Solar-powered irrigation proving its worth for Alberta operation

Cory and Lindsay Nelson are the first in the province to use solar for large-scale irrigation — and they’re happy they did

This array on Merlinds Farms is the first large-scale solar system in the province used to power irrigation pivots.
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Cory and Lindsay Nelson have always embraced innovation and after attending a talk on solar energy put on by a producer group, their interest was piqued.

So the brothers approached Enmax and a Lethbridge solar installation company called Solar Optix to look at their electrical bills. The numbers seemed to pan out, and it looked like the system would pay for itself in about 15 years, so they took the leap.

Solar isn’t new, but this application of it is in Alberta.

“It’s never a bad thing to be right at the start of things,” said Cory Nelson of Merlinds Farms near Grassy Lake. “My dad was always that way. He liked to try new things. Sometimes they work, sometimes they don’t, but it’s fun to try new things.

“In Alberta, Enmax said we were the first ones for a large-scale system.”

The Nelsons installed a 91.8-kilowatt array (estimated to produce 125.7 megawatt hours or enough to run a pivot irrigating four quarter sections of land), and a 44.6-kW array (producing approximately 60.66 MWh, or enough to irrigate two quarter sections of land).

The system is a net-zero setup. This means that the overall energy production and overall energy usage should come out to zero over the span of a year. While energy production is high in the irrigation season, so is usage, and the Nelsons need to draw on energy from the grid during that time. But in the winter, when usage is zero, there is still energy production, so it balances out over time.

Cory Nelson (on right with brother Nelson) says they are looking at adding more solar power. photo: Solar Optix and Merlinds Farms

When setting up the system, Solar Optix looked at the last couple of years of electrical usage to estimate a net-zero target, although in reality it could be more or less in any given year, depending on factors such as snowfall or differing irrigation seasons.

“We have some years that are drier, some that are wetter — so it varies,” said Erika Grintals, the company’s owner and solar sales manager. “That’s important for farmers to understand. If they want to do a net-zero array, you need to look at more than one year of consumption.

“We try to be conservative (with estimates of how much energy the system will produce to ensure that the customer is going to be happy with the result.”

The Nelsons didn’t reveal what their system cost, but said the estimated payback is 15 years. The Solar Energy Society of Alberta says the cost for a ground-mounted array runs about $3.50 per installed watt.

Merlinds Farms also accessed a grant through a program that is no longer in place, but a revamped On-Farm Solar Photovoltaics program offered by Growing Forward 2 actually offers higher grants that cover up to 35 per cent of the cost. (It requires systems be tied to the grid; approved under Alberta’s Micro-Generation Legislation; positioned to optimize sunshine; have manufacturer warranties; and be installed on a site ID that has a Distribution Rate Class of Farm, Irrigation, Grain Drying or equivalent. Producers must also obtain approval before the system is ordered, purchased, or installed. For more info, go to and search for ‘On-Farm Solar Photovoltaics.’)

Worry-free power bills

Solar for irrigation is a big investment, but it’s one with a long lifespan.

“The useful life is — just as a guess — about 35 to 40 years,” said Cory Nelson.

One of the advantages to pairing solar with irrigation is that the biggest electrical draw happens at the same time as the biggest electrical production. This means the benefit to the producer is greater because transmission fees will be lower.

“Right now the payback on irrigation pivots versus any type of other service is the best there is. They’re getting the best payback for their buck,” Grintals said.

Once the loans are paid and the system has covered its cost in energy savings, the only power costs for these pivots will be transmission and delivery charges.

“Once we’ve locked this in, this will produce all the power we need for quite awhile — certainly the rest of my farming career,” Nelson said. “Twenty years from now, if it costs me $40,000 for pumping and I get a (credit) for $40,000, then it comes to zero. It doesn’t matter if the price for power goes to $60,000, or drops to $10,000, it’s still going to be zero.”

Merlinds Farms is just wrapping up its first irrigation season with the solar-powered pivots, and it’s looking good so far.

“On a really good day in July it will produce close to 70 per cent of the power required during that heat of the day,” Nelson said.

The brothers are also looking at upgrading their systems in other ways to improve energy efficiency, such as using a variable frequency drive pump and lowering the pressure a little bit more.

“We do have drop tubes and low pressure, but we could even drop it down just a little bit more — maybe another five to 10 pounds,” he said. “That way if it’s just a little bit more efficient, then I’ll actually be producing maybe just a little more than what I’m using.”

It’s rewarding seeing the meter slow down, or even go backwards.

“It’s a two-way meter so it goes backwards when I’m not running and starts spinning when I am running,” Nelson said. “It’s kind of interesting to see on your bill — you see a negative number. That’s nice when the power company owes you money for a little while.”

The brothers have their eye on putting more irrigation pivots on solar power.

“We even talked to Enmax and said that in the off-season in November, once we’ve had a whole year to look at it, there’s a couple of other systems that we think would be a real nice fit,” Nelson said. “We gave them some preliminary numbers to look at and told them to get back to us but not until we’ve (gone) through the whole season.”

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