The Contract Analyst Team looked at available data from regional utilities in order to determine the maximum technical demand response impact for irrigation pumps. The main finding was the irrigation pump DR coefficient of 0.8, which produces the total input power of a group of pumps when it is multiplied by the sum of  the nameplate horsepower ratings. The coefficienct includes the conversion from horsepower to kilowatts and the electrical efficiency of the pump motor under loading conditions found in the field. The DR coefficient was approved by the RTF at the May 21, 2019 meeting. Further, the RTF noted that different pump types and conditions experienced in the field meant that the DR coefficient would vary from pump to pump. However, it does allow power planners to calculate the accurate average impact on the grid of turning off a group of pumps.


RTF Presentation  Irrigation Pump Controls DR Workbook DR Subcommittee Presentation  DR Subcommittee Notes 

Factors that affect the maximum technical DR impact

Only the coincident pump load during the DR event is available for control. The coincident load is greatest when irrigation is needed for the maximum acreage of crops, and depends on the month and season. Expert opinion of utility DR program staff cited a maximum coincident load of 80% of total pumping capacity during the month of July, and less in other months.

Irrigation systems with multiple pumps and large, cumulative pumping capacities are sometimes manually dispatched. For these systems, not all of the pumps have to be nominated for control. The irrigator may choose to turn off some or all of their pumps manually. The demand response only applies to the percentage of capacity nominated for control. The maximum technical DR impact will be modified by the willingness of irrigators to participate in the program. The number of DR events and the length of the events are the most important factors influencing participation rates.

In addition to the factors which modify the DR impact, more data on the number of variable speed pumps and the presence of auxiliary electrical loads could improve the accuracy of the irrigation pump DR coefficient. The coefficient would change to a small degree, if variable speed pumps became more common. Possible auxiliary loads about which more information would be useful are pivot and wheel line motors and booster pumps.

Follow up

The primary source of data for farm pumping and irrigation statistics is the 2013 Water Management and Irrigation Survey conducted by the United States Department of Agriculture. Results from the 2018 survey are expected mid-November from the National Agricultural Statistics Service. Data are available for the number of farms, number of pumps, and discharge capacity by state in Table 11.

With some engineering assumptions, it would be possible to calculate the horsepower of the pumps from the discharge capacity. However, the number of farms with cumulative horsepower above 1000, which would be useful to estimate demand response potential for manually dispatched pumps, is not available from the tables.