Incumbent clinker production practices fall short of meeting carbon-emission neutral targets, pressing the need to implement waste valorization approaches in cement plants to mitigate environmental impacts. However, there is a lack of knowledge on the future environmental performance of emerging waste-to-heat and fuel upcycling in clinker manufacturing. This study examines the prospective life cycle impacts of (1) solid recovered fuel (SRF) utilization and (2) on-site marine fuel production using integrated fluidized bed pyrolysis to substitute fossil fuels in clinker production and marine transportation. Environmental impacts are projected between 2025 and 2050 by applying learning effects in the foreground life cycle inventory and shared socioeconomic pathways (SSP1, SSP2), extended with the 1.9 W m−2 representative concentration pathway (SSP2-RCP1.9), in the background system. The highest decarbonization progress (−538.9 kg CO2-eq (t clinker)−1) is achieved under the SSP2-RCP1.9 development trajectory, driven by avoidance of emissions from waste management systems and converting biogenic carbon-rich municipal solid waste resources. The predicted CO2-eq impacts are found to be lower than the point source emission from raw meal calcination in several SSP scenarios, indicating that carbon-emission neutrality is attainable in combination with retrofitted carbon capture, utilization, and storage (CCUS) technologies. The assessment highlights the potential for burden shifting to other environmental impacts, e.g., particulate matter formation (+37.0 % by 2050), pointing to the need to evaluate additional pyrolysis oil upgrading and NOX emission mitigation strategies. Overall, synergizing waste pyrolysis with clinker production is found to be favourable due to (i) improved energy requirements, (ii) reduced fossil fuel use and impacts on climate change and ecosystem quality, and (iii) high potential for technological learning-driven environmental progress.
The “Initial IMO Strategy” was adopted in the 72nd session of the Marine Environment Protection Committee (MEPC 72) of the International Maritime Organization (IMO) in April 2018. It has set, among other things, ambitious targets to reduce greenhouse gas (GHG) emissions from ships, and purports to express a strong political will to phase them out as soon as possible. The most ambitious of these targets is to reduce GHG emissions by 2050 at least 50% vis-à-vis 2008 levels, and there is also an intermediate target to reduce CO2 emissions per transport work by 2030 at least 40%, again vis-à-vis 2008 levels. More than three years since the adoption of the Initial IMO Strategy, this chapter takes stock at the status of shipping decarbonisation and attempts to assess prospects for the future. Obstacles towards achieving the IMO targets are identified and discussed.
The “Initial IMO Strategy” was adopted in the 72nd session of the Marine Environment Protection Committee (MEPC 72) of the International Maritime Organization (IMO) in April 2018. It has set, among other things, ambitious targets to reduce greenhouse gas (GHG) emissions from ships, and purports to express a strong political will to phase them out as soon as possible. The most ambitious of these targets is to reduce GHG emissions by 2050 at least 50% vis-à-vis 2008 levels, and there is also an intermediate target to reduce CO2 emissions per transport work by 2030 at least 40%, again vis-à-vis 2008 levels (IMO, 2018). In the period after MEPC 72, the focus of the IMO discussion has been on the formulation and eventual adoption of the short-term measures, that is, measures that are to be agreed upon and implemented by 2023. In fact, MEPC 76, held in June 2021, and after a rather difficult discussion, adopted such a short-term measure. MEPC 77 (November 2021) saw the initiation of the discussion on mid-term and long-term measures, which include, among others, market based measures (MBMs) and alternative fuels. The discussion continued at MEPC 78 (June 2022) and is expected to continue at future meetings of MEPC.
The purpose of this short paper is to provide a brief and non‐encyclopedic commentary on the decisions made at IMO MEPC 76 (June 2021) and assess the prospects for the future of shipping decarbonization in the aftermath of that meeting. The recent action of the European Commission to include shipping into the EU Emissions Trading System (ETS) is also discussed.
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The decarbonisation of shipping has become a high priority on the environmental and political agenda. The prospect of implementing an Emissions Trading System (ETS) for shipping has come to prominence as a proposed mechanism for speeding up the decarbonisation of the industry, with the EU taking proactive action to include shipping within the EU ETS by 2023. This paper analyses and provides a qualitative review of the historical development of the discussions and actions taken at both global level (by the International Maritime Organization (IMO)) and at regional level within the EU. A SWOT analysis of the potential implementation of an ETS for shipping is then presented. The paper concludes that an ETS for shipping can incentivise greater investment in, and deployment of, green technologies that will have the effect of reducing the carbon footprint of the shipping industry. However, the speed and significance of this effect will depend upon the specific shipping market segment and the relative stage in shipping market cycles over time. It is further concluded that despite the imminent unilateral introduction of shipping into the EU ETS, it is important that the IMO continues its work to develop a global ETS that promotes a ‘level playing field’ for competition within the sector and eliminates the risk of carbon leakage.
Hydrogen energy is a promising solution for prompting low-carbon port development. This study introduces two hydrogen utilization strategies: hydrogen consumption-driven strategy (HCDS) and hydrogen storage-driven strategy (HSDS). Using data from a real port and a life-cycle assessment approach, a case study is conducted to compare their economic and ecological performances. The results show that HCDS enhances economic benefits, with an annualized cost of 66.1 million CNY, which is 11% lower than HSDS. Additionally, HCDS is sensitive to electricity prices and grid carbon emission factor. In contrast, HSDS offers superior ecological benefits, with an annualized carbon footprint of 31,300 tons of CO₂, which is 12% lower than HCDS, and is mainly sensitive to purchase prices and emission factors of electricity and hydrogen. This study provides critical insights into the trade-offs between economic and ecological performance under different hydrogen utilization strategies, offering practical guidance for implementing hydrogen energy system applications in ports.
