The ongoing reliance on fossil fuels for transportation poses critical challenges, particularly as global greenhouse gas emissions near irreversible thresholds. While electrification and hydrogen-based technologies offer solutions for some transport sectors, they remain impractical for aviation and maritime applications. Drop-in biofuels, derived from lignocellulosic biomass via thermochemical processes such as pyrolysis, present a viable alternative. Pyrolysis, particularly fast pyrolysis, can efficiently convert biomass into bio-oil, which can then be upgraded to biofuels through hydrotreatment. However, significant challenges remain, including scalability, process optimization, and feedstock variability.
This thesis presents a conceptual process model in Aspen Plus to simulate the thermal decomposition of lignocellulosic biomass into bio-oil and its subsequent upgrading into usable biofuels. The model combines pyrolysis kinetics with hydrodeoxygenation reactions to predict bio-oil and biofuel yields for various feedstocks. Simplifications, including species lumping, were necessary to ensure model feasibility but limited its accuracy and broader applicability.
The results show that the model performs best at pyrolysis reactor temperatures of 550–650 °C and vapor residence times of 2–3 seconds. Hydrodeoxygenation predictions align with literature in terms of hydrogen requirements and overall fuel yield, though limitations in distillation modelling result in a lack of detailed analysis for the fuel fractions. A comparative analysis of softwood and hardwood feedstocks reveals that woods with higher cellulose content yield greater bio-oil and biofuel quantities. However, this comparison overlooks the influence of other factors, such as specific lignin composition and structural differences, which also affect pyrolysis behaviour in real-life applications.
While the model provides insights into pyrolysis and upgrading processes, it demonstrates the need for further refinement to account for complex reaction mechanisms and real-world variability.

As the global aviation industry strives toward net-zero carbon emissions by 2050, sustainable aviation fuels (SAFs) derived from biobased feedstocks have emerged as a crucial pathway to decarbonization. While much of the existing research on SAFs has focused on environmental and technological aspects, limited attention has been paid to their broader sustainability dimensions, such as socioeconomic and human health impacts and supply-demand dynamics. This thesis addresses these gaps by providing an integrated assessment of the sustainability performance of biobased SAF production and supply chains, combining quantitative modelling with a holistic systems perspective.
The research first establishes that biobased SAF constitutes an emerging, complex sector that interacts with multiple industries and societal stakeholders. Given its developmental stage, assessing its full sustainability performance early on is vital for guiding policy and investment decisions. The thesis develops and applies methodological approaches to quantitatively evaluate underexplored sustainability dimensions, focusing on socioeconomic effects, life cycle human health impacts, and the balance between SAF supply and demand under future decarbonization scenarios.
The socioeconomic assessment employs a scenario-based Input-Output (IO) analysis, using Brazil’s projected SAF demand toward 2050 as a case study. The analysis demonstrates that biobased SAF production can generate substantial positive socioeconomic benefits, including net gains in employment and GDP. However, these benefits vary by feedstock type and conversion technology, highlighting the need for region-specific policies to optimize socioeconomic outcomes. Modest negative impacts on trade balance and fossil-sector employment are identified, for which proactive mitigation measures—such as retraining programs and labor reallocation—are recommended to ensure a just transition.
To complement the socioeconomic analysis, the thesis explores human health impacts through a comparative evaluation of six life cycle impact assessment (LCIA) methods. The results reveal that biomass conversion processes are the primary contributors to health-related impacts due to chemical use, energy consumption, and waste generation, followed by feedstock cultivation involving fertilizers and pesticides. The study concludes that no single LCIA method can universally capture human health effects in SAF systems; rather, the methodological choice should be context-specific, guided by study scope and regional conditions.
Further, a supply-demand analysis examines the potential of biobased SAF to meet the aviation sector’s decarbonization targets by 2050. Using European data and multiple scenarios, the findings suggest that sufficient SAF supply is only attainable if feedstock availability exceeds 60% of theoretical potential—an unlikely scenario given competition from other bio-based industries. The results underscore the regional variability in biomass distribution and the importance of aligning national and continental strategies.
Overall, the thesis concludes that biobased SAF holds significant promise in reducing greenhouse gas emissions—up to 75% compared to fossil jet fuel—while promoting socioeconomic development. However, its sustainability performance is highly context-dependent, influenced by technology choice, feedstock type, and policy design. The work advances an operational framework for integrated sustainability assessment that identifies trade-offs and synergies, supporting informed decision-making for SAF deployment. Beyond aviation, the methodological insights contribute to broader discussions on designing fair, effective, and context-sensitive transitions toward a sustainable bioeconomy.

