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Thinking about solar? Start here | Ep. 129

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Power costs continue to rise, and a lot of farmers are asking the same question: could solar work on my farm?

In this episode, you’ll hear from Chris McArthur from the Energy Efficiency and Conservation Authority’s (EECA) Solar on Farms programme and Rhys Mackenzie, a dairy farmer who’s making the move to solar on his farm. Together, they talk through what solar and batteries can realistically do on a dairy farm, where they add value, and what you need to think about before you invest.

You’ll get independent advice from Chris McArthur, alongside practical on-farm insight from Rhys Mackenzie as he shares what sparked the decision, what surprised him, and what he’d tell other farmers thinking about solar.

 

Find out more:

EECA Solar helpline for farmers

A dedicated solar helpline for farmers and growers, providing independent, practical guidance to help you make informed decisions. Call the team on 0800 300 643, or email us at solar@eeca.govt.nz 

Have feedback or ideas for future episodes? Email us at talkingdairy@dairynz.co.nz

Connect with DairyNZ

Stay up to date with advice, latest research, tools and resources. Read, browse, scroll, listen, or be there in person. Visit dairynz.co.nz/get-connected 



Introduction

Speaker

Kia ora and welcome to Talking Dairy. I'm Jac McGowan from DairyNZ. Power costs are rising and severe weather can leave farms without electricity when they need it most. So it's no surprise more farmers are looking at solar and batteries as part of the mix on farm. In this episode, we're talking about what solar can realistically do on a dairy farm, where it fits, and what you need to think about before you get started. Joining me are Chris McArthur from the Energy Efficiency Conservation Authority, or EECA, who works on the Solar on Farms program. And Rhys Mackenzie, a dairy farmer who's made the move to solar on his farm. We'll cover where solar can add value, what that process looks like, what Rhys Mackenzie has learned along the way, and the key things to weigh up if you're considering it for your farm. Alright, let's get into it. Tēnā kōrua, welcome to the podcast.

Speaker 1

Thanks, Jac. Thanks for having me. Good to be here.

Speaker

To start, could you introduce yourselves and a bit about your connection to on-farm solar? Chris, you go first.

Speaker 2

So my name is Chris MacArthur. I'm Auckland based for ECA and I have a background in the solar energy sector. I first was started working in solar way back in 2003 when the solar was very, very expensive and not nearly as reliable as it is now. Over the years, I've just watched the technology get better and better and cheaper and cheaper.

Speaker

Cool. Thank you, Chris. And Reese?

Speaker 1

Yes, I'm uh Reese and Kinsey. As you mentioned, we're dairy farming just north of Matter Matter, so family farm. I think my parents have been there for about 30 years, so for most of my life. I've moved a couple of times and it was just down the road, so not too far at all. I'm actually a veterinarian by trade, so I'm not full-time on the farm. I still have to drag myself back to the city, back to Auckland. But most weeks I'm down on the farm and quite heavily involved there. So I started working back there six or seven years ago. I was one of the Kiwis that got trapped back in New Zealand after COVID, much to my dad's delight, I think. He's a bit of a sideways thinker, and um during one of the very low payout years, he decided to employ an extra person to just drive some uh inefficiencies out of the business, I guess, and save some costs. So yeah, I ended up back there and things have just progressed from there. I do a good job and we save some money, so I kept my job.

Speaker

That's lucky.

Speaker 1

That was good. So he was pretty stoked. So we're 400 cows, we do about 600 to 650 milk solids a cow. I like to call it fairly high input, high output with split carving, so 80% autumn and 20% spring. So a little bit backwards compared to most New Zealand dairy farms. But by doing that, we've been able to kind of maximise our winter milk production and the premiums around that. So it seems to work for us.

Speaker

Okay, thank you. Uh

What EECA does

Speaker

Chris, what is e care for those who don't know?

Speaker 2

We're the Energy Efficiency and Conservation Authority. So we're a government agency and we're tasked with promoting energy efficiency and renewable forms of energy. We have a couple of levers we can pull to do that. We're able to regulate appliances and that sort of thing to make sure they're not energy wasting appliances. But we also do programs like the Solar on Farms program, which is about demonstrating the technology, sharing knowledge with farmers so they can make informed decisions about what they're going to do on their

Why this programme started

Speaker 2

farm.

Speaker

And Ica is running a Solar on Farms program. Why now? And what's that program trying to solve?

