Port Operational Strategies: Vessel Speed Reduction

Office of Transportation and Air Quality
EPA-420-F-21-008
March 2021
Port Operational Strategies: Vessel Speed Reduction
This fact sheet is one of a series of documents produced by the EPA Ports Initiative to inform port
stakeholders about potential emission reduction strategies.1 Each fact sheet contains basic information
about the strategy, emission impacts, cost components, and example programs. While each strategy
can achieve benefits on its own, implementing them together could create synergies.2
Strategy Summary
Description: Vessel speed
reduction (VSR) consists of
establishing a zone around a
port within which vessels
operate at or below a
defined speed—typically
less than normal cruise
speed. This reduces
propulsion engine emissions
and fuel consumption,
decreasing pollution in and
around the port. Ports such
as Los Angeles, San Diego
(Figure 1), and New
York/New Jersey have
established VSR zones
ranging from 20 to 40
nautical miles, with typical
speed limits between 10
and 15 knots.
Emission reductions from VSR programs depend on the size of the zone, vessel type, and vessel speed. As
one example, emissions savings from vessels traveling at 12 knots within 24 nautical miles from the Port of
Los Angeles were estimated to be 37 percent for C02 and NOx and 49 percent for diesel PM and S02.4
vvEPA
United States
Environmental Protection
Agency
Port of San Diego f Del Mar ^
Vessel Speed Reduction Zone N
/
Cargo vessels: 12 knots or less f
Cruise ships: 15 knots or less //
. ft
t Mission Bay
rL
I | Cruise Ship Terminal
I 1 f/ Tenth Avenue Marine Terminal
Point Loma — W N. * National City Marine Terminal
; / \w
1 San Diego Bay \
I'
J?
Pacific Ocean
Nautical Miles
Figure 1. Port of San Diego VSR Zone3
1 The emissions evaluated in these fact sheets include nitrogen oxides (NOx), particulate matter (PM), hydrocarbons (HC),
carbon monoxide (CO), carbon dioxide (C02), and sulfur dioxide (S02).
2 See the EPA Ports Initiative's fact sheets on virtual vessel arrival (https://www.epa.gov/ports-initiative/virtual-vessel-
arrival-svstems-ports-improves-air-quality-and-saves-fuel). port management information systems
(https://www.epa.gov/ports-initiative/management-information-svstems-improve-operational-efficiencies-and-air-
quality), and gate management (https://www.epa.gov/ports-initiative/port-gate-rnanagement-strategies-improve-air-
qualitv-and-efficiencv-ports).
3 Port of San Diego. 2020. Vessel Speed Reduction Map. https://www.portofsandiego.org/media/241. Accessed 3-5-2021.
4 California Air Resources Board. 2007. Vessel Speed Reduction for Ocean-Going Vessels Workshop.
https://www.arb.ca.gov/ports/marinevess/vsr/docs/pres07122007.pdf. Accessed 3-5-2021.

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Advantages: Reducing vessel speeds decreases fuel usage and engine emissions near port areas, which can
improve the health of port workers and nearby communities.5 Vessels such as container ships, cruise ships,
and roll-on/roll-off vessels, which have typical operating speeds above 20 knots, achieve larger fuel and
emission benefits than smaller, slower-moving vessels such as bulkers, general cargo ships, and tankers. For
example, a container ship with a typical cruising speed of 21 knots reducing its speed by 20 percent to 16.8
knots may reduce engine load by up to 50 percent, with corresponding reductions in fuel consumption, NOx,
and PM emissions. Meanwhile, a tanker slowing from 18 to 16.8 knots may reduce fuel consumption and
emissions by the still significant amount of 20 percent.
Figure 2 illustrates an often-cited relationship
between vessel speed and potential benefits,
based on the Propeller Law curve.6
While slowing down vessels near ports will
increase their transit time, the increase may not
be significant for most. For example, one study
estimated that slowing from 20 to 12 knots (i.e.,
by 40 percent) in a 20-nautical-mile VSR zone
would cut fuel consumption and emissions by
70-75 percent8 while adding only about 45
minutes to travel time. A 45-minute delay is
generally within the typical arrival window of tw
hours.
Considerations: Estimating how a VSR zone could affect a specific port requires compiling data on the
number and types of vessels that visit the port, including their speed within the zone. This is typically done
using Automatic Identification Systems (AIS) data. Vessels that use AIS transmit a signal every few seconds,
identifying their locations and speeds. AIS data are time specific and change from year to year.
