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.