Airport modelling: challenges and solutions - Katie Petty
1. Air Quality Around Ports and the Potential
Mitigation Options
Research Report for UKMPG
Katie Petty
Consultant – Arup
Katie.Petty@arup.com
2. Structure
• Introduction
• Aims & objectives
• Emission sources
• Trends in ambient air quality and the contribution of ports
• Mitigation study methodology
• Mitigation options
• Summary
3. 3
• The strategy sets out “ambitious plans to drive down emissions in each major
transport sector.”
• Developing a long-term UK Maritime Strategy (Maritime 2050) followed by a
Clean Maritime Plan (publishing in early 2019).
• Ports must develop effective and targeted Air Quality Strategies to reduce
emissions across the ports and associated waterways including emissions from
shore activities and visiting ships.
- Must reduce emissions while allowing trade to grow.
- Deadline of end of 2019.
Introduction
Defra Clean Air Strategy
• Defra published a draft Clean Air Strategy in May 2018 and a
final version in January 2019
• Notes that 50% of NOx emissions came from the transport
sector, 10% of total emissions were from domestic shipping
4. Introduction
• Commissioned by the UK Major Ports Group (UKMPG)
• the trade association representing most of the larger commercial ports in the United Kingdom.
• Examined the current air quality around three example UK ports focusing on the trends of:
• Nitrogen dioxide (NO2);
• Fine and very fine particulate matter (PM10 and PM2.5); and
• Sulphur dioxide (SO2)
• Examined the trends inside ports, outside ports and the contribution of port-related activities.
• Identified actions that ports can take to assist in creation of air quality strategies.
5. Example ports
The ports were anonymised in the study
but broadly they can be described as:
• Port A - Small port located in a city;
• Port B - Large port located in relatively
rural location; and
• Port C - Large port located in a city.
6. Aims and objectives
• An examination of the trends in pollutant concentrations around example ports in the UK
• Where information was available, determined the contribution of port operations to pollutant
concentrations in the local area;
• Identification of mitigation measures that could be applied to reduce pollutant emissions from
activities associated with port operations
7. Emission sources
Emissions from vessels
• Emissions from vessels largely consist of those from:
• The main propulsion systems (main engines)
• Auxiliary engines providing power to the vessels while manoeuvring and hotelling.
• Released at elevated height dispersed before reaching ground level some distance
from the point of emission.
• Port operators are not generally responsible for
the operation of the larger vessels using the ports
but often do operate other vessels such as pilot
craft and tugs.
* Photo Source: Arup
8. Emission sources
Emissions from port activities on shore
• Shore-side activities at ports which use diesel fuels that could result in emissions to
the air include:
• Loading/unloading machinery if operated using diesel or similar fuels (e.g. cranes and backhoe
loaders/diggers).
• Use of vehicles for moving freight within the ports e.g. straddle carriers);
• Internal vehicle movements in ports including
vehicles being loaded or unloaded from ships
using the ports, or staff movements between
terminals; and
• Emissions from diesel-powered locomotive
units on internal rail tracks in the ports.
* Photo Source: Arup
9. Emission sources
Emissions from port activities on shore
• Shore-side activities at ports release pollutants near to ground level
• Increased pollutant concentrations close to the port
• Disperse to negligible levels at distances more than a few hundred metres from the
point of emission.
• As an indirect part of the actual port
operations, vehicles travelling to and from the
ports transporting goods and passengers result
in pollutant emissions on the wider road
network.
* Photo Source: Arup
10. Trends near to example ports
• Port A - slightly declining trend in NO2 concentrations between 2012 and 2015 followed by a stable trend
between 2015 and 2017, this being typical of trends in other urban areas of the UK.
• Port B - NO2 concentrations have remained relatively stable over the last five years but reduced over the
long term period. SO2 emissions have significantly dropped.
• Port C – NO2 concentrations broadly stable, slight decline at roadside sites.
• All reflect UK trends in
concentrations and that
mitigation already
implemented is working.
NO2 concentrations at ten monitoring sites near Port C
11. Ports contributions to local air quality
• In addition to total predicted NO2
concentrations, the Pollution Climate Mapping
(PCM) modelling results provide information
on source apportionment, in terms of the
predicted NOx concentration from each
source.
• Port A – 1-5% shipping contribution to
total NOx concentrations
• Port B – 23-39% (lower background
concentrations)
• Port C – 20% at the link closest to port,
5% at link further from port (see figure)
Adjacent to port
A few hundred metres
from port
12. Port contributions to local air quality
• There is a study by Ricardo of the Port of Southampton air quality
• Modelled roads next to port and estimated how much is contributed from various port activities/sources.
