In hydropower plants, a local load, also known as a dump load, could be installed to balance theelectrical grid by consuming excessive power. This enhances the dam safety. A design for asmall-scaled three-phase dump load is presented in this thesis. The designed model is built andevaluated through simulations and experiments. The results show that the system is purelyresistive. The per phase resistance of the model can be calculated with geometrical analysis ofthe design.

Inflow forecasting is important when planning the use of water in a hydropower plant. The process of making forecasts is characterized by using knowledge from previous events and occurrences to make predictions about the future. Traditionally, inflow is predicted using hydrological models. The model developed by the Hydrologiska Byråns Vattenbalansavdelning (HBV model) is one of the most widely used hydrological models around the world. Machine learning is emerging as a potential alternative to the current HBV models but needs to be evaluated. This thesis investigates machine learning for inflow forecasting as a mixed qualitative and quantitative case study. Interviews with experts in various backgrounds within hydropower illustrated the key issues and opportunities for inflow forecasting accuracy and laid the foundation for the machine learning model created. The thesis found that the noise in the realised inflow data was one of the main factors which affected the quality of the machine learning inflow forecasts. Other notable factors were the precipitation data from the three closest weather stations. The interviews suggested that the noise in the realised inflow data could be due to faulty measurements. The interviews also provided examples of additional data such as snow quantity measurements and ground moisture levels which could be included in a machine learning model to improve inflow forecast performance. One proposed application for the machine learning model was as a complementary tool to the current HBV model to assist in making manual adjustments to the forecasts when considered necessary. The machine learning model achieved an average Mean Absolute Error (MAE) of 1.39 compared to 1.73 for a baseline forecast for inflow to the Lake Kymmen river system 1-7 days ahead over the period 2015-2019. For inflow to the Lake Kymmen river system 8-14 days ahead the machine learning model achieved an average MAE of 1.68 compared to 2.45 for a baseline forecast. The current HBV model in place had a lower average MAE than the machine learning model over the available comparison period of January 2018. / Tillrinningsprognostisering är viktig vid planeringen av vattenanvändningen i ett vattenkraftverk. Prognostiseringsprocessen går ut på att använda tidigare kunskap för att kunna göra prediktioner om framtiden. Traditionellt sett har tillrinningsprognostisering gjorts med hjälp av hydrologiska modeller. Hydrologiska Byråns Vattenbalansavdelning-modellen (HBV-modellen) är en av de mest använda hydrologiska modellerna och används världen över. Maskininlärning växer för tillfället fram som ett potentiellt alternativ till de nuvarande HBV-modellerna men behöver utvärderas. Det här examensarbetet använder en blandad kvalitativ och kvantitativ metod för att utforska maskininlärning för tillrinningsprognostisering i en fallstudie. Intervjuer med experter med olika bakgrund inom vattenkraft påtalade nyckelfrågor och möjligheter för precisering av tillrinningsprognostisering och lade grunden för den maskininlärningsmodell som skapades. Den här studien fann att brus i realiserade tillrinningsdata var en av huvudfaktorerna som påverkade kvaliteten i tillrinningsprognoserna av maskininlärningsmodellen. Andra nämnvärda faktorer var nederbördsdata från de tre närmaste väderstationerna. Intervjuerna antydde att bruset i realiserade tillrinningsdatana kan bero på felaktiga mätvärden. Intervjuerna bidrog också med exempel på ytterligare data som kan inkluderas i en maskininlärningsmodell för att förbättra tillrinningsprognoserna, såsom mätningar av snömängd och markvattennivåer. En föreslagen användning för maskininlärningsmodellen var som ett kompletterande verktyg till den nuvarande HBV-modellen för att underlätta manuella justeringar av prognoserna när det bedöms nödvändigt. Maskininlärningsmodellen åstadkom ett genomsnittligt Mean Absolute Error (MAE) på 1,39 jämfört med 1,73 för en referensprognos för tillrinningen till Kymmens sjösystem 1–7 dagar fram i tiden under perioden 2015–2019. För tillrinningen till Kymmens sjösystem 8–14 dagar fram i tiden åstadkom maskininlärningsmodellen ett genomsnittligt MAE på 1,68 jämfört med 2,45 för en referensprognos. Den nuvarande HBV-modellen hade ett lägre genomsnittligt MAE jämfört med maskininlärningsmodellen under den tillgängliga jämförelseperioden januari 2018.

