This thesis addresses the urgent need for more effective environmental sustainability assessments that can be integrated into the early stages of product design. Designers play a critical role in the environmental impact of their products, yet they often struggle to integrate environmental assessments into the early stages of design. Traditional linear production models cause environmental challenges such as resource depletion and pollution, while the Circular Economy offers a more sustainable alternative by aiming to reduce waste and close resource loops. However, simply applying CE principles does not guarantee sustainability, as unintended effects such as "CE rebound" can occur. This highlights the need for advanced tools that can accurately assess the environmental impact of circular designs early in the design process.

The primary objective of this study was to establish the requirements for an early-stage quantitative assessment tool that integrates Life Cycle Assessment (LCA) into circular design processes. The research aimed to determine how LCA can be effectively incorporated into early decision-making stages, identify suitable methods for evaluating circular design strategies, assess the usability of existing LCA tools, and address the challenges designers encounter when implementing environmental sustainability assessments.
The research was conducted in three phases. The first phase involved a detailed examination of designers' decision-making workflows. In the second phase, existing sustainability assessment methods and LCA tools were evaluated. The third phase focused on developing a program of requirements for a new assessment tool. Methodologies included comprehensive literature reviews, analysis of grey literature, interviews with experts in environmentally sustainable design, and usability testing of existing tools.

Key findings revealed a mismatch between the complexity of current LCA tools and the practical needs of designers in the early stages of design. Most tools are either too complex or too simple, making them unsuitable for the iterative and creative nature of early design processes. Designers often rely on intuitive approaches that are not adequately supported by traditional, data-intensive LCA tools. To address this gap, the study proposed a dual-interface tool: one interface for designers to facilitate easy integration into creative workflows, and another for sustainability experts to manage detailed modeling and scenario analysis. The tool emphasizes ex-ante LCA for predictive analysis, allowing for early-stage assessment and scenario modeling using estimated data. Additionally, integrating qualitative assessments alongside quantitative data will provide a more comprehensive evaluation of circular design strategies. This holistic approach aims to align LCA tools with designers' practical needs, enhancing the integration of environmental sustainability into early-stage product design.

The research concludes with recommendations for developing user-friendly LCA tools, improving the assessment of circular design strategies, and fostering collaboration between academia, industry, and tool developers. These advancements aim to improve the integration of environmental sustainability into early-stage product design.

