Glossary

"is, by common definition, equal to the additional costs that would be incurred to produce an additional unit of electricity sold in the market. As long as sufficient supplies exist, the competitive price is roughly proportional to the fuel costs required...

An independent power producer that generates electricity but lacks transmission and distribution

The cost of a past investment that would not be recovered in a developing or fully competitive electricity market because it would no longer be included in a utility's rates (also known as stranded investment

Any commercial, industrial or retail consumer of electricity

The electric load corresponding to a maximum level of electric demand in a specified period (also called peak demand)

A condition that restricts the ability to add or substitute one source of electric power for another on a transmission grid (more simply: congestion occurs when insufficient transfer capacity is available to implement all of the preferred schedules...

Integrated resource planning by electric utilities that uses a least-cost combination of demand-side management, conservation and new resources to meet projected future demands

The schedule of rates, terms and conditions that a utility submits to a state's public utilities commission for regulatory approval

An ancillary service that corrects any hourly mismatch between a transmission customer's energy supply and the demand ("load") it serves

The difference between a utility's electric generating capacity (usually expressed in MW) and anticipated peak load; Operating Reserve is a subset of Planning Reserve