When Mike and Rebecca Casey eliminated fossil fuels on their Mt Pisa cherry orchard, they expected the payback period to recoup their investment to be 11 to 12 years.

That was when diesel was $1.20 a litre and went as low as 90 cents, and now the price is $2.70 per litre, the payback period has shrunk to nine-and-a-half years in terms of pure cost savings.

They have reduced that even further by smart use of solar panels and batteries, and a computer programme Mr Casey wrote that buys electricity from the grid when it is at low spot prices, and exports it back when the spot price is high.

Energy efficiency . . . Forest Lodge Orchard founder Mike Casey has written a computer programme that buys electricity at low spot prices and sells it to the grid when prices are high. PHOTO: SUPPLIED/MILES HOLDEN

Last season, they sold their cherries under the consumer brand they created – NZ Zero – to a boutique supermarket chain in Auckland at a 15% premium.

That premium, about an extra $3 per cardboard box of cherries that used zero fossil fuels in the production, would bring their payback period down to under two years when in full production.

Forest Lodge Orchard, which the couple own with business partners, orchard manager Euan White and his wife Rachel, creates zero fuel emissions, and are also nearing zero overall energy costs.

Neither accountant Mrs Casey or her computer programmer husband had any experience of farming or horticulture, but not being bound by tradition led them to use non-traditional methods.

The pair spent 12 years in Sydney, Australia, before their growing family led them to return to New Zealand in 2019 and look for a home in the Central Otago and Lakes District.

Mrs Casey said they didn’t want to live in a big city anymore, and found a property with 9ha of land and an irrigation pond for what it would cost to buy a nice four-bedroom house in Wanaka.

“We had no idea what we were going to do when we came down here,” she said.

Mr Casey had founded an information technology start-up in Sydney that he sold to a major player in the field, and said he knew he wanted his next business to be in the climate space.

“You really have three choices. One is to ignore the science, the second is to do nothing and the third is to do something. I felt better about doing something.”

They planted 9250 cherry trees, but a study by Hawea firm, Environmental Accounting, showed them the orchard was far from carbon-neutral.

Their trees sequestered about 3.8 tonnes of carbon a year over their 25-year lifetime, and emitted about 2.5 tonnes through fertilising, meaning they offset their fertiliser use, he said.

“The issue was, in order to run a productive cherry orchard using all of the diesel technology everybody else uses, you probably emit between 50 and 80 tonnes of carbon emissions, depending on how you run the orchard.”

That information came from the Sustainable Energy Association of New Zealand, from which they won an award last year for the electricity system.

They have since replaced their diesel irrigation pump with an 18.5kw electric pump, which required spending more than $100,000 to upgrade their power connection from single phase to three phase, for total reliability.

Fossil fuel free . . . Forest Lodge Orchard founder Mike Casey during the growing season, with one of the property’s two 30kw electric frost fighting fans behind him. PHOTO: SUPPLIED/MILES HOLDEN

“You can see right there why farmers don’t ever replace the diesel technology,” Mr Casey said.

They imported two 30kw electric fans, put all household and orchard power generation to electric and ordered an electric tractor that is due to come off the production line in the United States in November.

“Fans will burn 30 to 40 litres of diesel per hour,” Mr Casey said. “If you’re fighting a 10-hour frost, that’s 300 to 400 litres of diesel per fan, and we needed two fans to effectively frost fight our orchard.”

The orchard also has two electric cars, a fleet of upgraded golf carts, an electric mower and a 40-year-old electric forklift in use.

Old faithful . . . Forest Lodge Orchard manager Euan White drives the property’s 40-year-old forklift. PHOTO: SUPPLIED/MILES HOLDEN

“There are no fossil fuels burnt anywhere on this farm. Everything is 100% electric, and we are close to a net zero energy bill,” Mr Casey said.

Associate Prof Michael Jack, director of the Energy Management Program at Otago University’s Physics Department, said such initiatives were definitely the future of energy use in New Zealand.

“In New Zealand, we have about 85% of renewable energy and it’s likely to go up.

“If this property is using PV solar also, they could be almost totally renewable.”

Prices of solar panels and batteries had fallen and would drop further, he said.

“It’s a really smart way in which they are buying cheap electricity and selling at a premium.”