Sasol Climate Change Report 2022 - Book - Page 13
INTRODUCTION
RISKS AND OPPORTUNITIES
OUR FUTURE SASOL STRATEGY
GOVERNANCE
DATA AND ASSURANCE
IMPROVING OUR EMISSIONS REPORTING (CONTINUED)
Methane measurement and reporting at our South African Operations
Studies on Pande-4 well
The well is under close observation through the Pande-4 remediation project with the
Sasol Mozambican team conducting regular monitoring and implementing controls
to manage the issue. Today, water and small quantities of methane continue being
reported in the surface area surrounding the well. As part of our PPA Concession,
we have an obligation to keep the Mozambican regulator informed of any substantial
changes or events relating to the Pande-4 site. We have been doing so for a number
of years and have an agreement with our partners and government to continue
monitoring and reporting on the well until a feasible solution to manage the release
of methane is found. The situation remains under control.
Methane emissions from our Secunda and Sasolburg Operations are determined
by measurement and mass balance calculations. These emissions have been fully
accounted for in our disclosed inventory and are being managed through our 2030,
30% GHG reduction target and the emission-reduction roadmap. Methane emissions
comprise a significantly smaller portion of our GHG profile, which is dominated by CO2.
Evaluations and assessments are underway to determine an accurate emissions
baseline and develop interventions to mitigate the release of these emissions. Due
to subsurface and geographic complexities associated with the well, there are limited
available methodologies to accurately quantify these emissions. Challenges also
exist as a result of trying to measure a small quantity of emissions that diffuse over a
large area around the well. Satellite monitoring data through GHGSat was employed
to determine a preliminary baseline with an inherent methodological error margin
of 45%. Initial estimates show that emissions could be between ~150 – 400 ktCO2e.
We are supplementing this approach with additional activities such as on-site weather
monitoring to create more accurate data models and reduce the error margin.
Sasol follows the mandatory South African government’s GHG reporting regulations,
which require the use of the 100-year methane global warming potential (GWP) from the
IPCC’s Third Assessment Report. Recent studies are highlighting the use of the 20-year
methane GWP because the gas is short-lived and has a higher potency in a shorter-space
of time as compared to CO2. We are monitoring developments on this emerging issue.
Sasol continues to engage with
specialist companies, individuals and
academic institutions to develop a better
understanding of this emission source and
the mechanics of methane emissions from
the well. A specialist company has been
appointed to evaluate the viability of a
surface capture and containment solution,
collect additional data (including satellite
monitoring of methane emission locations
and rates, as well as InSAR monitoring of
surface deformation) and to build a 3D
model using high resolution 2D seismic
lines. In parallel, using other expertise,
plausible scenarios will be generated
detailing possible reasons for the ongoing
methane release. A subsurface model is
likely to be available in 2023, at which
point effective and efficient management
interventions will be assessed. We will
continue reporting on progress as
information becomes available.
To calculate methane emissions, we measure and analyse the composition of our vents
to determine the percentage volume of methane. Flow rates are measured and
converted to a mass flow and reported accordingly for each entity that emits methane.
Management of our methane emissions is included in our scope 1 and 2 absolute reduction
target of 30% by 2030, as well as our scope 3 emissions reduction target negating the
need for an explicit methane target, however we continue to monitor the landscape.
In this reporting year, methane emissions comprised 4,9% of our total scope 1 and 2
emissions on a CO2e basis.
SASOL CLIMATE CHANGE REPORT 2022 12
