Greenhouse gas conversion factors for company reporting

2012 Guidelines to Defra / DECC's GHG Conversion Factors for Company Reporting
Annex 3 - Converting from purchased electricity, heat and steam use to carbon dioxide equivalent emissions
Last updated: Apr-12
How to use this Annex
Electricity
The factors presented in the three tables below (3a, 3b and 3c) are a timeseries of electricity CO 2e emission factors per kWh GENERATED (Table 3a, i.e. before losses
in transmission/distribution), electricity CO 2 emission factors per kWh LOSSES in transmission/distribution (Table 3b) and per kWh CONSUMED (Table 3c, i.e. for the
final consumer, including losses from the national transmission and local distribution grids).
In the majority of cases, the 'Grid Rolling Average' factor from Table 3c should be used. Tables 3a and 3b are included to assist companies reporting in a manner
consistent with the Greenhouse Gas Protocol format, which requires separate reporting of GHG emissions due to transmission and distribution losses.
To calculate emissions of carbon dioxide equivalents associated with use of UK grid electricity :
1) Identify the amount electricity used, in units of kWh;
2) Multiply this value by the conversion factor for UK Grid Rolling Average electricity. Use Table 3c for calculating GHG emissions resulting from electricity provided
from the national/local grid.
Heat and Steam
The factors presented in the Table 3d below are a timeseries of CO 2e emission factors per kWh supplied heat or steam based on information from the UK CHPQA
scheme, and are new for this 2012 update to the conversion factor Annexes. In most cases this energy will be provided directly, however in cases where district heating
is utilised an additional correction factor of 5% is applied to reflect average energy losses in the supplied heat distribution.
To calculate emissions of carbon dioxide equivalents associated with use of purchased heat/steam:
1) Identify the amount heat or steam used, in units of kWh;
2) Multiply this value by the conversion factor for heat or steam.
3) If the heat used is provided via a district heating scheme, add an additional 5% to the calculated CO 2e emissions to reflect distribution losses.
Annex 3 Scopes & Boundaries:
Scope 2 : Direct emissions of CO 2, CH 4 and N 2O from the combustion of fuel in power stations to generate electricity (Table 3a Direct GHG, i.e. excludes losses in
transmission and distribution) and Heat/Steam (Table 3d Direct GHG).
Scope 3: In electricity generation, this includes indirect GHG emissions associated with the extraction and transport of primary fuels as well as the refining, distribution
and storage of finished fuels (Table 3a, 3b and 3c). The Greenhouse Gas Protocol also attributes direct GHG emissions associated with losses from electricity
transmission and distribution (Table 3b) to Scope 3.
Direct GHG emissions given in Table 3c are a combination of (Scope 2) Direct GHG emissions from Table 3a and (Scope 3) Direct GHG emissions from Table 3b.
How are the factors calculated?
Electricity
The electricity conversion factors given in Table 3c represent the average carbon dioxide emission from the UK national grid per kWh of electricity used at the point of
final consumption (i.e. electricity grid transmission and distribution losses are included), factoring in net imports of electricity via the interconnectors with Ireland and
France*. This represents a combination of the emissions directly resulting from electricity generation (Table 3a) and from electricity grid losses (Table 3b). The Direct
GHG emission factors include only carbon dioxide, methane and nitrous oxide emissions at UK power stations (plus those from the proportion of imported electricity),
with the Indirect GHG emission factors including the emissions resulting from production and delivery of fuel to these power stations (i.e. from gas rigs, refineries and
collieries, etc).
This factor changes from year to year, as the fuel mix consumed in UK power stations changes, and the proportion of net imported electricity also changes*. Because
these annual changes can be large (the factor depends very heavily on the relative prices of coal and natural gas as well as fluctuations in peak demand and
renewables), and to assist companies with year to year comparability, a 'grid rolling average' factor is presented which is the average of the grid Conversion factor over
the last 5 years. This factor is updated annually.
From 2011, imported electricity has been accounted for in the calculations of the emission factors. The UK is a net importer of electricity from the interconnector with
France, and a net exporter of electricity to Ireland according to DUKES (2011). More details on the methodology, its impacts and the rationale can be found in the
methodology paper for the 2011 update, on Defra's website at:
http://www.defra.gov.uk/environment/economy/business-efficiency/reporting/
Heat and Steam
The heat and steam conversion factors given represent the average emission from the heat and steam supplied by the CHPQA scheme operators for a given year. This
factor changes from year to year, as the fuel mix consumed changes. This factor is updated annually. No statistics are available that would allow the calculation of UK
national average emission factors for the supply of heat and steam from non-CHP operations.
I generate my electricity onsite. How do I calculate emissions from this?
If you generate electricity from 'owned or controlled' renewable sources backed by Renewable Energy Guarantee of Origin (REGOs) within the UK, you should account
for these emissions using the 'Renewables' factor. Please see Annex G in Defra's Guidance on how to measure and report your GHG emissions for an explanation of
how to report on-site generated renewable energy:
http://www.defra.gov.uk/environment/economy/business-efficiency/reporting/
Page 13 of 54