FORUM AE Assessment on Aircrafts EmissionsGREENER AVIATION 2016 FORUM‐AE Environmental Assessment...
Transcript of FORUM AE Assessment on Aircrafts EmissionsGREENER AVIATION 2016 FORUM‐AE Environmental Assessment...
GREENER AVIATION 2016
FORUM‐AE Environmental Assessment on Aircrafts Emissions
Olivier Penanhoat (1), Paul Brok (2), Sigrun Matthes (3), Emanuel Fleuti (4), Paul Madden (5),
Bethan Owen (6), Xavier Vancassel (7), Peter Wiesen (8)
(1) Safran Aircraft Engines, Rond point René Ravaud, 77550 Moissy Cramayel, France
(2) NLR, Anthony Fokkerweg 2, 1059 CM Amsterdam, Netherlands
(3) DLR, Institute of Atmospheric Physics, Oberpfaffenhofen, Germany
(4) Flughafen Zürich AG, Postfach CH‐8058 Zürich‐Flughafen, Switzerland
(5) Rolls‐Royce plc, PO Box 31, Derby, United Kingdom
(6) Manchester Metropolitan Univ., Chester Street, Manchester M1 5GD, United Kingdom
(7) Onera, BP 80100, F‐91123 Palaiseau cedex, France
(8) Bergische Universität Wupperta,lGauss Strasse 20, D‐42097 Wupperta, Germany
1 Abstract An overview is presented of the European
coordination action FORUM‐AE dedicated to
aviation and emissions environmental issues.
Various workshops have been conducted
addressing (a) environmental impact assessment
on air quality or climate impact, (b) mitigation
solutions based on aircraft/engine/combustor
technology, ATM/green flight and alternative
fuels, (c) regulation technical issues linked to
CO2, NOx and particles standards. Some
monitoring of relevant RTD projects was also
realised. This coordination action is actively
supporting ACARE working group on
environment and energy (WG3) and permits to
identify main research priorities. In addition to
general information and recommendations
based on the first 2 years results, special focus
will be done on air quality issues.
2 Introduction The European project FORUM‐AE [FORUM on
Aviation and Emissions (& Environment)] is a
technical and scientific forum addressing all the
issues associated to the aviation environmental
concerns linked to emissions: impacts, technical
solutions and regulation. It supports the
appropriate European research and innovation
by giving it the necessary awareness and
visibility. It started in July 2013, and gathers a
large range of expertise at European level.
Series of focused workshops aim at better
understanding impacts, at identifying the
potential technical and technological solutions,
their expected benefits and maturity and at
addressing regulation technical issues. FORUM‐
AE also monitors and assesses the European
research and innovation in the field of aviation
environmental issues linked to emissions by
compiling relevant information from all existing
EU projects and main national ones, and making
assessment against the ACARE environmental
goals.
We provide in the following main results from
the first 2 years on (a) environmental impact
assessment on air quality or climate impact, (b)
mitigation solutions based on aircraft /engine
/combustor technology, ATM/green flight and
alternative fuels, (c) regulation technical issues
linked to CO2, NOx and particles standards.
Using additional material from most recent
workshops, we provide then consolidated status
& recommendations on air quality impact.
Paper 102
3 Intermediate results Main results obtained from the first 2 years
activity (1/01/2013 – 30/06/2015) are
synthesized hereafter. We provide the state of
the art, provide an up‐dated assessment of
progress towards ACARE goals and at the end we
list our main recommendations (focused on
research priorities).
2.1 State of the art and future trends
The scope of FORUM‐AE being very large as it
covers impact assessment, mitigation solutions,
and regulation issues; therefore appropriate
details should be found in the FORUM‐AE mid‐
term synthesis full document (www.forum‐
ae.eu); the gaps which are identified from
current state of the art are reflected indeed in
the list of recommendations given in 2.3.
Impact assessment: a good landscape of air
quality issues at airports was established, and
status on climate change impact shows the
progress, supported in particular by the
completed REACT4C project, since IPCC special
report on aviation in 1999 and the Lee & al 2010
paper [1].
Better knowledge was achieved on non‐CO2
direct and indirect impact but there remain
clearly open questions to be addressed.
