''AM/PM'' -- all-day module performance measurements

This paper analyzes the need for, and candidate characteristics of, a new approach to rating photovoltaic modules. It continues discussions recently stimulated by the proposal of the ''AM/PM'' daily-energy-based rating before standards bodies and an international conference. Issues which have emerged from consideration of these discussions are addressed, with attention to the effects of changing module design over recent years and the potential effects of terrestrial solar cell changes in the coming years. The paper considers the problem of field data bases covering the real application region, realistic application conditions, and various levels of system sizing. It suggests a specific approach to rating format (standard daily energy delivery) and a specific institutional framework for rating system development.