Speaker 2

Yeah, I think there was some great lobbying from Rewiring Antero. They've demonstrated that solar has huge potential on farms. So credit to them where it's due. So when we were tasked with picking up the program, you know, we did see a huge potential. And farmers have got the space that technology is now at a price point where it's a pretty compelling business case. We went out and talked to a number of farmers, and the barriers came back pretty consistently as wanting independent, up-to-date advice. So that's good that Ika can sit in that space and do that. But part of getting that advice is we needed to demonstrate how the technology was working on farm. So we recruited 37 farms across the country, Reese's farm being one of them. And they're all installing solar, and we're going to monitor it and share what we learn as we go.

Speaker

Okay.

Why this farm chose solar

Speaker

And Reese, what first got you interested in solar on the farm?

Speaker 1

Essentially, I'm going to blame Dad again for this. He came to me probably 12 to 18 months ago. And uh, like most farmers are always trying to find ways to save money. Um, we're spending, I think at the time, about $55,000, $60,000 a year on power. And it just seems to be going up every year. So we thought, well, you know, what can we do about this? And decided we'd have a look at solar. I guess as we go through the farming journey, um, you know, and tech developing that sort of thing, we seem to probably be using more power, not less power. I think now we've got about five computers running in the cow shed, either monitoring the cows or monitoring the plant or sorting out feed systems, that sort of thing. And um, as you're aware, I'm sure there's lots of new technology coming through as well. So we decided to have a look at solar, start doing a bit of research, and then came across the BECA pilot project amongst some of that research and decided to apply for that. And then we're one of the fortunate ones that got accepted. So that was pretty cool.

What happened after applying

Speaker

What's happened since you applied?

Speaker 1

Well, went out to probably four different companies originally and got some quotes and quickly realized that you get a lot of information, a lot of data, and there's a lot of assumptions. And I realised I was gonna have to try and upskill and learn a bit more. So I'm a bit of a fan of an Excel spreadsheet. So I started putting the information into there, and my spreadsheet grew and grew and grew. It's got lots of stuff in it now, but that kind of helped in terms of comparing the quotes. We weren't too worried about selling back to the grid. It was about trying to make sure we were putting in a system that was the right size, not a massive system, but one that kind of found the sweet spot. We had a few other criteria. I mean, Chris was talking before about a lot of farmers have lots of spare land. We're in Meta Matter, which is the heart of kind of the horse country and the market gardens and all that sort of stuff. So we don't have lots of hilly, steep land or anything like that, but we did have a lot of buildings and shed roofs and that sort of thing. So we were looking for a system that we could go roof-mounted rather than ground-mounted. Yeah, we wanted something that we could build on as well. So something that was expandable. We ended up going with a company called Trialect, which is based out of Auckland. All the quotes kind of were reasonably similar when you boiled them down, but we had a few kind of nuances. We were using a shed roof that was 300 metres away. Um DCK was a little difficult to run that far. So TriLact had done that in a few other places already. There's some really good equipment and technology that they were using as well. So yeah, kind of fit.

Speaker

Okay.

How to get started

Speaker

Chris, if a dairy farmer is just starting to look into solar, what would you suggest is the best first step?

Speaker 2

Well, we've learnt from the likes of Reese that sometimes, you know, there's a lot of information that gets bombarded on farmers. So we've put together some gardens on our website. So we'll plug our website as a good place to start. But just some checklists to think about on your farm. So think about where the solar's going to go. Is it going to be ground mounted or roof mounted? If it's going to be roof mounted, how are you going to clean it? And also, is the roof in good condition? Because you don't want to be putting solar on something you're going to have to replace in five years. There are lots of different considerations. So we have a solar and farms team with a lot of information on our website, but we also have an 0800 number that farmers can call and just get impartial advice, really. That's the intent, is to be able to hut and start with information and thinking about what they need to think about. And then at the point where they've actually gone out and got a few quotes, we can look at those quotes and we won't make a recommendation as to who they should go with, but we'll definitely give them insights on what you know what are the things to consider as they make that decision.

Learning from other farms

Speaker

Is there any part of that that involved getting on farm with them in the pilot project or going forward?

Speaker 2

Yeah, yeah. So we we are going to impose on our demonstration farms that they um they hold an open day or be a part of a case study. That seems to be a good appetite from the farmers to do that. They generally do want to share their knowledge. And there's a lot of the demonstration farmers who want to go and see other people's systems as well, see what they've gone with and and what worked well for them.

Early lessons from this farm

Speaker

Now, Reese, now the system's in place, what have been the biggest benefits for you so far?

Speaker 1

Yeah, so unfortunately we're not actually connected yet.

Speaker

So no benefits yet.

