Pictured Above: Installations of photovoltaic systems in eSwatini and northern KwaZulu-Natal by Durban-based company TRRC.

Macadamia farmers are turning to solar power in their numbers in a bid to keep irrigation systems on schedule as South Africa’s power grid teeters on the edge of collapse.

Matt Pender, technical sales manager at Durban solar company Starrate, says the demand for solar power by macadamia farmers in KwaZulu-Natal is on the increase.

“We are so busy; we are run off our feet. When load shedding first started we installed solar systems mainly on residential homes, now it’s more factories, businesses, storage facilities and in the agriculture sector, particularly macadamia farms.”

Solar power systems supplier Starrate install panels atop a pump house roof at a macadamia operation in Compensation, north of Durban.

Pender said the recent installation of a system at a macadamia farm in Compensation, north of Durban, was typical of the jobs they are doing. “Our client asked us to install a solar system for a pump house where water is pumped from a ground dam, up a steep gradient to a storage dam, before it is then used to irrigate the orchards.”

Pender said the only other option farmers had for keeping irrigation systems running in some instances was to install Eskom-powered transformers. This was not only costly, he added, but took time to hook up and farmers had to pay for the power. Another option was using diesel-powered generators, which could cost anything up to R35 000 a month to run, depending on the size of the generator and the length of time the pump was operational.

He said delivering diesel to remote rural areas was not only difficult but often farmers had to employ security guards to protect the stored fuel from theft.

“When we begin a job for macadamia farmers, we install a power logger system which gives us an indication of how much power the pump is ‘pulling’. Once we know that, then we can install an adequate number of solar panels, the appropriate-sized battery bank and inverters. The second phase for the system, Pender said, was to run a 700m overhead cable from the solar plant down to the river to supply power to transfer pumps, and then expand the system adding more PV panels to transfer water up to the irrigation dam.

“This will provide for the expansion of the fertigation plant for new trees. The photovoltaic system can be expanded for the farmers needs as they change and grow,” Pender said.

Jason Wise, from solar installation company TRRC, said rain was a particular challenge for installations to supply water to macadamia orchards. “There is no need for the pumps to operate as farmers stop irrigating their orchards when it’s raining. However, the excess power can be used for other operations on the farm,” he said.

He added that if a solar unit were installed for irrigation purposes without a back-up battery system, then watering would be preferable during the day rather than at night.

Wise said the demand for solar installations in the agricultural sector had grown exponentially since 2021. This was largely driven by the failings of the national power grid.

“The rising costs of power also play a large role in the rapid growth of the renewable industry systems, as they are now taking less time to pay for themselves. For example, a farmer who invests in solar this year will see an increase of up to 19% on his investment, due to the savings generated by the installation.”

Barrie Christie, group agricultural technical manager for the Green Farms Nut Company, said farmers were at the end of their tether. “Irrigation, dehusking and drying the nuts becomes a big issue when power supply is erratic. Those with micro and drip irrigation also have significant issues. Low flow drip irrigation allows farmers to irrigate the entire operation under macs all at once. Once the power is back on they can start the pumps and get the trees watered. However, if the system is micro- or drip-irrigation, then it becomes very tricky to manage which blocks in the orchard will get watered and when, according to the load shedding schedule,” he said.

A view inside of the pump house of the inverter and batteries used to store the power at the Compensation macadamia operation

Hein van der Merwe, owner of Off Grid Pro which operates in Mpumalanga and Limpopo province, said the investment farmers were making was less about the cost of the installation but rather, about the cost of not irrigating and losing the crop or the trees. “If the farmers can keep production steady, they can pay off a solar system over time.”

He said despite the pressure on farmers, they were tapping into financing plans or their savings to install the systems. “The one question they all ask though is whether they can push any of their excess power back on to the grid. Government keeps saying it is an option but the power lines servicing farms generally cannot handle the excess power. Also, if farmers want to have their lines upgraded, that is a cost they will have to bear and it’s just not feasible,” he said.

Wise offered the following advice to farmers wanting to install solar to irrigate their orchards:

  1. Assess your load properly to make you get the right inverter size;
  2. Determine your battery based on the load you want to run for the number of hours you want to run it: for example, a 45kw load for four hours requires 180kwh of usable battery;
  3. Lithium ion batteries are generally discharged down to 20%, meaning a 100kwh battery can only supply 80kwh of power
  4. PV panels produce power, batteries store power and inverters deliver power, so each one needs to be looked at individually

On the aspect of theft, Wise said while the equipment should be well secured, the large commercial systems had high voltage batters and inverters that are heavy and difficult to steal. And they cannot be used in any way or form by the average individual.

While panel prices had been on the increase, costs had stabilised over the past few years, he added.

Return on investment would be between 18% and 25% over a 10-year-period.