A variable frequency drive (VFD) lets an irrigation pump run only as fast as the field actually demands, cutting pumping energy 20 to 50 percent, while a cellular telemetry retrofit like FarmHQ or FieldNET adds remote start, stop, and alerts from your phone. Utility rebates of $50 to $100 per horsepower often cover a large share of the install.
That is the whole pitch in two sentences. The rest of this article is the math, the hardware, and the honest caveats - including when a VFD is not worth the money.
The first trip is the 2 a.m. drive. A set finishes, or a line blows, or you just cannot sleep without knowing the pump shut down, so you get in the truck. Multiply that by a season and you have burned days of windshield time babysitting a piece of equipment that has exactly two jobs: on and off.
The second trip is the one your electrons make through a throttling valve. Most irrigation pumps were sized for the worst day of the worst year, then installed with a gate valve to choke them back the rest of the time. The motor still pulls near full power. The valve turns the extra into heat and noise. You pay for all of it.
Both problems now have off-the-shelf fixes: a VFD in the pump panel, and a cellular telemetry box bolted on top. Neither requires replacing the pump.
A VFD sits between your power supply and the motor and varies the frequency of the power it feeds the motor, which varies the motor's speed. Instead of running at full speed and fighting a valve, the pump runs at exactly the speed that produces the pressure or flow you set.
The reason this saves so much money comes down to the pump affinity laws, and the third one is the moneymaker:
The cube rule means small speed reductions produce outsized power savings. Slow a pump to 80 percent speed and it draws roughly half the power (0.8 x 0.8 x 0.8 is about 0.51). At 50 percent speed, the pump draws about 12.5 percent of full power. The U.S. Department of Energy and the Hydraulic Institute publish the full engineering treatment in their Variable Speed Pumping guide, and utility efficiency programs across the Northwest use the same math to calculate rebate values.
Compare that to the valve. Throttling a pump back with a gate valve barely reduces motor draw - it just wastes the difference. If you are currently pumping against a partially closed valve for any meaningful part of the season, a VFD recovers most of that waste.
For irrigation duty, realized savings typically land between 20 and 50 percent, and where you fall in that range depends on one thing: how much of the season your pump can run slower than full speed.
Be honest about this before you spend anything. The savings come from variation. A pump that genuinely needs full flow at full pressure from the first set in May to the last in September has nothing for a VFD to trim - in that case the drive is mostly an expensive soft starter. The farms that see the big numbers are the ones with:
One caveat that belongs in your planning rather than the fine print: do not plan to run below about 30 percent speed. Standard motors cool themselves with a shaft-mounted fan, and at very low speeds the fan stops doing its job while pump efficiency collapses. The usable savings window is real, but it has a floor.
The energy math gets the attention, but ask anyone who services irrigation pumps what kills them and they will tell you: starts.
Water hammer. A pump slamming on at full speed can spike line pressure to several times normal - industry references commonly cite 5 to 10 times operating pressure - which is how mains burst, fittings loosen, and pivots get shaken apart. A VFD ramps the pump up over seconds instead of milliseconds, and ramps it down the same way. The pressure wave never forms.
Inrush current. An across-the-line start pulls a large multiple of the motor's running current for a moment. That is hard on the motor windings, hard on rural single-phase services, hard on generators, and it can trip demand charges on some rate schedules. A VFD starts the motor at low frequency and low current.
Protection built in. Most drives ship with dry-run protection, over-pressure and under-pressure faults, and phase monitoring. On a well, dry-run protection alone can pay for a small drive the first time the water table surprises you.
A note on terminology, because the two get conflated constantly: a soft starter also fixes the hard start, and it costs less. But a soft starter only manages the start and stop. It cannot vary speed while running, so it cannot hold constant pressure and it cannot save running energy. If starts are your only problem, a soft starter is the cheaper fix. If you throttle, a VFD does both jobs.
Yes, and you no longer need a SCADA integrator to do it. Three retrofit-friendly options cover most setups:
FarmHQ (from CODA Farm Technologies) is a cellular box that bolts onto essentially any brand of pump or hose reel. It monitors pressure, flow, and GPS position, and it can start and stop electric pumps through a dry-contact connection or kill a diesel remotely. Hardware runs around $1,449 per unit plus an annual subscription (the company does not publish the subscription price, so get a quote). FarmHQ claims meaningful per-season labor and water savings; treat vendor numbers as vendor numbers, but the 2 a.m. drive it eliminates is not hypothetical.