• Roads are the largest source
Location
Predicted NO2
concentration (µg/m3)
NOx Source Apportionment (µg/m3)
Mainbackgr
ound
Industrial
Rail
Portrail
Port
machinery
Shipping
Roads
Total
NOx
1
36.7 23.9 0.2 <0.1 <0.1 0.2 1.5 36.8 62.8
2
30.5 17.4 0.1 <0.1 <0.1 0.1 0.7 31.6 49.9
3
42.0 32.6* 0.3 <0.1 0.2 0.1 4.4 42 78.3
4
41.3 24.3 0.4 0.2 0.1 0.2 1.4 45.9 72.6
5
40.4 23.8 0.2 <0.1 <0.1 0.2 1.4 44.9 70.6
6
47.3 24.8 0.4 0.2 0.4 0.2 1.5 60.3 87.9
* Source: Ricardo-AEA (2014) Western Approach AQMA air quality assessment, Southampton. Table 2.4
13. Mitigation implemented in the past
• International action can have a large impact on
emissions e.g. SO2 emissions.
• An emission control area for Sulphur was
introduced in the North Sea in 2006
• Reduced sulphur levels in fuel from 4.5% to 1.5%
• Further reductions followed
• Source: Air Quality Expert Group. Impacts of Shipping on UK Air Quality, 2017
Change in SO2 concentration at four sites
14. Mitigation study methodology
• For each mitigation measure assessed, a summary dashboard was produced that details its potential impact on air
quality, the costs, the timescales for implementation and the geographic extent of its impact. A “High”, “Medium”,
“Low” ranking has been used to assess these four factors.
15. 15
• Encourage the increase in use of cleaner fuels for vessels operated by ports as well as
vessels using the port operated by other parties.
Increased use of cleaner fuels for vessels
• Fuels considered:
- Liquid natural gas (LNG);
- Gas to Liquid (GTL);
- Diesel emulsions;
- Hydrogen;
- Biofuel; and
- Synthetic fuels.
• LNG is the most feasible
Source: UKMPG
16. 16
• Key challenges
- Higher fuel costs per unit
- High initial capital expenditure: cost of engine retrofit can be costly, or new fleet is required
- Additional fuel storage maybe required on vessels which reduces payload
Increased use of cleaner fuels for vessels
£ £
• Key benefits
- Reduction in emissions of NOx, PM and SOx, depending on
the choice of fuel
- Direct substitution possible for GTL fuel without any engine
modification
- Long-term operational cost of running LNG on high-speed
passenger vessels could be lower than using traditional diesel
fuel
- Engine performance improvement is also possible
17. 17
• Encourage the increase in use of hybrid vessels,
such as diesel/electric hybrid, or even fully electric,
for those operated by ports as well as other vessels
using the port.
Increased use of hybrid vessels
• Involves using a battery usually during lower
speeds, lightly loaded conditions (i.e. hotelling)
- Likely to occur at ports
• Batteries can be charged by the diesel engines or
from the grid supply shore-side, when moored.
• Reduction of emissions of pollutants at ports
Source: TfL (https://tfl.gov.uk/travel-information/improvements-and-projects/woolwich-ferry-upgrade)
18. 18
• Key challenges
- High capital expenditure
- Not appropriate for all vessels
- Reduction in cargo space due to presence of batteries
- Depends how much electricity is used
Increased use of hybrid vessels
* Zhu J, et al. (2018) Optimal design of a hybrid electric propulsive system for an anchor handling tug supply vessel.
** Lindstad HE, Eskeland GS and Rialland A (2017) Batteries in offshore support vessels – Pollution, climate impact and economics. Transportation Research
Part D
• Key benefits
- Reduction in NOx emission (25-40% reported)*
- Hybrid (diesel/electric) propulsion systems use up to 20% less fuel**
- Possible to retrofit older vessels
- Batteries can be used for short haul journeys or ferries, so short trips can
be emission-free
- Lower maintenance costs
£ £
19. 19
• Provision of shore-side power from the national
grid to vessels at berth that auxiliary engines can be
turned off and significantly reduce emissions (cold-
ironing).
