Worldwide energy policies are built on three pillars: ‘cost competitiveness’, ‘security of energy supply’, and ‘environmental responsibility.’ This has brought about the integration of renewable energy sources into national systems with the deployment of policy instruments to make renewable energy sources electricity (RES-E) capable of nearly competing on a commercial basis with traditional forms of electricity generation. At the national level within the EU, there has been much experimentation with different policy instruments with varying levels of success. Nevertheless the EU as a whole will not meet its stipulated renewable energy target. This study challenges the theoretical and abstract evaluation presented in the literature about EU wind power delivery systems and has developed an integrative evaluation framework. This evaluation framework is used in this study to present the views of key stakeholders on their experiences with the performance of key policy instruments (feed-in tariff, and renewables obligation) implemented in three EU Member States namely: Germany, The Netherlands, and United Kingdom. It also challenges the EU-wide harmonised renewable energy policy agenda as proposed in Directive 2001/77/EC. The concept of path dependency of the historical institutional approach was adopted in order to explore the diversity of the wind power industry across the three country cases. An indepth semi-structured interview with fifty-five senior wind power policy makers and experts was conducted to explore the historical emergence, the architect, and the outcome of the support and implementation of the policy instruments. Findings showed that the approach to wind power deployment in the three country cases differs significantly and this has affected the pattern of each country’s wind power policy instrument. Also, the role and contribution of the stakeholder groups to the success of the wind power policy instruments differ significantly in each of the country cases. This helps to explain the performance of the different policy instruments adopted. Concerning the harmonisation of EU renewable energy policy instruments which have received much attention in recent times, this study found that harmonisation based on a single policy instrument is not feasible and may ultimately inhibit the growth of the European wind power market. A harmonised system may cause uncertainties amongst willing investors, thereby causing a withdrawal of further investment in the wind power market. If this happens, Europe may also lose its position as the world leader in the wind power market. Furthermore, national histories demonstrates that Member States have different culture, stakeholder groups, political, and business practices that will influence policy instruments and the likelihood of any policy succeeding. Thus, rather than promoting harmonisation and political market for wind power, it is important that Member States adopt and implement, stable, flexible, and transparent policy instruments that enable wind power and other renewable energy sources to emerge, develop, and go through the R&D stage to a point of maturity where they can compete with other energy sources with limited financial support.

Power grids constitute an essential infrastructure providing and distributing electrical energy. The grid structure is currently subject to rapid changes due to the integration of renewable energy sources. In this development one is confronted with several challenges and opportunities as, for instance, the reduction of inertial masses in the system, the strongly increasing decentralisation of generators, and the fluctuating power feed-in by generators relying on renewable energy sources. In this thesis, models are studied that describe the non-linear power-grid dynamics in the presence of fluctuating power feed-in from renewable energy sources, primarily wind turbines. Realistic features of wind-power feed-in are captured by using real data measured at a research platform located in the North Sea. This approach is applied to test systems provided by the Institute of Electrical and Electronics Engineers (IEEE), in which one conventional generator is replaced by a wind turbine. It is found that so-called dead ends and other weakly coupled network parts are particularly prone to power fluctuations and perturbations. In contrast to previous studies, the often pronounced heterogeneities of the power grid elements are taken into account when solving the non-linear power-flow and swing equations. Also reactances between locations of power generation and power feed-in are considered, which causes the link topology in the power grid to correspond to a full graph, where all nodes are effectively connected. Both the grid heterogeneities and the additional generator reactances have a decisive impact on power grid stability. Some structures considered as particularly stable in simplified models are prone to perturbations when utilising the more realistic model and vice versa. By the analysis of various quantities characterising functional grid operation, it is shown that a reliable assessment of power grid stability requires the consideration of heterogeneities and generator reactances.