In this paper the suitability of compressed hydrogen gas storage in salt caverns is analysed. The presence of microbial sulfate reducing bacteria create a contamination risk of H2S inside the cavern. Key cavern parameters that influence the production of H2S are highlighted by a chemical model. The model uses empirical data provided by Vattenfall, in order to predict what would happen inside an actual cavern. By doing so, it can be understood what cavern conditions are suitable for the storage of hydrogen. An analysis is done on the above ground process of a salt cavern storage plant to determine what extra separation steps are required to reach ISO limitations for hydrogen gas. The research is done by answering the following research questions: What are key cavern conditions that influence the suitability of hydrogen storage in salt caverns and for what purpose can the storage plant be implemented? The sub-research objectives are formulated as follows: 1. What are the potential process risks when storing hydrogen in salt caverns? 2. Are there substantial risks of contamination with subsurface hydrogen storage? What are the defining variables that contribute to said contamination? 3. How do these impurities build up when the salt cavern is used? 4. Is the equipment currently used in the gas storage facility in Epe useable for hydrogen gas storage? What changes should be made to the current storage process? When analysing future utilisation demands of hydrogen, one of the primary applications is energy con- version by fuel cells. There are severe limitations set by the International Organization for Standardization on the maximum amount of H2S in hydrogen gas used by fuel cells. This paper uses a chemical model based on PHREEQC to predict the chemical reactions in the cavern. In order to get close to actual results, the model input is constructed following empirical data of an existing salt cavern. With the chemical model different cases can be constructed each highlighting an important cavern constraint. What are the positive and negative forces on the production of H2S in salt caverns and what could be theoretically done to prevent H2S contamination? Primary aspects that positively contribute to H2S production, when the cavern is modelled as a batch reactor, sorted by significance are: • Bacterial growth and reduction rate • Brine volume and sulfate concentration. • Brine pH and ionic strength. • Cavern pressure and temperature. • Fe2+ and Fe3+ concentration. The chemical model only predicts what will happen in the cavern when there is no gas coming in or out, like a batch reactor. For this reason a dynamic model is constructed which predicts H2S outflow in the gas when applying different demand-cases to the cavern. The model results showed that with applying a maximum use case, which fluctuates between the maximum pressure and minimum pressure, there is still a minimum H2S output that is higher then the allowed limits. A demand curve is simulated where the cavern is used to power a hydrogen gas-turbine to profit from seasonal energy price changes. In this demand curve the cavern produces significantly less and less often, giving time for the H2S to build up. In two years, the H2S production reaches levels above the allowable limits set for hydrogen gas turbines. A gas process facility is required to eliminate H2S contamination, in order to size such a facility it was modelled in Aspen Hysys. The model is validated by using data from literature. After analyses of resulting process equipment and gas streams, the absorber tower’s efficiency is most dependant on its temperature its pressure and the absorbent flow rate. The water concentration is above ISO levels when withdrawn from the cavern. So to follow these limitations, an additional dehydration step is required. In conclusion the process is capable of accurately separating the H2S to below ISO limits. The process works using 6% of the potential chemical energy of hydrogen. The process is unable to purify the water concentrations. As a result of this research some conclusions can be made. When using salt caverns for long term hy- drogen storage can be a significant risk of H2S contamination as a result of microbial sulfate reduction. For the reference case the H2S concentrations reach above the levels set for fuel cell use and concentrations will increase in significance when utilisation of the cavern is decreased. For fuel cell application, a separation pro- cess based on MDEA gas sweetening can be used to get the hydrogen up to the demanded H2S purity. But a more economical solution would involve extensive testing of the cavern soil for any microbial activity. If there are no sulfate reducing bacteria there will be no problem. Other pre-process steps could involve increasing the pH of the brine in the cavern to avoid H2S production. As well as increasing the iron concentration in the brine.

