Emission performance of major ship classes: An estimation based on a new set of emission factors and realistic activity profile data

The maritime sector significantly contributes on the major environmental problems that humanity is being confronted with their consequences. The Greenhouse Gases (GHGs) emitted from the sector, which are responsible for the global phenomenon of climate change, are estimated in 2,89% of total anthropogenic GHGs. Ships are also an important source of local air-quality degradation in coastal areas by emitting major quantities of pollutants such as Nitrogen Oxides (NOx), Sulphur Oxides (SOx) and Particulate Matter (PM). The overall emitted quantities of the sector seem not to be equally allocated to the major ship classes (containers, dry and liquid bulk carriers, cruise ships, ro-ro ships etc.), even though the engine technologies that are being used in these classes are approximately the same (slow speed, medium speed, high speed diesel engines). A factor of differentiation among the ship types is the activity profile. Depending on the ship type, engines (main, auxiliary, boilers) present different power needs and therefore are being operated at different load points which among others are related with the sailing profile (cruising, maneuvering, hoteling), the cargo type and weight conditions (laden, ballast). In this context the target of the present paper is to evaluate the emission performance of the major ship classes. This evaluation is performed by using a new set of engine load-dependent Emission Factors for ships, which have been derived by a statistical analysis of emission rates found in literature, in combination with average activity profiles per ship type as these are found in dedicated shipping inventory databases and in literature. These activity data concern a global scale of consideration. Results aim to highlight the differences and similarities in the emission performance of ship types, enhancing the understanding of policy makers and ship operators, on the principle of tackling pollutants especially at ports, close to cities.

Assessing the Responses of Aviation-Related SO2 and NO2 Emissions to COVID-19 Lockdown Regulations in South Africa

Aircraft emit harmful substances, such as carbon dioxide (CO2), water vapour (H2O), nitrogen oxides (NOx), sulphur oxides (SOx), particulates, and other trace compounds. These emissions degrade air quality and can deteriorate human health and negatively impact climate change. Airports are the nucleus of the ground and low-altitude emissions from aircraft during approach, landing, take-off, and taxi. During the global lockdown due to the COVID-19 pandemic, tight restrictions of the movement were imposed, leading to temporary closures of airports globally. In this study, we look at the variability of emissions at two major airports in South Africa, namely the OR Tambo international airport (FAOR) and the Cape Town international airport (FACT). Trend analysis of aircraft movements, i.e., departures and arrivals, showed a sharp decline at the two airports coinciding with the lockdowns to prevent the spread of the COVID-19. Consequently, a decrease in NO2 emissions by 70.45% (12.6 × 10−5 mol/m2) and 64.58% (11.6 × 10−5 mol/m2) at FAOR and FACT were observed, respectively. A noticeable SO2 emission decline was also observed, particularly over FAOR during the lockdown period in South Africa. Overall, this study observed that the global lockdown regulations had a positive impact on the air quality, causing a brief decline in emissions from commercial aviation at the South African major airports.

Forecasting of Fouling in Air Pre-Heaters Through Deep Learning

Thermal power plants employ regenerative type air pre-heaters (APH) for recovering heat from the boiler flue gases. APH fouling occurs due to deposition of ash particles and products formed by reactions between leaked ammonia from the upstream selective catalytic reduction (SCR) unit and sulphur oxides (SOx) present in the flue gases. Fouling is strongly influenced by concentrations of ammonia and sulphur oxide as well as the flue gas temperature within APH. It increases the differential pressure across APH over time, ultimately leading to forced outages. Owing to lack of sensors within APH and the complex thermo-chemical phenomena, fouling is quite unpredictable. We present a deep learning based model for forecasting the gas differential pressure across the APH using the Long Short Term Memory (LSTM) networks. The model is trained and tested with data generated by a plant model, validated against an industrial scale APH. The model forecasts the gas differential pressure across APH within an accuracy band of 5–10% up to 3 months in advance, as a function of operating conditions. We also propose a digital twin of APH that can provide real-time insights into progression of fouling and preempt the forced outages.

Management tools for implementation and monitoring of requirements for enforcement of reducing sulphur oxides on ships: Latvia and Lithuania cases

The main type of bunker oil for ships is heavy fuel oil, derived as а residue from crude oil distillation. Crude oil contains sulphur which, following combustion in the engine, ends up in ship emissions. Sulphur oxides (SOx) are known to be harmful to human health, causing respiratory symptoms and lung diseases. Limiting SOx emissions from ships will improve air quality and protect the environment. From 1 January 2020, the limit for sulphur in fuel oil used on board ships operating outside designated emission control areas is reduced to 0,50% m/m. However, there are varying degrees of readiness among port and flag states for implementation and monitoring of requirements for enforcement of reducing Sulphur oxides on ships. In this paper are described management tools of states for implementing the inspection on Sulphur in ships fuel, analysed the states institutions activities for the enforcement of reducing Sulphur oxides on ships, and indicated the possibilities of increasing effectiveness of the management tools in Latvia and Lithuania.