Speaker 1

No, it was supposed to be Friday. And I I said to the guys last week, I was like, oh, we've got this podcast on Monday, it'd be really good if I can tell them it's connected, but we've we've had a few holdups. So yeah, we're not actually connected yet. It had a few delays with the weather, and this is a really good learning point as well. We got to the point of connecting it to the car shed, um, and we've got a 20-plus year old rotor tree, and we've kind of just built in, you know, with all the new technology built and ad put it over time, and when it came to actually connecting the solar, I mean we could have done it, but we've just decided to do it in a way that future-proofs it a little bit. So we've having to change out the entire fused water in the cow shed, which when you milk twice a day, every day of the year, is a little bit tricky, saying you have to rewire the shed in between milkings. So yeah, just held us up a little bit. But the um TriLate guys are out there today, and I'll be heading down there after this. And I'm really hoping uh it's gonna be connected. So we might have to do a follow-up podcast, and I can I can tell you how well it's working.

Speaker

Well, it sounds like you'll be hosting a demonstration day as well.

Speaker 1

So it'll definitely be running by then, Chris. So don't worry about that. But yeah, yeah. We're very excited to see set up and going. But um definitely a big benefit, as I can see already, we'll just be having some control over that power. And one of the things that's happened is it's motivated us to actually, even now before it's running, look at where we're using power and potentially how we can move that around. So it's things like uh heating water during the day instead of at night, or using pumps during the day instead of at night, or so what we can do on that. And we haven't even started using it yet. So definitely when you know there's a lot of monitoring that comes with these systems. So once that's up and running, we'll be able to actually see when we're using it and hopefully make some wiser decisions there as well.

Why batteries were added

Speaker

Did you go with batteries in the end?

Speaker 1

Yes, so we're going with batteries. They're a little bit harder to financially justify than just putting in solar alone, but definitely with the help of the grant, they were a no-brainer. We've actually made it so that we can quadruple the size of the batteries. So, you know, this technology is just getting cheaper as it develops, I guess. So um we've future-proofed ourselves a little bit there. Plan will be to put it in and then see when we're using it and whether adding more batteries makes sense. So yeah, we've got that that auction down the road as well.

How batteries help

Speaker

Chris, can you talk us through how batteries do fit into that picture in terms of cost and backup power supply?

Speaker 2

The battery does make the payback worse. So they've got a capital cost up front and they save you a bit, but they don't save you the huge amount. So we're kind of giving advice to people that, particularly farmers, that they're justified if you have regular outages. For a lot of farmers, that is the case. Getting anecdotes back, that outages aren't just like a a long outage of three or four days. So, like we we've got a great case study for a farm in Southland that had a big outage back in October, and they were that were out for three days. But I've also been told by from some farmers that they can sometimes quit quite regular short outages of just ten minutes. Yes. And that that's a real nightmare if you're milking because all the cups fall off and you have to reset everything. The batteries do kind of justify themselves on the reliability side of things rather than the economic side of things.

Speaker

Yeah, I suppose the benefits aren't always um seen in terms of money.

Solar payback time

Speaker

What is the return on investment, just average or range for a solar system on a dairy farm with and without batteries?

Speaker 2

Without batteries you can get quite low, like three to five years with a battery, it's probably pushing it up to about six or seven years.

Speaker

Is that better than for residential?

Speaker 2

Yeah, it is, especially with the battery side, I think. You can get good payback on residential if you s again size it right. But as soon as it's drawing the battery, it does push the payback out. But I'm saying that, you know, the first power cut you have when you've just got solar and no battery, when you're back on the phone to the installer, going, you should have got that battery. So yeah.

Do you still need a generator?

Speaker

Chris, for those who have generators wired into their sheds already, so they already have kind of backup for when the power goes down, do they still need those generators or or is that something they can sell?

Speaker 2

They can get away with a much smaller generator now. Okay. I don't know what the secondhand market for generators is like, but yeah, I don't know, Bruce, what are you gonna do? You've got a gin set on site already, haven't we?

Speaker 1

Yeah, we we already had a pretty big beast. When you've got cows doing 650 milk solids and you know, we've got a few cows and they're doing 1100, they really don't like not being milked. So we figured out a few years ago that that you know we needed that in there. We don't have enough battery to get through an entire day. We use about 400 kilowatts a day, and the battery is 84. You know, in the peak of summer, you're gonna be generating a large amount as well. But the disadvantage, I guess, with solar and farming systems without M battery is that a lot of your milking and winter's in the dark and using power outside of the kind of peak consumption time. So we have integrated our generator, and this is uh that raises another really good point for me. Um, I interestingly enough found out that a lot of solar systems don't work when there's no power.

