Incorporation of wind energy into the electricity generation system requires a detailed analysis of wind speed in order to minimize system balancing cost and avoid a significant mismatch between supply and demand. Power generation and consumption in the electricity networks have to be balanced every minute, therefore it is necessary to study wind speed on a one-minute time scale. In this thesis, we examine the statistical characteristics of one-minute average values of wind speed. One-minute wind speed is available from a single site in Great Britain while there are records of ten-minute wind speed available. We apply a modified Gibbs sampling algorithm to generate one-minute wind speed required for optimization modelling from the available ten-minute wind speed. System balancing costs are estimated through optimization modelling of the short-term electricity generation with wind energy contributing to the total supply. Two main drivers of additional system cost caused by wind energy are variability and unpredictability of one-minute wind speed. Further, a linear mathematical optimization model for a problem of short-term electricity generation is presented to calculate an additional balancing cost that appears as a result of wind energy variability. It is then shown that this additional balancing cost can be estimated using the statistical characteristics of wind energy present in the system. The unpredictable characteristic of wind speed is analysed with the techniques of stochastic programming. Uncertainty of the expected wind speed is represented through scenario trees and stochastic linear optimization models are used to calculate the extra cost due to uncertainty. Alternative optimization models are compared by calculating the additional balancing cost and the extent of imbalance between power generation and consumption in the system.

The purpose of the project is to determine the impact of solar cells and electrical vehicles on the future electricity grid and distribution network. Future electricity grids will be affected differently than it does today. Therefore, it is important to determine the impacts so that the current electricity distribution system can be developed and redesign to achieve the future demand. In Sweden, government has changed rules and laws in order to make it easier for private sector to invest in renewable energy sources. Our project focused on the impact of the solar cells and electric vehicles on the low voltage electricity distribution. Solar cells have become more popular than ever and that leads to many countries in utilizing their energy needs from solar and the same is going to happen here in Sweden. It is needed to find out how the impacts on the low voltage grids will be if many private individual install solar panels in their own homes and what will happen when they start to supply electricity, which is excess from the production of their solar cells, back to the grid? What should be done in order to maintain the electricity’s quality in term of voltage? Meanwhile, electric vehicle popularity rises every year, which means that electricity demand will rise proportionally with the number of electric cars in the country. Should something be done with the power supply to meet the power needs of electric cars? Is it possible to use the electrical car battery as a backup power? How electric vehicle charging’s behavior will impact on the low voltage? In this project, data and pictures has taken from different sources and consolidated for analysis purpose. This thesis contained information about solar radiation, solar cells, electric vehicles, and batteries, rules for installation of solar cells regulations, electricity grids, and electrical power quality, results of researching and eventual solutions for expected problems. / <p>Presentation har gjort med båda svenska och norska språket . </p>

In order to achieve Net Zero emissions in the UK by 2050 and decarbonize the energy sector the integration of increased volumes of additional renewable wind energy is critical. Distribution network operators face challenges in increasing the capacity of this variable source of energy onto the electricity networks. Distribution network operators in Scotland have integrated more wind energy onto their networks to date and have learnings through experience that are worth investigating. The research conducted in this thesis is a comparative analysis of the Network Development Plans of three UK distribution Network Operators, Scottish Power Energy Networks in southern Scotland, Scottish and Southern Energy Networks in northern Scotland, and UK Power Networks in the southeast of England area.  The method used is a comparative analysis of the Network Development Plan documents using a set of pre-selected variables while also allowing for other new emergent variables to be included in the analysis and results. The pre-defined variables are grid capacity, flexibility, grid integration technologies, market structures, planning and regulatory framework, operational experience, efficiency, and location / wind availability. Variable codewords were used to perform the document search and related keywords were used where returns were insufficient. Two further variables emerged frequently in the texts as a result of keyword searches which were transmission links and energy storage and were also included in discussions. Results of the research reveal that Scottish Hydro Electricity Power Distribution, who operate in the north of Scotland, and Scottish Power Energy Networks who operate in the south of Scotland, appear to have a more innovative and proactive approach to grid integration technologies, stakeholder engagement, and innovation projects for increased wind energy integration. UK Power Networks have a larger investment plan approved by the UK electricity and gas markets regulator, Ofgem, but lack of experience in integration of large volumes of wind energy leaves it lagging behind its counterparts when it comes to integration and management of wind energy. Findings from analysis of the Network Development Plans is backed up in literature which claim that energy storage, smart grid technologies, and infrastructure upgrades are critical for integration of wind energy to transform it into a reliable and predictable energy source and manage its integration on to the electricity networks.