The goal of this research is to be used as a framework for adding energy storage to aid in the connection of decentralized renewable energy generation in areas with limited connection availability to the electricity grid. The dependence on fossil fuels is reduced with the aim to reduce greenhouse gas emissions. In the Netherlands this means that natural gas is slowly faded out of our society. One consequence of this is the electrification of some functionalities that natural gas had, like heating houses and cooking. Additionally, more and more people are choosing to drive electric vehicles. On the supply side more and more renewable energy sources are being installed to increase the renewable energy mix in our electricity market. Because the supply and demand of electricity increases faster than new cables can be installed, the electricity grid is put under strain. The electricity grid was designed, decades ago, to only transport electricity from central, large energy generation plants to the consumer. However, nowadays there are also developers that are building 'decentralized' PV parks and wind farms. These decentralized generation systems are unable to be connected to the MV-grid. Energy storage has been identified to be a valuable asset to help with the penetration of renewable energy. Energy storage can help to match the supply and demand, improve the power quality, improve the variability of the power supply and smooth out the peaks of over-generation most associated with the congestion on the MV-grid. It is also possible to (temporally) replace the necessary grid reinforcement. However, energy storage is still very expensive. So it needs to be examined how energy storage can be interesting for this problem. A knowledge gap exist on energy storage for decentralized renewable energy generation for the Dutch medium-voltage grid. Additionally, no method was available to simulate such an problem. So this was researched in this study. The study has included a suitable financial model, various energy storage systems and operating strategies. Additionally, the interest of the developer of the DG plant and the DSO were included. For the developer the study has investigated the profitability of the system. The DSO is interested in minimizing the cost and resources of the connection of the hybrid DG system. From this the following research questions are formulated: Under what conditions can energy storage for decentralized renewable energy generation be economically feasible to mitigate connection scarcity on the medium-voltage grid? This was answered in three steps. Firstly, a model was built to accurately simulate energy storage in a hybrid DG system. This model must satisfy all technical requirements and be applicable to the Dutch electricity markets. Secondly, the simulation model was used to examine the hybrid system design to optimally profit from the storage system. From this it was concluded that a small energy storage system adds relatively more value in energy output and earnings than a large storage system. Additionally, it identified the pumped heat electrical storage system as the most profitable system for decentralized generation and the best performing technology is the LFP Li-ion battery. Also, storage is more beneficial for PV solar energy than for wind energy. In this section it was also found that in alleviating connection scarcity, grid reinforcement is more profitable than energy storage. And thirdly, different operating strategies for the hybrid system were investigated to optimally use the energy storage system. For a hybrid system with cable capacity limitations, peak shaving of over-generated energy is the most profitable operating strategy. This research has shown that energy storage can improve the energy output and revenue of a decentralized system with connection capacity limitations. Nevertheless, not adding energy storage is more profitable. A small energy storage system with a PV solar park can become economically feasible and more interesting than grid reinforcement. For this, energy storage technologies need to improve, especially the capital cost need to reduce, with more than half of the current cost. Additionally, this hybrid system needs to be located where grid reinforcement is costly or not possible.

Hydrogen enables renewable energy storage, and hydrogen carriers can allow easier transportation. This research was initiated to get more insight into transporting renewable hydrogen carriers (RHCs) by ship, which is one of the transportation options. The research was conducted in three steps. First, a system description with a literature study was made to select suitable RHCs, based on the production, and the performance as a hydrogen carrier. Secondly, a basic model for three transportation cases was made. Thirdly, a more detailed model was created to evaluate different transportation options. The four most attractive RHCs to be shipped are the synthetically produced: methanol, liquefied natural gas, liquid hydrogen, and liquid ammonia. In the model, short and long term options are evaluated for the same, mild and strict regulations compared to today. The following statements can be made, based on the results of the second model: • Ammonia is best suited in a scenario with strict regulation compared to today. Ammonia has a noncarbon nature; therefore, it is the most promising option in the long term. • Methanol is best suited for small scale transportation in the short and long term, in which the same regulations are active. The storage of methanol on board of the ship is relatively simple and it has a relatively high hydrogen density. • LSNG is best suited for large scale transportation in which the same regulations are active. LSNG has the highest hydrogen density of the discussed RHCs. The advantage of SNG is that during the reconversion to hydrogen, extra hydrogen will be produced because of the added steam, during steam methane reforming (SMR). • Liquid hydrogen is from a shipping point of view not the most suited for the transport of hydrogen, due to its low volumetric density and complex storage. Shipping liquid hydrogen has the advantage that it reduces extra conversion steps in other parts of the supply chain. Shipping RHCs and using the carriers as a fuel is an option which involves higher cost compared to current fossil fuel options. This relatively high share of fuel expenses using RHCs will make efficient powertrains relatively more attractive because it enables higher fuel cost savings. The most attractive engine configurations are a two-stroke internal combustion engine with a mechanical powertrain and a SOFC with a battery in an electric powertrain. The last option is especially promising for the long term, because of the technologic developments and increasing regulations in shipping. Overall the results indicate that shipping NH3 and using the carrier as a fuel is the most promising option for the transport of RHCs by ship. This research and constructed models can be used as a tool to evaluate different transportation options. However, used values are based on various sources and their corresponding assumptions, which can change significantly in the future.