Speeds can be verified using ground-based AIS out to approximately 40 miles from shore. Satellite-based AIS
effectively provides global coverage and can be used where terrestrial systems are not available, allowing
VSR zones to be adopted and monitored at virtually any port.
Appropriate port size and type: This strategy can be used for ports of any size and type, though larger ports
that service higher-speed vessels would see the largest reduction in fuel consumption and emissions within
the VSR zone.
5 Exposure to air pollution associated with emissions from diesel engines can contribute to significant health problems-
including premature mortality, increased hospital admissions for heart and lung disease, increased cancer risk, and
increased respiratory symptoms—especially for children, the elderly, outdoor workers, and other sensitive populations.
(See U.S. Environmental Protection Agency. 2014. Near Roadway Air Pollution and Health: Frequently Asked Questions.
https://nepis.epa.gov/Exe/ZvPDF.cgi/P100NFFD.PDF?Dockey=P100NFFD.PDF. Accessed 3-5-2021).
6 U.S. Environmental Protection Agency. 2020. Ports Emissions Inventory Guidance: Methodologies for Estimating Port-
Related and Goods Movement Mobile Source Emissions, https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockev=P10102U0.pdf.
Accessed 3-5-2021.
7 Developed using the Propeller Law curve, assuming a vessel maximum design speed of 21 knots.
8 Bialystocki, N., and D. Konovessis. 2016. On the Estimate of Ship's Fuel Consumption and Speed Curve: A Statistical
Approach. Journal of Ocean Engineering and Science 1(2): 157-166. http://ioes.situ.edu.cn/ueditor/net/
upload/2016-05-24/c4870989-3cb5-49e3-939f-278003e04a02.pdf. Accessed 3-5-2021.
100%
90%
3 80%
ao
.E 70%
S 60%
Q.
° 50%
tuo 40%
m 30%
20%
55%
65%
75%
85%
95%
Relative Vessel Speed
Figure 2. Engine Load vs. Vessel Speed7
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Furthermore, larger ports are likely to have professional staff who would be better able to monitor
participation. Constraints such as safety and navigation may prohibit full use of vessel speed reduction.
Emission Reductions9
Primary Pollutants affected: NOx, PM, HC, CO, C02, and S02
Anticipated reductions: Reductions will vary depending on the characteristics of the fleet that visit the port:
vessel type, engine tier level, design speed, and typical operating speed. Nitrogen oxides (NOx) reductions of
up to 45 percent were reported in one study.10 The VSR program operated by the Port of Long Beach was
estimated to reduce NOx emissions by 747 tons and C02e emissions by 28,600 tons in 2008, based on 2,477
vessel entrances per year.11
Calculation methodology: The data inputs required to calculate VSR program emission reductions, and
potential sources of these data, are listed below.
• Size and location of slow steaming zone (nautical miles), determined by port policy.
• Actual operating speed of vessels approaching port (knots), determined using AIS data for the VSR
area. (Alternatively, information can be obtained from the Marine Exchange and ship records.)
• Target slow steaming speed (knots), determined by port policy.
• Fuel type, determined by assuming 1,000 ppm distillate/residual fuel mix for ocean-going vessels
based on U.S. Emission Control Area zone requirements.
• Propulsion engine tier level and category, obtained from the participating vessels or classification
society vessel attribute data. (Most large vessel engines will be slow-speed, Tier 0, Category 3, but
newer vessels with higher-tier engines should also be accounted for as appropriate.)
• Propulsion engine power (kW), obtained from participating vessels, classification society vessel
attribute data, or defaults from EPA's Port Emissions Inventory Guidance.12
• Maximum design speed of vessels visiting the port (knots), obtained from participating vessels or
from classification society vessel attribute data. Anticipated cruising speed is assumed to be 0.94
times the vessel's design speed (from EPA's Port Emissions Inventory Guidance).
• EPA emission factors (g/kWh), based on EPA's Port Emission Inventory Guidance.
9 The information in this section is for illustration: although the types of inputs and methods used in this section are
generally consistent with EPA established methodologies, it does not constitute official EPA technical guidance for
regulatory purposes. Please note that EPA has comprehensive guidance on developing inventories of emissions from
ports and port-related goods movement. EPA's Port Emissions Inventory Guidance, September 2020, EPA-420-B-20-046,
is available at EPA's web site at: www.epa.gov/state-and-local-transportation/port-emissions-inventory-
guidance. Accessed 3-5-2021.
10 Boersma, K.F., G.C.M Vinken, and J. Tournadre. 2015. Ships Going Slow in Reducing Their NOx Emissions: Changes in
2005-2012 Ship Exhaust Inferred from Satellite Measurements over Europe. Environmental Research Letters 10(7).
https://pure.tue.nl/ws/files/22832393/BoersmaShipsgoing2015.pdf. Accessed 3-5-2021.