40% of the global population live in coastal cities. This figure is predicted to increase as
inland populations migrate to coastal areas. This is due to land availability steadily
decreasing due to several factors such as drought and increasing requisite cropland
stemming from growing populations and the growth of the biofuels market. Simultaneously,
sea level rise (SLR) means that further strain will be put on land availability in coastal areas.
It is important to have solutions prepared for this event. One such potential solution is the
use of Modular Floating Structures (MFS) as dynamic platforms for floating urbanisations. An
MFS consists of a floating substructure on top of which a superstructure (buildings) can be
built. While MFS technology is not currently used anywhere in the world the technical
feasibility and use case potential of MFS has been demonstrated in previous research.
However the environmental impacts of MFS technology had previously not been
investigated. A prospective life cycle assessment (LCA) of potential MFS substructure
designs was devised in order to quantify and compare the potential environmental impacts
and to find potential for optimisation of the environmental performance of the substructures.
A case study of Taranto, Italy, a city which has the potential for using MFS technology was
taken for this research. In the baseline case it was assumed that the substructures would
have to travel 1898 km across the sea throughout their lifetime. All cradle-to-grave life cycle
inputs were included, excepting cut-offs. Only two main materials were considered suitable
for use in substructure construction: steel and reinforced-concrete. However four designs
were deployed. Virgin steel (VS), recycled steel (RS), 35 MPa Portland concrete (35 PC)
and 50 MPa Portland concrete (50 PC). The concrete designs did not have equivalent
buoyancy to the steel designs given the default geometric dimensions so these dimensions
were altered considering several factors (bending moment, stress, second moments of area,
draft).
A holistic approach was taken and all impact categories were considered, however particular
attention was given to the impact categories of climate change and marine ecotoxicity. For
all designs the raw materials used and the transport across the ocean held the greatest
share of the impacts. In the concrete designs a surprising finding was that the stainless steel
rebars used in their design held a larger share of the impacts across the board. The 50 PC
design performed by far the best overall however due to issues with working with concrete of
higher strengths it is unclear if the 50 MPa Portland concrete can be easily applied to MFS
substructure construction in the present day. In terms of present-day usability and
environmental performance the two forerunning designs were the RS design and the 35 PC
design. Trade-offs were found between design choices. The RS design had significantly
lower CO₂-Eq emissions with 7,292 t compared to the 35 MPa concrete design, which had
9,770 t CO₂-Eq. However, the 35 MPa design had much lower marine ecotoxicity with 984 t
DCB-Eq, than the RS design 4,256 t DCB-Eq. This higher marine ecotoxicity for the RS
design was largely (63%) due to the local environmental impact of sacrificial zinc anodes
corroding into the sea. These are used as cathodic protection for the steel. Altering the
cathodic protection is a possibility for reducing the marine ecotoxicity impacts of the steel
designs.
Normalisation and even weighting were applied to compare the overall impacts of the
designs. When total oceanic transport distance of the substructures is 482 km, in terms of
overall environmental impacts the 35 PC design outperforms the RS design by 22%. At 1898
km this decreases to 3%. At longer distances the RS design performs better due to its lighter
mass and subsequent lower impacts from oceanic transport. At 2467 km the RS design
outperforms the 35 PC design by 2%.
In the context of the EU, the legislation surrounding deconstruction of end of life (EoL) ships
and offshore installations is a key factor to consider. For offshore instalments which are to be
recycled, the deconstruction can only take place in a limited number of shipbreaking yards.
This directly affects the distance which the substructures must travel across the sea. And
this is a main influencing factor which can lead to MFS substructure optimisation, in terms of
environmental impacts.
Finally, environmental impacts are not the only considerations important to design choice.
Other factors should be considered, namely the material availability in a given region and the
disparity in recyclability between steel and concrete. Further research can develop these
findings and investigate other highlighted potential concrete reinforcement material options
such as epoxy coated steel and plastic fibre reinforcements. Furthermore, this research can
be used as a building block for comparing the environmental impacts of MFS technology to
coastal urban expansion alternatives such as land reclamation.

This project is focused on the development of circular and sustainable playground equipment (PE), as the Netherlands and its municipalities have set targets to become a Circular Economy in 2050. Furthermore, the PE should also encourage children to play outside more and engage in physical exercise. The reason for this being that children in the Netherlands do not play outside enough, which is often due to uninteresting playground designs.

The project started off with a theoretical framework, in which the 10R design strategies, such as reuse, repair and recycling, for the CE were examined on their effectiveness in playground design. Both academic literature and stakeholder & expert interviews enriched the knowledge needed to answer the research question. This resulted in the following design considerations which were the basis for developing the PE as described in this thesis:

Create an interchangeable and customizable system with components that are easy to (dis-)assemble (product-service system with modular play modules)

Design with a mono-material

Design with a material which comes from a waste stream

Design with a material which allows for form freedom

Design with a material which is resistant to wear and tear and external conditions (cold, heat, moist, UV radiation, etc.)

Eliminate redundant elements

Design PE modules which can fulfil multiple play functions

Design a connection system which allows for easy (dis-)assembly and consists of a minimal number of parts and different materials

Design for effective and minimal repairs and maintenance

Design with materials which can efficiently be recycled

I performed a study on an appropriate material and production method for the PE and from this I concluded on the use of 3D-printed Geopolymer with recycled aggregates, as it comes from a large Dutch waste stream, can be produced and efficiently recycled in the Netherlands, has a lifespan of several decades, allows for form freedom and colouring, and facilitates straightforward repairs and maintenance, making it an appropriate material for the Dutch CE. I was able to visit a 3D printing facility to get in contact with the material and production process, and even prototype my product here with 3D printing.

Based on conclusions derived from academic literature and a design session with 131 children aged 6-11, I concluded that the play functions climbing and swinging & swaying, among several others, could encourage children the most to play outside more and engage in more physical activity. These functions are translated into the following themes: Treetop Retreat, Rapid Rush, Acrobatic Adventure and Hideaway Hunt, which are the focus of the designed PE.