Mitigation solutions at aircraft/engine/ATM level:
Current and future technological developments
to achieve the challenging ACARE 2050 CO2 goal
are essential to mitigate substantially the
increase of aviation CO2, with realistic traffic
growth assumption (see CO2 forecast figure). A
large part of the effort of the last decade was
supported within Clean‐Sky, and within other
European projects like LEMCOTEC, ENOVAL and
E‐BREAK. Most promising solutions appear to be
laminar wing, and ultra high by‐pass ratio
engines like Open Rotor (medium term) and
distributed propulsion (longer term as explored
in DISPURSAL project). New and light materials
(e.g. composites for fan blade) should also
provide benefits. It is unclear what is projected
on new aircraft architectures before 2050 but
AHEAD project illustrates a radical aircraft
configuration change.
Global aviation CO2 forecast
with ACARE assumption (assumptions: ACARE 2050 goal is achieved in 2050 and
fully introduced in the 2050 fleet ; there is a continuous
improvement of average efficiency from now to 2050 ; ICAO
37th Assembly projected average air traffic growth of 4.6%
is taken)
Non‐CO2 emissions reduction relies on future
low emission combustor technologies, which are
developed in a big cluster of dedicated projects,
and partly in LEMCOTEC and in SAGE ITD inside
Clean‐Sky. Focus was until recently on NOx, but
the new concern on particles involves that future
combustor technology should jointly satisfy
ambitious NOx and nvPM objectives. The
strategy which is generally adopted for
Turbofans is the lean combustion although
implementing lean combustion becomes more
complicated for smaller size and/or smaller OPR
engine combustors. Good progress was realised
in European R&T projects, but additional work is
necessary to achieve TRL6 maturity for the
various categories of engines.
Mitigation solution from alternative fuels:
environmental benefits from drop‐in fuels were
considered not only in terms of CO2, assuming
positive LCA budget, but also in their ability to
reduce particles. Fuel composition optimization
for environmental impact mitigation and better
~2%
~5.5%
~2.5%
~1.8%
engine compatibility appears as an important
topic which is not properly covered today.
Regulation (CO2, NOx, Particles): a first CO2
international standard and a first particles
international standard were delivered beginning
of 2016, whereas previous stringency of the
existing NOx standard was done in 2010 with
application in 2014. These standards are
naturally incentives justifying the development
of environmentally friendly aircraft/engine
solutions. Market Based Measures, currently
discussed at ICAO level, may also become a CO2
mitigation incentive.
A certification standard is constituted of a metric
system, an associated certification procedure,
and a regulatory level. The CO2 and particles
standards have been approved at the CAEP 10th
meeting beginning of 2016, with an application
date after 1st January 2020.
Concerning the CO2 standard, the first important
step was the definition of the metric system.
This was achieved in 2013 and this metric is
publicly available [2].
AgreedCO2standardmetricsystemMTOM=MaximumTake‐OffMass;SAR=SpecificAirRange(=distance/kgfuel);RGF=geometryfactor
The first particles standard is more “transition
standard”; it addresses non volatile Particulate
Matter (nvPM) and is looking at the nvPM mass
concentration at the engine exit. A second
standard, more relevant to air quality and
climate concerns, is being developed and should
be based on nvPM total mass or number emitted
during LTO (Landing & Take‐Off) cycle. In that
prospect, much work is still needed, addressing
various technical issues, among them the
potential fuel composition effect.
Fuel composition effect on particles formation (EI = Emission Index = number of particles per kg fuel;H=hydrogencontent)
2.2 Assessment against ACARE Goals
A new assessment which up‐dates the last one
done in 2012 by OPTI project, was performed
against ACARE CO2 and NOx goals and is
summarized in the following table. Although,
there is no ACARE objective related to ultrafine
particles, this is now a key environmental and
regulatory concern, which requires appropriate
mitigation solutions (combustor technology and
fuel composition).
