The Spangen neighborhood in Rotterdam West, the Netherlands, is highly vulnerable to pluvial flooding due to its low elevation, numerous impervious surfaces, and proximity to the Delfshavense Schie canal and a surrounding feeder canal. These factors contribute to high local surface runoff and strain on the local combined sewer system (CSS), leading to combined sewer overflows (CSOs) and local street fooding (“water op straat”). This study investigates the potential of integrating blue-green infrastructure (BGI) together with real-time control (RTC) to mitigate flood risk by reducing both the volume and frequency of CSOs and swale overflow events. A hydrological model, built utilizing 20 years of meteorological data with a 10-minute resolution from November 01, 2004 to October 01, 2024, simulated the hydrological effects of three progressively integrated bioswale configurations, a baseline scenario, and further modeled the effectiveness of RTC as valves outfitted at the base of the swale overflow tructure in preemptively releasing forecasted runoff over a 12-hour lead time. Results demonstrated that while the baseline scenario revealed 582.5 mm of CSO overflow over 188 events during the study period, when implemented, bioswales alone reduced net flow to the receiving water body by up to 95%, and RTC-enabled bioswales, in the most intensive configuration, could fully, pre-emptively remove stored swale volume to completely eliminate uncontrolled overflow. The 25% interception fraction performed best for Configuration 1, and 50% fraction performed best for Configurations 2 and 3, which all minimized the net flow out to the receiving water body, most efficiently integrating the existing CSS and proposed bioswales. Beyond mitigating flood risks, BGI offer co-benefits such as enhanced ecological connectivity, improved water quality, and urban livability, serving as a tool to provide Gemeente Rotterdam with a new possibility to achieve other sustainability goals, such as increasing green space access. This research demonstrates that the integration of RTC with BGI can serve as a scalable model for climate-resilient urban water management in Rotterdam, and worldwide.

This research has investigated how Sewer Water Harvesting (SWH) can be applied to provide a climate-proof fresh water source to support Urban Green Spaces (UGS) in Amsterdam. SWH is the process of extracting raw municipal sewage from the sewer and locally treating this to provide fit-for-purpose water in a dense urban environment while treatment residuals are discharged back into the sewer. SWH can help to meet the increasing water demand of UGS in Amsterdam, which experiences exacerbated dry periods as a result of climate change, while conventional water sources are unlikely to meet this demand.

The overall aim was to provide a conceptual design example of how SWH could be applied in the Amsterdam context to uncover what kind of impact can be achieved and advise on how SWH can be implemented From an analysis of potential applications, irrigation of UGS during dry periods was selected for the focus of the study. Suitable locations were identified, from which the Vondelpark was selected as study area for this research. Quality requirements for irrigation water and discharge of treatment residuals were determined. The water demand of the study area was determined by modelling the soil moisture balance using transformed weather data, taking into account climate change. Based on these requirements, a conceptual design of an SWH-unit comprised of fine screening, MF, NF and UV steps. To evaluate this potential impact for Amsterdam as a whole, the findings from the study area were extrapolated. The cost of SWH were compared to alternative water sources and the potential direct economic benefits. This demonstrated that costs of SWH are acceptable and can be further decreased. Furthermore, the potential impact on plant and soil health was
evaluated. Interviews with stakeholders identified barriers and opportunities of SWH and resulted in some recommendations for larger scale implementation.

The results of this research indicate that SWH can provide a new and reliable water source during dry periods to support UGS. SWH-units can be designed as mobile and modular units that can for a large part be operated and monitored remotely. The results further demonstrate that potential negative environmental effects can be prevented or mitigated and SWH can even improve the plant and soil health of UGS. From an engineering perspective, challenges related to the water quality are unlikely to be insurmountable. However, three aspects still require a significant amount of time and investment before SWH can be implemented on a larger scale. These are: (1) the lack of regulatory framework, (2) the unresolved responsibility for operation and (3) extensive water quality testing and environmental impact assessment. To accelerate innovation it is recommended to start as soon as possible with addressing these remaining issues. Commercial operation of SWH can provide an interesting opportunity, all the more so because SWH can also be used for household or industrial applications. The involvement of a wider variety of stakeholders can further help to overcome the remaining barriers.