Existing low-voltage networks may not accommodate high penetrations of low-carbon technologies. The topic of this thesis is unbalance, which if minimised can delay or avoid the constraining of these technologies or the replacing of still-useful network assets. Most of the discussion on unbalance, as seen in the standards and the literature, centres on the effects of voltage unbalance on consumer equipment. Its effects on the network are not equally reported. This thesis recognises fundamental differences between the consumer and network perspectives. It can inform distribution network operators on the interpretation of measurements taken on low-voltage networks and guide research on unbalance due to high penetrations of low-carbon technologies. Much of the work involved simulations of LV networks. Initially, existing 3 x 3 or 5 x 5 approaches to the forward-backward sweep method were thought suitable. After a review of these approaches however, there were doubts as to how accurately they accounted for the shared neutral-earth return path on which the out-of-balance current flows. This led to the derivation of a new 5 x 5 approach using only Kirchhoff s voltage (KVL) and current laws (KCL). Its results are validated thoroughly in the thesis. In addition to satisfying KVL and KCL, they match Matlab SimPowerSystems exactly and are in close agreement with measurements taken on a very unbalanced rural feeder. This thesis also investigates the mitigation of unbalance using the static balancer. This is a transformer with a single interconnected-star winding. It was used in 1930-1950s to correct unbalance. Contributions are made for its possible re-introduction as a retrofit option. They include a model for use in the forward-backward sweep method, validated by laboratory and field measurements, and the quantification of the static balancer s strengths and weaknesses as this can help identify when it should be used.

The UK’s decarbonisation strategy to increasingly electrify heating and transport will change the demand requirement on the electricity system. Additionally, under a climate change future, it is projected that the decarbonised grid will need to be able to operate under higher average temperatures in the UK, increasing the need for comfort cooling during summer and leading to additional electricity demand. These new demands will result in greater variation between minimum and peak demand as well as a significant increase in overall demand. Concurrently, supply-side decarbonisation programmes may lead to more intermittent renewables such as wind, PV, tidal and wave, elevating variability in electricity generation. Coupled with the anticipated higher variation in demand this brings on several challenges in operating the electricity grid. In order to characterise these challenges this research develops a bespoke electricity dispatch model which builds on hourly models of demand and generation. The hourly demand profiles are based on a high electrification of heating, transport and cooling coupled with future temperatures premised on the UKCP09 high emission scenario climate projections. The demand profiles show a significant increase in peak demand by 2050 reaching 194 GW, mainly due to summer cooling loads which contribute 70% of the demand. The cumulative CO2 emissions budgets of the GB power sector that are consistent with avoiding global climate change to 2°C are used to develop two low carbon generation scenarios distinguished by the amount of intermittent renewable generation technologies. The dispatch model tests the capability of generation scenarios with the use of hourly generation models in meeting future demand profiles out to 2050.The outputs from dispatch model indicate that there are shortages and excesses of generation relative to demand from 2030 onwards. The variability analysis outlines low and high generation periods from intermittent technologies along with the pace at which intermittent generation increases or decreases within an hour. The characterisation of variability analysis reveals the type of reserve capacity or smart solutions that are required to maintain the security of electricity supply. The solutions that could address the challenges quantified from the model outputs in operating a decarbonised GB electricity grid are explored using expert interviews. The analysis of the stakeholder interviews suggests smart grid solutions that include technologies as well as changes in operational procedures in order to enhance the operational resilience of the grid. Active Network Management through monitoring and control, demand management, storage systems and interconnectors are proposed to address challenges arising from varying demand and generation variability.