Operation of a pumped storage system is dictated by the time dependent price of electricity and capacity limitations of the generating plants. This thesis considers the optimization of the Smith Mountain Lake-Leesville Pumped Storage-Hydroelectric facility. The constraints include the upper and lower reservoir capacities, downstream channel capacity and flood stage, in-stream flow needs, efficiency and capacity of the generating and pumping units, storage-release relationships, and permissible fluctuation of the upper reservoir water surface elevation to provide a recreational environment for the lake shore property owners. Two formulations are presented: (1) a nonlinear mixed integer program and (2) a discretized linear mixed integer program. These formulations optimize the operating procedure to generate maximum revenue from the facility. Both formulations are general and are applicable to any pumped storage system. The nonlinear program retains the physical aspects of the system as they are but suffers from non-convexity related issues. The linear formulation uses a discretization scheme to approximate the nonlinear efficiency, pump, turbine, spillway discharge, tailrace elevation-discharge, and storage-elevation relationships. Also, there are binary unit dispatch and either/or constraints accommodating spill and gated release. Both formulations are applied to a simplified scheme of the Smith Mountain Lake and Leesville pumped storage system. The simplified scheme uses a reduced number of generating and pumping units at the upper reservoir to accommodate the software limitations. Various sensitivity analyses were performed to test the formulations. The linear formulation consistently performs better than the nonlinear. The nonlinear solution requires a good starting point for optimization. It is most useful as a verification tool for the solution from the linear program on all occasions. The formulations yield the best schedules for generating and pumping. A coarse time interval limits the use of all pumps in the presence of the spill constraint. A sufficiently large difference in the diurnal unit price encourages short-term pump back as opposed to a weekly cycle. The Leesville (downstream) reservoir affects the power production schedule with its large (approx. 9 ft) forebay rise for every foot drop at the Smith Mountain Lake. The linear formulation provides a valuable tool for studying the system under a wide range of conditions without having to worry about the computational difficulties associated with the nonlinear formulation. / Master of Science

The SNTEMP (U.S. Fish and Wildlife Service), QUAL2E (U.S. Environmental Protection Agency), and RQUAL (Tennessee Valley Authority) stream temperature prediction models were evaluated. All models had high predictive ability with the majority of predictions, >80% for Back Creek (Roanoke County, VA) and >90% for the Smith River tailwater (SRT) (Patrick County, VA), within 3°C of the measured water temperature. Sensitivity of model input parameters was found to differ between model, stream system, and season. The most sensitive of assessed parameters, dependent on model and stream, were lateral inflow, starting-water, air, and wet-bulb temperature. All three models predicted well, therefore, selecting a model to assess alternative water management scenarios was based on model capabilities. The RQUAL model, used to predict SRT temperatures under alternative hydropower release regimes, illustrated potential thermal habitat improvement for brown trout (Salmo trutta) compared to existing conditions. A 7-day/week morning 1 hr release was determined to best concurrently increase occurrence of brown trout optimal growth temperatures (+10.2% mean), decrease 21°C (state standard) exceedances (99% prevention), and decrease hourly changes in temperature (-1.6°C mean) compared to existing thermal conditions. The SNTEMP model was used to assess thermal habitat under flow, shade, and channel width changes occurring from future urbanization within the Back Creek watershed. Predictions reveal that additional urban development could limit thermal habitat for present fish species by elevating summer mean daily temperature up to 1°C and cause 31°C (state standard) exceedances compared to existing conditions. Temperature impacts were lessened by single rather than cumulative changes suggesting mitigation measures may maintain suitable thermal habitat. / Master of Science