11 OECD/lnternational Transport Forum. 2018. Reducing Shipping Greenhouse Gas Emissions: Lessons from Port-Based
Incentives, https://www.itf-oecd.org/sites/default/files/docs/reducing-shipping-greenhouse-gas-emissions.pdf. Accessed
3-5-2021.
12 U.S. Environmental Protection Agency. 2020. Ports Emissions Inventory Guidance: Methodologies for Estimating Port-
Related and Goods Movement Mobile Source Emissions. https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockev=P10102U0.pdf.
Accessed 3-5-2021.
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• Slow speed adjustment for each pollutant, based on EPA's Port Emission Inventory Guidance (for
cases where the speed limit requires a vessel to operate below 20 percent engine load).
Use the following equation to calculate emission reductions for a vessel whose original operating speed is
above the VSR program speed:
ERi =
+
SP,
MaxSP
SEG
SEG
X tttt- X SSA
SEG
t SPm \
1 ~ ( nnj X— >
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If the boiler power rating factor is unknown, a user may employ default power values (BP in kW) by ship
type, from the U.S. EPA Ports Emissions Inventory Guidance: Methodologies for Estimating Port-Related and
Goods Movement Mobile Source Emissions document's Appendix, Table E2.14
Except for cruise ships, auxiliary power and boiler impacts are minimal on emission reductions allowing
users to simplify the equation if desired, as shown in the following example.
Example calculation: A tanker has a propulsion engine of 9,000 kW and a maximum design speed of
18 knots. It reduces its speed from 15 to 12 knots as it enters the speed reduction zone. Assume a 10
nautical mile waterway segment. The propulsion engine load at the reduced speed is 29.6 percent, so a low
load adjustment is not needed. The pollutant being calculated in this example is C02, and the emission
factor for this engine was identified to be 589 g C02/kWh.
// SPi \3 SEG ( SPN \3 SEG\
ERco2 = \\.. x-—- ——x——)xVPxEFxC
\\MaxSPj SP1 \MaxSP) SPN J
(/15 NM/hr\3 10 NM (12 NM/hr\3 10 NM \ g C02
ERco^{{^Wm^ X lTNM/hr ~ \Wim/hr) * 12^)*9'°°°'^*589 ^* L1°231*
ERco2 = 0.8 tons of C02
This calculation should be completed for each vessel operating above the proposed speed limit, for all
segments included in the port's VSR area.
Cost Components15
Capital costs: Additional capital investment will likely be limited to:
• Purchase of vessel monitoring software to help compile real-time AIS data (may be included as part
of a renewable AIS subscription)
Capital costs should be annualized over the expected life of the software to estimate annual program costs.
Operational costs: Day-to-day operational costs may include:
• Labor for system administration (including communications, recordkeeping, and in-house
monitoring of AIS data)
• Fees to external parties to monitor vessel traffic (e.g., fees to one of the 13 local marine exchanges16
in the United States), in lieu of in-house monitoring of AIS data
• Fees for third parties to provide vessel and engine data for participating ships (e.g., annual
subscription fees to classification societies)
• Labor and other nominal operating costs from increased vessel transit times (if any)
14 U.S. Environmental Protection Agency. 2020. Ports Emissions Inventory Guidance: Methodologies for Estimating Port-
Related and Goods Movement Mobile Source Emissions, https://www.epa.gov/ports-initiative/port-and-goods-
movement-emission-inventories. Appendix Table E-2. Accessed 3-5-2021.
15 The information in this section is for illustration: it does not constitute official EPA technical guidance for regulatory
assessments.
16 Marine exchanges are local organizations that monitor ship movements, often in partnership with the U.S. Coast Guard
Vessel Traffic Service. These organizations can help identify vessels and evaluate their speeds.
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• Port operators may also incur costs from providing incentives to vessel operators to encourage
participation (see "Example Programs" below). These costs would amount to savings for vessel
operators (e.g., dockage fee discounts).
Cost savings: Costs savings may be realized from:
• Reduced fuel consumption near the port due to slower speeds
Example Programs17
The Port of Los Angeles launched its VSR program in 2001 and has seen steady increases in program
participation over time. Participation incentives include dockage fee discounts for vessel operators with 90
percent or greater compliance for the calendar year. Between 2008 and 2019, the Port paid out $19.9
million in incentives to VSR program participants. Participation also qualifies operators for a VSR recognition
award to recognize their environmental contributions.
