To achieve climate neutrality, the Netherlands is phasing out fossil fuels and expanding renewable energy, with offshore wind playing a key role. The European Commission aims to increase offshore renewable energy capacity to 300 GW by 2050. As wind farms are built further offshore, high-voltage direct current (HVDC) technology is becoming essential for efficient grid connection. TenneT's 2GW program supports this transition by standardizing offshore platforms, enabling faster deployment and scaling of offshore wind energy to meet climate targets efficiently.

A critical component of these platforms is gas-insulated switchgear (GIS), which ensures safe and reliable operation by controlling the connection of wind turbines to the grid. Traditionally, GIS relies on sulfur hexafluoride (SF₆), a potent greenhouse gas with a global warming potential (GWP) of 24,300. In response to environmental concerns, Regulation (EU) 2024/573 mandates a phase-out of SF₆ in switchgear up to and including 145 kV by 2028, necessitating the transition to alternative technologies.

This study evaluates SF₆-free alternatives for high-voltage GIS in offshore converter stations, considering environmental impact, economic feasibility, long-term reliability, safety, technical performance, and regulatory compliance. A multi-criteria decision analysis (MCDA) is conducted, assessing 42 alternative gases and insulation technologies based on GWP, ozone depletion potential, flammability, toxicity, boiling point, and dielectric strength. Two viable alternatives emerge: a gas mixture of C₄F₇N, CO₂, and O₂ (GWP 301–614) and vacuum GIS insulated with clean air (GWP 0).

To determine the feasibility of both technologies for next-generation converter stations, expert interviews are conducted to identify key challenges and drivers. Challenges include its current voltage limit of 145 kV, larger space requirements, and limited supplier availability. A major driver is the transition from 66 kV to 132 kV inter-array cables, reducing the number of required switchgear installations from 40 to 24. This mitigates space constraints and makes vacuum GIS a viable long-term solution. Additionally, ongoing developments in vacuum switchgear technology reduce dependency on a single manufacturer.

A comparative life-cycle assessment (LCA) of SF₆, C₄F₇N, and vacuum GIS focuses on manufacturing and use phase emissions, as these contribute most to greenhouse gas emissions and exhibit the most significant differences among technologies. Results show that C₄F₇N technology has the lowest total emissions in these phases, as vacuum GIS production requires more aluminum, leading to higher manufacturing emissions. While sustainable aluminum sourcing could mitigate this, no regulatory or economic incentives currently exist.