Shore-side power
* Source: Ricardo-AEA (2014) Western Approach AQMA air quality assessment, Southampton. Table 2.4
** Comparison of emissions from auxiliary engines and from national grid. Source: Entec UK Limited. Service Contract on Ship Emissions: Assignment,
Abatement and Market-based Instrument, Task 2a – Shore-side Electricity. August 2005
• Hotelling for container ships alone represents an
annual emission of 940 tonnes of NOx per annum*
• Estimated reduction in emissions (in
tonnes/year/berth) of 97% for NOx, and 89% for
PM**
Source: MartiTerm AB. Shore-Side Electricity for Ships in Ports. Report 2004-07-06
20. 20
• Key challenges
- Complex installation, major upgrade of port’s power supply system and
infrastructure may be required
- Grid strengthening outside of port area may be required
- Very high capital expenditure
- Number of compatible vessels
Shore-side power
• Key benefits
- Greatly reduces local emissions from auxiliary
engines
- Reduction in noise and vibration levels
£ £ £
21. 21
• Encourage the increase in use of cleaner fuels,
such as liquified natural gas (LNG), or hybrid
and electric technology, for machinery operated
at the ports
Increased use of cleaner fuels, hybrid and electric machinery
* Source: Combined data from emission inventories for Port of Los Angeles, Long Beach, Puget Sound, Oakland, New York-New
Jersey, and Vancouver
• Non-Road Mobile Machinery (NRMM)
accounts for:
- 2% to 10% of the total NOx emission from
port*
- 4% to 15% of total PM10 emissions from
port *
Source: UKMPG
22. 22
• Key challenges
- High fuel cost
- High equipment cost
- Long life-span of existing machinery (e.g. Rubber tyred gantry
cranes life-span ~ 20 years), but changeover is happening
- Other practical and H&S considerations (e.g. run of long
electric cables)
Increased use of cleaner fuels, hybrid and electric machinery
• Key benefits
- Direct and sole control by port
- Partial or complete reduction in emissions from
port’s machinery
Cost
Impact on air quality
Timescale
Geographical extent
£ £
23. 23
• Able to displace a significant number of HGVs
travelling on the roads where sensitive receptors or
AQMAs are located.
Increased use of trains to transport freight to and from ports
* Aecom, Arup, SNC.Lavilin (2016). Future Potential for Modal Shift in the UK Rail Freight Market
• Removes the equivalent of up to 76 HGVs from
the UK road network per train*
• Change in location of pollutants emissions away
from roads
• Especially effective for ports where AQMA has
been declared close by, with road traffic being the
main pollution source Source: Member of UKMPG
24. 24
• Key challenges
- Not economically viable for short journeys
- Many railways already at capacity
- Uptake has depended on the level of the Mode Shift
Revenue Support grant (MSRS) from government
Increased use of trains to transport freight to and from ports
• Key benefits
- Takes HGVs off the roads and improves local air
quality near to the ports and the road network
- Reduces congestion, which further improves local
air quality
25. 25
• EU definition*: “the movement of cargo and passengers by sea between ports situated
in geographical Europe or between those ports and ports situated in the non-European
countries having a coastline on the enclosed seas bordering Europe”
Increased use of short sea shipping (SSS)
* European Commission. (1999). The Development of Short Sea Shipping in Europe
** The capacity of container vessels varies from a minimum size of 1,000 twenty-foot equivalent unit (TEU) to over 14,500 TEU. An ordinary HGV can
transport one container only (i.e. 1 TEU).
• One SSS voyage would
reduce the number of HGV trips
on the road network between
their pick-up points and
destinations by between 1,000
and 14,500 trips**.
Source: The Norwegian Coastal Administration (http://www.kystverket.no/en/About-
Kystverket/aid-scheme-for-short-sea-shipping/ )
26. 26
• Key challenges
- Net emissions may not be significantly different between SSS and
HGVs
- Additional logistics for shipping companies, e.g. extra HGV trips
and associated delays
- Potential to attract additional HGVs to and from ports
- Potential to increase overall delivery time
Increased use of short sea shipping (SSS)
• Key benefits
- Moves emissions offshore and away from sensitive
areas
- Reduces use of HGVs
27. Conclusions
• Ports are areas which inevitably concentrate transport-related emissions (both
from roads and shipping)
• The contribution to local pollutant emissions from the actual port operations is
small
• These measures are a summary of the main options identified
• The measures that have the largest impact on reducing emissions require
international agreement and government intervention e.g. freight transport by
trains
• Other mitigation measures are available that ports can implement as a package
of measures but have a lessor impact.