In a scenario whereby several energy consuming systems are not sub-metered because they account for less than 10% of the annual energy consumption (see Ene 02 methodology), and this results in less than 90% of the estimated annual energy consumption of that fuel being metered, the M&E consultant should review the metering strategy and advise which of these energy consuming systems would most benefit from sub-metering to make up the 90%.
This may be based on which of the energy consuming systems has the highest annual energy consumption, or which has the most potential for reducing energy consumption as a result of sub-metering. This will not necessarily have to mean that the energy consuming systems chosen have to have their own sub-meter, the M&E consultant may decide they would most benefit from metering alongside another consuming system. However ultimately 90% of each fuel must be metered.
Justification should be given within the metering strategy and the BREEAM assessment report as to which lower energy consuming systems were chosen to be sub-metered to make up the 90%, and how this was done to best suit the development (i.e. individual sub-meters or paired with another consuming system).