Attainment of speed targets is measured by the Marine Exchange of Southern California, based on weighted
average speeds measured over trip segments 5 nautical miles in length.18 In 2019, the Port achieved a 91
percent participation rate within 20 nautical miles and an 87 percent participation rate within 40 nautical
miles. Selected operator participation rates are shown in Figure 3 (on the next page) along with incentive
thresholds, based on data for 2019.
Other programs include:
• The Port Authority of New York and New Jersey offers incentives for ocean-going vessel operators to
comply with its VSR by giving additional points to its Clean Vessel Incentive score. The Clean Vessel
Incentive Program rewards operators that reduce vessel emissions through voluntary engine, fuel, and
technology enhancements; points are also awarded for exceeding current international emission
standards based on established metrics such as Environmental Ship Index scores. Accumulated points
can be applied to financial incentives managed by the Port Authority. Based on the 2018 port emissions
inventory, VSR accounted for a reduction of 598.5 tons of NOx, 7.1 tons of PM, and 15,626 tons of C02e.19
• The Port of Long Beach provides a 25 percent reduction in dockage fees for fleets with a 90 percent
participation rate within 40 nautical miles of Point Fermin, and a 15 percent reduction for participation
within 20 nautical miles. The Port achieved 95 percent participation within the 20-mile zone and almost
90 percent within the 40-mile zone, which the port estimates resulted in the reduction of 28 tons of
diesel particulate matter, 1,311 tons of NOx, 38 tons of sulfur oxides and 58,964 tons of C02e in 2017.20
17 Emission reductions and cost-effectiveness can vary substantially from port to port depending on fuel type, vessel mix,
program compliance rates and other factors. Accordingly, care should be taken when comparing program benefits and cost
across different programs.
18 Port of Los Angeles, n.d. Vessel Speed Reduction Incentive Program Guidelines.
https://www.portoflosangeles.org/environment/air-quality/vessel-speed-reduction-program. Accessed 3-5-2021.
19 Port Authority of New York and New Jersey. Clean Vessel Incentive Program, https://www.panyni.gov/port/en/our-
port/sustainability/clean-vessel-incentive-program.html. Accessed 3-5-2021.
20 Renee Moilanen, Manager of Air Quality Practices Port of Long Beach. Email communication, 11-19-2018.
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20 nm Compliance ¦ 40 nm Compliance
Incentive Threshold
Vessel Operator
Figure 3. Selected VSR Operator Participation, Port of Los Angeles (2019)21
• San Diego asks cargo vessel operators entering or leaving San Diego Bay to observe a 12-knot speed
limit. Cruise ships are requested to observe a 15-knot speed limit. The VSR extends 20 nautical miles.22
Based on the 2016 port emissions inventory, VSR accounted for a reduction of 62 tons of NOx and 2,670
tons of C02e.23
Table 1 summarizes key VSR program elements for selected U.S. ports.
Table 1. VSR Program Summary for U.S. Ports24
Port
Speed Limit
Zone Size
Fee Discount/Incentive
Los Angeles
12 knots
2 0-40 nm
15%-30%
Long Beach
12 knots
20-40 nm
15%-25%
San Diego
12 knots
20 nm
Public recognition
New York/New Jersey
10 knots25
20 nm26
Additional incentive points
21 Port of Los Angeles Vessel Speed Reduction Program Operator Summary Report, 2019.
https://kentlco.portofiosangeles.org/getmedla/f899bdfl-4el5-419e-8ec3-2d024c6f75fl/2019 VSR Counts POLA.
Accessed 3-5-2021.
22 Port of San Diego, n.d. Maritime-Environment, https://www.portofsandiego.org/environment/energy-
sustainability/maritime-environment. Accessed 3-5-2021.
23 Port of San Diego 2016 Maritime Air Emissions Inventory. ICF, June 2018.
https://pantheonstorage.biob.core.windows.net/environment/2016-Maritime-Air-Emissions-lnventory.pdf. Accessed
3-5-2021.
24 OECD/lnternational Transport Forum. 2018. Reducing Shipping Greenhouse Gas Emissions: Lessons from Port-Based
Incentives, https://www.itf-oecd.org/sites/default/files/docs/reducing-shipping-greenhouse-gas-emissions.pdf. Accessed
3-5-2021.
25 Port Authority of New York and New Jersey. 2018. Clean Vessel Incentive Program, http://www.panyni.gov/about/clean-
vessel-incentive-program.html. Accessed 3-5-2021.
26 20 nm outside the Territorial Sea Line.
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