Here is an explanation of the terms used on your monthly UPPCO bill:

Units used for measuring heating and cooling requirements. Daily degree days are calculated by subtracting the average daily temperature from 65ºF. Heating degree days result if temperatures are less than 65ºF; cooling degree days if more than 65ºF.
Varies with the amount of electricity you use. Electricity is measured in kilowatt-hours (kWh). You are charged for each kWh of electricity you use for the delivery of electricity.
This is a fixed charge. It helps cover the costs of supplying equipment used to serve customers, issuing bills and providing customer service programs.
An estimated reading is based on actual past use, seasonal trends and weather. Any difference between the estimated reading and the actual one will be made up the next time the meter is read.
A measurement of electric energy. One kWh will light a 100 watt bulb for 10 hours.
Commission authorized charge on unpaid service balances that are past due.
Fee to help fund energy-efficiency programs.
Varies with the amount of electricity you use. This usage amount is for the actual electric supply you use.
Accounts for any difference in an energy supplier’s costs of producing or purchasing electricity to meet your needs. It appears as a credit or charge on your bill based on how actual costs compare to the Power Supply Service.