To protect your and your company’s wallets, it is very important to understand the rates you are being charged for electricity. In this segment, I am going to share with you and discuss in detail the large commercial and industrial electric rates of a typical utility. The example I am using is a utility that publishes their rates on the Internet. The electric rates you are being billed may vary greatly from my example. I recommend that you contact your utility to get a copy of your rate and to find out what other rates are available to you. Some of the terms I am using in this article have been previously defined and discussed in parts 1, 2 and 3 of this series.
Large General Service Rate
For our example utility, their large general service rate is for all customers that have a summer maximum demand of 300 kW or greater. This is the rate for most large department stores, office buildings and industrial customers. For our example utility, this rate has a customer charge of $159.63 per month. The energy charge for the summer months is 8.9571 cents per kWh for energy used during on-peak time and 6.3569 cents per kWh for energy used during off-peak time. The energy charge for the winter months is 9.5444 cents per kWh for energy used during on-peak time and 6.7667 cents per kWh for energy used during off-peak time. For this rate, on-peak hours are 6:00 a.m. to 10:00 p.m. Monday through Friday. During Daylight Savings Time (summer), on-peak hours are 9:00 a.m. to 10:00 p.m. Monday through Friday. Note that the on-peak hours during Daylight Savings Time (summer) are not just one hour different from the winter times. I find it odd that the energy rates are higher in the winter months than during the summer months.
For this rate, the demand charge is $26.128656 per kW in the summer months and $17.784842 per kW in the winter months. The good news is that the demand is a sixty-minute demand. The sixty-minute demand allows much more opportunity for load management. Note that this is not a clock-hour sixty-minute demand. It is a rolling sixty-minute demand. The metering looks for the maximum sixtyminute demand. Some utilities have a clock-hour sixtyminute demand. For this rate, the measured demand for any month is the greater of the maximum demand established during any sixty-minute period of the month during on-peak hours as measured by the demand meter, taken to the nearest whole kilowatt or one-third (1/3) of the maximum demand established during any sixty-minute period of the month during off-peak hours. You will recall that under the medium general service off-peak rate (detailed in part 3 of this series), the off-peak demand could be ten times the on-peak demand but the customer only paid for the on-peak demand. Under the large general service rate, if the off-peak demand exceeds three times the on-peak demand, the customer pays for it.