve it, but if they can pick it up with a, what is it called? A noise meter? A decibel meter? Yeah, whatever that doodad’s called. If they can pick it up on that, then they can, they can fix the problem for you. And yeah, it’s just, uh, it, it upsets me that, you know, people are really, are really getting worked up [00:32:00] about this issue, but there’s a, a process to go through.

Matt’s holding it now for everyone just listening in. It’s like the size of, I don’t know, a liter of milk. It’s just not it’s not, not a complicated thing.

Matthew Stead: I think one of the big challenges that we’ve had is that there’s been a lot of negativity around noise, and then people get sensitized. And so, um, the, you know, what I’ve, um, what I, what I’ve heard many times is, um, the sensitivity to noise can be communicated Um, so, you know, like Rosie, if I tell you you’re gonna be really annoyed by this thing, this thing is coming, you’re not gonna like it, you’re gonna hate it, and then you’re sensitized to it, and then you’ll tend to have more of a, you know, a, a response

Rosemary Barnes: If we’d gone on a nationwide campaign to, you know, visit every house that’s within 600 meters of a y- you know, of a road and, um, you know, given impassioned speeches to them about [00:33:00] how it would ruin their life, then yeah, it is easy to see how we would be so fixated on it that our lives would really be ruined.

Allen Hall: Meanwhile, the Australian band AC/DC came to Charlotte the other day to a sold-out concert at the huge football stadium, and I guarantee you that concert was way above the noise level of a wind farm.

Rosemary Barnes: I hope so. Imagine if imagine if a, a bunch of whingers in the audience are like, “Excuse me, I’ve got my little noise measuring doodad and it’s over 40 decibels.”

Allen Hall: Well, that wraps up another episode of the Uptime Wind Energy podcast, and thank God for that. If today’s discussion sparked any questions or ideas, we’d love to hear from you. Reach out to us on LinkedIn, and if you found some value in today’s conversation, please leave us a review. It really helps other wind energy professionals discover the show.

And don’t forget to subscribe so you never miss an episode. And so for Rosie, Yolanda, and Matthew, I’m Allen Hall, and we’ll see you here next week on the Uptime Wind Energy [00:34:00] podcast.

Blade Breaks at He Dreiht, Suzlon Posts Record Quarter