Total hours the unit was fully offline due to forced events.
Total hours the unit was electrically connected to the system.
Hours the unit operated at reduced capacity due to equipment failure.
Percentage of capacity lost during the derated hours.
Eq. Forced Derated Hours (EFDH):0.00 Hours
Total Forced Outage Time (Num):0.00 Hours
Total Operating Time (Denom):0.00 Hours
EFOR:0.00%
Equivalent Forced Outage Rate (EFOR) Guide
The Equivalent Forced Outage Rate (EFOR) is a critical performance metric in the power generation industry. Unlike the standard Forced Outage Rate (FOR), which only accounts for complete shutdowns, EFOR incorporates partial outages (deratings) to provide a more accurate representation of a generating unit's unreliability.
Why Use EFOR?
In power plant operations, equipment failures do not always result in a complete trip or shutdown. Often, a component failure (such as a feedwater heater leak or a coal mill failure) forces the unit to reduce its output while remaining online. These are known as "deratings."
If a 500 MW unit is forced to run at 250 MW for 24 hours, it has not experienced a forced outage in terms of hours offline, but it has lost 50% of its generation capability. Standard FOR calculations would ignore this loss. EFOR captures this by converting the partial loss into "equivalent" full outage hours.
The EFOR Formula
Based on standards such as IEEE 762 and NERC GADS reporting, the simplified calculation for EFOR used in this tool is:
EFOR = [ (FOH + EFDH) / (FOH + SH) ] × 100%
Where:
FOH (Forced Outage Hours): Time the unit was fully offline due to forced events.
SH (Service Hours): Time the unit was synchronized to the grid (includes derated time).
EFDH (Equivalent Forced Derated Hours): The equivalent full-load hours lost due to deratings.
Calculating EFDH
The Equivalent Forced Derated Hours is calculated by weighting the duration of the derating by the magnitude of the capacity loss:
EFDH = Forced Derated Hours × (Size of Reduction MW / Net Max Capacity MW)
Note: In our calculator, we simplify this by asking for the percentage of capacity lost directly.