ghg-inventory-1990-2013

Figure
3.3.7
Carbon dioxide implied emission factor (IEF) – Gaseous fuel combustion c
(1990–2012)
Note:
As discussed in section 3.3.2 under ‘Emission factors’, carbon dioxide emission factors for
New Zealand gas fields are established through gas composition analysis and are known
to be high by international standards.
3.3.5
Uncertainties
and time-series consisten
ncy
Uncertainty in greenhouse gas emissions from fuel combustion varies, v depending on the
type of greenhouse gas. The
uncertaintyy of CO 2 emissions is relatively low. This is
important as CO
2 emissions made up over 98 per cent of CO2-e 2 emissionss from fuel
combustion in New Zealand in i 2013. By comparison,
emissions of o the non-COO 2 gases are
much
less certain
as emissions vary withh combustion
conditions. . Uncertainties for CO 2 ,
CH 4 and N 2 O activity data and emission factors are supplied in table 3.3.4. Many of the
non-CO 2 emission factors used by New Zealand are
the IPCC default values. Further
detailed information around uncertaintiess for each fuel type cann be found in annex 2,
sections A2.1, A2.2 and A2.3.
58
New Zealand’s Greenhouse Gas Inventory 1990–2013