Firm Flow

The Firm Flow is the rate of water discharge from a water catchment or reservoir that can be relied upon for design and economic evaluation of a hydropower project. It is usually defined as a probability, for example:

  • The flow rate that will be exceeded 95% of the time; or perhaps
  • The constant flow rate that can be abstracted from a reservoir with a failure rate of no more than one month in ten years.

Each power utility has its own definition of Firm Power. Isolated generating stations generally require higher reliability than stations connected to a large network of many stations, or connected to a utility network that can trade power with adjacent utilities.

Published by hydrogray

Hydropower specialist

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