The increase of the average world temperature, as a result of greenhouse gasses, is one of the greatest challenges the world is currently facing and will be facing in the future. One of the many efforts to reduce the increase of carbon dioxide, is to decarbonize the gas network by replacing natural gas with renewable gasses like green gas. Since the current gas network is not always suited for the injection of big green gas volumes, especially during summer periods, the process of decarbonizing the natural gas network requires adjustments of the current functioning of the gas network. Several technical adjustments for obtaining an increased green gas injection capacity exists, although, up to now, the potential green gas injection capacity obtained per solution was not known. Within this study, a dynamic gas network simulation model was developed wherein different gas network function strategies can be explored to obtain the potential green gas injection capacities. With the developed dynamic gas network simulation model one is capable to implement and simulate different gas distribution network configurations, specify green gas suppliers on the location of choice, simulate different gas demand scenarios and consumer profiles, adjust the city gate station pressure used for simulations of static- and dynamic pressure management, and to model the injection of excess green gas into a storage- and from the storage into the network. Within this study, the gas distribution network of Northeast Friesland, The Netherlands was analyzed on its green gas injection capacity after applying static pressure management, dynamic pressure management, and a pressure management strategy combined with storage. The gas network of Northeast Friesland was explicitly chosen since currently, green gas injection problems are experienced within this network. Following the results obtained from the simulations, a city gate station inlet pressure - demand table was defined. Within this table, the total gas demand measured within the network was plotted against the minimum city gate station inlet pressures, while still in compliance with the lower pressure boundary condition. Using this table, the optimal period to statically decrease- and increase the city gate station inlet pressures from 8.3 to 6.5 bar and from 6.5 bar to 8.3 bar, appeared to be respectively 1 May and 1 October. By changing the pressure to 6.5 bar, a safety margin of 1.5 bar was taken into account. For both static- and dynamic pressure management, green gas injection capacities ranging from 400 to 1600 m³/h, divided over three green gas suppliers, were analysed. The results were depicted against the total injectable hours, providing insight in the maximum green gas injection capacity while remaining eligible for the Stimulation of Sustainable Energy Production (SDE+) subsidy. Since with dynamic pressure management the city gate station can inject at lower inlet pressures, dynamic pressure management results in a greater green gas injection capacity. To point out, static pressure management provide 450 m³/h green gas injection capacity, whereas dynamic pressure management provides 650 m³/h green gas injection capacity without experiencing any injection problems.

The goal of this thesis is to identify under which boundary conditions
there is a business opportunity for an innovative electric thermal energy storage, with regards to the future electricity and heat markets. To meet this target, a novel optimization model has been developed as the main tool for the analysis of the storage and its profitability under different situations.

In this thesis, the applicability of a novel method – the Participatory Value Evaluation method – to the transition towards zero natural gas use at the local level of the case study neighborhood Hengstdal in Nijmegen was researched. The main objective of this thesis is to contribute to the development of the PVE method by researching the applicability of this novel method to the transition towards zero natural gas use at the local level of an existing neighborhood.

As a result of the research, only 6 respondents filled in the web tool and participated in the experiment. It must be concluded that it was not possible to apply the Participatory Value Evaluation method to the case study about the transition towards zero natural gas use of the neighborhood Hengstdal in Nijmegen. The process of implementing the PVE method is analyzed in order to identify factors that might have complicated the application process in this specific case study. To avoid future applications of the PVE method to suffer from the same complicating factors, several conditions are formulated. If these conditions are met, they could avoid or mitigate the impact of the complicating factors and could therefore make it possible to successfully apply the PVE method. However, future research is necessary in order to determine whether these conditions are sufficient for a successful implementation of the method.

Market organisation on energy networks is increasingly complex due to frequent emergence of new markets within and related to energy infrastructure. This research is conducted in cooperation with the Dutch Ministry of Economic Affairs and Climate Policy, and analyses the impacts of role demarcation policies on the development of the electric vehicle charging infrastructure market in the Netherlands by applying Exploratory System Dynamics Modelling and Analysis. In-depth behaviour based sensitivity analysis and scenario discovery has highlighted the most relevant dynamics on the market development over a period of 20 years. Limiting or restricting market access for network companies has showed to effectively influence market attractiveness positively and price developments negatively, both mainly on the short-term (within the first period of 10 years). The most significant and uncontrollable effects of uncertainties occur mainly on the long-term, granting the decision-maker the opportunity to adjust previous decisions when more accurate predictions can be made concerning the development of a specific market.

