Enter Power Balance

The power balance of the Cement CO2 and Energy Protocol refers to electrical power consumed and/or produced in a cement plant. Thus, power here means electrical energy.

In the Protocol Spreadsheet power consumption and production in a cement plant is distinguished according to the sources of the power:

Consumption of external electrical power

In most cases, cement plants use electrical power from external sources (grid power) which was produced for example in power plants. The total consumption of external power is reported in line033c in the Protocol Spreadsheet and separately for different consumers as follows.

line033ca: external power consumption at the cement plant including the kiln, cement grinding, raw material preparation and the quarry (= purchased power minus power sold back in case of own power production).

Additionally, external power from the grid may be consumed at facilities for on-site power generation or waste heat recovery (see below), e.g. to cover the consumption of auxiliaries in the power generating system. This external power consumption should be reported in the line033cb and line033cc, respectively. Together with the external power consumption at the cement plant (line033ca), the sum of all external power consumption from the grid in line033c is denoted as “Total external power consumption for cement manufacturing”.

The power consumed in the plant up to and including clinker production is specified in line033e.

This value includes the power consumption of the kiln system, for the preparation of raw materials, kiln fuels and power consumption in the quarry. It allows calculating the KPI on the specific power consumption of the clinker production (line098).

Always use measured values from your plant measuring system, if available. Please also use your measuring equipment to check each of the values in the power balance. For example the total external power consumption in line033c should correspond to an external power consumption measurement for grid power. Alternatively, the split of certain parameters, e.g. the actual amount of internal and external power delivery, must be calculated based on auxiliary information available at plant level or estimated, if measuring systems do not exist for each individual parameter of the power balance.

Note that the measuring unit is MWh/yr. Therefore, if you have another measuring unit system, you must convert it to MWh/yr units to avoid calculation errors.

Please see the Protocol Guidance Document (Appendix A5) for further information on units and conversion factors.

On-site power generation and waste heat recovery

The plant may have its own power generation facilities. For the reporting in the Protocol Spreadsheet two types of facilities are differentiated:

  1. Separate on-site power generation - which in most cases uses additional non-kiln fuels to produce electrical power. A separate section exists for reporting the non-kiln fuels used for on-site power generation (line304).
  2. Waste heat recovery - which uses waste heat from the kiln system to produce electrical power. In most cases the energy for these facilities is originally derived from the use of kiln fuels. The waste heat recovery is then a way to save power and increase the entire energy system efficiency.

The total power production of these generation facilities has to be specified in line033a and line033b, respectively (if visible, depending on the selected inventory boundaries).

The power produced by on-site generation unit(s) (line033a) is normally consumed by power consumption unit(s), e.g. stationary equipment, at the cement plant itself (line033aa) or externally outside the cement plant (line033ba). In line033ac power produced on-site and used to cover the internal consumption of the power generation unit has to be reported. In line033ad the CO2 emission factor per kWh is calculated based on the non-kiln fuels used by the on-site power generation facility. For the calculation of the key performance indicators (KPICloseds) of electrical energy consumption you have to fill in these values which explain how this generated power had been used. The remaining difference between the total on-site power production and its delivery to the cement plant or external consumers is the power consumed at the on-site power generation equipment itself (line033c).

The power produced from waste heat recovery (line033b) is subject to the same differentiation. The corresponding power deliveries and consumption of the waste heat recovery system itself are reported in the line033ba, line033bb and line033bc, respectively.

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