Academy · 01 / 01 · Technical principles
Power, energy and load profiles
Separate kW from kWh, demand from consumption, and nameplate capacity from actual output.
- Level
- Foundation
- Reading time
- 9 min
- Reviewed
- 2026-08-24
- Next review
- 2028-08-24
- Jurisdiction
- Global
What you will learn
- 01Distinguish power, energy, demand and rated capacity.
- 02Read an hourly load or generation profile.
- 03Calculate duration and capacity factor without calling them efficiency.
Core concepts
01
The essential distinction
Power is an instantaneous rate; energy accumulates that rate over time. At constant output, energy equals power multiplied by time. A 20 MW / 80 MWh battery is nominally four hours, but usable energy can be lower because of state-of-charge limits, auxiliaries, temperature, efficiency, degradation and warranty conditions.
02
Decision use
A monthly average hides ramps and coincident peaks. Sizing normally needs interval data, a clear metering boundary, gross-versus-net energy and an explicit definition of the period. Capacity factor measures utilization, not conversion efficiency.
Decision notes
- 01Always label PV capacity as MWdc or MWac.
- 02Rated power alone does not prove annual energy.
Primary sources
Open the official source and confirm its current edition, jurisdiction and adoption before applying it.