C3.3.1 Sources of Data

 

There are numerous different data sources, some examples of which are provided below.

 

Examples of simple sources of data 

Data Source Issues to be aware of for data quality purposes
Electricity invoices
  • Accruals over the year end (calendar or other reporting year)
  • Over/ under estimate by supplier
  • Incorrect meter reading by supplier
  • Incorrect reconciliation to site meter readings
  • Gaps or missing bills
  • Unit reported eg KWh, GJ, TJ etc and conversion to an appropriate unit for reporting
  • Incorrect transfer of data to calculation spreadsheets etc
  • Incorrect reconciliation to site meter readings
  • Gaps or missing bills
  • Unit reported eg KWh, GJ, TJ etc and conversion to an appropriate unit for reporting
  • Incorrect transfer of data to calculation spreadsheets etc
  • Apportionment of power usage where only one main site meter is in place (ie validity of mass balance etc calculations)
  • Provision of calorific values (CVs) and emissions factors that may differ from relevant scheme rules
Gas invoices
  • As outlined above for electricity bills
  • Is the supplied emissions/ carbon factor the correct one for the specific reporting purpose
Diesel/ Oil invoices
  • Over/ under estimate by supplier
  • Do invoices account for all deliveries to site (if not how else is input data recorded)
  • Incorrect meter reading by supplier
  • Incorrect reconciliation to site meter readings
  • Gaps or missing bills
  • Incorrect transfer of data to calculation spreadsheets etc
  • Purchased amount vs consumed amount (ie a stock reconciliation is required)
  • Calibration status of measurement device(s)
Solid fuels invoices
  • Over/ under estimate by supplier
  • Incorrect meter/weighbridge reading by supplier
  • Purchased amount versus consumed amount
  • Wet versus dry weight of fuel (ie if weights are used, weight and CV at time of use – not time of delivery – is the important data)
  • Compaction of fuel if volume estimates used (ie volume at time of use is likely to be less than at time of delivery if it has been in storage for some time)
  • Incorrect reconciliation to site weighbridge records (if appropriate)
  • Validity of calorific value data from   supplier
  • Batch sampling of calorific values vs average calorific values
  • Calibration status of measurement device(s)
Direct metering/ weighing of fuel etc
  • Maintenance, calibration and checking of meters, weighbridges etc (both main and sub)
  • Apportionment of usage where only one main site meter etc is in place (i.e. validity of mass balance etc calculations)
Direct measurement of emissions concentration   and flow rate
  • Maintenance, calibration and checking of measurement equipment

 Source: IEMA “Environmental Data Management: for emissions trading and other purposes” 2005.

 

 

Examples of complex sources of data

Data Source Issues to be aware of   for data quality purposes
Derivation of   consumption from equipment run time data
  • Recording of actual run time (as opposed to if it’s on it’s assumed to be on all day)
  • Accurate and supported calculation of theoretical energy consumption per hour/day for specific technical units
Estimation of energy   use from production throughputs
  • Accurate and supported calculation of theoretical energy consumption per production unit
Derivation of emissions   from chemical formulae
  • Generally accepted calculation methodology
  • Correct taking of samples of, for example, gas for laboratory analysis, to avoid contamination by air etc
  • Use of accredited laboratories for analysis
Derivation of carbon   factors by stoichiometric calculation
  • Generally accepted calculation methodology
  • Appropriate/correct standard conversion factors
  • Correct taking of samples of, for example, gas for laboratory analysis, to avoid contamination by air etc
  • Use of accredited laboratories for analysis
Derivation of emissions   by mass balance analysis
  • Maintenance, calibration and checking of meters, weighbridges etc (both main and sub)
Dis-aggregation of data   for two emissions streams from one data source1
  • Accurate and supported basis of calculation/ estimate if metering is not in place
  • Avoidance of double counting

 Source: IEMA “Environmental Data Management: for emissions trading and other purposes” 2005.

 

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