The integration of Variable Renewable Energy Sources (VRES) creates challenges for meeting load demand. The lack of on-demand power generation of these VRES effectively threatens energy security. Therefore, storage facilities, especially hydrogen, have been broadly researched for potential implementation in our energy system, enabling on-demand power "generation". This thesis adds to this research by providing a framework on how VRES and long-term storage technologies can be most optimally utilized to ensure weekly or monthly energy security. This framework is explicitly applied to the Netherlands and reviews the opportunities of a VRES dominated future energy system. The framework consists of a VRES generation model and load model and identifies the optimal load coverage using single- and multi-objective genetic algorithms. The VRES generation model is designed for a weekly and monthly timeframe by using 31 years of available weather data (1988-2018), specifically average wind speeds and solar irradiance, for a number of locations in the Netherlands. Using the available weather data, power generation per MW of onshore wind, offshore wind, and solar PV are calculated. Subsequently, this calculated VRES power generation is compared to available real-world VRES power generation data and a correction factor is determined. Applying the correction factor to the more extensive weather data set allows to effectively create a VRES power generation model, based on the weather circumstances as in these 31 years. Additionally, a weekly and monthly 31-year load profile is determined, using available data for load demand in the Netherlands. Thereafter, both a single and multi-objective algorithm is tasked to provide load coverage in two main scenarios at minimum cost. First, load coverage is achieved exclusively utilizing VRES capacity. Secondly, a variety of long-term storage facilities are introduced in combination with VRES capacity to acquire energy security. Furthermore, these two methods for achieving energy security are restricted in a number of sub-scenarios, which represent the societal preference restrictions regarding VRES installations.
Generally, energy security is most cost-effectively achieved utilizing long-term hydrogen storage facilities, as compared to an exclusive VRES approach. Specifically, alkaline electrolysis and hydrogen combined cycle gas turbines seem to be the most promising technologies to be applied for the hydrogen storage facility electrolysis and reconversion sub-steps respectively. Furthermore, societal preference has a significant effect on the total costs, increasing it considerably when offshore wind capacity is forcefully introduced in the VRES capacity mixture. Lastly, the timeframe considered for achieving energy security, either weekly or monthly, has a substantial effect on the total cost. The smaller weekly timeframe results in additional costs, as the long-term hydrogen storage facility, is utilized more broadly to meet load demand, increasing the capacity requirements for charging, discharging, and storage. Overall costs range between 139 and 211 billion Euros to achieve energy security using the more cost-effective long-term hydrogen storage approach, depending on the timeframe and societal constraints applied.

Future energy systems will present high penetrations of variable renewable energy (VRES). Due to the uncertainty that is related to the intermittency of wind and solar energy, and loads such as electric vehicles, the need for flexibility will be higher. This research identifies the possible sources of flexibility in a power system. Firstly, using statistical errors and probability theory, the required reserves of flexibility that a system needs to ensure a proper operation are quantified. Secondly, with the increase of VRES, the amount of synchronous generators is expected to decrease. This will mean that the inertial response used to keep a stable frequency will be reduced. On this paper, a method to quantify inertia and the concept of minimum required reaction time of flexibility are explained. Finally, an optimization problem is proposed to allocate the different types of flexibility taking into consideration their technical capabilities. This problem minimizes the cost of reserving different flexibility sources in a distribution grid.

In our current society both the demand for electricity is increasing and the demand for electrical energy as energy carrier is increasing. Renewable sources will play an important role in future energy generation due to societal developments. These distributed energy resources introduce new challenges to our current electrical power system. One of these challenges imposed on our current electrical power system is the introduction of a new grid user, the prosumer, who consumes and produces electrical energy. Another challenge is the intermittent nature of renewable sources such as solar and wind energy. During the past year Blockchain gained momentum as a technology mainly through the evolving industry of cryptocurrencies such as Bitcoin and Ether. Application of the Blockchain to the electrical power system could oer solutions to some of these challenges that the future electrical power system will face. The main goal of this thesis is to identify the opportunities, advantages and technical challenges of applying the Blockchain to the electrical power system. First, as part of the literature study the Blockchain has been studied and the operation of the Blockchain has been analyzed. The Blockchain has been dened as a collective of technologies that can be described as a database, which is distributed among a peer to peer network, combined with securitization elements relying on multiple cryptographic technologies. Second, the opportunities where the Blockchain could be applied in the current electrical power system were identied. In order to study the application of the Blockchain to the electrical power system four case studies have been introduced. These case studies dierentiate themselves in the level of adoption of the Blockchain and the functionality which could be provided to the electrical power system. Ranging from a local peer to peer trading infrastructure to the entire market being operated via the Blockchain with advanced features such as the control of power ows. Third, the various advantages of applying the Blockchain to the electrical power system have been explored based on the proposed case studies. A distinction has been made between advantages which are inherently linked to the characteristics of the Blockchain and the provided functionality to the electrical power system. Fourth, the challenges of applying the Blockchain to the electrical power system have been analyzed and discussed. Based on the dierent case studies a segregation has been made between challenges attributable to the characteristics of the Blockchain and challenges specically linked to the implementation of the case studies. Last, the practical application of the Blockchain to the electrical power system of the dierent case studies have been discussed. Explanation is given how the dierent case studies could be implemented within the electrical power system and what the role will be of dierent parties currently involved within the electrical power system.