Biobased value chains (BBVCs) are increasingly seen as a promising pathway for fossil-free transition. For hard-to-abate sectors, such as maritime industry, drop-in biofuels are considered as short- to mid- term solution for achieving the climate targets by 2030 and 2050. However, after decades of research and development, biobased value chains still faces numerous challenges for real-world implementation. These challenges are diverse and complex in nature such as technical, economic, environmental, and social. These barriers are to be addressed, to enable large-scale commercial deployment of bio-based value chains which is needed for bulk sectors such as maritime biofuels. This dissertation approaches the problem in a holistic manner and aims to develop context-specific, inclusive, and sustainable design of bio-based value chains for marine biofuels through hydrothermal liquefaction (HTL) technology. A transdisciplinary approach (including process simulation, participatory methods for stakeholder engagements, and integral sustainability analysis) is implemented to integrate the technical and non-technical aspects of the value chain in the early stages of conceptual design. The investigation focuses on the underutilized or mismanaged lignocellulosic residues from the olive sector in Spain, Coffee sector in Colombia, and the encroacher bush sector in Namibia with a special consideration on local socio-economic development at or near the region of biomass production. As a result, various biohub models were co-designed using multi-actor approach tailored to local context of BBVC implementation. The techno-economic assessments indicated that the economic performance of the HTL biofuels are expensive than their fossil counter parts, however with a potential to compete when existing infrastructures are utilized. In terms of environmental performance, the HTL biofuels were able to reduce emissions, specifically carbon-di-oxide, by at least 89% adhering to the policy regulations. This dissertation concludes that early stage integration of (technical and non-technical) contextual knowledge in the conceptual design has the ability to identify, address, and overcome the existing challenges for implementing bio-based value chains in more responsible manner thereby leading to a global, sustainable, and inclusive fossil-free future.

This doctoral thesis investigates the concept of responsibility in the setting of industrial research and innovation (R&I). Companies have multiple responsibilities in society: profit generation for shareowners, legal and contractual liabilities, as well as socially and morally binding obligations beyond legal compliance. These responsibilities coexist in R&I, and at times, stand in conflict with each other. Moreover, the radical uncertainty of innovation activity raises dilemmas with regard to responsibility. For instance, can R&I practitioners be held responsible for those future impacts of their innovation that still remain unknown at the time of R&I? Furthermore, how should such responsibility be distributed between developers (R&I), enablers (funders, regulators) and appliers (users) of the innovation? To address such questions, the broad notion of responsibility first needs to be opened up, to distinguish between its different meanings and elements. This thesis develops a framework that supports identification and coordination of various responsibilities in the inherently uncertain R&I settings. The main research question of the thesis is: How do different elements of responsibility become identified and carried out in R&I? As outcome, this thesis will present a meta-responsibility map: A tool for industrial R&I teams and consortia to reflect on their responsibilities, in situations such as goalsetting, problem-solving, decision-making, and stakeholder interaction.