Addressing climate adaptation is one of Rotterdam’s critical challenges as it seeks to achieve a fully circular economy by 2050. However, language barriers and limited literacy levels, particularly in neighbourhoods like Carnisse, prevent many residents from engaging in the city’s climate initiatives. This thesis explores the potential of Augmented Reality (AR) as an innovative tool to bridge these communication gaps, making complex Circular Economy (CE) principles more accessible by increasing engagement, comprehension and making the experiences more memorable for residents with lower levels of literacy.

Using the Delft Innovation Method (DIM), this design research iteratively develops and tests two AR prototypes to assess AR’s effectiveness in increasing comprehension, engagement, and retention among residents of Carnisse. Apart from the DIM, a mixed-method approach was utilised, including literature reviews, stakeholder interviews and observations. The first prototype translates a municipal website that explains CE-principles into an AR experience, and thus aims to establish whether the technology is suitable for use in Carnisse. The second prototype, The Digital Sustainability Tour, leverages learned lessons from the previous prototype to improve, and expands the scope and generalises the findings to another neighbourhood with a similar profile.

Results from A/B testing and community feedback suggest that AR has the potential to enhance user engagement and understanding compared to traditional text-based methods. Based on these findings, this thesis proposes three strategies that align with municipal goals and capabilities, in which AR can be leveraged effectively to: Improve Communication via Inform & Remember, Increase Participation via Analyse & Apply and lastly enhance self-efficacy via Evaluate & Co-Create. These strategies aim to foster a more inclusive dialogue and empower inhabitant to participate in sustainability efforts.

Plastics have become indispensable in modern life due to their versatility and affordability. However, their widespread use has resulted in far-reaching environmental damage, including the accumulation of plastic waste, fossil fuel depletion, and significant greenhouse gas emissions. Bio-based plastics have been proposed as a sustainable, circular solution to the environmental issues associated with plastics. However, bio-based plastics are not implicitly sustainable or circular. These aspects are influenced by how a plastic is produced and how it is recovered at end-of-life, implying that careful attention needs to be paid to material development and product design. This thesis explores the sustainability and circularity of bio-based plastics by looking at: how they are perceived by value chain actors, potential recovery pathways in a circular economy, and environmental impact.


Although bio-based plastics have the potential to be sustainable, the emissions associated with producing them depend heavily on the biomass sourcing. At the same time, bio-based plastics are not de-facto biodegradable and thus efficient recovery at end-of-life needs to be guaranteed. Circular product design with bio-based plastics requires careful consideration of biomass sourcing and recovery. Although much information regarding these aspects is still missing, the research presented in this dissertation provides some guidelines for circular product design with bio-based plastics. In order to reduce environmental impacts, bio-based plastics should be produced with agricultural by-products or with biomass types with a high conversion efficiency. Biomass for bio-based plastics should be cultivated with minimal use of land, water, chemicals and fossil fuels. Environmental impacts can be reduced further by using renewable energy in the production process. Product designers should also consider what recovery pathway they want to target at end-of-life of a product. The plastic composition and product architecture need to reflect the targeted recovery pathway.@en

Current cravings for more are taking a great toll on the Earth and its most vulnerable communities. The rise in ’fast furniture’ has contributed to this issue, popularizing the idea that furniture can be cheap, to the point of being disposable. To understand the size of this issue and how much more damage to the environment might be in store if these trends continue, we need to measure the amount of the furniture stock now and project what might be needed in the future. Currently, there is a knowledge gap in understanding how much furniture is in our homes, especially on a national scale. This thesis aims to quantify the stock and flows of household furniture materials in the US, distinguished by income and area type (i.e., urban or rural). To inform strategies toward circularity in household furniture, a second object of the study is to investigate the effects of repair and reuse – lifetime extension strategies – on the behavior of the American household furniture stock. To quantify the stock of furniture units, the average number of furniture units per m2 of residential floor space was collected using a bottom-up approach. The results were scaled to the national level using residential floor space data from the Integrated Model to Assess the Global Environment (IMAGE), scenario SSP2. Dynamic stocks and flows were calculated based on projected changes in residential floor space to understand how the stocks and flows might behave over time. The lifetime extension scenarios were simulated by extending the lifetime and adding mass (for repair) of a percentage of the furniture in the stock. Overall, demand for household furniture is not expected to saturate until the end of the 21st century. The highest-earning quintile owns half of the furniture stock mass, and material inequality is expected to remain until the end of the century in the base case. Urban residents own a majority of the household furniture and are expected to own a larger share as urbanization continues. About three-quarters of the furniture stock is wood-based, presenting opportunities for carbon storage but challenges in the volume of hard-to-recycle and low-durability particleboard. Circularity efforts to decrease furniture demand should target higher-income groups and separate strategies for lower-income groups should aim to increase affordability and access to more durable furniture. Urbanization also presents opportunities for local furniture circularity projects and hubs to attract skilled furniture repairers and secondhand distributors.