The iron law of oligarchy claims that the complex organisation will always end up in an oligarchy, no matter it was constituted originally. In that sense, the oligarchy should also happen in the Community Energy System (CES) as a complex self-govern common-pool resource system. The oligarchy situation raises the issue of the fairness and the health in the community since that subgroup of the member may steer the future decisions to be more favourable on one side than the others or may drive the rules to limit the active participation of others, or decrease the community cohesion. This paper specially concerned with the emergence of oligarchy in the CES and the effect of the iron law of oligarchy on the health and the fairness in the CES. The result shows that the iron law of oligarchy occurs in CES, but it is needed to make CES has the level of fairness and health required to support its continuity

More than 200 million Indians are without electricity, and the majority lies in the rural areas, where the central grid fails to reach due to unreliable distribution and inconsistent terrain. The solutions that reach include majorly, decentralized energy resources via solar micro-grids, or solar home systems. New projects of energy sharing are coming up which allows a household to become a consumer, as well as a producer of energy in case of excess and sell it to make profit. But these projects fail within few years due to number of social, technical, cultural, political, and environmental dynamic factors playing role in the community. Thus, the research question is raised that “Given the dynamics of rural communities of India, how can socio-technical systems of solar electrification be sustained?" This project develops an institutional innovation framework that helps answer this question. The framework is conceptualized and operationalized to understand that how the institutions around these factors can be changed by the community and individual actions in such socio-technical innovations and infrastructure systems. The study follows empirical analysis and develops simulation model (agent based model) for the case study of rural solar electrification in India, which helps in developing the institutions. The case study and the framework together emphasizes the importance of the institutional innovation approach, where institutions need to be adapted and diffused within the community to make the sustenance of the project possible in various domains. The final results show that new type of projects, labelled as hybrid projects, would be most sustained. These would be sharing projects and would only use the existing micro grids, when there is higher demand. Also, it emphasizes on the need to look at institutions development, not just as a collective perspective which happens with interactions of actions, but also a perspective of majority or collection of actions. The policies generated at two levels of usage (prioritization of resource usage, constraints on resource usage, etc.), and for acceptance of innovations (co-operative shops, in-house manufacturing, etc.) prove to help the sustenance of these electrification systems further.

Intermittent generation behaviour of wind and solar power units requires Transmission System Operators (TSOs) to activate balancing power to maintain a stable grid frequency. With the current strong growth in installed renewable energy capacity in The Netherlands, it is therefore expected that the volumes of activated balancing power will grow accordingly. In the Dutch balancing power market system, the activation of balancing power is remunerated against the highest activated balancing power bid in the respective time-block. Without a proportional increase in affordable balancing power bids, the economic costs of grid balancing in The Netherlands are expected to increase as a result. Imbalance power prices for positive balancing power, the counterbalancing of net shortages of power supply, may see a particularly strong rise, as the opportunity to quickly increase grid frequency places influential restrictions on the operation status of suitable power assets.
The financial opportunities inherent to this trend have gained the attention of non-traditional suppliers of technical positive balancing power potential, amongst which the energy-intensive industry and greenhouse farmers. However, limited insight into the exact value potential of market participation, and contradictory developments in the German market are currently preventing these parties to invest in unlocking their technical balancing power potential. A limited supply of new balancing power bids will further increase the economic costs of grid balancing. This study therefore sets out to identify a method to quantitatively determine the profitability potential of providing positive balancing power to the Dutch balancing power market to an individual market participant. A case study is conducted at AkzoNobel, whose sizeable chlorine plant possesses significant balancing power potential.

It is found that a Unit Commitment Model based on a Mixed Integer Linear Programming solver can be used to successfully replicate the market environment. To simulate market profitability to AkzoNobel over time, it should be supplied with input data of the future development of balancing power activation, the merit order of balancing power bids, and balancing power capabilities of the AkzoNobel plant.
Whilst the balancing power capabilities of the plant can be relatively simply and accurately modelled into a Unit Commitment Model, the same does not hold for the future activation of balancing power and respective prices in the merit order of balancing power bids. On the one hand, the future development of the various factors that comprise these sub-systems is characterized by significant uncertainty, as power system dynamics are notoriously hard to predict. On the other, both are the emergent behaviour from complex systems of interacting power system agents and assets. Their actions result from a large number of factors that may vary strongly on a short time scale. This causes difficulties in obtaining accurate projections of their behaviour on the required minute-by-minute time scale.
The activation of a high balancing power bid price in general also implies a strong grid frequency deviation. This implies that the profitability of providing balancing power is particularly sensitive to deviations in high imbalance power prices. As imbalance power prices are primarily determined by the specific height, volatility and frequency of high balancing power activation peaks relative to the height of prices in the merit order for those respective fifteen-minute time blocks, the choice of a method to obtain the input data of balancing power activation and the merit order must be based on a clear substantiation of their accuracy.