FORUM‐AE assessment against ACARE
emissions goals
ACARE 2020 Goals
(at TRL6)
High Level High Level detailed (SRIA)
CO2 "‐50% per pass km""‐75% per
pass km"
aircraft & engine:
‐68%
ATM: ‐12%
Other: ‐12%
aircraft + engine +ATM:
≈ ‐38% in average
per pass km
NOx
(LTO)"‐80%" "‐90%"
engine: ‐75% CAEP6 ;
complement achieved by
aircraft + ATM
engine:
[‐55%, ‐65%] CAEP6
NOx
(Cruise)"‐80%" "‐90%"
Achieved through ‐75%
Fuel Burn & further cruise
EINOx reduction
not quantified
Other
emissions
"damaging
emissions
reduced"
"emissions‐
free taxiing"
+ qualitative
reduction
knowlegde of emissions
(particles, VOC) and
better understanding of
impacts
better knowledge of engines
particles emissions
Reference 2000
ACARE 2050 Goals
(at TRL6)FORUM‐AE
Assessment (2015)
(extrapol. at TRL6 in 2020)
Representative
technology of
aircraft & engine
with 2000 EIS, &
representative
2000 ATM
2.3 Recommendations
Recommendations & needs (Air Quality)
Mid‐term recommendations (2015) have been
consolidated more recently and are given in §3.
Recommendations & needs (Climate Change)
I. Studies show how results (estimates)
vary with and depend on different emission
inventories and so sensitivity analysis to
emissions inventories are recommended.
(a) Aviation NOx in 2006
(b) Resulting Ozone perturbation
II. Clear documentation of assumptions in
future scenarios and sensitivity studies on such
assumptions are also fully relevant for gaining
understanding of the impact of the assumptions.
III. Metric is still an open key issue.
Quantitative estimates should be provided for a
set of typical metrics (e.g. radiative forcing,
average temperature response, global warming
potential...) to demonstrate sensitivity of results
on choice of metric. Then, there is a need of
careful selection of calculation methods and
metrics, appropriate to the question to be
answered.
IV. Sources of uncertainties must still be
analysed; and there is a need to develop means
for robust decisions under uncertainty.
V. Climate‐optimised flight routing must be
further developed, ideally considering the
individual weather situation. Using climate cost
functions, measuring with the appropriate
metric the effect of an unit of a given species
emitted locally on the climate warming, may be
an efficient approach for flight routing
optimisation.
VI. Better correlation between
contrail/contrail cirrus properties and particle
emissions is required both for prediction
accuracy and for mitigation strategy.
Recommendations & needs (CO2 mitigation
technology)
I. ACARE 2050 very challenging CO2
reduction objective would permit to mitigate
substantially the increase of aviation CO2, with
realistic air traffic growth assumption. Therefore,
it is essential to pursue a tremendous effort at
the aircraft level, the engine level and the ATM
& flight operation level in order to progress
towards this ambitious goal.
II. Aircraft/Engine panel of technologies (an
exhaustive list would be very long and one can
refer to SRIA‐Vol.2 enablers table and to
FORUM‐AE relevant workshops proceedings)
must be further and continuously improved or
newly introduced both for evolutionary aircraft
or engine applications and longer term
disruptive applications.
III. Unconventional configurations like
aircraft equipped with Open Rotor (OR) concept
or Ultra High By‐pass Ratio (UHBR) concepts,
must be further developed. Their mitigation
potential, complemented with laminar wing
benefit, must be maximised and their maturity
must be pushed over TRL5, recognizing there is
still some gap towards ACARE 2020 CO2 goal.
URANS CROR calculation (left) (CROR:Contra‐RotativeOpenRotor)
Laminar wing test bed (right)
IV. More radically unconventional solutions,
like distributed propulsion aircraft, should also
be considered for much longer term and at
lower TRL (up to TRL3‐4).
Recommendations & needs (non‐CO2 mitigation
technology)
Consensus appears that particles (nvPM)
reduction must also be achieved, in addition to
NOx. This induces critical R&T on:
I. The combustor technology itself in order
to ensure both NOx & nvPM ambitious low levels:
enhanced lean combustion in general (achieving
TRL6 maturity & extending its application to
smaller size and/or smaller OPR engine
combustors), and focus on more specific aspects
which may be beneficial to particles reduction
(improved atomisation…)
Lean combustion technology
(Safran‐AE calculation)
Lean combustion technology
(Rolls‐Royce solution)
II. The modeling of emissions, which for
particles emissions is far from being predictable
today, because of the physical complexity of
particles formation (involving amongst others
gaseous precursors formation, and particles
nucleation & oxidation), and the modeling of
combustion related operability aspects.
