The growth of world trade has led to a rapid increase in the volume of goods transported by sea, making seaports major centres of economic activity.
With the priority on reducing emissions from shipping, ports are being forced to develop strategies to reduce the impact of atmospheric emissions from their operations, both locally and globally.
Measuring and managing the carbon footprint of ports is essential to reducing their environmental impact and contributing to global emissions reduction targets.
How is the carbon footprint of ports calculated?
The concept of carbon footprint refers to the total amount of greenhouse gases emitted both directly and indirectly by an activity, organisation or product.
The calculation of GHG emissions is usually expressed in terms of CO2 equivalent weight, taking into account the global warming potential of each gas. In the port context, this includes emissions from direct port operations as well as those associated with the supply chain and transport of goods operating in the port.
GHG emissions in ports
In ports, GHG emissions can be linked to the consumption of energy from various sources, in particular oil derivatives and electrical energy. The most common greenhouse gases that need to be monitored under the Kyoto Protocol are:
- Carbon dioxide (CO2): mainly emitted by the combustion of fossil fuels in ships, vehicles and cargo handling equipment.
- Methane (CH4): although emitted in smaller quantities, it has a significant impact on the atmosphere as it has a global warming potential 28 times greater than CO2.
- Nitrous oxide (N2O): is associated with combustion processes, mainly in industrial activities, and has a global warming potential 265 times that of carbon dioxide.
Hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6) and nitrogen trifluoride (NF3) must also be taken into account when calculating the carbon footprint. GHG emissions can be linked to energy consumption from a variety of sources, including electricity and petroleum products.
To measure, analyse and control pollution in ports, it is essential to have the appropriate instrumentation, as discussed in our article “How to measure air pollution in ports“.
Calculating the carbon footprint of a port authority
Ports provide various services which, depending on their nature, are developed directly by the port authority or by companies under its licence.
Calculating the carbon footprint of a port is an essential starting point for port authorities to identify and promote strategies and actions aimed at reducing greenhouse gas emissions from port activities and optimising energy consumption.
The first step in the calculation is to define which port activities are included in the calculation and where they are located:
- Port or ports included in the boundaries of the CF.
- Port service area
- Port infrastructure, specifying that which is included in the boundaries of the CF.
- Terrestrial accesses.
- Includes land and services concessioned by the port authority.
- Commercial services and port services provided by or under licence from the port authority.
Determining the scope of emissions and emission factors
In the context of carbon footprinting, the term scope of emissions allows greenhouse gas emissions to be categorised according to their origin and control:
Scope 1: direct emissions from sources owned or directly controlled by the organisation, including stationary combustion, mobile combustion, fugitive processes and industrial processes.
Scope 2: indirect emissions associated with the production of electricity, heat or steam purchased and consumed by the entity for the development of its activities and attributable to the facilities where the energy is produced.
Scope 3: refers to other indirect emissions generated in the entity’s value chain, which may include activities in cargo and passenger terminals, mooring services or the handling of tourist cruises. Calculating these emissions is often complex.
Emission factors are tools used to estimate the amount of greenhouse gases emitted by a unit of activity and are essential for calculating the carbon footprint as they allow activity data (e.g. fuel consumption, electricity use, etc.) to be converted into greenhouse gas emissions.
These factors are tabulated and are usually expressed in units such as kilograms of CO2 equivalent (CO2eq) per unit of activity, making it possible to compare emissions between different entities or sectors.
For example, if a port consumes 10,000 litres of diesel and the diesel emission factor is 2.67 kg CO2 per litre, the resulting emissions would be: 10,000 litres x 2.67 kg CO₂eq/litre = 26,700 kg CO₂eq.
Methodology for calculating the carbon footprint in ports
According to the Methodological Guide for calculating the carbon footprint in ports, the general formula for calculating the carbon footprint in ports is (Carbon footprint = activity data x emission factor).
The next step is to identify the emission sources and group them into the different scopes. The ‘activity data’ related to fuel, electricity or transport is then collected and the corresponding emission factors are applied to each activity.
Finally, the emissions from all scopes are added together to give the total carbon footprint of the port (Total CF=CF Escope 1+CF Escope 2+CF Escope 3).
Using this methodology, port authorities can effectively identify and manage their environmental impacts and develop strategies to reduce emissions and improve the operational sustainability of ports.
