A building plus its addition whose electricity and natural gas usage is being measured by the original building's meters requires the installation of additional meters to comply with Energy and Atmosphere Prerequisite, Building-Level Energy Metering. This is because the prerequisite requires the installation of energy meters to track a building's total energy usage for compliance. Separate meters are needed for segregating energy uses, including electricity, natural gas, fuel oil, steam, chilled water, hot water, biomass, propane, etc. Utility meters may be used to demonstrate compliance and track energy usage, and delivery tickets from any fuels transported to the building may also be used. The other scenarios do not require additional meters, as they already have meters that measure their energy usage at the building level or the service entrance level.
References:
* LEED AP O+M Exam, page 13
* Building-Level Energy Metering and Energy Metering | LEEDuser