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Powering Down

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As Almond Facts went to press, the power supply and cost scenarios for California almond growers remained unclear. Some progress had been made on rate structures, but not on significant new sources of power or on the question of prior notice of power interruptions. What is certain is that electric power will cost vastly more (double, triple or more) than in years past and frequently will be unavailable during periods of peak demand.

Power interruptions will most likely occur during peak-use hours - noon to 6 p.m. - and last from one to two hours. Predictions of the number of blackouts to expect this summer continue to increase. Some recent estimates go as high as one thousand hours and 34 days of blackouts.

The prospect of having an unannounced blackout during an irrigation cycle or at harvest when huller/shellers are running around the clock is unsettling to say the least. Unexpected power interruptions could wreak havoc with such operations, waste large amounts of water and product, and add more costs to growers' shrinking bottom line.

While there's little that an individual grower can do to prepare for unannounced blackouts, he can take steps to minimize his power consumption or cost of power. Some experts on the subject have shared some tips on what you can do to help ease the pain this summer.

Tto Options

There's no in-between. The laws of physics are firm on this. According to Wateright (a web site of CSU Fresno's Center for Irrigation Technology), to reduce energy use, you must either reduce the kilowatt-hours required to pump each acre-foot of water or reduce the number of acre-feet pumped. In other words, to use less energy, your irrigation system or plant operation must run less or more efficiently. But begin your quest for lower power costs by making sure you are on the right rate schedule.

Get Right Rate

Are you paying the lowest possible rate(s) for your electric power usage? Agricultural users have a variety of options based on horsepower requirements as well as operating hours, days and seasons. Time-of-use schedules can save you money if you have the flexibility to pump during non-peak periods. The CPUC announced new base rates on May 14 that will have rippled through power suppliers' rate schedules by the time you read this. If you haven't already, check with your supplier to make sure you are being billed on the lowest possible rate for your usage and to see if you can adjust your peak usage to a better rate schedule.

Reschedule Operations

Many growers don't have the option of limiting their pumping or hulling/shelling to off-peak periods, but if you do, avoid the noon to six p.m. time slot to ease the load and save some money. The California Energy Commission (CEC) advises signing up for Time of Use rates with your utility company to lower your costs and, perhaps, avoid power interruptions. The likelihood of blackouts occurring during peak times is higher than during off-peak periods.

You'll need to calculate whether or not your pump and irrigation system can deliver the water your orchard needs in 18 instead of 24 hours. If it can, you are a candidate for off-peak scheduling. Also, if you can operate your huller/sheller during off-peak hours and still get the job done, you could schedule operations between 6 p.m. and noon the following day and reduce your likelihood of an unplanned shutdown due to a blackout.

Tune Up Pumps - Inefficient pumps and motors waste money.

Tim Jacobsen of the Center for Irrigation Technology strongly advises conducting a head-works or pumping station audit. He points out that PG&E has discontinued its pump testing service, but your local pump company can test your equipment for you or tell you who can.

A pump test is nothing more than a comparison between how much energy your pumping plant is using and how much it is producing, Wateright explains. In an electric-powered plant, the "wire-to-water" efficiency compares how much electric energy is being consumed to the water flow and pressure produced.

When your pump is tested, Jacobsen says, and the technician finds it running at less-than-rated efficiency, "the technician will loosen the nut on top and re-set the impellers. This brings the pump back into tolerance. It will increase the amount of water the pump produces and the load will go way up, but the pump is running more efficiently, which saves power." The cost of this test runs around $50 to $60, he says, but can soon pay for itself in less power consumption.

The CEC recommends adjusting the impeller on pumps that test between 55 and 60 percent efficiency. Pumps that rate between 50 and 55 percent efficiency should have their impeller adjusted, but if that doesn't improve their efficiency, the pump should be repaired or replaced. Pumps with less than 50 percent efficiency should be repaired or replaced.

According to Wateright, one factor to consider when interpreting the results of a pump test is how representative the operating conditions were. Was the pump operating under normal conditions when the test was performed? If on a water well, was the water table lower than normal? If so, the pump will not be as efficient.

Motor efficiency has improved greatly in recent years. The CEC suggests buying the new energy-efficient models when replacing a standard motor. At today's electric rates, the new motor will soon pay for itself.

If you operate a deep well with frequent startups on a Time of Use rate schedule, the CEC points out that you can reduce power consumption by installing variable speed drive controllers.

Check the System

An efficient irrigation system saves money. By maximizing its efficiency you minimize the run time and, therefore, the amount of power consumed, says Jacobsen.

"When testing your irrigation system, make sure the pressure regulator valve is set correctly," Jacobsen says. "If you have a micro-irrigation system, make sure that the filter station is backwashing as often as it should and that the pressure loss over the filters is correct." Jacobsen says that the pressure loss should be only a pound or two. More loss than that means the system is not cleaning itself often enough.

"Check every point where there might be a pressure loss. When you find a drop in pressure, make sure you know why it is less and if it is appropriate for that piece of equipment," he adds.

Sources of Information

For details on how you can calculate your energy requirements and costs, options for reducing energy use and cost, and much more, visit the Wateright web site at www.wateright.org.

For energy advisories, visit PG&E at www.pge.com or the Association of California Water Agencies at www.acwanet.com, or the California Farm Bureau at www.cfbf.com. And that's just the beginning. Each site has links to other agencies or associations that offer an abundance of information.