The format the text is saved as is unreadable, so i retyped it to my best ability.  This master thesis contains my work of studies of a short term planning model, with the time span of one week, or 168 hours. The models are based on the future hydropower system in pjorsa- and Tungnaa- river system, located in the south part of Iceland. The purpose ot this thesis is to formulate and develop one week operation schedules for this future power generation system, which for a given inflow-and load forecast returns a good schedule for each power stations in the system. The planning problem is formulated as a mathematical programming problem. The models used to describe and implement the system under study are a piecewise linear models. For piecewise linear models the breakpoints of the model are the local best-efficiency points. The objective is to return operation plan for each power station in the system, where the the volume of stored water in the end of the planning period is maximized through optimal discharge plans. It is needed to supply contracted load, regulation- and balance power for each hour during the planning period under study. Two test cases are made for each model in this theises. The former case describe winter operation, with high consumptions and lower natural inflow to the reservoirs. In the latter case the consumption is low and river inflow high and is meant to describe summer time operation. Obtained results show that piecewise linear model gives more realistic results when the load consumption is high and the inflow is low. During summer time, with low load and high inflow. The piecewise linear models schedule more often discharge not on local best-efficiency points. This behavior can be decreased by insertion a penalty cost of discharge changes.

Samhällets beroende av fossila bränslen leder till en varmare atmosfär och högre havsnivåer. För att bromsa utvecklingen måste utsläppen minska. En lösning är att implementera förnybara elproduktionsanläggningar och energilagring i större utsträckning. Då Sveriges vattenkraftsutbyggnad har stannat av de senaste 30 åren behövs en implementering av andra förnybara metoder, i kombination med den redan utbyggda vattenkraften, för att förse framtidens elbehov. För arbetet ligger fyra olika orter med redan installerade vattenkraftverk i fokus, nämligen Fredriksberg, Hällefors, Grythyttan och Sävenfors. Syftet med arbetet är att se hur man kan integrera solcellsanläggningar med och utan batterienergilagring i redan installerade vattenkraftsystem för energiproduktion i mindre lokala elnät. Målet med arbetet är indelat i två olika delmål. Det första målet är att få fram hur stora solcellsanläggningar som är implementerbara i mindre orter utifrån ett ekonomiskt perspektiv, det vill säga hur stor kapacitet som är möjligt att installera samtidigt som anläggningen är ekonomiskt lönsam. Det andra delmålet är att få fram hur stor del av orternas egna elbehov som kan täckas med vattenkraft, solceller och med eller utan batterilagring. En modell för systemet byggdes i Simulink, där vattenkraften antogs producera kontinuerligt över året vid vissa tider på dygnet. En känslighetsanalys gjordes på solcellsanläggningarnas ekonomiska lönsamhet vid olika framtidsscenarier gällande elprisutveckling i Sverige fram till år 2050. Resultat från simuleringar visar på att orterna får olika hög grad ekonomisk lönsamhet vid olika mängd installerad kapacitet solceller. Generellt ger ett högre elbehov och ett lägre förhållande mellan producerad el från vattenkraft och elbehov ekonomisk möjlighet att installera större solcellsanläggningar. Gällande de olika framtidsscenarierna finns det vissa scenarier som kan förlänga solcellsanläggningarnas återbetalningstid. Ett scenario, med stor implementering av småskalig förnybar energi i Sverige, medför att mindre kapacitet solceller bör installeras för att garantera ekonomisk säkerhet för investeringen. Batterilagring bidrar till ett ökat försett behov då det finns ett överskott på producerad el från solcellerna. Andelen egenförsett behov ökar dock mer på orter där vattenkraften är mindre dominerande. Det kan bero på att det finns fler tillfällen då det kan förse ett elbehov på orten, vilket vattenkraften annars tagit över i andra orter. En viktig grundpelare till att batterilagringen inte resulterar i en ekonomisk förlust är multifunktionen att förse eget behov och vara kopplad till en stödtjänst. Stödtjänsten är en uppreglering av nätets frekvensvariation vilket behöver prioriteras över stora delar av dygnet. Över de tre olika orterna resulterade förhållandet installerad MWp solceller genom MWh batterier på cirka 3. / Society's dependency on fossil fuels leads to a warmer atmosphere and rising sea levels.  Emission levels need to be reduced to slow down this development. One solution is to implement renewable energy and renewable energy storage systems on a wider scale. Sweden’s expansion of hydro power has come to a stop 30 years ago, which leads the focus to other methods of renewable energy generation in combination with the already built hydro power plants for future energy supply. This work focuses on already built-in hydro power plants in smaller communities as Fredriksberg, Hällefors, Grythyttan and Sävenfors. The scope of this work is to investigate the possibilities of integrating photovoltaic systems, with and without battery energy storage, in operating hydro power plants in smaller local grids. The goal of this work is divided into two sub-goals. The first sub-goal is to find out what size of photovoltaic systems can be implemented in smaller communities from an economic perspective, that is, how much capacity is possible to install at the same time as the plant is economically profitable. The other sub-goal is to find out how much of the communities’ own electrical demands are covered with hydro power, photovoltaics and with or without battery energy storage. A model was built in Simulink, where the hydro power was assumed to produce electricity continuously throughout the year at certain times of the day. A sensitivity analysis was performed on the profitability of the photovoltaic systems using different scenarios for the future electrical price in Sweden until the year of 2050. Results from the simulations show that different communities have different degrees of profitability for varying capacities of photovoltaics. A higher electricity demand and a lower ratio between produced electricity from hydro power and electricity demand provides financial opportunities to install larger capacities of photovoltaic systems. Regarding the future price scenarios, there are some scenarios that will prolong the photovoltaics payback-time. One scenario, with a great implementation of small-scale renewable systems, results in a recommendation to install lower capacities of photovoltaics to ensure financial security on the investment. Battery energy storage contributes to increased provided demands because of the surplus electricity produced from the photovoltaics. The proportion of provided demands is increasing more in communities where hydro power is less available. It can be a result of opportunities where the hydro usually is providing needs in those timeframes in other communities. An important pillar in the positive result of the economy of battery energy storage is its multifunction to supply demands and provide a support service, where the service of regulating frequency on the main grid needs to be prioritized over large parts of the day. The ratio between installed MWp photovoltaics and MWh battery energy storage resulted in approximately three across three different communities.

