Reading the data

Check the timestamp

A reading describes a time or interval. That is different from the time you opened the page or the time the source published it. Use the timestamp shown beside the data and check whether a time is labelled UTC or local time.

Sources have different reporting intervals and publication delays. Do not assume every chart updates at the same rate.

Missing is not zero

A gap means that a reading is missing or unavailable; it does not mean demand or generation fell to zero. A stale reading is an older reading, not evidence of present conditions. A partial set of readings may not describe a complete total.

Keep those distinctions when comparing values or describing a change. A difference between adjacent readings is not necessarily meaningful when their intervals or definitions differ.

Actuals, estimates and forecasts

A forecast describes an expected future value. An estimate may use a model or incomplete observations. A reported actual value can still be revised by its source. None of those labels should be replaced by a stronger claim that the value is measured or final.

Capacity is not output

Installed capacity describes a generating asset’s rated ability to produce power. It is not the power that asset is producing now. A station catalogue and a live generation feed answer different questions.

Check the method

Use the attribution and explanatory notes alongside a chart or map. The main site’s methodology page provides the public overview. These guides do not add a new calculation method or replace a source’s definition.