III. The experimental analysis, which is
absolutely necessary to support modeling
development or to assess technology. This
assumes advanced measurements (in particular
intrusive and non intrusive measurements of
particles in the combustion chamber) and
appropriate test capability (from multi‐sector
tests to full annular tests, with ability to achieve
high pressure levels)
Recommendations & needs (Mitigation from
Alternative Fuels)
I. Harmonisation is needed to converge on
a common and technically satisfactory CO2 LCA
methodology in order to assess alternative jet
fuel production pathways.
II. The aromatic content of future jet fuels
(fossil or renewable) should be minimized as
much as possible in order to reduce particles
emission. Reduction of sulphur content may also
be beneficial.
III. There is a need to develop predictive
tools to model the fuel interaction with the
aircraft fuel system or with the engine. This will
permit fuel composition optimisation to improve
fuel compatibility and it will help reducing ASTM
certification costs.
As there is currently nothing on‐going except at
the national levels, most EC effort being put on
the production pathways, a dedicated European
program supporting these topics (composition
optimization, modelling tools) is strongly needed.
It would accelerate the ability to specify fuel
composition or predict fuel/engine interactions.
Recommendations & needs (Regulation on CO2,
Particles, NOx)
I. On CO2, further developments of
European modelling capabilities should be
pursued and there is some agreement on the
idea of a future technology review to support
the CAEP technology goal setting process
associated to the standard‐setting process.
II. Concerning NOx regulation, as there
exists a well established standard for which the
last stringency was agreed in 2010 for
application in 2014, appropriate monitoring
work is justified.
III. Further work is required to support the
future nvPM standard, in particular to populate
an aero‐engine nvPM database for in‐production
engines (turbofans>26.7KN, turbofans<26.7KN,
turboprops, turboshafts, and APUs), and to
provide the information needed for a
certification requirement (fuel specifications,
corrections, and analysis procedures etc.).
IV. Research organisations and engine
manufacturers need to work together with
airports to help update their PM models, and to
help them find good measurement techniques to
identify different PM sources at the airport.
4 Consolidated status and
recommendations on Air
Quality issues After the first FORUM‐AE Air Quality (AQ) Impact
Workshop hosted by MMU in Manchester (UK)
in 2014, a second one was organised beginning
of 2016 in Amsterdam (Netherlands), hosted by
NLR. This second workshop attracted thirty‐six
(36) participants from France, Germany, Italy,
Netherlands, Switzerland, Ukraine, United
Kingdom and United States of America
representing stakeholder organisations from the
aircraft and engine OEMs, airline and airport
operators, governmental bodies, consultancies,
research centres and universities. It permitted to
consolidate the status on Air Quality issues
linked to air transport, and R&T
recommendations. Key Statements, Research
Gaps and Priorities are following.
I. The key airport and aircraft pollutants,
linked to air quality (AQ) impact and
environmental concern, are nitrogen dioxide
(NO2) and particles. The particle issue should be
addressed both in terms of PM2.5 mass
concentration and in terms of ultrafine particles
(UFP) for which number concentration appears
more relevant. Sulphur dioxide (SO2) emissions
from the aircraft engine might be an important
contributor to PM2.5.
II. There is a strong regulation framework
on emission source level, at workplace level and
at ambient air quality level. However, nothing
exists (yet) for auxiliary power units (APUs)
which explains strong uncertainties on their
emission factors (in particular for NOx and
particles).
III. The measurements in Europe of PM10
and PM2.5 in the airport vicinity are rather well
harmonised (recent assessment from European
Aquila project) and demonstrate a good quality
level; this does not really apply to ultrafine
particles. A robust assessment would be useful
and is recommended.
IV. PM2.5 mass concentrations linked to
airport activities appear most of the time to be
small compared to contributions from other
sources, and very small against AQ limits. UFP
contributions from airport activities are of
stronger concern with elevated concentrations
observed not only close to runways but also
distances away from the airport.
