ASB Farmsmarts:
From a pub to a power station

This story originally appeared on The Country as part of the ASB Farmsmarts series with NZME, and the NZ Herald.

The Harwood family's farming innovations in Takaka began in 1899 and were built around 1000 acres - and a pub.

Fast forward by 118 years and the beer served at the pub on the original property has been replaced by a thirst for a far more valuable farming liquid - water.

Nigel Harwood is one of three brothers now running the property, which has swelled to 2400 hectares (just under 2000 hectares of effective farming land), along with their "semi-retired" father - whose definition of semi-retired means working 12 hours a day running the lamb finishing operation of 8500 animals. In fact, the scale of the Harwood farm has come a long way since the brothers' great-grandfather rode his horse over the Nelson hills. When he returned, says Harwood, "he'd either bought 1000 acres with a pub attached or a pub with 1000 acres attached. "Either way, he had to ride back for a day and a half to tell his wife, a devout Presbyterian, that she was now a publican's wife." Harwood is not sure how the news went down but recounts that the pub had a rule that existed until the 1950s: patrons were allowed "one stiff drink" or "two beers" in a single sitting. "What that meant was a continuous stream of people walking outside and coming back in."

The Harwoods' grandfather took over the farm (and his sister the pub) and began the succession leading to the present-day 2400 hectare property - farming dairy (885 cows and 400 bulls), deer (1060 hinds), 3800 breeding ewes, 110 breeding cows, lamb finishing, a pine plantation, it has native bush areas in Queen Elisabeth II covenants (which trampers love), wetlands and the biggest innovation of all: their own hydro-electric generation plant. The main farm incorporates valley floor, sweeping up to steep hillsides leading to the peak of Takaka Hill. Much of the 2000 effective hectares needs water - as always, farmers' liquid gold. Summers in the area can be dry and bringing in supplementary feed to the Golden Bay area can be highly expensive, leaving an ugly hole in the accounts. So stock are fed mainly on grass stimulated by controlled irrigation - but the Harwoods did not have enough irrigation to properly service the dairy farm.

The Takaka River runs nearby and they take some water for irrigation - but supply is limited and subject to the flows released by the Cobb Hydro Station when it is generating. So, in 2008, they built an intake in the nearby Waitui River with a large settling pond and ran 1.8km of small gauge PVC pipe to the irrigation pump. So far, so good - but they were always keen to build up their own hydro-electric capacity. In 2012, the first stage of their power station was completed - a small gauge pipeline connected to one turbine to drive their centre pivot irrigation scheme, generating 100KW of electricity. The brothers always had their eyes on more capacity - but the prohibitive cost of piping and laying it stalled them until pipe costs came down. In 2015, they added two more turbines and ran a 1m-diameter pipeline 2.3km from the river to the power station, lifting maximum capacity to 420KW.

What does all this mean? For a start, it opens up a revenue stream of about $180,000 a year, more than enough to pay off the interest on loans incurred to build the $1.8m system; the hydro scheme means they can sell power back to the network when possible. They have also been early adopters of technology producing more efficient irrigation. Soil moisture meters installed under the irrigation ensure only the required water is used. In some circumstances, they can irrigate at night, when power prices are most expensive and the water evaporates less. Water not being used for irrigation during the day can be put through a turbine when power prices are higher. The scheme has helped their power bill drop from about $60,000 annually to about $10,000. "We have quite a bit of water in winter when power prices are higher; in summer we direct quite a bit of our water to irrigation," says Nigel. "Before we built this, we were buying electricity on the spot market - expensive, I can tell you.

The $1.8m was spent not just on the three turbines and piping but also using 20- and 30-tonne diggers to crunch through solid rock to lay the pipes and pack them with tonnes of gravel to support the pipes when transporting a torrent of water at 1340 litres per second - and the vacuum created when supply is turned off. Foresight saw them lay fibre cable as they laid the pipes - two years later, they were cheaply able to link computers to control the irrigation system, generators, intake pond controls and speed of the irrigation pumps.

In the future, the brothers plan to switch irrigation off when conditions allow and ramp up generation - taking advantage of price peaks. The Harwoods think there may also be room to form a company to run the hydro scheme as a separate business, getting into retail and selling to neighbours or others. Investing $1.8m is not for the faint-hearted but the brothers see it as a long-term investment which will likely realise a return of over 10 per cent annually.

Either way, it's a long way from the original 1000 acres and the "one stiff drink" pub.