In the southern part of Sweden, specifically in price zone SE4, there is an increasing cost of electricity and a contemporary supply deficit. This research aims to elaborate on the deficit in electrical generation to consumption in SE4. The found values indicate a 42% unmet demand, equaling 5.152 TWh annually. However, long-term solutions on a European and Swedish regional level require years to be implemented, and the complications of permitting and public acceptance of new renewable projects pose a delaying factor. Henceforth, repowering aging wind farms, which are nearing the end of their operational lifetime, presents a viable solution. In this research, a case study for SE4 old wind sites has been identified and assessed, using three repowering scenarios: Scenario I - wind, Scenario II - wind & solar, and Scenario III - wind, solar & storage system. The scenarios have been simulated using the available renewable resources in the case study area and retrofitted within the exact required surface area that the current case study system occupies of 42.71 km2. The results have shown that all scenarios have great potential to limit the 42% deficit of supply in SE4 when implemented. The share of annual generation found for each scenario was 0.939 TWh, 3.08 TWh, and 3.962 TWh, respectively. These annual generations will contribute to 7.7%, 25.32%, and 32.5% of the annual electrical consumption found for SE4. The first scenario of only wind energy is the most economical and has the highest capacity to productiveness of area ratio, at a 22.27 GWh/km2/year for 68 MW installed capacity.

This thesis presents novel algorithms and a revised modeling framework to evaluate residential aggregate electrical demand response performance under scenarios with limited device-state feedback. These algorithms permit the provision of balancing reserves, or the smoothing of variable renewable energy generation, via an externally supplied target trajectory. The responsive load populations utilized were home heat pumps and deferred electric vehicle charging. As fewer devices in a responsive population report their state information, the error of the demand response program increases moderately but remains below 8%. The associated error of the demand response program is minimized with responsive load populations of approximately 4500 devices; the available capacity of the demand response system scales proportionally with population size. The results indicate that demand response programs with limited device-state feedback may provide a viable option to reduce overall system costs and address privacy concerns of individuals wishing to participate in a demand response program. / Graduate