The construction sector is responsible for 39% of the global energy- and process-related CO2 emissions, of which 11% is due to the production of construction materials. The municipality of the city of Leiden in the Netherlands has set goals to build 17,000 new dwellings between 2020-2030 and to lower its overall carbon footprint. In this study, the environmental impact reduction potential of wood construction systems (WCSs) for the construction of 17,000 mid- and high-rise residential buildings in Leiden was explored. The two WCS alternatives studied are cross-laminated timber (CLT) construction systems built with either the modular or flatpack method. A number of sustainability choices expected to lower the environmental impact of WCSs through prolonged biogenic carbon retention time were quantified in a scenario-based life cycle assessment (LCA). These choices included high-end reuse of WCSs, wood material downcycling into particleboards, extending the building service life (BSL), dwelling size reduction, and wood resource country selection. Results showed a maximum hypothetical impact reduction of 92.3% for modular CLT and 91% for flatpack CLT WCSs. This hypothetical reduction was achieved when all sustainability choices were combined. The selected scenarios used and the level of detail of the LCA model do not fully align with current trends in the construction- and housing sector. Therefore, the actual realization of the impact reductions presented should not be perceived as highly feasible. Two originally included WCS alternatives consisting of CLT and timber frame construction (TFC) hybrids could unfortunately not be quantified due to technical issues with the used LCA modelling software.

This study answerd the research question, What is needed to enable design students, particularly at the Industrial Design Engineering (IDE) faculty in Delft, without prior experience in Life Cycle Assessment to effectively incorporate the fundamentals of the LCA method into their design practices? Through empirical research (interviews and observations) at the IDE faculty in Delft, student problems regarding LCA have been identified. The data analysis finds 5 themes that overarch the problems and so influence the effective incorporation of LCA from within the designer. The 5 themes are a designers’ motivation, mindset, time for LCA, capabilities and comprehension of LCA. Additionally, there are 5 external themes influencing the effective incorporation of LCA. The total 10 themes are interrelated and make up a system. The external themes and system dynamics lead to possible interventions of which one is tested at the IDE faculty with Master students. The main student problems have been implemented into an improved LCA tool and tested through an assignment. The main tool improvements were a better fit to design practices and a complete overview of LCA fundamental elements. It also offers early LCA implementation through an inventory phase that slowly increases complexity matching to the designers’ capabilities. This is supported by easier and earlier implementation of robustness assessment (sensitivity analysis or scenario tests) to enable low threshold assumption making and testing to help nuanced result interpretation. Students responded positively to the main tool improvements. Further testing of the tool is needed and other interventions to the system should be tested as well.

Concrete is one of the most widely used materials in residential building construction. It contributes about 4% to 7% of global greenhouse gas emissions annually. Thus, better understanding the material stocks and flows of concrete can support efforts to better manage this resource and its use. Concrete is especially popular for the construction of building foundations. Previous research has shown that foundations can account for 25% to 60% of residential housing mass. Despite this, no in-depth analysis of material requirements of foundations has been conducted. Foundation design depends on the housing type and soil type. Considering foundations’ substantial share of building mass, I analyze them in this thesis in the form of a case study of residential housing built in Trondheim between 2010 and 2020. To account for all emissions from cradle-to-construction site I also compare the concrete production emissions to the last-leg transport emissions. The residential building foundations’ material requirements were estimated with a model I specifically developed for this thesis. 507 000 tonnes of concrete were used from 2010 to 2020 to build residential building foundations in Trondheim. The results show that the concrete production emissions represent 99% and the last-leg transport emissions 1% of the total cradle-to-construction site emissions. The average material intensity coefficient across all buildings in Trondheim is 402 kg of concrete in the foundation per one m2 useful floor area. I disaggregated the buildings into five types: single family house, semi-detached house, rowhouse, apartment building, assisted & communal living. When disaggregated, the building types’ material intensities vary, on average, 8% around 402 kg/m2 useful floor area. The largest difference being 20% below the mean. As a result, there are no substantial differences of material requirements per m2 useful floor area between different building types. However, building on peat and bog soils increases the material requirements by 80% compared to all other soil types found in Trondheim. This is due to the low bearing capacity of peat and bog soils. Trondheim currently plans its residential zoning until 2034. 5% of the planned zones are located on peat and bog. A rough estimate suggests that up to 380 000 tonnes of carbon could be stored in the affected peat and bog areas, which could be released as construction on this land begins. Together with the 80% increased material requirements of foundations on peat and bog, this can cause a lot of emissions. As a result, my short-term recommendation is that these areas are either preserved as nature reserves or only light structures that do not need a foundation are constructed. In the long-term I recommend that new zoning types for city planning are developed that take soil types into account. Lastly, the effects of soil types should be taken into account in future studies of the material stock in residential housing. Feel free to contact the author for more information and the supporting information.

