[en] The harmful effects on citizens' health caused by the emission of air pollutants from the load transport such as, sulphur oxides (SOx); nitrogen oxides (NOx); methane (CH4), carbon dioxides (CO2) and particles emission (PM2,5/PM10), have motived an increasing concern in the public opinion. The need to integrate the economic development with the environmental sustainability that permits to ensure the standards of the European quality life for the next generations have leaded to new strategies in the European Policy of the intracommunity transport (short distance) taken by the European Union which are focused on the intermodality. This is so, due to the fact that the land transport was traditionally accepted as the most polluting transportation alternative for the load transport and otherwise the maritime transport proved to be the most sustainable one. Nevertheless, several aspects have currently carried to discuss these assumptions: the technical features of the vessels which operate under Motorway of the Sea conditions (Short Sea Shipping integrated in intermodal chains) do not favour the environmental sustainability; small and fast vessels which must be able to respond to the intermodality requirements, the unbalanced development of the limitations in the emission of pollutant agents in the European Union for the different transport systems. Whereas the European normative about gas emissions for the road transport were quickly tightened by forcing the technological development of solutions to increase the sustainability of the vehicles, the European maritime normative remains are supported by the IMO (International Maritime Organization) normative. This one, with international character beyond the European Union, results to be much slower in the establishment of the compulsory restrictions for the pollutant emissions. Due to the previous arguments the convenience of the maritime transport for the loads in short distance are currently under discussion. The published studies about this issue in the European Union are very scare and most of them are focused on technical solutions to reduce the pollution of vessel which operate in ECA (Emission Control Areas) and SECA zones (Sulphur Emission Control Areas). In other words, they try to offer technical solutions to accomplish with OMI normative by evaluating their economical impact from the standpoint of operation and investment but without evaluating their environmental impact with regard to the unimodal alternative. The highest expectations are provided by the use of gas based engines. However numerous recent publications alert about the existence of other pollutants which are not being regulated by the IMO but very harmful. Concretely, the methane slip due to the incomplete burning and bunkering operations for the gas maritime engines have alerted to many countries about the risk of greenhouse effect of the methane (25 times the CO2 effect). Due to the fact that the European Union have shown numerous times its intention to develop an own environmental normative for the maritime transport, it is expectable that in a next future this is a reality and its requirement level is comparable to demanding levels for the European road vehicles, Euro VI technology. Consequently, the present dissertation tries to tackle this issue which has been scarcely attended taking into account that the adaptation of the vessel fleets to the Short Sea Shipping in Europe has been become in an immediate challenge due to the expected new environmental restrictions (they will be comparable to the road ones) and to the need to keep the competitiveness of the intermodal chains against the conventional transport modes. Therefore, this dissertation tries to widen the current methodological framework of the optimization of fleets for the Short Sea Shipping traffic in Europe which must be integrated in intermodal chains with the comparative analysis of the environmental impact of the fleets and their intermodal chains regarding to the unimodal transport; this traffic is called Motorways of the Sea in the European context. The thesis will try to obtain a tool capable to define the optimal fleet from a technical and operative standpoint which offers competitive intermodal solutions to the unimodality in terms of time, cost and sustainability. For that, it will be necessary to define the different propulsive solutions not only from a technological standpoint but also by considering the combustibles associated to them, their impact in terms of the environmental costs, operative costs, investment costs, maintenance costs and the reduction of the cargo capacity by ensuring the required stability for the vessels. Thus, it will be necessary to propose a calculation system for the emission coefficients of several pollutants and their unitary costs. These results must be integrated in a mathematical model which will resolve the definition of fleets of optimal and feasible vessels by ensuring the highest competitiveness of the intermodality with regard to the unimodal alternative for the door to door transport. Thus, optimization process of this complex mathematical model will be carried out with multi-objective genetic algorithms. The Research Group associated to this thesis has developed a methodology for the optimization of fleets operating under Maotorways of the Sea Conditions. However, this thesis tries to advance in that research line by providing the environmental impact in the definition and evaluation model of the relative competitiveness between transport modes and ensuring the technical feasibility of the obtained fleets with the stability analysis of the vessels. Finally, the actual dissertation will try to be a making decision tool about the sizing and operation of fleets and their vessels, which by operating in short sea shipping conditions, provide sustainable solutions to the real transport needs. The proposed solutions will be to possible propulsion plants and their optimal combustibles. Therefore, the results will be useful not only for the ship-owners but also for the policy makers who will be able to evaluate in quantitative terms which solution must be supported from the administrations and how this can be included in the strategies of the transport policy. The consequence of the unbalance treatment from the Institutions to the different transport modes will be analysed as well.

