Techno-economic analysis of BESS integration for the revamping of a 3.0 MW photovoltaic plant

The growing infiltration of photovoltaic (PV) generation and the maturation of the current plants have amplified the necessity to devise cost-efficient approaches in increasing energy output whilst adjusting to grid export limitations. This thesis examines the technical and economic viability of the project to upgrade an existing power plant with 3.0 MW of photovoltaic power generation and considers the use of battery energy storage systems (BESS) to optimize the profitability of the project. The work is based on a real production data of eight years of real production data which gives a solid empirical foundation to evaluate the performance of a plant and prevent uncertainties that come along with purely synthetic generation models. Various revamping cases were investigated, with incremental growth in the installed PV capacity taken into account, taking into consideration technological improvements in the modern modules. Constant price of electricity sales and fixed grid interconnection limit was taken and long term effects like degradation, operating cost and system lifetime were considered. This was an initial economic screening which was performed through the use of spreadsheet calculations to approximate revenues and net present value (NPV) as a result of several PV-BESS configurations. The most interesting cases were then modeled in detail with the System Advisor Model (SAM) which allowed detailed analysis of hourly operation, seasonal behavior, degradation and financial performance with a 20-year horizon. The findings indicate that PV revamping is a significant way of boosting the yearly energy generation and profitability of the project. In the cases investigated, the maximum economic benefit is gained at 20% increase in PV capacity. Though the setup with a small BESS would theoretically give the highest NPV, time-series analysis shows that the battery is practically idle since the grid export limit will never be hit. Therefore, the battery will not lead to the extra energy-saving or income generation. The paper concludes that a 20 percent PV revamping without battery storage would be the most technically and economically viable solution to the problems analyzed. The results suggest that economic optimization should be used together with intensive operational simulation in order to prevent excessive system complexity and also to make sure that investments are consistent with actual operational limitations.