Maritime shipping is considered as the most eco-friendly and fuel-efficient method of transport in ton-miles terms and moves about 90% of the worldwide trade (UNCTAD, 2020) [1]. The third GHG study (IMO, 2014) [2] estimates that shipping accounts for approximately 2.2% of the global anthropogenic CO2 emissions, addressing a 0.5% decrease from the second GHG study measures (IMO, 2009) [3]. However, the sector has seen increasing pressure, through new guidelines to improve its environmental performance, especially considering its commitment to harmful contamination emissions on human wellbeing. Sea transport represents 5–8% of the worldwide SOx emissions (Eyring et al., 2005) [4], and around 15% for NOx (Corbett et al., 2007) [5], while PM emissions from transportation close to coastlines and ports have been connected to fatalities attributed to respiratory health issues. The IMO is regulating the greatest sulfur limits in fuel through the changed MARPOL Annex VI, which additionally assigned sulfur emission control areas (SECA) where more tight limits apply. Current SECAs incorporate the Baltic Sea, the North Sea, the North American Emission control area (ECA) that broadens 200NM from the US and Canadian coasts, and the US Caribbean ECA. The last two ECAs have likewise set limitations on PM and NOx emissions. The first results of the SECAs on emissions limitation show critical enhancements. In relevant literature, there has been no recent update on the portion of sea transport in SOx emissions, and the most recent solid estimate is in the previously mentioned investigation of Eyring et al., back in 2005. On a later publication, Zis and Psaraftis (2018) [6] utilized information from the Organisation for Economic Co-operation and Development (OECD) on its part nations and assessed those SOx emissions from all transportation modes represented 3.5% in 2015. Taking into account that road transport represented 0.48%, the portion of maritime transportation in SOx emissions has been radically diminished since 2005. Notwithstanding the introduction of SECAs, as of January 2010 the European Union (EU) set a sulphur limit of 0.1% for ships berth in EU ports with stays longer than 2 h, as well as when sailing on inland waterways [7]. European Commission has advanced the further arrangement of shorepower to its part states through an authority suggestion [8]. Port authorities all throughout the planet have launched initiatives that advance utilization of low-sulfur fuel in their proximity, with the port of Singapore being a notable example under the Green Ship and Green Port programs offering monetary incentives for clean practices that reduce CO2 and SOx emissions. At last, the ports of Los Angeles and of Long Beach have presented voluntary speed reduction programs (VSRP) in their proximity in return for a decrease of port disbursements accounts and are moving towards making the use of shorepower for ocean going ships mandatory. Concerning guidelines focusing on sulfur outflows, ship owners can consent by one or the other changing to ultra-low sulphur fuels like Marine Gas Oil (MGO) or investing in scrubber systems that treat the exhaust gases to remove SOx and PM emissions hence permitting the utilization of Heavy Fuel Oil (HFO). Additionally, to adapt to guidelines on emissions at ports a vessel can either utilize cleaner fuel or, on the other hand, be retrofitted to get shorepower if the port has cold ironing facilities. Thusly, to address ecological regulation the shipowners have to pay to obtain abatement technology or increase their operating costs by utilizing cleaner yet more expensive fuel. Which option of the above mentioned is more cost-effective for the shipowner depends on various factors, including ship type, ship size, regulations affecting the waters in which the ship sails, and ports of call. Simultaneously, the choice of a port to put resources into innovations that permit the arrangement of shorepower relies upon a few variables, which stem from emissions decrease strategies, and the entrance pace of the innovation in the calling ships. The last decades the demand of energy is being increased continuously. The massive use of different types of non-renewable sources of energy has led to very important problems in the earth, as global warming, by the production of big amounts of greenhouse gases (GHGs) [52]. Nitrogen oxides (NOx), carbon monoxide (CO) and carbon dioxide (CO2) are some of the elements that are being produced by the burning process of marine diesel engines and pollute the atmosphere. This fact is a result of the use of Heavy Fuel Oil (HFO) in vessels’ engines which is preferred by the shipowners especially for economy reasons [53]. New technologies concerning alternative sources of energy have started to provide new environmental standards by reducing the emissions of harmful for the environment gases as CO2. More than the 80% of the harmful emissions in the atmosphere are related to carbon [54]. Consequently, decarbonization constitutes on of the biggest environmental problems and despite the fact that the efficiency in terms of energy in the maritime transport has been increased significantly, shipping industry has the responsibility of almost 940 million tons of CO2 emissions in the atmosphere per year. Taking into consideration the continuously increase of the global fleet we can easily understand that these emissions are going to reach a higher level in the next few years [55]. The use of alternative fuels seems to be the only solution for the environment and European Union has already include in her White Paper on Transport their introduction [56]. More specifically, in 2016, European Union has already released a «Strategy for liquefied natural gas and gas storage» in order to highlight the advantages and the potential of the use of LNG to all members of the Union. Moreover, in October 2014, the executive committee of the European Union obliged 139 ports in Europe to act appropriate in order to have the possibility to offer bunkering facilities for LNG until 2020 [59]. Additionally, the effort to control the pollution emissions was strengthen by the International Maritime Organization (IMO) through the introduction of new regulations. More specifically, International Convention for the Prevention of Pollution from Ships (MARPOL) was embraced by the IMO which also adopted amendments to MARPOL Annex VI (Resolution MEPC.203 (62)) through the introduction of an energy efficiency design index in order to reduce the CO2 emissions [54, 61]. This paper discusses the possibility of different types of fuels or technological investments to be used as marine fuels from the perspective of shipowners, terminal operators, and regulatory bodies while considering the extent of ecological improvement that can provide. The first section of this paper presents a concise literature review of relevant research in port emissions as well as regulations that are used nowadays, which are imposed by the International Maritime Organization (IMO). The subsequent section presents an analysis and evaluation of different types of fuels which should appraise the new ecological equilibrium following the established environmental and safety regulations. In the last part, the benefits and drawbacks of its kind of fuel are widely expressed.