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Glossary of Terms Used in Subscription Power Product Descriptions
 
November 5, 1997
 

 
Glossary Terms

The purpose of this glossary is to supplement the Standard Power Business Line Product Descriptions.

It is our hope; the definitions contained in the glossary will provide additional clarity to the technical terminology used in the product definitions. In general, the glossary focuses on operational and contractual concepts. The definitions follow industry-accepted procedures; however, the power market is changing and some of the definitions may require refining.

If you have questions or comments regarding the glossary, please contact Carolyn A. Richardson at 503-230-5163.

 
 

AGC (Automatic Generation Control)

A real-time control scheme used by all control areas to ensure that generation is continually adjusted to meet load requirements and scheduled interchange commitments as required by the National Energy Reliability Council (NERC).

 

Ancillary Services

Products currently provided by BPA's Transmission Business Line under the APS, PF, IP, and NR rate schedules: Load Regulation; Energy Imbalance; Control Area Reserves for Resources; Control Area Reserves for Interruptible Purchases; Transmission Losses.

 

Capacity

Also defined as Firm Capacity without Energy or naked capacity. Power purchased from BPA during heavy load hours (HLH) with the return of associated energy within (usually) 24 hours.

 

Control Area

A part of a power system or a combination of systems to which a common generation control scheme is applied to match generation and load. BPA's control area is interconnected with 13 control areas in the Northwest. Points of interchange are metered as part of automatic generation control (AGC).

 

Displacement

A customer's right to reduce its purchase of energy from BPA in order to purchase from another supplier. Economic displacement is for the purpose of buying less expensive power from another supplier.

 

Firm Energy

Energy that the supplier will make continuously available to the purchaser during the period covered by its contractual commitment, except for reasons of certain uncontrollable forces and force majeure events.

 

Firm Power

Power guaranteed to be continuously available to the purchaser during the period covered by its contractual commitment, except for reasons of certain uncontrollable forces and force majeure events.

 

Heavy Load Hours (HLH)

The hours in the peak period of high system demand, on BPA's system 6 a.m. to 10 p.m., Monday through Saturday, Pacific Prevailing Time (Pacific Standard Time or Pacific Daylight Time, as applicable). This definition is subject to change if the definition in the 1996 Wholesale Power and Transmission Rate Schedule changes.

 

Interruptible Energy

Energy sold under terms that allow the supplier to terminate delivery.

 

Light Load Hours (LLH)

The hours in the off-peak period with low system demand, on BPA's system 10 p.m. to 6 a.m., Monday through Saturday and all hours Sunday, Pacific Prevailing Time (Pacific Standard Time or Pacific Daylight Time, as applicable). This definition is subject to change if the definition in the 1996 Wholesale Power and Transmission Rate Schedule changes.

 

Load Factor

The ratio of average load to the peak load during a specified period of time; expressed in percent.

 

Load Factoring

The exchange (delivery and return) of equal amounts of energy during a specified period of time. Energy delivered at a certain time and the return of energy at another time, generally within the same day. Other variations of this service energy can be return within a week, a month, or a year.

 

New Large Single Load

A load that will result in an increase in power requirements by 10 average megawatts or more in any consecutive 12-month period, as defined in section 3(13) of the Northwest Power Act: Load associated with a new facility, an existing facility, or an expansion of an existing facility that is not contracted for, or committed to, (as determined by the administrator, by a public body, cooperative, investor-owned utility, or Federal agency customer prior to September 1, 1979).

 

Operating Reserves

The unloaded generating capacity, interruptible load, or other on-demand rights that the customer is able to access within ten (10) minutes of a power system disturbance and that are capable of being used to serve load on a sustained basis for up to one (1) hour. Operating reserves includes both spinning reserves and non-spinning reserves. The Northwest Power Pool requires that each control area maintain an operating reserve obligation equal to at least 5 percent of hydro and 7 percent of thermal and other non-hydro on-line generation within the control area.

 

Option

An option can be used to reserve customers' right(s) to purchase energy at a specified price for a specified period of time in the future (call option); or to decrease the amount of power taken (put option).

 

Preschedule

Amounts of energy (scheduled in MWs) to be delivered, established on the workday (i.e., day observed by all parties as a normal workday) prior to the day of delivery for all hours of the prescheduled day.

 

Real-Time Operations

The hourly operations of a power system as opposed to those operations that are prescheduled a day or more in advance.

 

Remarket

BPA will remarket the power that a purchaser cannot use if the purchaser does not legally have the right to resell that classification of power. BPA markets the power. The revenues BPA collects will be credited against the amount owed to BPA. Risk of underrecovery or benefits of a firm sale are borne by the customer.

 

Resale

Customer has right to take title and resell the power that cannot be used for the purpose intended at the time the purchase contract was executed. Risk or benefit of sale is borne by the customer.

 

Reserve Services

Products currently provided by BPA's Power Business Line under the FPS rate schedule: Supplemental AGC; Spinning Reserves; Non-Spinning Reserves; Forced Outage Reserves.

 

Retail Access Load Loss

Sales lost by a BPA customer due to consumers purchasing from other power suppliers.

 

Secondary Energy

Traditionally, called nonfirm energy or surplus energy. Surplus energy that is available beyond existing firm contractual commitments (short and/or long term).

 

Transmission Losses

The amount of energy lost as power is transmitted over the Federal Columbia River Transmission System (FCRTS).

 
 
Return to "Standard Power Product Descriptions" web page
 
 
Web page updated November 7, 1997.
Information provided by: Carolyn Whitney, BPA Power Business Line.