Over the past few years, the number of photovoltaic (PV) solar panels that are being installed in Amsterdam has been growing considerably. The amount of PV panel installations averages an annual growth of 50%, which is stimulated by the city its ambition to leave no roof unused by 2040. However, little attention is paid to what should happen with these PV panels once they reach end-of-life (EoL) and must be disposed of. This research aims to identify barriers and solution directions to upscale the circularity of EoL management for PV panels located in Amsterdam. This is done to collect better insights on what role cities can play to decrease the size of future PV waste streams. To accomplish this, the research goal is divided into three sub-goals. First, to estimate the size of future PV panel waste streams in Amsterdam over the period 2022-2050. Second, to enhance the understanding of the stakeholders involved in PV panel EoL management system and the barriers that hinder the implementation of innovative reuse and high-value recycling strategies. Third, to identify the ongoing socio-technical developments in the Netherlands to promote innovative reuse and high-value recyclng activities for EoL PV panels.

This study focussed on the position of the Coal-to-Gas (CtG) transition of Almaty (Kazakhstan) within its wider energy goals to become energy neutral in 2060. Within CtG-transition the focus was mainly on the biggest coal-based power plant (CHP-2) of the city, which is planned to convert gas-based energy production.

The methodology consist of a multidisciplinary analysis that includes three
fundamental dimensions of energy transitions, the socio-technical, techno-economic and political dimension. These dimensions are first individually analysed, to later interpret the outcomes and their interrelatedness. The analysis consist of qualitative desk research, and descriptive and correlational quantitative analysis. Research is conducted with secondary data sources. Prior to studying the three dimensions, specifics of the CtG-transition and Almaty’s current energy situation are described.

The techno-economic dimension is characterised by the sufficiency potential of renewable energy in the region of Almaty. Various analysis have concluded that a RES alternative based on solar and wind energy is favourable from a financial and carbon emission point of view. Implementation of solar and wind as compensation for CHP-2 appears to be technically feasible for Almaty. The socio-technical dimension is identified by the emergence of new technologies(RES) within the embedded existing energy system (coal and gas-based). For Almaty, this dimension is typified by being stuck in a carbon lock-in. The obsolete infrastructure and need for financial investment provide a possibility to breach this lock-in and avoid renewed path dependence towards fossil energy. However, currently there is a lack of sufficient RES stimulating measures, and the existing are insufficient to compete with fossil energy. Various arguments promote for RES stimulation on the long term, such as decreasing the fossil fuel dependency, (inter)national climate ambitions, fast energy transition activities of major trade partners, and a change to diversify economic activity. The political dimension explains the political landscape of the city, consisting of current policies, stated ambitions, and political dynamics. For Almaty, action in the political dimension is
required to catalyse the energy transition, promote RES implementation, to breach with the carbon lock-in and to prevent renewed path dependence on fossil energy. Political actors have to decide between short term economic growth and political stability, or long term planning towards a sustainable and diversified energy system. Two policy cycles have to be adapted. First, regulations of fossil fuel energies have to gradually be phased out. However, a gradual and slow change is required since economic growth and political stability are major drivers of these regulations. Second, stimulating policy for RES development and implementation are required. Currently RES cannot compete with fossil fuel alternatives, and therefore cannot penetrate the heavily fossil oriented market.

Current energy systems contains many barriers that oppose to reaching the energy climate goals of Almaty. Most important is to breach the dependency on fossil energy from an economic, technical, and political point of view. This dependency is identified as a carbon lock-in, and additional investments in Almaty’s gas-based energy infrastructure lead to path renewed path dependence on fossil fuels, and a remained carbon lock-in. Implementing solar and wind energy as alternative of the CHP-2 conversion is an important step towards breaching the carbon-lock in and stimulating RES. Therefore local government should considering heavily investing in implementation of renewable alternatives instead of using CHP-2, in order to seriously work towards the climate ambitions, and to prevent another carbon lock-in.