A quantitative study on the requirement for additional inertia in the european power system until 2050 and the potential role of wind power

A significant amount of conventional power plants in the European power system is anticipated to be replaced by solar and wind power in the future. This may require alternative sources for inertia support. The purpose of the paper is to learn about the consequences on the frequency deviation after a fault in the European power system when more wind and solar are introduced and when wind is considered as a possible provider of inertia. This study quantifies the expected maximum requirement for additional inertia in the future European power system up to 2050. Furthermore, we investigated the possibility of wind power to meet this additional need by providing emulated inertia. The European power system of the EU-28 countries has been clustered to the five synchronous grids, UCTE, Nordic, UK, Baltic and Irish. The future European energy mix is simulated considering twelve different scenarios. Production units are dispatched according to their expected environmental impacts, which closely follow the minimum natural contribution of inertia, in descending order. The available capacity for all the types of production is considered the same as the installed. For all the simulated scenarios the worst case is examined, which means that a sudden disconnection of the largest production unit of the dispatched types is considered. Case study results reveal that, in most cases, additional inertia will be required but wind power may fully cover this need for up to 84% of all simulated horizons among all the scenarios on the UCTE grid, and for up to 98%, 86%, 99% and 86% on the Nordic, UK, Baltic and Irish grids, respectively

The Need for Additional Inertia in the European Power System until 2050 and the Contribution of Wind Power

In future years, a considerable share of conventional power plants in the European power system is expected to be replaced by solar and wind power, which may require additional inertia support for frequency control. Motivated by that, this paper quantifies the need for inertia in the future European power system until 2050. This paper also investigates the potential role of wind power as a provider of that by emulated inertia. The European power system of the EU-28 countries has been clustered to the four synchronous grids, UCTE, Nordic, UK and Baltic. A total of twelve different scenarios, developed by others, are considered, regarding the future energy mix in the EU. For each of these scenarios the worst case is examined. Production units are dispatched according to their sustainability which is coherent with the minimum natural contribution of inertia, in descending order. The available power output for all types of production is equal to the corresponding installed capacities, while a sudden disconnection of the largest production unit of the dispatched types is considered. Simulation results show that in most cases there will be a need for additional inertia and wind power could fully cover the additional inertia requirement up to 66.4% on the UCTE grid and for 98.3%, 92.4% and 99.1% on the Nordic, UK and Baltic grids, respectively

Continuous Assessment In Electric Power Engineering For Marine Engineers

To tackle the climate challenge, all sectors need to contribute, including electrified shipping. Electrified shipping is not only propulsion but also loading and unloading equipment. This transformation requires increased skills and understanding of electric power engineering for the personal onboard, not least for the marine engineers. Therefore, a changed in the curriculum was needed. However, when more theoretical course content was added to two consecutive courses, the student view and passing rate dropped. Although the student view improved quickly, the passing rate recovered slower. To address this issue, continuous assessment was introduced to counteract the drops. The aim of this study was to evaluate the theoretical parts and determine if continuous assessment could contribute to improve student learning and increase passing rate. The students expressed satisfaction with the changes, and the passing rate has increased. Most students also claimed that they learned more compared to standard assessment methods

Autonomous Power Systems based on Renewables - On generation reliability and system control

Today one billion people are living in non-electrified areas. A majority of the people are living in rural areas in developing countries where there are no possibilities, neither economical nor technical, for grid extension. Instead energy sources like wood and fossil fuels are used. However, these sources are not suitable due to environmental reasons and therefore electricity is favourable. Autonomous power systems are for that reason needed to secure a decent living standard and still preserving the environment. </p> To be able to study the availability of solar power for electricity production in rural areas a method for solar insulation simulation is proposed. The method is based on cloud coverage according to the Oktas-scale. Cloud coverage is often available due to its low demand on technical equipment during measurement. Since continuous data series are hard to find the model is based on transitions between different levels of cloud coverage. A stochastic model for wind speeds for electricity production based on quantified wind speed measurements is also proposed. The model is only dependent on the site-specific yearly mean value of the wind speed if a distribution of wind speeds from a location with a similar distribution is available. Other models used are for a weak constant flow-of-river and for storage. The load considered was industrial with its maximum during daytime. </p> The generation reliability of using only one production source was found to be low. Combinations of production sources or a storage capacity significantly improve the situation. Even if several different sources are used some over-capacity of power production is required.</p> Normally, the generation is cut down to control the frequency of a system. The generation is cut down to save fuel but in systems with “free” fuel energy will only be wasted. To limit the waste a method based on load frequency control of a frequency converter is proposed. Some new frequency converters are equipped with an active rectifier also voltage control can be implemented. A control design for voltage control is also proposed. Both the frequency and voltage control are tested through simulations and are verified in a laboratory environment. The behaviour of the frequency control as well as voltage control is even better as compared to normal control methods. It has been shown that both the frequency and voltage controllers can easily be implemented in the same off-the-shelf frequency converter

Linking household and productive use of electricity with mini-grid dimensioning and operation

Off-grid systems, and mini-grids in particular, are expected to play a significant role in improving electricity access to one billion people until 2040. One of the major challenges for mini-grids is associated with their high costs, low financial viability and local development impact. Productive use of electricity can be an important driver of local development and impacts the total load in a mini-grid. By using a mixture of high-resolution (minutes) measurements and long-term data (years) on electricity expenditures and purchased electricity from a mini-grid in the Tanzanian highlands, we analyse the technical and economic impact from household and productive use of electricity, respectively. The high-resolution data is analysed using performance indicators and the long-term data using regression tools. We find that a mixture of household use and productive use of electricity provides both technical and economic benefits for the operator. In addition, we find that while productive use customers only represent 25% of the customers, they generate 44% of the operator\u27s income. Furthermore, productive use of electricity customers are also likely responsible for the peak demand in the mini-grid, which occurs during day time. Lastly, we find empirical evidence suggesting that expenditures and demand are unit elastic, which has implications on economic policies for supporting rural electrification

