TSA Insight Magazine Issue 11 - Magazine - Page 36
DECARBONISING
AV I AT I O N – S A F
TA K I N G O F F
In this article,
Stopford advises on
recent government
initiatives and its
involvement in
the development
and manufacture
of Sustainable
Aviation Fuels (SAF)
promoting these
areas via innovation
and collaboration.
Deb Pal, Consultancy Director,
Stopford
•
orldwide, the aviation
sector generates 3%
of all greenhouse
gases
(GHG).
A
myriad of future technologies are
being explored in the aviation sector
to reduce GHG’s, such as hydrogen,
fuel
cells
and,
electrification.
However, they all present challenges,
especially for long haul flights that
requires fuel to have a high energy
density. In the short and medium
term, SAF has been identified as a
pathway to reducing greenhouse gas
(GHG) emissions.
W
The combination of bio and synthetic
SAF has the greatest potential to
reduce the carbon footprint in the
aviation sector in the medium term.
Governments are introducing tax
incentives for the manufacture of
SAF. In August, US Congress passed
the Inflation Reduction Act of 2022.
Among the incentives in the act is a
SAF fuel tax credit of $1.25 to $1.75
per gallon, depending on usage and
production.
In the UK, the government announced
in July the following measures
following a consultation1 to:
36
I N S I G H T
M AG AZ I N E
SAF mandate equivalent to at
least 10% (c1.5bn litres) of fuel
to be made from sustainable
sources by 2030. The mandate
will operate as a greenhouse gas
emission reduction scheme with
tradeable certificates.
•
The mandate will apply to jet
fuel suppliers and will begin in
2025, outside of the Renewable
Transport Fuel Obligation (RTFO).
•
Eligible fuels will be wastederived
biofuels,
recycled
carbon fuels (making use of
unrecyclable plastic and waste
industrial gases) and power to
liquid (PtL) fuels.
•
SAF must meet strict sustainability
criteria including delivering at
least 50% GHG savings relative to
fossil jet fuel.
•
SAF derived from hydroprocessed
esters and fatty acids (HEFA) will
be capped and a PtL subtarget
will be introduced to encourage
the development of strategically
important SAF pathways.
Stopford are working with partners to
produce SAF from a variety of waste
products; one such feedstock is nonrecyclable waste plastic. There are
several challenges, from availability
of sufficient quantities of feedstock to
certifying the fuel as a SAF.
SAF
must
have
the
same
characteristics as conventional jet
fuel, i.e. it must be fully fungible. No
modifications are required to the
aircraft engine or any of the fuel
delivery infrastructure to use SAF, so
the same tanks, pipes and hydrant
systems can be utilised.
International specifications have been
developed for jet fuel, such as ASTM
D1655.
This standard specifies criteria such
flash point, freezing point, combustion
heat, sulphur content, viscosity,
thermal stability and density. The
specification for technical certification
of SAF is ASTM D7566. Once
certified, SAF can then be blended
up to a maximum certified limit with
conventional jet fuel. In addition, the
production route of SAF must also
meet a set of sustainability criteria
to be eligible for use within the ICAO
Carbon Offsetting and Reduction
Scheme for International Aviation,
more commonly known as CORSIA.
The standard practice for evaluation
and approval of aviation fuels (ASTM
D4054) is expensive (costing in excess
of $5 million) and time consuming (3-5
years) and the US aviation industry
and regulators have recognised that
a different approach is required for
SAFs.
ASTM D4054 was modified in 2020 to
include a fast track option, which is a
faster and more cost effective route
to entering the SAF market. There
are currently 9 approved aviation fuel
alternatives, which include fuels using
feedstocks of waste oils, biomass
(from a variety of sources), natural
gas, coal and algae. Fuel using waste
plastic as a feedstock, processed
using pyrolysis and hydrotreatment, is
not currently approved. Work is being
conducted to demonstrate that this
process is suitable for an additional
annex to the standard, widening the
process routes available and, to be
considered for fast track approval.
The UK government in their Jet Zero
strategy state a PtL sub-target. The
PtL-Power to liquid process seeks
to address concerns that other
process routes have the potential to
increase the use of natural resources,
land, water and food sources. PtL,
which produces synthetic liquid
hydrocarbon fuels using renewable
electricity (for hydrogen generation
from water electrolysis) and non-fossil
carbon dioxide (CO2) as the main
feedstocks, is seen as a promising
SAF pathway. A flowsheet2 of the
process is shown below.
An overview of the PtL process
Stopford are currently identifying
areas for collaboration with Cranfield
University in several areas within the
circular economy. Cranfield University
have a long and distinguished track
record in aviation innovation and
development. They are developing
and optimising the PtL process with
industry partners so that it can be
effectively scaled up.
The TSA has a critical role in ensuring
that the storage and distribution
sector facilitates the increased
production and throughput of SAF
across UK airports. We are pleased
to be partnering with Word Fuel
Services to present more insight on
the Take-off of SAF at this year’s TSA
Conference.
For further information, visit
www.stopford.co.uk; contact
Deb
Pal, Consultancy Director, at
deb.pal@stopford.co.uk.
References
1. Mandating the use of sustainable
aviation fuels: https://www.gov.
uk/government/consultations/
mandating-the-use-of-
2.
sustainable-aviation-fuels-inthe-uk
Cranfield University, slides on
SAF from Dr Ming Ming Zhu
Issue
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