Float glass is a largely unexplored material flow in the context of circularity. As the Dutch government wants construction to be fully circular by 2050, new ways have to be found to deal with float glass. Five scenarios for sustainable glass handling are discussed: what would happen if all available secondary windows would be recycled, remanufactured, reused, repaired, or if glass use would be reduced? The effects on material demand, energy use, value chain processes, and product are explored and compared. Finally, policy options are proposed to stimulate these sustainable strategies.

The growing world population gaining affluence is driving the extraction of raw materials. Resource availability is finite and concerns about future supply shortages rise. An approach to tackle this problem is circular economy which entails multiple strategies to reduce the demand of virgin materials. The implementation of those strategies require knowledge about material stocks and flows in a society. Material Flow Analysis can provide those insights. This fast developing field brought about MaTrace models which allow to trace the fate of materials in an open-loop recycling system. Recycling is only one of multiple circular strategies, thus the purpose of this research is to integrate an elaborate reuse model into a MaTrace model to build the foundation of a model which considers multiple circular strategies in sufficient ways.

Two existing models were combined to achieve this: Consumer goods present in the MaTrace model were redirected into a reuse model and the end of life products of the reuse model were fed back into the MaTrace model. The impacts of this model extension were investigated by comparing the total in-use stock when considering one, two, and three consumer products' use cycles. Furthermore, Monte Carlo simulations were conducted to gain an understanding of the model behaviour.

The results show that the total in-use stock increases in the peak by 8 % when reuse is considered. However, the gross stock dynamics do not change significantly in comparison to the original model. The evaluation of the Monte Carlo simulations revealed that the input which contributes the most uncertainty to the total in-use stock is the split of the initial material inflow. Furthermore, the results of the Monte Carlo simulations appear to be strongly connected to the initial input data. On the basis of this research it can be recommended to further extend MaTrace models to obtain a more comprehensive representation of a circular economy. Furthermore, MaTrace models using time series data for inflows and model parameter have to be created, this way MaTrace models can follow the evolution of MFA from static to dynamic models.

The implications of a CE and the transition towards it are widely researched. However, there is a lack of research into the relevant geographical scales of CE. Thus, this research aims to present a framework that identifies the optimal geographical scale for the recycling of materials based on various factors. The framework is tested against a case study of recycled concrete and copper for the municipality of Leiden. For the economic factor, a crude cost benefit analysis is carried out. For the environmental factor, a life cycle assessment (LCA) of both concrete and copper recycling is conducted.
Based on the results of the analyses, the framework indicates that concrete rubble can be transported up to 70km by truck and 110km by barge. Under present circumstances, economic cost is not a limiting factor, with an upper limit of 160-170km. The results for copper seem to indicate that environmental impact and economic cost are not the determining factors for geographic scale. Based on environmental impact scrap copper can be transported 4330km by truck or 11500km by barge. Based on economic cost the copper scrap can be transported as far as 12300km.
The framework has the potential to help decision making on the geographical scale of the recycling process for specific materials. The results of the framework could be used by government agencies for new policies or spatial planning. Within academic research the framework can add practical knowledge. This will add to the understanding of how CE can contribute to minimising environmental impact.