Offshore grids can play key roles in the transition of energy systems toward sustainability. Although they require extensive infrastructure investments, they allow for the exploitation of additional resources and may be important in providing for part of the increasing electricity demands driven by sector coupling. This paper quantifies the socioeconomic value of offshore grids and identifies their major drivers, performing energy system optimization in a model application of the northern–central European energy system and the North Sea offshore grid towards 2050. The increasing wake loss with the sizes of hub-connected wind farms is integrated in the modeling. We find that without sector coupling no offshore grid may develop, and that the higher the level of sector coupling, the higher the value of offshore grids. Therefore, it can be strongly stated that offshore grid infrastructure development should not be discussed as a separate political topic, but seen in connection to sector coupling.
Tropical marine ecosystems provide a wide range of provisioning, regulating, supporting and cultural services to millions of people. They also largely contribute to blue carbon sequestration. Mangroves, seaweeds, and seagrass habitats are important because they store large amounts of organic carbon while fish play a fundamental role in the carbon transport to deep waters. Protecting and restoring tropical marine ecosystems is of great value to society because their decline impairs the vital services they provide, such as coastal protection and seafood supplies. In this marine policy paper, we present options for enhancing blue carbon sequestration in tropical coastal areas. In addition, we outline the economic value of four components of coastal ecosystems (mangroves, seagrass beds, seaweed forests and fish) and discuss the economic levers society can apply to ensure the end of the current gross mismanagement of tropical blue carbon ecosystems. Market-based solutions, such as carbon taxes or fines for violations that use the ‘polluter pays' principle, can be very effective in achieving national or international climate agreements. Private investment can also finance the preservation of blue carbon ecosystems. One widely known financing method for blue carbon conservation, particularly of mangroves, is the use of municipal bonds, which can be issued like traditional bonds to finance the day-to-day obligations of cities, states and counties. Non-philanthropic investments can also be used in order to protect these ecosystems, such as debt-for-nature swaps and the improved application of regulatory frameworks. Overall, the protection of tropical marine ecosystems is an ecological imperative and should also be seen as an opportunity for new revenue streams and debt reduction for countries worldwide.
Driven by regulatory mandates, International Maritime Organization (IMO) decarbonization targets, market pressure, and evolving societal expectations, the maritime industry is undergoing a fundamental transition towards full decarbonization. This shift has renewed interest in Wind Propulsion Systems (WPSs) as viable propulsion alternatives, reflected in their increasing adoption. However, widespread implementation remains challenging. Each WPS installation design excels under specific conditions, which makes selecting the most cost-effective WPS installation complex. Failure to optimize design and placement can lead to suboptimal fuel savings or unprofitable deployments, limiting industry confidence, and slowing adoption.
To address these challenges, this PhD Thesis presents a novel modelling framework to optimize WPS installation designs by evaluating their cost-benefit trade-offs. The framework identifies the optimal WPS class, design, positioning, and arrangement to maximize fuel savings and emission reductions while minimizing investment costs, tailored to an operator’s specific profile. The study addresses three main objectives: (1) determining the most cost-effective WPS installation design, (2) enhancing industry understanding of WPS performance, and (3) supporting informed decision-making for shipowners and operators.
The results demonstrate that there is no on-size-fits-all WPS solution; instead, each optimal configuration requires a use-case-specific evaluation, accounting for factors such as ship type, route, wind conditions, emissions reduction targets, and operational constraints. However, general trends emerge. Higher emissions reduction ambitions – requiring larger WPS installations — favor high lift-to-drag ratio and lightweight technologies for costeffectiveness. In contrast, low lift-to-drag ratio systems are more sensitive to deck placement and wind conditions due to the resulting hydrodynamic penalties to counteract aerodynamic
forces, though these effects become less significant for lower emissions reduction targets. Installation viability is further constrained by factors such as maximum air draft and cargo space loss due to weight penalties, which may significantly impact economic feasibility.
Optimization of WPS installation design is found to be critical for maximizing economic returns and ensuring fair comparisons across different WPS classes, as each class has unique performance characteristics. The most cost-effective configurations generally involve max imizing unit spacing to reduce aerodynamic interactions and placing units near the hydrodynamic center of lateral resistance to minimize added resistance penalties. Suboptimal designs can extend payback periods by over 150% compared to optimized configurations. Additionally, while WPS-equipped vessels require higher upfront investment, they demonstrate rapid payback periods and strong profitability, particularly in favorable operational and economic conditions.
A critical threshold of limited return on investment is identified for retrofit installations, occurring when additional WPS units no longer yield increased fuel and emissions savings. This is due to hydrodynamic penalties required to maintain yaw moment balance, ultimately offsetting the WPS benefits. This also underscores the need for an optimized deployment strategy to maximize savings while minimizing investment costs, preventing unprofitable installations that could foster skepticism and hinder adoption.
The methods and findings presented in this PhD Thesis provide a foundation for unlocking the full potential of wind propulsion systems, supporting a more sustainable, cost-effective, and decarbonized shipping industry.