The deregulation of the Electricity Sector in US has led to a tremendous increase in the inter-regional wholesale electricity trade between neighboring utilities or regions. For instance, the generation deficit regions may choose to import power from surplus regions; thus the wholesale electricity market prices in the regions are also affected by the dynamics of its electricity trade with other regions. Valuable insights into such imports/exports ahead of time have become crucial market intelligence for the various academicians and the market players associated with the industry. In this thesis, the task of short-term forecasting of the power flows over three major transmission interties of the Pacific Northwest region, namely the Pacific AC Intertie, the Pacific DC Intertie and the Northern Intertie, is successfully accomplished. The Pacific AC and the Pacific DC interties connect the Pacific Northwest region of US with the state of California. The Northern Intertie is the only intertie connecting the British Columbia region in Canada with the Pacific Northwest US. Box-Jenkins ARIMA (Auto Regressive Integrated Moving Average) and Transfer function methodologies are used as the statistical tools to identify the forecasting models in this thesis. The data requirement for all of the models is restricted to publicly available data. / Master of Science

To ensure that production is equivalent to consumption, hydro power units are used becauseof their high reliability as a regulation power source.Regulation is used due to the unbalance in the power grid between the production and con-sumption, for which reserved hydro power units for Primary and Secondary regulation areused. Primary regulation is done to balance the frequency in the grid by automatically ad-justing the water flow that runs through such units.Secondary regulation units are used for compensation of lost power production or for takingaway the surplus of power production and has become more intermittent today, which re-sults in more starts and stops of units. The increased intermittency of the units causes strainson the various components especially the generators. Therefore it is of great interest to knowthe total start-stop cost of the secondary regulated units. The theoretically calculated costsmay not coincide with the actual costs, as there are many parameters and complex calcula-tions that are included in the start-stop costs.A revised version of a calculation model was done for the secondary regulated units, basedon an earlier work, and showed higher start-stop costs compared to the earlier study, mostlybecause of these parameters:• Start and stop frequency for each unit has increased because of a higher flexibility in theelectrical market prices.• Age of the generators and turbines. Many of these components are near their time forrehabilitation which results in a higher maintenance cost.• The average failure frequency for each hydropower unit was thoroughly investigated andshowed to be higher than earlier estimated. A more individually calculated failure fre-quency for each unit showed to be higher than the earlier used standard average values.One important result is that the units with the lowest start and stop costs are preferred to beused, with the exception that the units with high start and stop cost, because of considerableleakage cost, should be used as much as possible. / För att säkerställa att elproduktionen är likvärdig med konsumtionen, används vattenkraf-ten för reglering eftersom den är lätt att reglera; såväl i det omedelbara tidsperspektivet (s)som i det lite längre (minuter/timmar/dagar). Reglering i kraftnätet krävs på grund av attobalans i elnätet mellan produktion och konsumtion hela tiden uppstår. Aggregat reserverade för primär- och sekundärreglering används för detta syfte. Primärreglering sköts auto-matiskt efter hur nätfrekvensen varierar genom att snabbt justera vattenflödet som går ge-nom ett aggregat. Sekundärreglerade aggregat används för kompensering av förlorad elleröverskott av effekt och används mer intermittent, vilket innebär många start och stop avdessa aggregat. Den mer intermittenta användningen av enheterna har blivit vanligare desenaste decennierna och orsakar påfrestningar på de olika komponenterna i aggregatet, särskilt generatorn. Det är därför av stort intresse att veta den tillkommande kostnaden somuppstår p.g.a. start-stopp av sekundärreglerade enheter. De teoretiskt beräknade kostna-derna sammanfaller ibland inte med de faktiska kostnaderna, eftersom det finns många pa-rametrar och komplicerade beräkningar som ingår i start-stopp-kostnaderna.I denna studie har det tagits fram en reviderad beräkningsmodell för de sekundärregleradeaggregaten. Resultatet visar på högre start-stopp-kostnader jämfört med en tidigare studie,främst på grund av dessa parametrar• Start- och stoppfrekvensen för varje enhet har ökat på grund av den ökade flexibilitetenpå elpriserna i elmarknaden.• Åldern på generatorer och turbiner. Många av dessa komponenter är nära deras tid förrehabilitering vilket resulterar i en högre underhållskostnad.• Den genomsnittliga felfrekvensen för varje vattenkraftaggregat undersöktes grundligtoch visade sig vara högre än tidigare bedömt. En mer individuellt beräknad felfrekvensför varje aggregat visade sig vara högre än det tidigare använda genomsnittliga värdetför alla aggregat. Ett viktigt resultat är att detta examensarbete visar tydligt på att aggregaten med Ett viktigt resultat är att detta examensarbete visar tydligt på att aggregaten med lägst start-och stoppkostnader bör väljas för drift i första hand. Undantag från detta är de aggregat medhöga start- och stoppkostnader som en följd av betydliga läckagekostnader, som bör köras så mycket det går.

