THE CLIMATE CHANGE
IMPLICATIONS OF AIR TRAFFIC
CONGESTION AT MAJOR
EUROPEAN AIRPORTS:
RECONCILING DEMAND AND
SUSTAINABILITY
Daniel Irvine, Lucy Budd, Stephen Ison and Gareth Kitching
WCTRS SIG 3 Conference, Malta
April 2015
Introduction
• Air Transport faces a major challenge:
• Capacity constraints at key airports
• A growing contribution to climate change
• Growth seems incompatible with reducing
emissions
Aim
• To assess the impact of constrained capacity on
emissions from airborne aircraft
Aviation and Climate Change
• Air Transport accounts for around 3% of global anthropogenic
emissions (and rising)
• Intl. aviation often excluded from targets
• Technology is improving efficiency, but growing demand far
outweighs any positive progress
Airport Capacity and Airborne Holding
• Lack of runway capacity
may oblige inbound aircraft
to hold
• Holding burns more fuel and
generates more emissions
Source: Matt Hintsa, Flickr.com
Heathrow (LHR)
• LHR has the highest capacity utilisation in the world
(Gelhausen, 2013)
• Operates at 99.2% of available runway capacity
• Airport expansion is a politically charged and polarising topic
in the UK
• UK’s Airports Commission will publish its final report on the
case for new capacity this summer
LHR Holding Patterns
• 57% of inbound aircraft
require the use of holding
patterns
• Four patterns exist, spread
across Greater London and
the surrounding counties
Source: HeathrowAirport.com
Method
• Arrivals for one peak hour
were monitored using an
online flight radar database
• Data was recorded on
aircraft registration, which
hold was used and times
entering and exiting the
pattern
Source: Flightradar24.com
Method
• Individual a/c registrations cross-referenced with JP fleets to
establish aircraft type and engines
• EASA fuel burn and emissions indexes used to calculate
pollutants (CO2, NOx, HC, CO)
• Fuel burn x emissions index x time in hold = total hold
emissions
The Study Hour
Holding Pattern activity for flights in study hour
7
6
5
4
3
2
1
13:25:00
13:10:00
12:55:00
12:40:00
0
12:25:00
Number of aircraft holding
• 23 of the 46 arrivals were
required to hold
• The average hold was 6
minutes, and the longest
was 15 minutes
• Most holds occurred
between 12:35-13:10
8
Aircraft Fuel Burn
600
A380
500
400
Seat Capacity
• High avg. seat capacity at
LHR – 202 (vs.160 at AMS)
• Narrow-body aircraft burn
30-50KGs of fuel per min
• Increasing aircraft size
appears to increase fuel
burn by around 0.5KGs/min
per extra seat
Fuel burn of aircraft in study hour
B747
300
200
100
0
0.00
50.00
100.00
Fuel burn (KG/minute)
150.00
200.00
Variance Between Aircraft
Aircraft emissions comparisons
• Individual aircraft influence
the emissions observed at
each stack
• Significant variances
between aircraft of similar
size/type
Comparative emissions (1=Average)
Fuel (kg/min
CO2 (kg/min)
HC (g/min)
CO (g/min)
Nox (g/min)
14
12
10
8
6
4
2
0
B737
A320
B777
A330
Aircraft Type
B747
A380
Emissions Hour Profiles
Profile of Emissions for Study Hour
• Emissions vary across the
hour as a result of aircraft
variance
• However most follow the
broad pattern of aircraft
activity, with the exception of
HC
Variance By Location
• The number of flights was
spread fairly evenly across
the stacks
• However the emissions
observed varied, in part due
to the length of the holds,
but mainly due to influences
of larger/smaller aircraft
Share of emissions by stack
Biggin
Bovingdon
Lambourne
Ockham
60%
50%
40%
30%
20%
10%
0%
Share of Holding Fuel (kg) CO2 (kg)
flights
time
(mins)
HC (g)
CO (g)
Nox (g)
Profiles by Location
NOx profile by stack
Biggin
Bovingdon
Lambourne
Ockham
3,500
NOx emissions (g per minute)
• The chart shows how,
although total emissions
differ, variations across the
hour are even greater
• Stack observations are only
for the study hour, and it is
likely that this is not
representative of the overall
picture
3,000
2,500
2,000
1,500
1,000
500
0
12:30:00
12:40:00
12:50:00
Time
13:00:00
13:10:00
Results and Extrapolation
• Observed in the study hour:
•
•
•
•
32 tonnes of CO2
0.1 tonnes of NOX
19KG of CO
0.8KG of HC
• These have been
extrapolated using
assumptions for a whole
year
Hold
(mins)
Fuel
(kg)
CO2
(kg)
HC
(kg)
Study
Hour
138
10,180 32,139 0.85
Annual
Estimate
4.7
(Avg)
75.4m
CO (kg) Nox (kg)
19.0
114
238m 9,700 133,000 801,000
Summary
• Airborne holds at capacity constrained airports are a
significant contributor of emissions
• 232KG of CO2 is emitted per minute of holding for an average
aircraft at Heathrow, although aircraft performances vary
greatly
• CO2 produced in holding patterns at is equal to around 0.6%
of LHR’s total aviation CO2 emissions
• Estimated cost of this carbon is £1.1m, rising to £17m in 2035
Issues to consider
• Is there an environmental case for prioritising heavy arrivals?
• Are holding patterns an inefficient method of spacing arrivals
at capacity constrained airports?
• Is the idea of restricting runway capacity to address aircraft
emissions simplistic and misleading?
Contact details
• Daniel Irvine, Research Engineer
• daniel.irvine@aviationeconomics.com
• Centre for Innovative and Collaborative Engineering (CICE),
Loughborough University
• Funded by EPSRC
• Aviation Economics – 40 Friar Lane, Nottingham, United
Kingdom, NG1 4DQ +44 (0)1158 523043