Energy & power systems guide
Reserve Margin
A simple capacity-planning concept comparing expected available resources with forecast peak demand.
Systems note: terminology, market structures, voltage classes and reliability rules vary by jurisdiction. Use current local standards and utility information for real projects.
Where this fits
A simple capacity-planning concept comparing expected available resources with forecast peak demand.
Core system ideas
Reserve margin provides headroom above expected peak demand.
A percentage alone does not capture resource outages, variable output, transmission constraints or correlated weather risk.
Formal adequacy studies use more detailed probabilistic and system-specific methods.
Interfaces and tradeoffs
Planning uses scenarios because demand, resource additions, retirements, weather, project timing and technology are uncertain. Models are decision aids rather than perfect predictions.
What organizations measure
Available capacity, peak demand, uncertainty and outage assumptions.