Speaker

Okay.

Speaker 1

So it's a question to ask when you're um installing, and I found that really interesting. I thought, you know, people put in their solar systems so that when the power goes out, you have power. But even, you know, if you've just got the panels, often the inverters need AC power from the grid to actually continue running. So it's a really good question to ask. The batteries do help, but even some of the battery systems won't work if there's no grid power. So you've got to have a special type of inverter and a special gateway in there to make sure you can actually use it. So definitely a key learning for us. We've got a system as well where it has a zero millisecond change over time. So Chris was talking before about the cups dropping off. Our change over time in between the grid going down and the batteries is so small that the vacuum won't even drop in the car shed and the computers won't shut down or anything like that, which is a nice little trick because you're not running around trying to resettle your computers because the power went out for a second or two.

Why some solar systems need grid power

Speaker

Chris, that really surprises me to hear that a solar system still needs electricity. Can you t tell us more about that?

Speaker 2

Yeah, it's more of the old traditional systems. They basically said that if the grid goes down, you have to disconnect or switch off. Um, and that was a safety issue for the linesmen working on the lines. But as the battery technology has improved, they've got these parts of the system that are called automatic transfer switches or gateways. They have different names depending on the manufacturer. They'll isolate the battery and the network from the grid and resist one in in zero seconds. And basically that allows the farm or the shed, maybe, to operate as its own little microgrid.

Speaker

Uh okay, so this is when because you can have a solar system that's not connected to the grid, right? But perhaps not usual on a on a farm.

Speaker 2

No, I think if the grid's there, you're justified in getting it because it mil it takes away a lot of the hassle of managing like those seasonal variations and that sort of thing.

Speaker

Yeah.

What to ask before you buy

Speaker

Okay. Chris, what are the key questions farmers should ask before investing in a solar and battery system?

Speaker 2

You really want to see in the proposal what the equipment is and how it will perform in an outage. It would be useful to get an understanding of what kind of apps a farmer will have and what kind of control they have. So some of the systems allow you to charge from the grid at night, which I think is a really important functionality. That also gives you the ability to switch it into backup mode if you know there's a weather event coming. So rather than cycling the battery, just have it there full, ready to go. So those are two core bits of functionality. We've just launched an approved product list for solar products. We've only just launched it. And making sure that products are on that list would be worthwhile as well.

Can you shift power use to daytime?

Speaker

Reese, you mentioned that your milkings are mostly in the dark. Well, perhaps your morning milking. Have you considered changing your milking times as part of that shifting power to daylight hours?

Speaker 1

Probably not so much the milking time. Yeah, milking times are more centered around animal welfare and animal health side of things. In summer, it's not so bad. But you know, in winter when then it's getting dark at 5 p.m., yeah, all the effluent pumps or whatnot are running kind of right after milking. And you're chilling and that sort of thing. And obviously your peak solar generation is going to be in the middle of the day. So but then like Chris alluded to as well, if you can charge your batteries back up overnight while power's cheap, then it's not so bad. But not so much moving the milkings. But anything else we can move around that?

Speaker

I'm sure at this time of year you wouldn't have enough hours in the day to do anything between milking if they were both in daylight hours.

Speaker 1

Yeah, we could go once a day. The staff would probably love that.

Speaker

Okay,

What not to overlook

Speaker

so Reese, looking back, what are the big things not to overlook? Or what do you wish you had known earlier? You did talk about some delays.

Speaker 1

Probably the key thing for me would just be not to rush it. I mean, it it's taken considerably more time than I thought. It's not like buying UK, you just rock up and pick it up. You've got to make sure you're getting a system that works for your operation. Having what ECA's done before we started would have been great. So I'm a little bit jealous of all the farmers that are coming after us because you know what what they're doing now in terms of helping understand all that you know the stuff I was talking about before, all the numbers and the assumptions and what you're getting is it does take a bit of time. At the start as well, it's important to know what you're trying to achieve. You know, for those system guys that are trying to use it as a a backup is quite different potentially to what you put in compared with the guys that are just trying to generate a bit of power to save a bit of money versus not relying on it so much as a backup.

What to do first

Speaker

And Reese, if another dairy farmer rang you tomorrow and said they were thinking about solar, what would you tell them to do first?

