Transport by sea and ports is the major global route by which nations deliver the diverse cargoes of goods, food and materials across the world. In Malta, the port terminals in Valletta’s Grand Harbour are the obvious gateway for the shipment or transhipment of cargo from shore to sea and vice versa in our country.

During the last decades, the increased popularity of cruise ships is also evident in Valletta harbour. This generally increased ship traffic is associated with air emissions from the marine fuel burnt onboard in the vessels’ main and/or auxiliary engines (for electricity supply and ship maintenance/management) when in harbour.

Today, global air quality concerns are playing an increasingly important role as demonstrated by the introduction of the world ports climate initiative (WPCI) by a group of worldwide seaports in 2008. WPCI identified and categorised greenhouse gas (GHG) emissions in ports. The categorisation of the GHG was essential to control indirect and direct sources of these emissions which contribute to the global climate change.

In view of the very serious impacts of global climate change, 196 parties at COP21 in France 2015 pledged (Nov-Dec L’Appel de Paris or the Paris Pledge for Action) to control global warming by limiting global temperature rise to not more than 2⁰C and to aim for 1.50⁰C. The EU directive 2018/410/EC commits the EU to reduce the GHG emissions from shipping with direct reference to the International Maritime Organisation (IMO) and the Paris agreement (COP21).

To consolidate its climate change targets, the European decision 2009/406/EC on the reduction of GHG emissions was emphasised and should be implemented by this year with a main target for member states to reduce their GHG emissions by 20 per cent when compared with 2005. The European Commission strategy is to reduce air emissions in the European port areas with implementation of the Directive 2014/94 by December 31, 2025. In Malta, it is planned to introduce shore-to-ship electrical power connections (‘cold ironing’) in the Valletta seaport terminals to minimise these GHG emissions, that is carbon dioxide (CO2) from ship engines when berthed.

Sound, evidence-based policies

Cold ironing (electrical cable connected from the wharf to the ship, see Figure 1) provides the necessary electrical energy to compensate for the reduction or switching-off of ships’ engines during ‘hoteling’ (ship berthed beside the wharf for a period).

The strategy for the government to reduce GHG emissions by 90 per cent is achievable if the GHG emissions per kWh of electrical energy supplied by cold ironing are 90 per cent less than the GHG emissions that would have occurred per kWh of electrical energy generated on board from the ships’ main and auxiliary engines.

However, substituting on-ship electrical energy generation in Valletta port terminals with electrical energy generated by Marsaxlokk or Sicily looks very unlikely to reduce GHGs by the amount desired (90 per cent reduction) to meet the COP21 climate change pledge.

Referring to the table, it can be seen that the carbon intensities of electricity for EU national grids had an average of 296g CO2 per kWh but a great deal of diversity in 2016. Provision of electricity by the combination of the interconnector cable (Sicily grid) and local solar panels and natural gas generation in Malta is not managing to meet with the European average of 296g CO2 per kWh. According to the European Environment Agency (EEA), in 2016 the average CO2 emission from electricity generation in Malta was 648g CO2 per kWh.

Using this value, the CO2 emissions per kWh from potential cold ironing would reduce CO2 emissions only by 10 per cent in the Valletta seaport area as compared with on-ship generation (690 to 722g CO2 per kWh (±20per cent uncertainty). If we were to assume electrical power via the interconnector cable from Sicily for cold ironing, then the CO2 emissions would reduce by 65 per cent.

Cold iron electrical connections from wharves to ships undoubtedly offer a pathway to minimising overall (rather than just local) GHG air emissions in ports if the shore-based electricity supply has a lower carbon intensity than on-ship generation.

This is what Malta needs to achieve and assure. It is also true that additional, local benefits can accrue in the port area from cold ironing because not only GHGs but other air pollutants (e.g. NOx and SO2) are produced by on-ship combustion of the three common types of marine fuels (marine gas oil (MGO), marine diesel oil (MDO) and residual oil (RO)).

Furthermore, the incineration of a ship’s garbage can also produce SO2 and NOx (contributors to acid rain) and accidental releases of chloro­-fluoro­carbon gases to the atmosphere during the repair/maintenance of a ship’s ventilation system can degrade the ozone layer. Thus, the government is dealing with a set of complex, interlinked issues when seeking better management of the anthropogenic activities that cause unwanted air pollution, both within our port of Valletta and elsewhere.

Sound, evidence-based policies on initiatives like cold ironing, coupled with incentives (e.g. for seaport operators to renew the handling equipment to further decrease air emissions; introduction of alternative fuels and battery pack power sources in the marine sector) offer a responsible and effective pathway to a sustainable future for Malta’s vital ports and maritime activities.

Ing. Alfred Buttigieg, PhD researcher in environmental engineering at Surrey University

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.