Impact of demand-side management on the sizing of autonomous solar PV-based mini-grids

Solar PV-based autonomous mini-grids represent an economically affordable and robust electrification option for rural communities. However, the initial investment cost for renewable energy technologies such as solar PV remains high for rural communities. Implementation of demand-side management (DSM) could increase the cost-efficiency of mini-grids in rural areas. This requires demand-side knowledge, but little is still known of electricity demands in recently electrified areas and, in particular, of how DSM implementation could impact mini-grids. The few studies available focus either on systems or on appliance levels while this study aims to determine cost-efficiency impacts of DSM implementation at a category level. A shifting strategy is applied based on classification into high priority loads and low priority loads. Autonomous rural mini-grid components sizing for four different load categories and load flexibility are carried out using particle swarm optimization. The results show that different load category combinations result in large variations in terms of possible levelized energy cost reductions and, thus, in terms of the cost-optimal sizing of the mini-grid components. The DSM implementation on the household and productive use categories have the largest capacity of reducing the levelized energy cost, by 45.8% and 20.7%, respectively, compared to the no demand-side management case

Final Project Report of Cloudgrid

The CloudGrid project is done in cooperation between NTNU, IPE, ZHAW, Chalmers and STRI/ABB. The work is split in six work packages where ABB/STRI, ZHAW, Chalmers and NTNU were package leaders. Besides the authors of this report, the following persons contributed to the project: I. Zikmanis (IPE), M. Calder (ABB), M. Javdani (ABB), A. Babak (Chalmers), A. Bahmani (Chalmers), P. Chen (Chalmers), C. Agathokleopus (Chalmers), O. Lennerhag (STRI/ABB), G. Pinares (STRI/ABB), A. Perez (STRI/ABB) and S. Sanchez (NTNU). The cooperation between the parties is established on many levels. Laboratory facilities and field measurements were shared to a certain extent and data sharing through a cloud was accomplished. This has a high significance for future smart grids where data exchange is essential for stable operation as well as short term and long-term planning. The scope of work covers of the work packages covers a broad range of topics, including stability of current and future power grids, ancillary services, energy management as well as multiterminal HVDC links and high power converter design and control

Categorisation of Ancillary Services for Providers

The focus of the work presented here is to raise awareness of how ancillary services within the NordPool area could be of value in supporting the future grid, and who could be the provider of these services. The ancillary services considered here are not limited to the current market, but also services for future market solutions as well as services for fulfilment of grid codes. The goal is to promote the development of existing and novel solutions to increase the utilisation and thus the value of equipment within the power system. The paper includes a techno-economical categorisation of ancillary services, from a provider\u27s perspective, presenting opportunities and competition. Furthermore, procurers of services could utilise this kind of categorisation to identify possible providers or partners. The analysis of the categorisation shows a broad range of possible providers for each service and a broad range of possible services from each provider

Hydrokinetic Turbine Effects on Fish Swimming Behaviour

Hydrokinetic turbines, targeting the kinetic energy of fast-flowing currents, are under development with some turbines already deployed at ocean sites around the world. It remains virtually unknown as to how these technologies affect fish, and rotor collisions have been postulated as a major concern. In this study the effects of a vertical axis hydrokinetic rotor with rotational speeds up to 70 rpm were tested on the swimming patterns of naturally occurring fish in a subtropical tidal channel. Fish movements were recorded with and without the rotor in place. Results showed that no fish collided with the rotor and only a few specimens passed through rotor blades. Overall, fish reduced their movements through the area when the rotor was present. This deterrent effect on fish increased with current speed. Fish that passed the rotor avoided the near-field, about 0.3 m from the rotor for benthic reef fish. Large predatory fish were particularly cautious of the rotor and never moved closer than 1.7 m in current speeds above 0.6 ms-1. The effects of the rotor differed among taxa and feeding guilds and it is suggested that fish boldness and body shape influenced responses. In conclusion, the tested hydrokinetic turbine rotor proved non-hazardous to fish during the investigated conditions. However, the results indicate that arrays comprising multiple turbines may restrict fish movements, particularly for large species, with possible effects on habitat connectivity if migration routes are exploited. Arrays of the investigated turbine type and comparable systems should therefore be designed with gaps of several metres width to allow large fish to pass through. In combination with further research the insights from this study can be used for guiding the design of hydrokinetic turbine arrays where needed, so preventing ecological impacts

Cost Effective On-line Master Thesis Fair

Under corona restrictions it was expected to be extra hard to find an opportunity to do a master thesis in cooperation with a company as is the praxis in the investigated context. To mitigate this, a special master thesis fair was held in the area of Electric power engineering as most normally arranged fairs and other opportunities for the students to meet companies had been cancelled.For economic and practical reasons was Zoom and the function on break-out room used. A two-hour event was held with 15 companies, consisting of a mix of local, national, and international companies. The companies were given a great freedom to act within their respective break-out room. Around three quarters of the second-year students, in a two-year program, attended as well as a few from the first year. Initially the students, especially the international, focused on the big and international companies, like Ericsson, ABB and Volvo Cars, but then they were also looking for opportunities at smaller local companies. This created some waiting times, both for the students and some of the small and less known companies. Both the students and most of the companies were satisfied and it was clear that all wanted the arrangement to be repeated, some even if there would be no pandemic. The fair fulfilled its purpose but also gave insights on how future fairs, with limited economical resources, could be arranged, The recommendations are presented in form of a list at the end