Solar water pumping for bores, stock water and irrigation

A litre of diesel gives a pump engine about 3.7 kWh at the shaft. That's the NSW DPI method: 38 MJ per litre at 35% engine efficiency (NSW DPI, checked 21 Oct 2026). At today's prices that makes diesel an expensive way to lift water.

What diesel pumping costs (example)

These are teaching figures with the assumptions shown. Your figure depends on your delivered price, engine and pump.

• Diesel terminal gate price, Brisbane, 21 Oct 2026: 264.6 c/L inc GST (AIP)
• Less GST (claimed back by a registered business): 240.5 c/L
• Less fuel tax credit, 53.7 c/L from 3 Aug 2026 (ATO): 186.8 c/L
• Shaft energy per litre: 38 MJ x 35% = 13.3 MJ = 3.69 kWh
• Fuel cost per shaft kWh: about 51 cents, before delivery, servicing, oil and your time refuelling

Delivered farm diesel costs more than the terminal gate price, so treat this as a floor.

Three ways to set it up

Direct solar pumping

Panels drive the pump through a controller in daylight. You store water in a tank or dam, not in batteries. It suits stock water and bores where a day's pumping is enough.

Solar-diesel hybrid

Solar does the daylight pumping and the diesel picks up nights or long cloudy runs. NSW Farmers and the NSW Government publish a checklist for exactly this (Solar Diesel Hybrid Pumping Systems).

Solar plus battery

For pumps that run on demand or overnight, or sites sharing power with a house, shed or cold room.

Fix the pump first

An efficient pump needs less solar. Pipe friction, a worn impeller or an oversized pump all add panels to the design. A pump check is often the cheapest saving on the place, and we'll say so.

Published results from other farms

CottonInfo's case study of a NSW solar-diesel hybrid irrigation system reports pumping cost falling from $76 to $41 per megalitre and diesel use cut by 45,000 to 55,000 litres a year (CottonInfo, checked 21 Oct 2026). That's another farm's result, not one of our jobs.

Help in Queensland

Ergon's Solar Pump Program offers cashback to eligible farmers who swap a pump-only, end-of-line grid connection for a solar pump and abolish the connection (Ergon). QRIDA offers Sustainability Loans up to $1.3 million and QFF runs free farm energy audits (QRIDA). More on our commercial rebates page.

FAQs

Can a solar pump run irrigation?

Yes, sized to the flow and head you need. Big irrigation pumps usually suit a hybrid, with solar covering daylight hours and diesel or grid covering the rest.

Do I need batteries for a solar bore pump?

Often not. Most bore and stock water systems pump in daylight into a tank, and the tank does the storing.

How much does diesel pumping cost per kWh?

Using the NSW DPI method and Brisbane terminal gate diesel on 21 October 2026, less GST and fuel tax credits, fuel alone works out about 51 cents per shaft kWh. Delivered prices and servicing push it higher.

Can I keep my diesel pump as backup?

Yes. A hybrid keeps the diesel for nights and cloudy runs so it runs fewer hours.

Get a custom design

Send us your fuel invoices and pump details (flow, head, hours). We'll work out your cost per kWh and come back with a custom design. Get a custom design