Software + Tools

The Maritime Transport Emission Model (MTEM) was first developed in 2019. MTEM is an energy-based ship exhaust emissions model. It uses detailed data on local ship movement (Automatic Identification System - AIS, terrestrial or satellite) and ship characteristics. The model is designed to make accurate predictions at fleet level at local, regional or national level.

The fuel algorithms first predict representative fuel consumption rates for
different ship classes in four modes of operation, ‘transit’, ‘manoeuvring’,
‘berth’ and ‘anchor’. Fuel rates for moving ships in transit are simulated as a function of ship class, ship size, service speed and actual vessel speed.

The main ocean-going vessel (OGV) types considered in the model
are: ‘bulk carrier’, ‘container’, ‘cruise ship’, ‘general cargo’, ‘reefer’,
‘roro’ (roll-on-roll-off), ‘tanker (oil)’, ‘tanker (other)’, ‘vehicle carrier’
and ‘other’. Ship engine type is broadly defined as: 1) main engine (ME),
auxiliary engine (AE) and boiler (BL), 2) slow speed (SS), medium speed
(MS) and high speed (HS) diesel engines, or gas/steam turbines (GAS/
STM), and 3) International Convention for the Prevention of Pollution
from Ships (MARPOL) Annex VI NOx emission certification limits, which
relate to year of vessel construction, i.e. ‘pre-control’ (<2000), ‘Tier I’
(2000–2010) and ‘Tier II’ (2011+).

Marine fuel oils are classified as follows (intermediate) residual fuel oil (RO), marine distillates (MD) and ultra-low sulphur diesel (ULSD). The fuel use and fuel-based emission factor values are similarly defined as a function of engine system, fuel type and MARPOL Annex VI emission certification limit (NOx only), as well as operating conditions. A ship energy-balance approach was deployed to calibrate (and expand) model parameters of the empirical functions.

The model incorporates fuel-based emission factors (g of pollutant per kg of fuel burned) for air pollutants and greenhouse gases based on a review of published research reports and scientific papers . The emission factor values are a function of engine system, engine type, fuel type and MARPOL Annex VI emission certification limit (NOx only). These emission factors are combined with estimates of fuel consumption for each minute of individual ship activity.

This is done for all individual ships that operate in the study area in a
selected base year and emissions are aggregated to give total emission
loads. Total emission loads are aggregated at grid cell level and calculated
for each hour of the year.

MTEM publications can be found here.