Weather climate fluctuations cause large variations in renewable electricity production, which requires substantial amounts of energy storage to overcome energy drought periods. Based on daily hydroclimatic data and information about renewable power systems covering Europe, here we quantify the complementarity in the solar-wind-hydro energy components of the continental climate system. We show that the spatiotemporal management of renewable electricity production over Europe can induce a virtual energy storage gain that is several times larger than the available energy storage capacity in hydropower reservoirs. The potential electricity production matches the consumption by spatiotemporal management of suitable shares of solar and wind power complemented with the present hydropower. While the mixed renewable energy potential varies less than anticipated at the continental scale, utilization of the complementarity requires new continental electrical transmission lines and stable international trade. We highlight that management models need to consider incentives beyond national boundaries to appropriately benefit from continental climate conditions.

Municipal waste, comprised partially of plastic, has negative ecological impacts on a global scale. Developing countries face unique challenges in collecting and recycling their waste, where even in developed countries, recycling rates of plastics rarely approach 100%. Reshaping plastics into usable products requires a considerable amount of heat energy and infrastructure, which particularly impacts the accessibility of recycling technologies to developing countries. In regions with sufficient sunlight, solar cookers designed for the 150–200 °C range most useful for food preparation may be able to reach temperatures hot enough to also melt plastics, where the melting point of most common plastics is below 200 °C. The aim of this study was to test the feasibility of applying a parabolic trough collector for melting plastic waste. The lack of published data on this particular application of solar thermal collectors highlights a significant research gap. Two different prototypes were tested after improvements in the sheet metal material and parabolic shape were realized. Results demonstrated that a non-evacuated tube solar cooker constructed with simple methods and locally available materials could reach temperatures as high as 139 °C within one hour of testing in Stockholm, Sweden. ABS plastic waste from a 3D printer was successfully melted in this process. The final prototype was tested in Ioannina, Greece in collaboration with the refugee-aiding FabLab, Habibi.Works. Temperatures inside the collector were measured at a maximum value of 211 °C in Greece. The results were examined in the context of developing areas and refugee camps and suggest that this may be feasible and affordable for developing countries. Further research should be conducted on the potential of solar cooker designs to be applied for waste reduction in these areas of the world.

In this paper, the influence of gap consideration on load identification under various Halbach-array-based topologies (HABOs) is investigated while the system is on-duty. The load characteristics of a radial flux generator with closed-slots and the exterior rotor topology is discussed, where the effect of eddy-currents are observed. This comparative study deals with the consideration of the combined moment of inertia calculation that demonstrates how electromagnetic-based post processing calculations are estimated without the aid of nominal machine parameter values. The analysis was performed using a 2-D finite-element simulation of different HABOs with the gap consideration between the segments. Additionally, a comprehensive comparison with no gap is considered. Also, the dynamic analysis using an uncontrolled conventional rectifier model is used to derive effected key output parameters such as torque, output power, power factor, and line-to-line voltage. The major objective of the study is to determine corresponding load results in order to employ the most suitable and capable magnetization topology from the load perspective in the PM synchronous generator (PMSGs). Accordingly, the maximum power (MP) point was carried out to maximize the output DC power. With respect to the combined moment of inertia estimation, the load parameter estimation is verified experimentally on a surface-mounted PMSG using different magnetization topologies. Furthermore, commercial and environmental issues of the project are considered to reduce CO2 emissions as part of green power generation development. 

This paper studies a dual-level response surface methodology (DRSM) coupled with Booth's algorithm using a simulated annealing (BA-SA) method as a multiobjective technique for parametric modeling and machine design optimization for the first time. The aim of the research is for power maximization and cost of manufacture minimization resulting in a highly optimized wind generator to improve small power generation performance. The DRSM is employed to determine the best set of design parameters for power maximization in a surface-mounted permanent magnet synchronous generator with an exterior-rotor topology. Additionally, the BA-SA method is investigated to minimize material cost while keeping the volume constant. DRSM by different design functions including mixed resolution robust design, full factorial design, central composite design, and box-behnken design are applied to optimize the power performance resulting in very small errors. An analysis of the variance via multilevel RSM plots is used to check the adequacy of fit in the design region and determines the parameter settings to manufacture a high-quality wind generator. The analytical and numerical calculations have been experimentally verified and have successfully validated the theoretical and multiobjective optimization design methods presented.

The aim of this project is to investigate and evaluate the suitable area on the existing buildings at the Royal Institute of Technology (KTH) campus for the installation of solar PV panels along with the resulting potential for electricity production. The building evaluations were conducted to determine the available campus rooftops that could be utilized by eliminating those with visible contributions to shading. Two sample buildings were chosen for further simulation in the software PVsyst. The results of the simulation were further evaluated in terms of losses and applied to the whole campus suitable area in order to determine a total potential energy production. The resulting electricity production through PV installation was significantly lower in comparison to the total building energy consumption. Therefore, the importance of reducing energy usage and increasing energy efficiency is highlighted instead of focusing on renewable energy installations. This may result in a greater contribution from PV panels to the share of energy production in the future, making the campus more self-reliant and less dependent on the grid.