Optimization of renewable energy systems

X Aggelis, Optimization of renewable energy systems, Postgraduate Thesis, 104 pages, Department of Water Resources and Environmental Engineering – National Technical University of Athens, Athens, February 2013.



In an autonomous hybrid system comprised of photovoltaic panels, wind generators and pumped storage to cover the needs of 100 000 households, the optimal combination of energy sources and reservoir is investigated for a given service level. To achieve this, a numerical model was created on Pascal. The resulting computational software supports is capable of handling a much larger number of steps than a spread sheet, as well as multiple scenario processing. Using weather station timelines, statistical data (mean and standard deviation) on average intensity of solar radiation, average wind speed and average electricity requirements are processed for every day of the year. Parts of the model regarding energy calculations for each iteration, as well as the statistical values of the meteorological data are verified by calculating capacity factors, the values of which are compared to literature. Using weather data and energy requirements, scenarios capturing all combinations of reservoir size, production safety factor and percentage of wind generators in the total production are performed. It is observed that the use of photovoltaic panels, although having a positive effect on service levels, is financially inadvisable in every scenario as a result of their high cost and low capacity factors. As a system with two variables is consequently examined, conclusions are extracted on the variations of service levels with respect to the safety factor of energy production and the reservoir size; however, an optimal economic solution is not provided due to inconsistencies in reservoir expenditures.

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