The current regulatory regime regarding GMOs within the Netherlands and Europe does ensure safety but struggles in balancing this notion with innovation. In particular, the way the Precautionary Principle (PP) is operationalized in GMO legislation has resulted in a highly precautionary culture in which there is little room to conduct research with associated uncertain risks or uncertainties – it has resulted in a culture of compliance. Although the debate on how ‘new’ genetic engineering techniques such as CRISPR should be assessed in comparison to recently exempted techniques is ongoing within the European Union (EU), this might not have any consequences for GMO regulation at all. These issues do not only stifle innovation but also illustrate that the current regime is not resilient in dealing with emerging techniques. To break free from the impasse between safety and innovation, researchers should be able to learn what uncertain risks entail, for instance, through Safe-by-Design (SbD).
The main question addressed in this thesis is: “How to create an environment that is suitable to learn safely and responsibly what uncertain risks associated with emerging biotechnologies entail?”. I conclude that to enable responsible learning by means of SbD, 3 conditions are needed; regulatory flexibility, co-responsibility and awareness. Thereby, SbD could be a suitable approach to arrive at responsible learning, given that the 3 conditions are met. If not, SbD provides guidelines to lower or mitigate known risks but fails to provide a step-by-step approach to gradually learn what uncertain risks entail. This will leave a knowledge gap between known and uncertain risks which stifles innovation and hinders risk management in ensuring future safety for people, animals and the environment.

To continue the success of the Port of Rotterdam (PoR) in the future, a transition to a sustainable industry is essential. Though this is easier said than done. The energy transition involves a variety of initiatives which are at the same time highly dependent on each other. Whilst the increasing scarcity of available area and resources result into the situation that a decision will have to be made. As long as this decision is not made, it leads to high uncertainty on which activities are going to take place in the PoR and at which point in time they are expected.

To support the decision making on which activities to should focus on, there is an urgent need for a decision tool at the PoR authority.

The main conclusion, however, is that it is impossible to develop a decision tool which is able to make a choice among different activities. This decision is impossible because every activity has its own demands and requirements and differs in the contribution it has to the strategic goals. Besides this, the set requirements cannot be expressed in a single unit, leading to the situation that a comparison cannot be judged.

Following from the above, it is being discouraged to develop a decision tool. The allocation process and the involved requirements are too versatile to be simplified in a single tool. If such a simplification is made, this will result in missing essential opportunities and potential bottlenecks in the sequential project phases.

Based on the above conclusions, it is investigated whether it is possible to provide the PoR authority with guidelines that support the comparison of different activities. To do so, the involved requirements in the allocation process are substantiated. These requirements are evaluated from three different points of view: demand side (client), resources side (Port of Rotterdam authority) and their priority in the decision making. By means of the evaluation, the aspects have been identified that must be implemented into the guidelines.

In addition to the requirements, it is important for the PoR authority to incorporate its communicated strategy into the daily activities. To do so, the commercial strategy has been developed. At first sight, the integration of the commercial strategy is not acknowledged to be a requirement in the allocation process. Though, as the research proceeded, it turned out that the commercial strategy has a more important role in the decision making than anticipated. Resulting in the situation that if the PoR authority is really looking to fulfil its climate targets, the commercial strategy should function as a self-contained requirement in the allocation process.

From the conclusions, the recommendation for the PoR authority is to develop a central team that involves the experts of the relevant requirements to judge the potential activities. This team will have the primary task to evaluate and judge the potential activities prior to entering the project phases. The judgement of the potential activities will be founded on four main themes for evaluation: demand, supply, priority and contribution to the commercial strategy.

Though, this recommendation is not aimed at making the decision itself. The main focus is to supply the evaluations on the potential activities to the decision makers. The decision itself will be based on the supplied evaluations through which a decision can be made on which activities should be allocated in the PoR.

The biobased economy is regarded as a possible solution for
addressing the challenges associated with climate change and
the growing human population. Due to progress in science
and technology the biobased economy can provide additional
food and renewable energy to meet the needs of the expected
9 billion people by 2050.
However, the implementation of the biobased economy also
raises many questions about the transition paths, including the
political and regulatory climate for new technologies that are
necessary to accomplish this transition. Policy decisions and
new regulations require input from the scientific community.
While most policy stakeholders agree that we need new technologies
that can reduce or eliminate greenhouse gas emissions,
we witness controversy about the best solutions to realize
sustainable production. Scientists have the potential to play an
important role in policy debates and processes, but presently
their involvement is not adequate.
This thesis explores how scientists perceive their role in policymaking
and which factors are relevant for their motivation for
policy engagement. Using the empirical data from the research
with agricultural biotechnology scientists this thesis identifies and
describes a new role for scientists in controversial policy-making
and provides recommendations for institutional strategies that
are needed to facilitate that scientists adopt this role in practice.