Participating in the ancillary services market, alongside the day-ahead market, can be economically beneficial for market actors. However, adopting an optimal bidding strategy is not straight forward. The decision-making process is subject to uncertainty, due to the prices being unknown before gate closure times. Furthermore, at some instances, the day-ahead production schedule might have to change to obtain the ability of reserving capacity. Previous research have studied the gains of adopting a coordinated bidding strategy. However, most of this research focus on the day-ahead market and the intraday market. Less focus it put on the ancillary services market. Additionally, smaller case studies are often carried out in previous research. For producers owning multiple power plants, treating every plant individually turns into a time consuming and complex process. This project constructs a model that instead uses a top-down approach. A system of hydropower plants is aggregated into one curve, representing the water valuation. This, together with a representation of available capacity for the system, gives the cost of delivering capacity. The cost is incurred through not producing optimally on the day-ahead market. Thereafter, modern portfolio theory is applied when determining how to allocate between the different products. Modifications to the traditional theory are made in order to better suit this context. Price forecasts are modelled as expected return, and historical price forecasting errors represents the risk. The model output is bid ladders for all capacity ancillary services. A top-down approach makes it possible for large scale producers to adopt the methodology, and results in a structured way of constructing the bids, while aiming at spreading the risk.

O interesse mundial e os investimentos em fontes renováveis de energia têm aumentado consideravelmente nos últimos anos. Estas tecnologias têm a vantagem de aproveitar os recursos disponíveis localmente, reduzindo a dependência de fontes externas. Entretanto, um dos principais problemas associados a muitas das tecnologias de energias renováveis é sua imprevisibilidade ou intermitência. O armazenamento de energia é a técnica mais utilizada para moderar estas intermitências. Para aproveitamento em grande escala, os reservatórios hidrelétricos (de usinas hidrelétricas convencionais com reservatório e usinas hidrelétricas reversíveis) representam a tecnologia mais madura e amplamente aproveitada para armazenamento de energia elétrica na forma de energia potencial no volume de água. Isto faz destes uma opção importante a ser incluída no projeto de um sistema autônomo híbrido de geração de energia. Segundo diferentes autores consultados, o software HOMER (Hybrid Optimization Model for Electric Renewables) é a ferramenta mais amplamente utilizada em pesquisas relacionadas à simulação e configuração ótima deste tipo de sistemas. Esta tese apresenta um conjunto de procedimentos para determinar, em nível de pré-viabilidade, a configuração ótima (em termos do custo presente líquido) e o conjunto de arranjos viáveis de um sistema autônomo de geração de energia incluindo fontes renováveis intermitentes e reservatórios hidrelétricos. O software HOMER é aplicado na simulação e avaliação dos sistemas híbridos dos estudos de caso hipotéticos do presente trabalho, utilizados para validar os métodos propostos. Estes exemplos foram criados a partir de dados reais relacionados ao Estado de Rio Grande do Sul. Os procedimentos descritos são aplicáveis a qualquer região do mundo onde exista um local com potencial para reservatórios hidrelétricos, assim como dados de disponibilidade e custos relacionados a fontes renováveis intermitentes. Além de determinar a configuração ótima e o conjunto de arranjos viáveis, os resultados obtidos indicam que os procedimentos descritos podem ajudar na definição da melhor utilização de um local com potencial hidrelétrico. Igualmente, permitem estimar a quantidade de eletricidade excedente que poderia ser recuperada através de usinas reversíveis. Os resultados mostram que configuração ótima depende de muitos fatores, tais como restrições hidrológicas, a carga a ser atendida e o custo de geração de cada fonte. / Global interest and investments in renewable energy sources has increased considerably in recent years. These technologies have the advantage of using locally available resources, reducing dependence on external energy sources. However, most renewable energy technologies suffer from an intermittent characteristic due to the diurnal and seasonal patterns of the natural resources needed for power generation. Energy Storage is the most used technique to buffer this intermittency. For large-scale applications, hydropower reservoirs (of conventional and pumped storage plants) are the most mature and the most widely employed technology for electricity storage in the form of potential energy. For this reason, a hydropower reservoir is a suitable option to consider including in an autonomous hybrid power system. According to many authors, the HOMER model (Hybrid Optimization Model for Electric Renewables) is the most widely used tool in research studies related to simulation and optimal design of this type of systems. This thesis presents some procedures to define, as a pre-feasibility assessment, the optimal configuration (in terms of Net Present Cost) and set of feasible designs of an autonomous hybrid power system that includes intermittent renewable energy sources and hydropower reservoirs. The HOMER software is used for simulating and evaluating the hybrid power systems of the hypothetical case studies, used to validate the proposed methods. These examples were created based on real data related to the State of Rio Grande do Sul, Brazil. The procedures described can be adapted to any other region of the world where exists a site suitable for the construction of hydropower reservoirs, along with available data regarding intermittent renewable sources and generation costs. Besides defining the optimal configuration and the set of feasible designs, the results indicate that the procedures explained could help in the definition of the best use of a site with hydropower potential. Likewise, these methods can also be used to estimate how much excess electricity can be recovered by means of pumped storage hydropower. The results show that the optimal system design depends on many factors such as hydrological constraints, average load to serve and energy cost of each source.

