Taming the seasonal load with critical peak wholesale

Imagine a load class with the potential to double total system demand and runs only four months of the year - in some places as little as 400 hours per year. Now add a double dose of weather variability to the mix - temperature and rainfall. If it rains, this load may not be running the next day regardless of temperature. If weather is dry, the load can create annual peaks. This load can run ldquofull onrdquo one day, and off the next day - unscheduled! The load class described above is the "800 lb. gorilla" that rural power operators across the Midwest call "electric irrigation". There is a positive side to this load however, and that is the value it brings to the local community. In Nebraska, economic development studies have shown that areas of the state where irrigation has been utilized for the past 50 years are significantly richer than areas without irrigation. G&T co-ops have tried many approaches to serving and managing electric irrigation, but one program stands out for its longevity, integration to daily power supply operation, and the degree of participation. The Nebraska Electric G&T (NEG&T), in partnership with Nebraska Public Power District, has developed a wholesale power rate that works well for the second most irrigated state in the nation. This paper will detail Critical Peak Wholesale, known to Nebraskans as the "Billable Demand" Program. More traditional programs and some experimental methods will also be compared.