As the capacity of wind power continues to increase globally, stricter requirements regarding grid connection of wind generators are introduced by system operators. The development of wind turbine technology is inevitably affected by the new grid codes, and wind power plants are expected to support the grid and provide ancillary services much like conventional power plants. The most demanding regulations are found in Europe where wind penetration levels are higher. This paper presents the main aspects of current grid code requirements for the integration of wind power in European countries and suggests performance characteristics in order to satisfy the most demanding requirements. The dynamic behavior of wind turbines with doubly fed induction generators is investigated and a solution for low voltage ride through compliance is presented.

In the present work, the operating results from an innovative, renewable, energy-based space-heating and domestic hot water (DHW) system are shown. The system used solar thermal energy as its primary source and was assisted by a shallow geothermal application in order to accommodate the space-heating and DHW needs of a domestic building in Austria. The system incorporated phase-change materials (PCMs) in specially designed containers to function as heat-storage modules and provide an energy storage capability for both the space-heating and DHW subsystems. This system was designed, implemented, and tested under real operating conditions in a building for a period of one year. The operating and energy results for the system are demonstrated in this work. The system was compared with a conventional one, and a reduction in the primary energy consumption equal to 84.3% was achieved. The maintenance and operating costs of the system were reduced by 79.7% compared to the conventional system, thus significantly contributing to the NZEB target of the building. The newly proposed system, although presenting an increased operating complexity, utilizes an innovative self-learning control system that manages all of its operations. The combination of a solar thermal energy source with thermal energy storage increases the use of renewable energy by extending the capacity of the system beyond the solar hours and using excess solar energy for space-heating needs. The thermal energy storage unit also increases the energy and economic efficiency of the geothermal heat pump by operating it during the hours of a reduced electricity tariff and using the stored energy during hours of a high electricity demand. The cost for the installation of such a system is higher than a conventional one, but due to the significantly decreased operating costs, the pay-back period was calculated to be 8.7 years.

Recent developments show that renewable energy sources are considerably contributing to the electrical power generation and offer a future-oriented, sustainable and environmental-friendly alternative to fossil energy sources. Wind energy in particular has experienced a rapid growth over the past decades, so that wind energy conversion systems (WECS) will occupy an important role in the power generation having to reliably supply electric energy. Especially in remote rural areas or in weak distribution grids, unbalanced grid voltage conditions are common and need to be addressed by appropriate control measures. They evoke negative sequence grid voltages resulting in torque and active/reactive power oscillations at twice the grid frequency, thus inducing heavy mechanical stress in the WECS drive-train and increasing grid load respectively. An improved space vector control methodology which can simultaneously regulate positive and negative sequence components based on proportional-integral and resonant controllers is presented to effectively mitigate the impacts of grid voltage unbalance.

This paper presents the innovative key knowledge breakthroughs achieved as one of the results of the BUILD2050 Erasmus+ project, focused on its contribution to advancing climate-resilient building engineering education and practice. In a recent work, the new methodologies applied in the BUILD2050 initiative were presented. This work discusses the incorporation of new knowledge in the courses and dissemination for the sustainability of the trans-European training experience. The challenge faced by the European Union for 2050 is achieving climate neutrality and decarbonization across all economic sectors, including the significantly impactful construction sector. To achieve this objective, it is necessary to develop technologies in an integrated way, following a holistic approach appropriately adapted to climatic conditions, cultural contexts, and natural resource availability through circular economy methodologies. To this end, it is necessary to develop innovative training methods with multidisciplinary content, incorporating a transnational perspective and scope, enabling continuous updating through learning cycles. These study cycles could be shorter and more complementary, allowing greater flexibility in knowledge acquisition while also enabling the creation of specialized training programs similar to those currently available. The BUILD2050 project has developed a transformative educational framework comprising eight comprehensive “Pilot Training” courses to address the critical challenge of integrating sustainability and circularity concepts into educational curricula at all levels, building engineering training and professional development. Addressing this gap is essential for transforming the construction sector and achieving global climate goals. The results of the BUILD2050 project demonstrate the potential of structured, trans-European training experiences to enhance professional competencies and support the transition to climate-neutral construction. Moving forward, widespread adoption and continuous dissemination of these educational advancements will be vital in ensuring a sustainable built environment by 2050.