Lindsay FieldNET M2 Control monitors and controls up to two pumps or pump stations from the same app and web dashboard FieldNET users already run their pivots from, with real-time alerts and water-delivery reporting. If your operation is already on FieldNET, this is the path of least resistance.
Wildeye comes at it monitoring-first: flow-meter telemetry that retrofits most major meter brands. It is the right tool when what you really need is to see flow and totals remotely, with control as a secondary concern.
There is also a built-in path. Some pump packages integrate the drive directly - Grundfos's SQE line puts the VFD electronics in the motor itself for constant-pressure well service - and most pump-panel OEMs, Franklin Electric included, sell drive-and-telemetry-ready panels. Retrofit boxes win on flexibility across mixed fleets; integrated systems win on simplicity for a single new install.
This one surprises people: many VFDs accept single-phase input and output three phase to the motor. For farms miles from the nearest three-phase line, that means running an efficient three-phase pump motor without paying the utility for a line extension or fooling with a rotary phase converter. Drives doing this duty need to be oversized relative to the motor, so spec it with your supplier, but for rural single-phase services it can be the difference between a $5,000 panel and a $50,000 line extension.
Ballpark figures, small to large:
Run your own numbers with your actual kWh rate, your horsepower, and an honest estimate of how many hours per season the pump can run slowed. Your utility's ag program can usually help with the calculation for free.
In irrigation country, probably yes, and the amounts are not trivial. Current published programs include:
The pattern across programs is $50 to $100 per horsepower, which on a 75 hp turbine pump can mean $5,000 to $7,500 back. Two rules: call your co-op or utility before you buy, because most programs require pre-approval, and get the rebate paperwork moving before the installer shows up, not after.
A few things separate a clean install from a callback:
If you are throttling a pump against a valve, pumping into zones with different pressure needs, or running a pump whose demand varies across the season, the VFD math almost certainly works - start with a call to your utility's ag program and a quote from a pump contractor. If your pump runs one fixed duty point all season, skip the drive for now and spend the first dollar on telemetry instead; remote start, stop, and dry-run alerts will save you more windshield time than a drive will save you kilowatts. For the bigger picture on where pumping fits in your whole water plan, see our guide to water management technology.
Either way, the decision gets easier when your irrigation thresholds and pump records are written down instead of carried in your head. That is exactly the kind of operating detail we built The Practitioner's Playbook for - a 128-page field operations manual with irrigation threshold worksheets, monthly calendars, and record-keeping templates you can hang on the shop wall. It pairs well with a winter afternoon and a stack of power bills.
Typically 20 to 50 percent of pumping energy, depending on how much of the season the pump can run below full speed. The savings come from the pump affinity laws: power draw falls with the cube of speed, so running at 80 percent speed cuts power draw roughly in half. Pumps currently throttled with a valve see the biggest gains; pumps that need full flow all season save little.
Yes. Cellular retrofit systems like FarmHQ bolt onto nearly any brand of pump and allow remote start and stop of electric pumps, plus shutdown of diesels, from a phone app. Lindsay's FieldNET M2 Control manages up to two pumps alongside pivots, and Wildeye offers flow-meter telemetry for remote monitoring. Hardware typically runs $1,000 to $1,500 per pump plus an annual subscription.
Many do, especially in the West and Northwest. Energy Trust of Oregon pays $1,000 to $9,000 per installed VFD up to 100 hp. Rural electric cooperatives commonly pay $50 to $100 per nameplate horsepower. BPA and PG&E both run agricultural VFD programs. Most programs require pre-approval, so call your utility or co-op before purchasing equipment.
A soft starter only manages starting and stopping - it ramps the motor up gently to prevent water hammer and inrush current, then runs it at full speed. A VFD does that and also varies motor speed continuously while running, which lets it hold constant pressure and cut energy use. If hard starts are your only problem, a soft starter is cheaper. If you throttle flow, a VFD pays for both jobs.
Yes. Many VFDs accept single-phase input and deliver three-phase output to the motor, which lets farms without three-phase service run efficient three-phase pump motors without a utility line extension or rotary phase converter. The drive must be oversized relative to the motor for this duty, so have your supplier spec it, but it is a standard, well-supported configuration.
Join our list for practical guides on farm tech, precision agriculture, and tools that work.