Standard or multiple metering arrangements

Ofgem categorises each Non-Domestic RHI installation as having standard or multiple metering arrangements.

Standard metering arrangements

One quantity is required to be measured to calculate the EHO. This can be either:

  • the heat generated by the eligible installation or the heat used for eligible purposes (where they are equal), or
  • the heat generated by the eligible installation (where there are no ineligible heat uses), or
  • the eligible heat use (where there is no ineligible heat generation)

Multiple metering arrangements

Two or more quantities are required to be measured to calculate the EHO. These must include both:

  • the heat generated by the eligible installation, and
  • the heat used for eligible purposes

and one of the following:

  • the total heat generated by all the plants supplying heat to the system, or
  • the total heat used

When an ineligible plant can have no effect on the heat meter readings from an eligible plant, it may be possible to classify it as decentralised or isolated. In these situations, additional metering is not required.

Installations with multiple metering arrangements require an Independent Report on Metering Arrangements (IRMA).

Steam Metering 

In addition to the normal metering requirements, where steam meters are used, the installation must also include heat/steam meters to measure the heat returned from the eligible purpose in the form of condensate, low pressure steam or a two phase flow of condensate and steam.

The steam pressure and temperature must be measured and the steam meter must be positioned after any steam traps. This ensures heat to any other purposes (ineligible heat uses) or steam released to atmosphere under normal operating conditions is not included.

Metering is one of our specialities and we can assist with both heat and steam meter specifications and positioning.

For more information please email or call on 01242 677 877.