Various approaches to obtain data projections with the required accuracy have been assessed, for which the following conclusions are drawn. To determine the development of the future activation of balancing power bids it is advised to evaluate a combined method of statistical convolution of probability distributions and hidden Markov chains. However, this method must be preceded by significant additional research on critical complexities and uncertain developments in the balancing power market, for which it may not be possible to draw definite conclusions.
To obtain scenarios of the various potential developments in the volume and price elements of balancing power bids in the merit order it is suggested to use a stochastic modelling approach, such as Monte Carlo simulation, to evaluate the range of different compositions the merit order may take over time. It will, however, be difficult to strategize on the results, as the potential range of states of bid prices and volumes placed by individual agents with balancing power technologies are very wide.

These methods must be synthesized into an approach to determine balancing power market profitability based on the above combination of methods. Projections of the development of the key determinants of profitability in the balancing power market will inherently be associated with strong uncertainty. Considering the sensitivity of model output to inaccuracies it is very questionable whether the effort of further research weighs up against the benefits. It is concluded that it is not deemed feasible to obtain quantitative long-term indications of balancing power market profitability to an individual market participant. As a result, it is not advised to proceed with the execution of the suggested methods. It appears that alternative approaches to ensure the future affordability of balancing the power grid are more worthwhile pursuing.
It is instead advised to focus continued research on public incentive schemes to attract non-conventional suppliers of positive balancing power to provide their technical potential to the market if the market fails to find an economic optimum. Continued research could also focus on enhanced regulatory designs to reduce total balancing power requirements.

This research determines the value of local electrical energy storage. This value on one hand consists of a value for the DSO, which is the deferral of investments in their grid. On the other hand, the value of trading with these storage unit is determined. The trading value is constrained by the usage by the DSO.

Nowadays, by using the new ICT technologies the functional efficiency of the Smart Grid is increased but at the same time leads to a more vulnerable system and makes the Smart Grid a potential target for cyber-attacks. In fact, cyber-attacks are becoming one of the most serious threats in critical infrastructures. More than 80% of energy companies dealt with a growth in the incidents of successful cyber-attacks in 2015 (Herring, 2016). These facts show the importance of investigating the impacts caused by cyber-attacks on the system, and the need for a systematic way to assess it. In order to gain insights into the degree of influence of cyber-attacks regarding the energy prices and the power demand, the objective of this thesis is to shed light on the impact of two types of cyber-attacks, targeting the signals along the communication link, on the normal behavior of the system and their influence on the behavior of consumers and utilities, when a price based Demand Response (DR) program is used.

Increased use of the distribution grid due to the uptake of distributed energy resources and the expected penetrations of Electrical Vehicles (EVs) could lead to congestion problems in the distribution grid. Congestion refers to issues related to the overheating of components or voltage issues in the distribution network. Avoiding these issues is crucial to maintain a stable, economical and reliable electricity grid. By using the flexibility of aggregated EVs large investments in grid reinforcement can be avoided. However, a holistic approach is necessary to manage the procurement of flexibility services for all stakeholders involved. One approach is the Universal Smart Energy Framework (USEF), a framework that integrates the existing electricity market with a market for flexibility services from the aggregator to the Distribution System Operator (DSO). This master thesis presents a study on the flexibility market as described by USEF from the perspective of a commercial aggregator of EVs. USEF presents a framework in which flexibility potentially provides financial opportunities for aggregators of EVs. However, it is not clear what the financial impact on the charging costs of an aggregator of EVs is and in what way an aggregator has to adapt its charging logic when trading with DSOs. Therefore, the aim of this thesis is to answer the following question: how can an aggregator of EVs offer flexibility services to a USEF compliant market at distribution level? This report presents an in-depth analysis on USEF, determines the impact of network constraints from USEF on the charging costs of an aggregator of EVs and improves the charging strategy under USEF constraints.