Environmental impacts related to the global food system are increasingly addressed by academia, institutions, policy-makers and businesses. Fundamentally, decisions about food consumption rest with the customer, and although they are the largest stakeholder group in the food system, they are not adequately equipped to consider the environmental impact of their choices at the time of purchase. The Water-Energy-Food Nexus is a useful perspective to analyse and communicate emissions along the production system, supply chain and consumption context of food. Through the lens of the Nexus, this study investigates the LCA methodology as a mechanism to provide local consumers with useful information about permanent decrease of upstream water and energy availability and associated impacts of restaurant meals. A simplified ‘farm-to-fork’ LCA assessment was carried out for 12 popular meals that were frequently offered in the Dutch city of Leiden and could be grouped into the four categories red meat-based, poultry-based, fish-based and vegetarian. The ReCiPe and Cumulative Energy Demand impact assessments were applied to identify poultry-based meals with the highest water depletion potential and cumulative energy demand. This surprising result was found to be driven by the large proportion of starch ingredients in the recipes and the absence of significant amounts of starch ingredients in the Red Meat-based meals. The findings revealed a directly proportional relationship between refrigerated storage duration and both assessed impact categories. Normalization of meals per weight significantly reduced the range of impact scores across meals and the normalization of impact categories highlighted the disproportionately large effect of ‘freshwater eutrophication’ cause by beef cultivation. The results of the study provide high-level insight for policy-makers, businesses and consumers. The comprehensive metrics in this study are useful for communicating complex environmental impacts with consumers and supporting their decision-making process in favour of less environmentally impactful option. For businesses, a challenge arises from the disproportionately high impacts associated to inexpensive ingredients such as potatoes. Policy-makers are encouraged to further regulate maximum shelf-life durations and thereby curb energy demand for cold storage. In the context of the Water-Food-Energy Nexus, it was found that the study results support integrated measures that allow consumers to make more informed decisions, businesses to shift to low-impact ingredients without an economic disadvantage and policy-makers to stimulate more rigorous and feasible management of impacts along the food system.

The Dutch government set two environmental goals by 2050. One of them is being climate neutral and the other one is to have a circular economy. In order to meet both goals in the best environmental conditions, extensive environmental research is required. This thesis is one of these researches and its main focus is on the climate neutral goal by 2050. In this thesis I start by creating a generic model in ArcGIS that will calculate the required materials and their environmental impacts for the implementation of high and low district heat networks and for air-water heat pumps in residential buildings. The model uses national spatial data of buildings, heat networks, and energylabels and combines them with material data that is retrieved from life cycle inventories (LCI) out of life cycle assessment (LCA) papers, material databases, several manuals, technical specifications on websites and own examination. The model is applied to the Merenwijk in Leiden. The model’s results show that for the Merenwijk the indirect environmental impact of the materials will reduce the total reduction in the heat pump scenario by approximately 10% and will be covered in the first 2 years of operation. On the material demand side, the model shows that the Netherlands will face problems with the demand for glass and glass wool. The current market for both materials should be intensified by 4 to 5 times in order to meet the expected demand. Glass wool demands will even reach 2% of the current global mineral wool market. In conclusion this thesis provides an addition to current environmental calculations by looking at the material environmental impact in the Dutch heat transition. The environmental impact of materials does have a significant impact on the overall environmental calculations.

Cobalt is one of the most important critical raw materials for emerging technologies. There are many incentives for analysis of this metal, from increasing demand for rechargeable batteries, rising prices and social issues involved. This paper is the first attempt to perform a substance flow analysis of cobalt at a city level. The analysis resulted in a generic cobalt city flow model that can be adjusted for another CRM or city. The model is meant to help create a better, more accurate national, and subsequently EU level, analysis. The generic city flow model is the first step to extrapolate the bottom-up approach to get reliable results on a broader scale. A case study for the city of The Hague quantified the main cobalt flows within the city. Based on the results it was possible to suggest policy recommendations regarding critical raw materials at an urban level. The main recommendations were the lack of specific data from several sectors and the need for collaboration between governments, statistical offices and entrepreneurs. Those actors should work together to create a database accessible for researchers.