O interesse mundial e os investimentos em fontes renováveis de energia têm aumentado consideravelmente nos últimos anos. Estas tecnologias têm a vantagem de aproveitar os recursos disponíveis localmente, reduzindo a dependência de fontes externas. Entretanto, um dos principais problemas associados a muitas das tecnologias de energias renováveis é sua imprevisibilidade ou intermitência. O armazenamento de energia é a técnica mais utilizada para moderar estas intermitências. Para aproveitamento em grande escala, os reservatórios hidrelétricos (de usinas hidrelétricas convencionais com reservatório e usinas hidrelétricas reversíveis) representam a tecnologia mais madura e amplamente aproveitada para armazenamento de energia elétrica na forma de energia potencial no volume de água. Isto faz destes uma opção importante a ser incluída no projeto de um sistema autônomo híbrido de geração de energia. Segundo diferentes autores consultados, o software HOMER (Hybrid Optimization Model for Electric Renewables) é a ferramenta mais amplamente utilizada em pesquisas relacionadas à simulação e configuração ótima deste tipo de sistemas. Esta tese apresenta um conjunto de procedimentos para determinar, em nível de pré-viabilidade, a configuração ótima (em termos do custo presente líquido) e o conjunto de arranjos viáveis de um sistema autônomo de geração de energia incluindo fontes renováveis intermitentes e reservatórios hidrelétricos. O software HOMER é aplicado na simulação e avaliação dos sistemas híbridos dos estudos de caso hipotéticos do presente trabalho, utilizados para validar os métodos propostos. Estes exemplos foram criados a partir de dados reais relacionados ao Estado de Rio Grande do Sul. Os procedimentos descritos são aplicáveis a qualquer região do mundo onde exista um local com potencial para reservatórios hidrelétricos, assim como dados de disponibilidade e custos relacionados a fontes renováveis intermitentes. Além de determinar a configuração ótima e o conjunto de arranjos viáveis, os resultados obtidos indicam que os procedimentos descritos podem ajudar na definição da melhor utilização de um local com potencial hidrelétrico. Igualmente, permitem estimar a quantidade de eletricidade excedente que poderia ser recuperada através de usinas reversíveis. Os resultados mostram que configuração ótima depende de muitos fatores, tais como restrições hidrológicas, a carga a ser atendida e o custo de geração de cada fonte. / Global interest and investments in renewable energy sources has increased considerably in recent years. These technologies have the advantage of using locally available resources, reducing dependence on external energy sources. However, most renewable energy technologies suffer from an intermittent characteristic due to the diurnal and seasonal patterns of the natural resources needed for power generation. Energy Storage is the most used technique to buffer this intermittency. For large-scale applications, hydropower reservoirs (of conventional and pumped storage plants) are the most mature and the most widely employed technology for electricity storage in the form of potential energy. For this reason, a hydropower reservoir is a suitable option to consider including in an autonomous hybrid power system. According to many authors, the HOMER model (Hybrid Optimization Model for Electric Renewables) is the most widely used tool in research studies related to simulation and optimal design of this type of systems. This thesis presents some procedures to define, as a pre-feasibility assessment, the optimal configuration (in terms of Net Present Cost) and set of feasible designs of an autonomous hybrid power system that includes intermittent renewable energy sources and hydropower reservoirs. The HOMER software is used for simulating and evaluating the hybrid power systems of the hypothetical case studies, used to validate the proposed methods. These examples were created based on real data related to the State of Rio Grande do Sul, Brazil. The procedures described can be adapted to any other region of the world where exists a site suitable for the construction of hydropower reservoirs, along with available data regarding intermittent renewable sources and generation costs. Besides defining the optimal configuration and the set of feasible designs, the results indicate that the procedures explained could help in the definition of the best use of a site with hydropower potential. Likewise, these methods can also be used to estimate how much excess electricity can be recovered by means of pumped storage hydropower. The results show that the optimal system design depends on many factors such as hydrological constraints, average load to serve and energy cost of each source.

