Pacific Gas & Electric - PG&E

To estimate the load profiles, PG&E followed these four steps:

• Estimated the average half-hourly loads for each rate class for each year used in the load profile estimation process. For example, PG&E estimates that the average A1 customer half-hour demand was 2.9840 kW at noon on April 1, 1994. Note: to estimate hourly demands, add the two half-hourly demands and divide by two. For example, the hourly demand for the hour ending noon on April 1, 1994 is (3.0036 + 2.9840) / 2 = 2.9938.
• Mapped each day in 1998 to the most similar day in 1994, 1995, and 1996. For example, Friday, March 27, 1998, is mapped to Friday, April 1, 1994, Friday, March 31, 1995, and Friday, March 29, 1996.
• Averaged each year’s half-hourly loads according to the date map The table below describes the load estimation for March 27, 1998.

• The mapping process yielded eleven days in 1998 for which some or all of the corresponding dates in 1994, 1995, and 1996 are missing. These are November 6, 7, 9, and 19, and December 21, 23, 27, 28, 29, 30, and 31. For these days, the average by month and daytype (weekday or weekend) for the month was used instead of a specific day. For example, Monday, November 9, 1998 was estimated as the average of November 14, 1994, November 13, 1995, and the average of all weekdays (excluding Holidays) in November of 1996.
• Last, normalized the load profiles by multiplying each half-hour value by 10,000, and dividing by the sum of all half-hour values

For example, the load profile normalized value for 12 pm in the table is 0.82014, calculated as follows:

Three-year average load: 2.68783

Sum of all half-hour intervals in the three-year average load: 32,772.975

Load profile value for March 27, 1998 at 12 pm = 2.6878 X 10,000 / 32,772.975 = 0.82014