Having topped $4 per gallon, diesel prices have made farmers consider the propriety of continuing to use the fuel to power water pumps. That's especially true when diesel costs are compared to electricity.

Ron Sheffield, LSU AgCenter agricultural engineer, says Louisiana producers are increasingly curious about making the switch from diesel to electricity.

“There was a lot of interest — especially earlier in the season. Now, since we're so far into the season it's slowing down. And, in southern Louisiana, fields have been getting a lot of rain.”

As fuel prices have risen, “there is a cost benefit — at least it's worth a look — from switching from diesel to electric. Most folks, especially with older power plants, could see cost savings fairly quickly. They can probably get a return on their investment within two years. At least that's what most of the growers I've worked with have penciled out.”

As far as efficiency, diesel engines are usually between 15 and 20 percent total energy efficient. An electrical equivalent is about 85 percent efficient.

Unfortunately, electricity is no blanket panacea for massive diesel bills. Producers can incur major expense in having lines run to pumps off main energy routes.

“To be honest, the challenge is the huge variability of electrical costs across the state,” says Sheffield. “Essentially every power company, every electric co-op, has a totally different rate structures for projecting what electrical costs will be.

“So, when someone calls and says, ‘This is what I need to do,’ I say ‘That's great. But you're going to have to wheel and deal with your power company to see how this will pencil out. I can't just answer your question right off.’”

Sheffield says the inability to calculate costs of shifting to electricity is a major hindrance.

“Even within the same company, depending on where you are in a parish or within a section of a power grid, the rate structure may differ. The basic rate may be the same, but what you'll be charged for surcharges and connection fees vary tremendously. That's where the biggest cost variability comes in.”

Typically, how much does an electric pump run?

“For a 100-horsepower system, you're looking at around $6,000. The control panel for it may cost another $1,000.”

Unfortunately, the numbers crunching isn't done yet.

“The challenge is where the pump is located. You've got to get three-phase power to the pump. If it's right next to the road and a power line, you're golden. But if you're in the middle of the boonies, you're potentially looking at much more expense. It costs about $7 per foot to put in poles and three-phase line. That can run up costs very quickly.”

When asked for help with a switch to electricity, Sheffield normally sends producers information ahead of meeting.

“That allows them to do some of their own calculations. In one Vermilion Parish operation, the producer was growing rice rotated into soybeans. He also had some crawfish.

“We looked at where the pump was located. He was using a surface-water pump rather than a deep-water well. The operation was feeding two major irrigation networks from one major pump.

We reviewed the pumping capacity, the irrigation lines in place and then how far he'd have to bring in electrical lines.”

Luckily for the producer, his power company allowed him to defray the cost of power line installation for three years.

“He had to sign a five-year usage contract but could make payments for three years. He bought the system at $4.15 diesel. It turned out the monthly fee for putting in the power line cost the same as one day's worth of irrigation.”

It's worth reiterating, says Sheffield, that while commodity prices are currently high, so are input costs.

“Irrigation costs are part of that. Irrigation costs need to be evaluated just like everything else in a grower's business. Looking at a cheaper source of pumping power is worth doing.

“Electricity may not lower pumping costs by 90 percent. But most systems we've reviewed are looking at between 40 and 50 percent cost reduction.”

Asked about government programs to assist producers making a switch to electricity, Sheffield says Natural Resources Conservation Service programs “are only for existing systems — not for putting in new ones. In Louisiana, we're looking at some NRCS programs for well development/well reconditioning that there's cost-share money for.”

However, the “biggest thing” being considered is a joint program between the LSU AgCenter and NRCS.

“That would allow us to go out and do audits of irrigation and pumping systems. Then we'd be able to say, ‘Ok, landowner, this is where your irrigation system is pumping currently. Looking at these general values for new or refurbished systems, this is what your system should cost in the future if we switch (from diesel to electric).’ We're trying to get funding to put in at least two or three pilot programs in southwest and northeast Louisiana.”

What about new pump technology?

“Variable-frequency drives are the newest type of pumping system out. Really, they make use of the same pumps with a different way to control them.”

The variable-frequency drives allow users to “vary the flow rate in the system to match what your delivery needs to be. It also reduces the amount of power consumption during the start-up phase. The variable-rate pumps don't cause huge surges of electrical usage.”

At $2,000 to $4,000, the new control units are more expensive — about twice the cost of conventional types. “And some of the control units need to be in extremely well-ventilated buildings or in air-conditioning. That can increase the cost even more.

“But they do use less electricity. And demand charges — when power is used and how much is used during peak times — can be taken into account” and manipulated for the most cost effectiveness.

“For a normal rice or crawfish producer, though, the variable-rate pumps are probably above and beyond what's needed.”

Solar-powered pumps are still a ways off, says Sheffield. Using current solar technology “would require many, many panels in the field to produce the needed energy. You'd be covering a large portion of the field with the panels.”