The heating transition goals of the Netherlands are ambitious. To reach the goal of an 80% reduction of CO2 emission by 2050, the total residential heat consumption would need to be drastically cut down. The Dutch government is leaning towards implementing large-scale heating networks and reusing waste heat from non-renewable industry. However, doubts exist whether or not that is the most viable solution. Other research lacks an overlapping approach to the modelling of a complex problem like the heating transition. The aim of this paper is to make a GIS-based framework to develop scenarios for the heating transition in cities and evaluate the implementation of different combinations of technologies to reach the Dutch climate goals. This analysis focusses on residential buildings because there is an ongoing discussion who is going to pay for the investment necessary to achieve the heating transition for this type of building. The case study of this paper focusses on the Merenwijk in the city of Leiden in the Netherlands

The technologies covered in this paper are heat pumps, low temperature heating networks and high temperature heating networks. These technologies are evaluated on their technical, financial and environmental aspects to determine their impact. Next to these impacts the trade-offs of implementing these technologies are evaluated and which impact these could have on the stakeholders involved. Three scenarios were made to cover a few combinations of these technologies: 1) a scenario based on the warmtevisie from Leiden utilizing heat pumps and low temperature heating networks; 2) a scenario utilizing only heat pumps; and 3) a scenario implementing low and high temperature heating networks for the whole neighbourhood. 
All technologies have specific characteristics which should be considered before implementing on a large scale. Financial assistance from the municipality or the government is needed for the home owners in order to achieve the heating transition within 32 years. The energy sources used by the heating technologies will be crucial for reaching the climate goals. At some point the Dutch government has to choose between a quick wins solution by reusing waste heat from the harbour of Rotterdam, or to implement a long term sustainable energy transition with heat pumps and low temperature heating networks. This paper provides an overview of the three mentioned heating technologies to be implemented during the heating transition as an alternative to natural gas. Moreover, it will hopefully invoke some debate about the Dutch government’s heating transition agenda.

Cities account for approximately 75% of Greenhouse Gas (GHG) emissions. This, along with the fact that cities also account for 75% of natural resource consumption and 50% of global waste production, makes urbanization a world-wide issue (Sukhdev, Vol, Brandt, & Yeoman, 2017). Additionally, the widely-practiced urban linear economic structure only amplifies the problems of city life, taking goods from far-off places, using them for a limited time and discarding them in such a way that cuts value chains. A shift toward a circular economy (CE) with the aim to reduce, reuse or recycle materials could be a winning sustainable development strategy for cities aiming to lower their negative environmental impacts. Problems of urbanization are only expected to increase. In Europe, cities house 70% of the population, making it one of the most urbanized regions in the world. In the Netherlands particularly, the percentage residents living in cities has grown from 87% in 2010 to over 91% in the last 8 years (United Nations Population Division, 2018).A major challenge facing the Netherlands is the sustainability of the food system that accompanies this urbanization. Cities depend heavily on imported food to fulfil the needs and preferences of their residents. Besides the negative environmental consequences of excessive and often fossil-fuel driven importation, cities also produce a large amount of food waste which is often simply incinerated or landfilled. A more circular and localized food system, in this case addressed through Circular Urban Agriculture (CUA), would address both the issues of the linear economy and the growing food needs of cities. The Hague presents an interesting opportunity for CUA with its increasing popularity, carbon neutrality goals, location in a highly-productive agricultural area and expanding innovativeness. This research assesses the current state of CUA in The Hague, its potential for growth and possible future scenarios in which it is a larger part of The Hague’s food system. A conceptual framework comprised of quantitative and qualitative criteria from various frameworks leads the way into The Hague’s sustainable future. The contributing frameworks are the Urban Harvest Approach, Strategic Niche Management and Backcasting and draws from three domains: urban metabolism, sustainable transitions and future studies. A literature review gives insight into the current state of both urban agriculture (UA) and circularity in The Hague. Using the three examples of macro-level CUA initiatives available in The Hague (the Edible Park, Urban Farmers and Haagse Zwam), network development, learning opportunities and expectations regarding CUA create a strong story for the future potential of the sector. Those involved externally with the CUA sector, such as municipality representatives, circularity experts and researchers, also contribute to the analysis by providing insight into the landscape of The Hague. Finally, taking expectations, interviews and knowledge of Industrial Ecology into account, a future vision for The Hague in 2050 exemplifies what “could be” for the future food system. The use of multi-level investigations for individual CUA initiatives, the CUA sector, the larger food system and the sociotechnical landscape of The Hague allows for an in-depth analysis that ultimately leads to recommendations for next steps related to CUA’s development.