The aviation sector must reduce greenhouse gas emissions. The European Commission introduced the Fit for 55 package and ReFuelEU Aviation regulation to reduce the emissions. Part of ReFuelEU is the obligatory use of sustainable aviation fuels, including synthetic variants (eSAF). eSAF can reduce greenhouse gas emissions by around 90% compared to traditional kerosene. Power2X and Advario have decided to partner up and build the first large-scale eSAF production facility in Rotterdam by 2030, producing 250,000 tons of eSAF annually. This accounts for 40% of the needed European supply based on ReFuelEU aviation blending obligations. Currently, the feasibility of these large-scale production facilities remains uncertain due to high production costs, immaturity of hydrogen and eSAF production technologies, and unclear regional (national) policy support that does not align with international policies. Existing research emphasizes the need for a systemic change apart from..

Heavy-duty road transport needs to make a transition to become climate neutral in 2050. Not considering the negative impact on the environment, road transport remains a competitive way of transportation in the hinterland of maritime ports. Policymakers and strategists of the Port Authority have a lack of knowledge to decarbonize heavy-duty transportation in the hinterland, without deteriorating the competitive position of a maritime port as a transit node. Various studies are made about the transition in the heavy-duty road transport segment. However, a social cost-benefit analysis that assesses social-economic welfare effects of energy carriers to decarbonize heavy-duty road transport in the hinterland of maritime ports remains unaddressed in the literature. This resulted in the following main research question: What is the socio-economic feasibility of strategies for decarbonization of heavy-duty road freight transport in the hinterland of maritime ports towards 2050? In the literature review promising energy carriers and technologies to decarbonize heavy-duty freight were: battery electric vehicles that drive on renewable electricity, a catenary electric road system that supplies more direct electricity, fuel cell electric vehicles that drive on green hydrogen and conventional trucks that use e-diesel. Considering the availability and the total cost of ownership of these energy carriers and technologies, strategies are developed in which the usage is mandated or stimulated by subsidies. The strategies are compared with the continuation of diesel (the zero-alternative) in a social cost-benefit analysis. The costs and the benefits included are the direct, indirect effects and the societal costs from a tank-to-wheel scope and external effects from a well-to-wheel scope in order to ensure that the emissions do not shift to another part of the chain. The results show that at the current CO2-valuation, all proposed strategies are not welfare enhancing and have severe losses of tax on fossil fuels. However, at an increased CO2-valuation of 500 euro per ton emitted CO2, the strategy in which battery electric vehicles are stimulated by subsidy would be feasible from socio-economic perspective. The social cost-benefit analysis provides insights for infrastructure investments in port areas.

Energy storage systems can play a vital role in the implementation of a sustainable energy grid by allowing the wide scale implementation of fluctuating renewable energy sources like wind and solar. Therefore it is expected that in the coming years, the total amount of energy storage systems will drastically increase. Analysing the sustainability
of these storage systems before widespread implementation is therefore of great importance. In this thesis such a life cycle assessment has been conducted to assess the environmental sustainability of one type of energy storage system: the Organic Redox Flow Battery produced by the Baliht research group.