[gl] O impacto perxudicial na saúde dos cidadáns polas emisións de axentes contaminantes tales como o óxido de azufre, óxidos de nitróxeno, dióxido de carbono, metano, así como de partículas producidas polo transporte de mercadorías motivaron unha crecente preocupación na cidadanía. A necesidade de integrar o desenvolvemento económico coa sostentabilidade ambiental que permitan garantir os estándares europeos da sociedade do benestar ás próximas xeracións levou á Unión europea a propoñer estratexias na política europea de transporte intracomunitario (curta distancia) baseadas na intermodalidade, xa que tradicionalmente aceptouse que o transporte rodado de mercadorías era o máis contaminante e o transporte marítimo o máis sustentable. Con todo, varios feitos puxeron en cuestión estas hipóteses: as características técnicas dos buques que operan en réxime de Autoestrada do Mar (tráfico marítimo de curta distancia integrado en cadeas intermodais); buques pequenos e rápidos que deben ser capaces de dar resposta ás cadeas intermodais e a desigual evolución normativa das limitacións en emisións de axentes contaminantes para os distintos métodos de transporte na Unión Europea, non favorecen a sustentabilidade ambiental. Mentres que a normativa europea sobre emisións do transporte terrestre endureceuse rapidamente forzando a desenvolver tecnoloxicamente solucións de vehículos máis sustentables, a regulamentación marítima europea segue apoiándose na normativa OMI (Organización marítima Internacional), que de carácter mundial, resulta ser moito máis lenta en forzar restricións ambientais. Por todo o anterior non está a resultar obvia a conveniencia do transporte de mercadoría por mar para curta distancia. Os estudos publicados respecto diso resultan ser moi escasos e a maioría enfócanse en solucións técnicas que reduzan a contaminación dos buques en zonas ECA (Emission Control Areas) e SECA (Sulphur Emission Control Areas), é dicir, que cumpran con normativa OMI achegando as mellores condicións económicas tanto de investimento como de operación pero sen avaliar o seu impacto ambiental respecto da alternativa unimodal. A gran esperanza neste eido achégaa a adopción de motores baseados en combustibles a gas. Con todo non son poucas as publicacións que alertan de que existen máis axentes contaminantes que os regulados pola OMI, en concreto as emisións de metano provocadas polo bunkering e a combustión incompleta dos motores mariños a gas alertaron a moitos países sobre o risco que supón o efecto invernadoiro do metano (25 veces maior que o do dióxido de carbono). Dado que a Unión europea deu numerosas mostras de tentar desenvolver normativas ambientais marítimas propias, é predicible que nun futuro próximo isto sexa unha realidade e que o seu nivel de esixencia sexa comparable ao requirido pola tecnoloxía en vehículos terrstres europeos Euro VI. Por todo o anterior a presente tese doutoral pretende abordar esta cuestión escasamente atendida xa que a adapatción das flotas ao tráfico de curta distancia en Europa é un reto inmediato considerando as restricións ambientais esperadas (equiparables ás esixidas en terra) e mantendo a competitividade das cadeas intermodais en custo e tempo respecto das alternativas de transporte convencionais. Por tanto o presente proxecto de tese ampla o actual marco metodolóxico de estudo da optimización de frotas de portacontedores para trafico regular de curta distancia en Europa integrado en cadeas multimodales coa análise comparativa do impacto ambiental das frotas en relación a alternativas de transporte unimodal; tráfico coñecido no contexto europeo como Autoestradas do Mar. Así se pretende obter unha ferramenta capaz de definir técnica e operativamente a flota óptima de buques capaces de establecer solucións intermodais de transporte á unimodalidad en termos de tempo, custo e sustentabilidade. Para iso será necesario definir as distintas solucións propulsivas tanto tecnolóxicas como os combustibles asociados a elas e o seu impacto en custos ambientais operativos, custos de instalación, mantemento, operación, redución de capacidade de carga garantindo a estabilidade dos buques. Para iso será necesario establecer un sistema de cálculo de emisións dos distintos axentes contaminantes e o seu custo unitario e integralo nun modelo matemático que resolva a definición das flotas de buques óptimos e viables asegurando que a solución intermodal sexa máis competitiva para o usuario que a alternativa unimodal para o transporte porta a porta. Para iso aplicaranse procedementos de optimización con algoritmos xenéticos multiobjetivo a modelos matemáticos complexos. O grupo de investigación no que se circunscribe o proxecto desenvolveu unha metodoloxía para a optimización de flotas operando en Autoestradas do mar integradas en cadeas intermodais. Con todo a presente tese pretende avanzar nesta liña integrando o impacto ambiental no modelo de definición e avaliación da competitividade do transporte marítimo e asegurando a viabilidade técnica da flota desde o punto de vista da súa estabilidade. A presente tese pretende ser una ferramenta de decisión sobre o dimensionamiento e operación de buques e flotas que operando en tráfico regular de curta distancia ofrezan solucións realmente sustentables ás necesidades de transporte. As solucións propostas estarán vinculadas a solucións de plantas propulsoras e combustibles óptimos. Os resultados non serán só de utilidade para armadores senón tamén para os lexisladores que poderán valorar en termos cuantitativos que solución pode apoiarse desde as administracións para establecer estratexias na política de transporte e cales son as consecuencias do trato desigual aos distintos modos de transporte.