Smart Metering & Sub-metering
What are they?
Smart utility meters allow a utility company to access energy consumption data remotely. Energy readings are typically recorded on a fifteen minute basis, providing much more accurate and up-to-date energy usage data than is available through monthly or quarterly bills. The fifteen minute data is transmitted over a communications network to a meter reading company that relays the data to the electricity retailer. The data can then be passed on to the building management team for analysis.
Similarly, smart meters can be used as sub-meters (i.e. non-utility) to provide more accurate and up-to-date energy consumption data for a sub-meter which measures a specific location or energy load. Data for these non-utility meters is transmitted to an internal meter reading system (typically a dedicated metering system or the Building Management System) where performance can be analysed to ensure efficient operation and to identify energy reduction opportunities.
In a high quality installation, sub-metering should enable the categorisation of energy use by sub-system, e.g. chiller plant, heating plant, fans, lifts, lighting, and plug loads.
Advantages / Disadvantages
- Provides better understanding of energy consumption and where energy efficiency opportunities exist; also provides better information with which to promote behaviour change.
- Enables more detailed benchmarking of performance, including setting subsystem \ targets.
- Allows owners and tenants to cross check that they are being billed correctly.
- Reduces facilities management costs in a building where regular manual readings take place by reducing the requirement for manual meter inspections.
- Requires time and resource for the active monitoring and reporting of data and setting targets and actions for reducing energy consumption.
Energy efficiency
Smart meters and sub-meters do not by themselves save any energy. However, they are a valuable aid to any efforts to reduce energy consumption.
Running costs
There are additional maintenance, data collection and analysis costs associated with a smart metering and sub-metering strategy. However, the benefits of accurate billing and increased transparency and understanding of energy consumption generally warrants the investment.
Retrofit / improvement opportunities
Retrofit installation of submeters is straightforward, although often an electrical shut-down will be required to permit installation of meters on major risers. If this is done after hours there is little disruption to tenants.
Applicable buildings
Smart meters and sub-meters can be used in all building types.
Floor plate implications
None.
Occupant comfort
No issues.
Maintenance implications
The energy utility company will carry out all necessary maintenance on the main electricity or gas meter. Periodic checking and servicing of any sub-metering will need to be undertaken by the building owner.
How to identify them
Utility meters are typically located in or near the main switch board and in or near the switchboards the serve tenancies. Submeters will typically be found in plant areas and riser cupboards.
Questions to ask
- Is there smart metering in place covering both the mains electricity?
- Is there remote reading of gas meters, providing time-of-use information on gas consumption?
- Is there remote reading of water meters, providing time-of-use information on water consumption?
- Is there a sub-metering system in place that is automatically read, with the information collated and presented in a manner that facilitates its use in managing building operations?
- How extensive is the sub-metering strategy e.g. location specific (such as each floor or tenant) or energy user specific (such as lighting, power, heating or cooling), as opposed to a general strategy that may mix multiple unassociated items onto a single meter?
- Have meters been validated in accordance with the NABERS standard in order to ensure that the meters are correctly configured and the readings are being read correctly?
- Who monitors and reports the data and is taking action to reduce energy consumption?
- On what basis are energy bills split and recharged to tenants?
More information