UFP concentrations at Los Angeles Airport [3]
V. Airport emission inventory and air
quality modelling improvements are required,
which will make models more accurately predict
concentrations at and around airport.
a) General recommendations (summarised in the
table below):
Further consolidation is needed in
knowledge of relevant airport emissions
sources and their activity (performance),
emission factor and calculation
algorithm.
Better representativeness of operational
data should be pursued
In that prospect, there is a need for
harmonisation in performance based
emissions modelling
CAEPport offers a good benchmarking
case to compare codes
Modelling should be validated against
field measurements.
Status & Identified Gaps in Airports Inventory
Red: improvements still required; Yellow: in‐progress
or less required; Green: knowledge is good Emission
[in grams] = Emission Factor [in g/s or g/km] x
Activity [in s or km distance covered]
b) Recommendations more specific to particles
(concentration predictions require important
modelling improvements):
Better non‐volatile PM emission factors
and better knowledge on volatile PM
precursors are needed. In this respect,
and as long as nvPM data availability is
insufficient for main aircraft engines,
potential improvement of the first order
approximation (FOA3) method could be
encouraged
UFP dispersion prediction should be
consolidated by replacing coarse
hypotheses such as a correlation
between UFP (number concentration)
and PM10 (mass concentration).
VI. Aircraft cruise emissions might impact
ground air quality. Most modelling effort on this
topic is currently performed in the U.S.A. It
appears that NOx and SOx emitted in cruise by
the aircraft engines have a dominant
contribution to ground PM2.5 whereas nvPM
cruise emissions are more marginal. However,
estimation of uncertainties associated to the
predicted levels is strongly needed.
Complete technical material and conclusions of
the workshop can be found in the proceedings
available on www.forum‐ae.eu.
All these open issues justify a dedicated
European research project which would also
include a better prediction of ground pollutant
concentrations from aircraft cruise emissions.
5 Conclusion
This paper provides an overview of most results
from FORUM‐AE based on topical workshops
and further exchanges ; they will be completed
and consolidated with outputs from recent
workshops focused on inventories (summarised
nevertheless in [4]), green flights & operations,
basket of measures to reduce CO2 ; in the
forthcoming year, 3 key last workshops are
planned respectively on Climate Change (jointly
with ECATS) in Athens, on non‐CO2 emissions
reduction technology in Berlin, and on CO2/Fuel
Burn reduction technology in Reims. On this
basis, final conclusions will be delivered in 2017
and will help in defining research priorities in
ACARE.
6 Acknowledgement The FORUM‐AE Coordination action receives
funding from the European Union`s Seventh
Framework Programme (FP7/2007‐2013) under
Grant Agreement n° 605506.
These results and recommendations were based
on all the technical material provided by all the
FORUM‐AE consortium specialists (see below the
table of all partners involved) and external
experts invited to the different workshops, and
the various consecutive exchanges. They are
thanked for all their inputs.
7 References [1] Lee et al, « Transport impacts on
atmosphere and climate : Aviation » ; Atm. Environment, 2010 (Vol. 44)
[2] http://www.icao.int/Meetings/Green/Document
s/day%201pdf/session%203/3‐Dickson.pdf
[3] Hudda et al, EST 2014 [4] Brok, “Aviation Emissions Inventories &
Projections ‐ Feedback from FORUM‐AE workshop”, ANERS symp., La Rochelle 2015
List of ParticipantsParticipantN°
Participant Organisation Name Shortname
Country
1 (CO) Snecma SN FR2 Airbus SAS AI FR3 Deutsches Zentrum für Luft und Raumfahrt e.V. DLR DE4 Deutsche Lufthansa AG DLH DE5 ECATS ECATS BE6 Flughafen Zurich AG FZAG CH7 IFP Energies nouvelles IFPEN FR8 Manchester Metropolitan University MMU UK9 Stichting Nationaal Lucht - En Ruimtevaart laboratorium NLR NL10 Office National d’Etudes et de Recherches Aerospatiales ON FR11 Rolls Royce Group plc RR UK12 Rolls Royce Deutschland Ltd & Co KG RRD DE13 SENASA SENASA ES14* Eurocontrol ECTL FR15* Joint Research Center JRC BE16* Turbomeca TM FR* Third parties