Shipping and Air Quality in Italian Port Cities: State-of-the-Art Analysis of Available Results of Estimated Impacts

Populated coastal areas are exposed to emissions from harbour-related activities (ship traffic, loading/unloading, and internal vehicular traffic), posing public health issues and environmental pressures on climate. Due to the strategic geographical position of Italy and the high number of ports along coastlines, an increasing concern about maritime emissions from Italian harbours has been made explicit in the EU and IMO (International Maritime Organization, London, UK) agenda, also supporting the inclusion in a potential Mediterranean emission control area (MedECA). This work reviews the main available outcomes concerning shipping (and harbours’) contributions to local air quality, particularly in terms of concentration of particulate matter (PM) and gaseous pollutants (mainly nitrogen and sulphur oxides), in the main Italian hubs. Maritime emissions from literature and disaggregated emission inventories are discussed. Furthermore, estimated impacts to air quality, obtained with dispersion and receptor modeling approaches, which are the most commonly applied methodologies, are discussed. Results show a certain variability that suggests the necessity of harmonization among methods and input data in order to compare results. The analysis gives a picture of the effects of this pollution source, which could be useful for implementing effective mitigation strategies at a national level.

A Comparative Life Cycle Assessment of Marine Desox Systems

With new sulphur oxides emission limits carried out in 2020, multiple desulphurisation methods have been proposed. The main desulphurisation scrubber systems were chosen and investigated using life cycle assessment. The whole system life is divided into the construction and operational phases. Three different systems classified by desulphurisers, namely, seawater, NaOH, and Mg-based systems, were modelled in GaBi software. Moreover, environmental, economic and energy aspects (3E model) were introduced for further analysis. Through this study, some conclusions have been drawn. As for the environmental aspect, the seawater system has the most pleasing performance since the primary emissions come from 1.24E+03 kg CO2 and 1.48E+01 kg chloride. The NaOH system causes 1000 times more emissions than the seawater. The Mg-based system has less pollution than the NaOH system, with 5.86E+06kg CO2 and 3.86E+03 kg chloride. The economic aspect is divided into capital expenditure (CapEx) and operational expenditure (OpEx) to estimate disbursement. The seawater system also has the most favourable cost appearance, which takes 1.7 million dollars without extra desulphuriser expenses, based on 10MW engine flue gas treatment. The next is the Mg-based system, which cost 2 million dollars in CapEx and $ 1200/year in OpEx for the desulphuriser. NaOH uses about 2.5 million dollars for construction and $ 30000/year in desulphuriser. As for the energy aspect, the seawater and Mg-based systems use less non-renewable energy than the NaOH system in the construction phase. In conclusion, the seawater system shows the best performance and could be an alternative in SOx control technologies. This study sheds light on the comprehensive evaluation of marine environmental protection technologies for further optimisation.

Comparison of the Economic Performances of Three Sulphur Oxides Emissions Abatement Solutions for a Very Large Crude Carrier (VLCC)

Ship-source air pollutants, especially sulphur oxides (SOx), have a major impact on human health, the marine environment and the natural resources. Therefore, control of SOx emissions has become a main concern in the maritime industry. The International Maritime Organization (IMO) has set a global limit on sulphur content of 0.50% m/m (mass by mass) in marine fuels which has entered into effect on 1 January 2020.To comply with the sulphur limits, ship owners are facing the need to select suitable abatement solutions. The choice of a suitable solution is a compromise among many issues, but the economic performance offers the basis for which ones are attractive to ship owners. Currently, there are three technologically feasible SOx abatement solutions that could be used by ships, namely, liquified natural gas (LNG) as a fuel (Solution A), scrubbers (Solution B) and low-sulphur fuel oil (LSFO) (Solution C). To compare the economic performances of the mentioned three solutions for a newbuilding very large crude carrier (VLCC), this paper proposes a voyage expenses-based method (VEM). It was found that, within the initial target payback period of 6 years, Solution A and C are more expensive than Solution B, while Solution C is more competitive than Solution A. Five scenarios of target payback years were assumed to compare the trends of the three proposed solutions. The results show that Solution B maintains its comparative advantage. As the assumed target payback years becomes longer, the economy of Solution A gradually improves and the economics of Solution B and C gradually decline. A comparison between Solution A and C shows 6.5 years is a turning point. The advantage of Solution A is prominent after this payback period. In addition, the performance of a certain solution in terms of adaptability to the IMO greenhouse gas (GHG) emissions regulations is also a factor that ship owner need to consider when making decisions. In conclusion, when the IMO air pollutant regulations and GHG regulations are considered simultaneously, the advantages of using LNG are obvious.

Influence of Pollutants from Transport on Life Expectancy in the EU Countries

Road transport has become the major source of environmental pollution and it is also one of the biggest environmental risks in the EU countries. Good air quality is very important for population as pollutants have negative impacts on human health. The paper deals with relationship between air pollutants generated by road transport and the life expectancy in EU countries. At the beginning of the paper the main pollutants from motor vehicles are described and impact on human health is summarized too. We use regression analysis of panel data to analyse the relationship between chosen air pollutants and life expectancy. Our results show negative impacts of nitrogen oxide and sulphur oxide, specifically reduction in life expectancy by 1.49 years for nitrogen oxides and 0.28 years for sulphur oxides with an increase of the pollutant by 1%. So according to our findings economic policy makers should focus primarily on the reduction of nitrogen and sulphur oxides.