As of 2016, governments globally adopted the task to achieve social, economic and environmental sustainability by committing to the targets from the UN Sustainable Development Goals (SDGs). The SDGs incorporate a set of 17 goals and 169 targets accompanied with more than 200 indicators that can guide towards achieving sustainable development by 2030. Sustainable development and human wellbeing fundamentally rest on the capacity of the biosphere to sustain us. In other words, the economy or society related SDGs can only be reached if the biosphere related SDGs, in which they are embedded, are respected. To ensure the achievement of all SDGs, the environmental impact as a result of human activity needs to be reduced to safe levels. Doing so requires quantification of both impacts and safe operating spaces in the environmental domain. However, from the SDG framework it does not become clear what safe operating spaces are because for many of the environmental issues addressed, quantitative targets based on ecological boundaries are lacking. Life-Cycle Assessment (LCA) is a method that enables holistic analysis of the environmental impact of product-systems by analyzing the impacts over the complete life cycle. Yet, as a comparative method it can only identify the most sustainable product system relative other alternative product-systems. In contrast, there have been developments to develop Absolute Life Cycle Assessment (ALCA), in which the environmental impact of a product-system is compared against a benchmark based on the earth’s ecological carrying capacity, in order to define if the system is absolutely sustainable. Such a benchmark is obtained by allocating a share of the environmental carrying capacity to the product system, using a specific allocation principle. The most recognized expression of environmental carrying capacity has been provided by the planetary boundary (PB) framework, offering a set of quantitative biophysical limits for nine critical earth system processes (ESP). The functioning of these ESPs is critical to keep the earth in its stable Holocene state, which is required for anthropogenic prosperity. Using the LCA method to quantify impacts, and the PB framework to provide quantitative ecological boundaries, ALCA could be useful to identify absolutely sustainable product-systems and support contributions from product-systems towards environmental SDG targets. Yet, an overview showing the availability of different ALCA methods and their applicability at the product level is lacking. Therefore, this master thesis provides a systematic literature review of ALCA methods and applications, that use the planetary boundary (PB) framework as an implementation of carrying capacity. The main research question is formulated as: To what extent is absolute life cycle assessment possible and does it enable a comparison of environmental impact against product-level benchmarks based on the PB-framework, to support the identification of absolute sustainable products contributing to the UN SDGs? With a database search on Web of Science (WoS) and a snowballing approach, possibly relevant publications were identified. Afterwards, 14 key publications were selected that entail either an ALCA method or application. The review was conducted with criteria primarily based on an absolute environmental sustainability assessment (AESA) framework identified from literature. The criteria cover aspects related to LCA, the PB framework and allocation approaches needed to obtain benchmarks at the product-level. The results showed that there are 5 dominant methods, and 9 applications of these methods. Only one of these methods includes a direct comparison of impact against a benchmark specifically allocated to the assessed product-system. Therefore, we concluded that only one method can truly be considered as an ALCA method that is also potentially usable in the context of SDGs. However, even claims of absolute sustainability that are made using this method are not fully conceptually consistent because a comparison is made between an annual benchmark (derived from the PB framework) and LCA impacts that are in reality exerted over many years. Other methods were considered usable for different purposes. Some methods only facilitate a comparison of impact against a per-capita benchmark, representing the occupation of an individual’s environmental budget by the product-system. These methods are rather usable for identifying sustainable consumption patterns. Some methods only enable the determination of impact reduction targets against which future impact reductions might be compared. Others do not involve any form of absolute sustainability comparison and are rather usable in conventional comparative LCA. We provided a terminology proposition for PB related concepts because there seemed to be inconsistencies across publications regarding the use of PB-related concepts and their terminology. Also, there were inconsistencies in the terminology for different allocation principles. We stated that all allocation principles could be classified in three main categories. Yet, further research is recommended to find common ground on the choice for specific allocation principles to obtain benchmarks for product-systems. Also, we recommend further research to focus on getting insights in linkages between LCA impact categories, PB’s and SDGs and combining these insights with the knowledge on ALCA methods that has been provided in this thesis. Such a combination would be the next step to find the potential of ALCA methods for supporting contributions from product-systems towards environmental SDG(-target)s.

Low-grade heat sources are abundant on earth but are majorly untapped due to lower thermodynamic efficiency at low temperatures and cost considerations. A cost-effective technology is needed to convert this energy resource into useful forms of energy. This work aims at optimizing Organic Rankine Cycle (ORC) based heat engine and a cogeneration system developed to produce electricity and refrigeration from a heat source below 100℃, from both thermodynamic and economic point of view. Exergoeconomics, an algebraic thermoeconomic method, was used to analyze and optimize the systems for cost-effectiveness and exergetic efficiency. Also, the prototype of the cogeneration system was experimentally tested. The results exergoeconomic optimization show that the cost-effectiveness of the cogeneration system can be significantly improved by design parameter changes. The experimental results obtained were comparable with the results obtained from theoretical simulations.