Speaker 1

Oh, send them to the Echo website. I was having another look at it yesterday just uh in preparation for this, and man, they've really developed it. So yeah, kudos to Chris and their team. It's definitely all this stuff you know that I've had probably upskill on. It's essentially now a crash course. So I would head over there and and have a good read because it yeah answers a lot of your questions and it's independent as well. So you know, solar guys are like anybody else that's selling your product. So you yeah, they'll tell you what either what they're selling or what they think you want to hear. So um having something independent is really cool. And plus, I've got a hotline, which I discovered yesterday for the first time, Chris. I think that's I mean, if you're not sure and you can't make sense of the website, then just ring them and you know, they're on the other end, they can help you work through what you need. So that'd be where

Where to get independent advice

Speaker 1

I'd start.

Speaker

All right, Chris, this is your opportunity to pull it all together. If someone listening wants to explore solar further, what independent tools and support are available to them to help make a sound decision?

Speaker 2

Well, this is the hotline 0800 number. Um we know we know farmers are busy. So yeah, sometimes I don't want to trawl through a website.

Speaker

Does that run 24 hours a day?

unknown

No.

Speaker 1

Links links straight to Chris's farmers as well, doesn't it, Chris?

Speaker 2

Yeah. No, there's three of us saw on farm advisors, and yeah, it just it goes to one of us if it was available, but it's only office hours.

Speaker

All right, so you've got the 800 number.

Speaker 2

And as Reese mentioned, a lot of information on our website, and it will be adding to that as we go, you know, when we get data off Freezer's system, and there's another dairy farmer in the Waikato who wants to know because it's yeah, this time of year it's really dark. So how does the system perform in in winter versus summer? And that like Chris said, impartial advice as well. We're not saying solar's right for every farm, but we think it is probably right for most farms, but it's about getting that system size right. So you're not exporting a whole lot of electricity, not getting paid much for that, and buying it at an expensive rate. One of the other things I think we'll see from having these batteries and solar on farms is that people like Reese will look at their energy use and they'll be able to find efficiencies and be able to move stuff around. And I think dairy farms in particular, they've got a ton of non-battery energy storage in terms of their thermal loads, their chilling and their lot of hot water washed down and effluent pumps. Those sorts of things are, in a sense, the energy storage in a different way, really.

Speaker

Interesting. Okay.

The future of solar on farm

Speaker

Uh now looking ahead, what role do you think solar and batteries could play in the future of dairy farming?

Speaker 2

Yeah, eco really are trying to push the electrification message. There's a lot of stuff on farming you can electrify it right now. There's some things you can't. The big tractors are not there yet, but in the future they will be. And that it essentially becomes another form of energy storage on your farm. It just becomes a big battery. So I think that's exciting because those those will be two-way. Those batteries won't just be going into the tractor, they'll be able to power equipment on the farm as well.

Speaker

Right, yes. Reese.

Speaker 1

It's gonna be a big part. Like I said, there's lots of technology and innovation coming through in terms of you know the wearables and the computers and whatnot. But then you were seeing electric ATVs, and we just earlier this year looked at um buying an electric loader actually. It wasn't quite financially justifiable, but um, when Chris is running his electric loader trial, I'll come back and we'll go down that route, hopefully. There's a lot just across most industries, there's a lot of stuff going on electric. And then like Chris said earlier, we've got farms where you've got space. A lot of businesses and cities don't have the same opportunities we have to be able to put in solar and things like that. But you know, farms have got the room and space to do it. So yeah, I think it's important. We're we're already great efficient producers of dairy in New Zealand, but you know, you shouldn't be in business if you can't improve and we can't afford to stand still. So I think you know, anything we can do to be more sustainable and more efficient is good.

Speaker

All right,

Episode summary

Speaker

thank you, Reese. I think that's a great note to finish on. And that was a really useful look at what solar and batteries can offer on a dairy farm. Reese, I can't wait to hear what you think of it once it's actually hooked up. But one of the big takeaways was that solar can be a strong option, but it has to start with understanding how your farm uses power and sizing the system to fit. And if you do that homework with the help of ECA, it can help you manage power costs, improve resilience, and support lower emissions farming. Huge thank you to Chris and Reese for sharing your guidance and expertise and experience. If you'd like to explore it further, you'll find links in the notes below. Thanks for listening and we'll catch you next time. Matewa. If you'd like to get connected with DariNZ's latest advice, research, tools, and resources, whether it's reading, scrolling, listening, or in person, you can visit dairynz.co.nz forward slash get connected, and don't forget to hit follow to keep up to date with our latest episodes. As always, if you have any feedback on this podcast or have some ideas for future topics or guests, please email us at talkingdairy at dairynz.co.nz. Thanks for listening and we'll catch you next time on Talking Dairy.