This study concludes that vacuum GIS is the most viable alternative to SF₆ for offshore converter stations, aligning with future platform developments and regulatory compliance. TenneT is advised to prepare for a transition to vacuum GIS, supported by 132 kV inter-array cables, enabling a more sustainable and scalable offshore grid. Future research should focus on a comprehensive life-cycle assessment to fully evaluate the long-term environmental impact of alternative technologies.
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Industrial CO2 emissions account for approximately one-third of global emissions, primarily driven by heat demand. While heat pumps are key to decarbonizing this demand, their deployment is hindered by challenges in identifying techno-economically feasible solutions in a rapidly evolving environment. This dissertation develops a comprehensive method to foster industrial heat pump deployment in the process industry by addressing two critical challenges: 1. how process modifications from CO2-mitigation measures affect heat pump performance, and 2. how heat pump cycle configurations and varying electricity prices impact their economic viability.
Using pinch-based methods, the research developed appropriate heat pump placement strategies for transitioning processes. Exergy-based analysis identifies cost optimal configurations, while super-structure optimization determines effective combinations of heat pumps with other power-to-heat and storage technologies. The methods are illustrated through case studies in chemical and paper processing plants, providing practice-based context.
The resulting method enables industries to apply robust heat pump deployment strategies that remain viable under different energy price scenarios and future plant layouts, thereby contributing to industrial decarbonization.
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The research is conducted with the case of Shell Netherlands Refinery (SNR), which has already implemented certain NOx reduction measures such as steam injection in gas turbines and Low NOx Burners in furnaces. The decisions to implement these technologies were primarily based on the level of NOx emissions and financial considerations. This thesis aims to support decision-makers by providing a comprehensive comparison of multiple NOx abatement systems based on multiple criteria.
SNR has various emission sources for NOx, such as burners in furnaces with the emission point being the stack. Each emission point and NOx source within SNR has its own technical limitations and possibilities, which have been carefully assessed to determine the appropriate NOx abatement systems for each emission point.
The Multi-Criteria Decision Analysis (MCDA) approach was employed to answer the above research question. MCDA is a structured approach that evaluates and compares different options or alternatives based on a set of criteria. It enables decision-makers to make informed and objective decisions by considering multiple criteria and weighting their relative importance.
The study concludes that combustion-based systems, specifically ULNB for furnace burners and (U)DLN burners for gas turbines, are more advantageous than end-of-pipe systems for NOx reduction in SNR. However, in cases where combustion-based technologies are not technically feasible, the integration of end-of-pipe systems is necessary. In such scenarios, the ClO2 wet scrubber is recommended due to its high final utility score. SCR, SNCR, and LOTOX technologies are generally not advised due to their lower final utility scores but SCR or LOTOX could be viable when high NOx emission reductions are required (>90%).
According to outcomes of MAUT, the ULNB was identified as a particularly effective NOx abatement technology, showcasing a consistently high final utility score at numerous emission points, specifically O, P, Q, N, L, I, J, E, M, F, D, B, and H. in contrast, at emission points R, A, E, G, K, S, and W, the most efficient solution was found to be the ClO2-based wet scrubber system, which achieved the highest final utility score. For the final emission points, namely T, U, and V, the (U)DLN burners scored the highest final utility score, thereby earning the recommendation as the preferred NOx abatement technology for these emission points.
However, this study had its limitations. The cost analysis conducted was somewhat superficial. A more in-depth exploration of the CAPEX and OPEX, coupled with the use of complexity factors per emission point, could refine the MCDA outcomes. It is recommended that future studies integrate Cost-Benefit Analysis (CBA) into the MCDA for a more rigorous examination.
Another constraint was the limited scope and quality of data used. It is recommended that subsequent research take a more rigorous approach to data collection, including engaging factories that have already implemented NOx abatement systems. Such an approach could yield a more comprehensive dataset, enhancing the reliability of MCDA outcomes. ... Read more

Power-to-methanol (PtM) technologies have a potential to store excess renewable energy in methanol molecules. However, there is a lack of understanding about the role of these technologies in the course of energy transition. In this research, the influence of PtM technologies on power grid’s reliability and CO2 reduction are studied. An agent-based model is developed in order to explore possible future scenarios created by deployment of PtM technologies, in case green methanol is primarily supplied to the shipping sector as an alternative low-carbon fuel. The model outcomes are explored using two sets of experiments representing two hypothetical cases: "flexible grid" experiments in which the power grid is assumed to have several flexibility options, and "low flexibility" grid that the grid cannot easily adapt to high levels of renewable power production. The results show that deployment of PtM technologies can help with absorbing excess renewable energy and improving the reliability of the power grid. However, PtM alone is not sufficient to keep the grid reliable. PtM is shown to be successful in enabling high levels of CO2 reduction. The results obtained in this research can be used as the starting point to open up a discussion between system operator and policy makers in order to define a proper support plan for PtM or other Power-to-X (PtX) options. ... Read more

As the energy transition evolves, more fossil-driven base-load generation is being replaced with intermittent renewable energy sources. Peak power plants will continue to play a crucial role in future renewable energy systems to complement renewable energy supply. The focus of this thesis is on alternative fuels that can be utilized in conventional gas turbines. Several alternatives fuels exist, such as hydrogen, methanol and bio-fuels, and each alternative fuel has different technical, economic, social and environmental implications for the energy system and the society as a whole. Decision makers across the energy sector face difficult trade-offs between quantitative and qualitative criteria when selecting and alternative technology to invest in. This paper applies the analytical hierarchy process (AHP) to select an alternative fuel for a peak power plant in Rotterdam. The fuels analysed are methanol and hydrogen, and are ranked according to nine sub-criteria. Two contributions are proposed to improve the AHP method. Firstly, incorporating a technology readiness level indicator to quantify the technological maturity. Secondly, multiple perspectives are incorporated from key stakeholders in the criteria weighting. A sensitivity analysis is then performed on the most relevant criteria. ... Read more

With the growing population and urbanization of the living environment, challenges have come up for cities to bring down their emissions and become more smart. Smart city development can respond to these challenges. ... Read more