O interesse mundial e os investimentos em fontes renováveis de energia têm aumentado consideravelmente nos últimos anos. Estas tecnologias têm a vantagem de aproveitar os recursos disponíveis localmente, reduzindo a dependência de fontes externas. Entretanto, um dos principais problemas associados a muitas das tecnologias de energias renováveis é sua imprevisibilidade ou intermitência. O armazenamento de energia é a técnica mais utilizada para moderar estas intermitências. Para aproveitamento em grande escala, os reservatórios hidrelétricos (de usinas hidrelétricas convencionais com reservatório e usinas hidrelétricas reversíveis) representam a tecnologia mais madura e amplamente aproveitada para armazenamento de energia elétrica na forma de energia potencial no volume de água. Isto faz destes uma opção importante a ser incluída no projeto de um sistema autônomo híbrido de geração de energia. Segundo diferentes autores consultados, o software HOMER (Hybrid Optimization Model for Electric Renewables) é a ferramenta mais amplamente utilizada em pesquisas relacionadas à simulação e configuração ótima deste tipo de sistemas. Esta tese apresenta um conjunto de procedimentos para determinar, em nível de pré-viabilidade, a configuração ótima (em termos do custo presente líquido) e o conjunto de arranjos viáveis de um sistema autônomo de geração de energia incluindo fontes renováveis intermitentes e reservatórios hidrelétricos. O software HOMER é aplicado na simulação e avaliação dos sistemas híbridos dos estudos de caso hipotéticos do presente trabalho, utilizados para validar os métodos propostos. Estes exemplos foram criados a partir de dados reais relacionados ao Estado de Rio Grande do Sul. Os procedimentos descritos são aplicáveis a qualquer região do mundo onde exista um local com potencial para reservatórios hidrelétricos, assim como dados de disponibilidade e custos relacionados a fontes renováveis intermitentes. Além de determinar a configuração ótima e o conjunto de arranjos viáveis, os resultados obtidos indicam que os procedimentos descritos podem ajudar na definição da melhor utilização de um local com potencial hidrelétrico. Igualmente, permitem estimar a quantidade de eletricidade excedente que poderia ser recuperada através de usinas reversíveis. Os resultados mostram que configuração ótima depende de muitos fatores, tais como restrições hidrológicas, a carga a ser atendida e o custo de geração de cada fonte. / Global interest and investments in renewable energy sources has increased considerably in recent years. These technologies have the advantage of using locally available resources, reducing dependence on external energy sources. However, most renewable energy technologies suffer from an intermittent characteristic due to the diurnal and seasonal patterns of the natural resources needed for power generation. Energy Storage is the most used technique to buffer this intermittency. For large-scale applications, hydropower reservoirs (of conventional and pumped storage plants) are the most mature and the most widely employed technology for electricity storage in the form of potential energy. For this reason, a hydropower reservoir is a suitable option to consider including in an autonomous hybrid power system. According to many authors, the HOMER model (Hybrid Optimization Model for Electric Renewables) is the most widely used tool in research studies related to simulation and optimal design of this type of systems. This thesis presents some procedures to define, as a pre-feasibility assessment, the optimal configuration (in terms of Net Present Cost) and set of feasible designs of an autonomous hybrid power system that includes intermittent renewable energy sources and hydropower reservoirs. The HOMER software is used for simulating and evaluating the hybrid power systems of the hypothetical case studies, used to validate the proposed methods. These examples were created based on real data related to the State of Rio Grande do Sul, Brazil. The procedures described can be adapted to any other region of the world where exists a site suitable for the construction of hydropower reservoirs, along with available data regarding intermittent renewable sources and generation costs. Besides defining the optimal configuration and the set of feasible designs, the results indicate that the procedures explained could help in the definition of the best use of a site with hydropower potential. Likewise, these methods can also be used to estimate how much excess electricity can be recovered by means of pumped storage hydropower. The results show that the optimal system design depends on many factors such as hydrological constraints, average load to serve and energy cost of each source.