Glossary

There are a few terms that the user of this document needs to be familiar with. Below is a listing of common terms and their definitions.

Billing Demand: The billing demand is the demand that is billed to the customer. The electric billing demand is generally the maximum demand or maximum average measured demand in any 15-, 30-, or 60-minute period in the billing month. The gas billing demand is determined over an hour or a day and is usually the greatest total use in the stated time period.

British Thermal Unit (Btu): Quantity of heat needed to bring one pound of water from 58.5 to 59.5 degrees Fahrenheit under standard pressure of 30 inches of mercury.

Btu Value: The heat content of natural gas is in Btu per cubic foot. Conversion factors for natural gas are:

Contract Demand: The demand level specified in a contractual agreement between the customer and the utility. This level of demand is often the minimum demand on which bills will be determined.

Controllable Demand: A portion or all of the customer's demand that is subject to curtailment or interruption directly by the utility.

Cubic Foot: Common unit of measurement of gas volume; the amount of gas required to fill one cubic foot.

Curtailable Demand: A portion of the customer's demand that may be reduced at the utility's direction. The customer, not the utility, normally implements the reduction.

Customer Charge: The monthly charge to a customer for the provision of the connection to the utility and the metering of energy and/or demand usage.

Demand Charge: The charge levied by a utility for me-tered demand of the customer. The measurement of demand may be either in kW or kVA.

Dual-Fuel Capability: Some interruptible gas rates require the customer to have the ability to use a fuel other than gas to operate their equipment.

Energy Blocks: Energy block sizes for gas utilities are either in MCFs or in MMBtus. The standard measures of energy block sizes for electric utilities are kWhs. However, several electric utilities also use an energy block size based on the customers' demand level (i.e. kWh per kW). Additionally, some electric utilities combine the standard kWh value with the kWh per kW value.

Energy Cost Adjustment (ECA): A fuel cost factor charged for energy usage. This charge usually varies on a periodic basis, such as monthly or quarterly. It reflects the utilities' need to recover energy related costs in a volatile market. It is often referred to as the fuel cost adjustment, purchased power adjustment or purchased gas adjustment.

Excess or Non-Coincidental Demand: Some utilities charge for demands in addition to the on- or off-peak demands in time-of-use rates. An excess demand is demand used in off-peak time periods that exceeds usage during on-peak hours. Non-coincidental demand is the maximum demand measured any time in a billing period. This charge is usually in addition to the on- or off-peak demand charges.

Firm Demand: The demand level that the customer can rely on for uninterrupted use.

Interruptible Demand: All of the customer's demand may be completely interrupted at the utility's direc tion. Either the customer or the utility may implement the interruption.

MCF: Thousand (1000) cubic feet.

MMCF: Million (1,000,000) cubic feet.

Minimum Charge: The minimum monthly bill that will be charged to a customer. This generally is equal to the customer charge, but may include a minimum demand charge as well.

Off-Peak Demand: Greatest demand measured in the off-peak time period.

On-Peak Demand: Greatest demand measured in the on-peak time period.

Ratchet: A ratchet clause sets a minimum billing demand that applies during peak and/or non-peak months. It is usually applied as a percentage of the peak demand for the preceding season or year.

Reactive Demand: In electric service, some utilities have a special charge for the demand level in kilovoltamperes reactive (kVAR) that is added to the standard demand charge. This value is a measure of the customer's power factor.

Surcharge: A charge levied by utilities to recover fees or imposts other than taxes.

Therm: A unit of heating value equal to 100,000 Btu.

Transportation Rates: Rates for the transportation of customer-owned gas. These rates do not include purchase or procurement of gas.

Voltage Discounts: Most electric utilities offer discounted rates to customers who will take service at voltages other than the general distribution voltages. The voltages for which discounts are generally offered are Secondary, Primary, Sub-transmission and Transmission. The actual voltage of each of these levels vary from utility to utility.

References

1. Acton, J.P., Gelbard, E.H., Hosek, J.R., & Mckay, D.J. (1980, February). British Industrial Response to the Peak-Load Pricing of Electricity. The Rand Corporation, R-2508-DOE/DWP.

2. David, A.K., & Li, Y.Z. (1991, November). A Comparison of System Response For Different Types of Real-Time Pricing. IEEE International Conference on Advances In Power System Control, Operation and Management. Hong Kong, p. 385-390.

3. Anonymous (1997, August). Energy User News. Chilton Co., p. 32.

4. EPRI (1980, October). Industrial Response To Time Of Day Pricing—A Technical and Economic Assessment Of Specific Load Management Strategies. Gordian Associates, EA-1573, Research Project 1212-2.

5. Hanser, P., Wharton, J., & Fox-Penner, P. (March 1, 1997). Realtime Pricing—Restructuring's Big Bang? Public Utilities Fortnightly, 135 (5), p. 22-30.

6. Kirsch, L. D., Sullivan, R.L., & Flaim, T.A. (1988, August). Developing Marginal Costs For Real-Time Pricing. IEEE Transactions on Power Systems, 3 (3), p. 1133-1138.

7. Mykytyn Consulting group, Inc. (1997). Electric Utilities and Tariffs. PowerRates [Online]. Available: http://www.mcgi.com/ pr/samples/utility_list.html [November 4, 1997].

8. O'Sheasy, M. ([email protected]). (1998, March 12). RTP. E-mail to Mont, J. ([email protected]).

9. Tabors, R.D., Schweppe, F.C., & Caraminis, M.C. (1989, May). Utility Experience with Real-Time Rates. Transactions on Power Systems, 4(2), p. 463-471.

10. Tolley, D.L. (1988, January). Industrial Electricity Tariffs. Power Engineering Journal. p. 27-34.

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