This paper proposes a metering cost minimisation model that minimises metering cost under the constraints of sampling accuracy
requirement for clean development mechanism (CDM) energy efficiency (EE) lighting project. Usually small scale (SSC) CDM
EE lighting projects expect a crediting period of 10 years given that the lighting population will decay as time goes by. The
SSC CDM sampling guideline requires that the monitored key parameters for the carbon emission reduction quantification must
satisfy the sampling accuracy of 90% confidence and 10% precision, known as the 90/10 criterion. For the existing registered
CDM lighting projects, sample sizes are either decided by professional judgment or by rule-of-thumb without considering any
optimisation. Lighting samples are randomly selected and their energy consumptions are monitored continuously by power meters.
In this study, the sampling size determination problemis formulated as a metering costminimisationmodel by incorporating a linear
lighting decay model as given by the CDM guideline AMS-II.J. The 90/10 criterion is formulated as constraints to the metering
cost minimisation problem. Optimal solutions to the problem minimise the metering cost whilst satisfying the 90/10 criterion for
each reporting period. The proposed metering cost minimisation model is applicable to other CDM lighting projects with different
population decay characteristics as well.