Techno-economic assessment of battery storage integrated into a grid-connected and solar-powered residential building under different battery ageing models

• Battery storage in solar residential applications has the potential to improve system flexibility under high renewable energy penetration. A better understanding of the dynamic operational conditions of batteries is of high importance for the technical and economic feasibility of the associated system. This study evaluates key parameters for the proper battery management design, control, and optimization of a battery system integrated into a grid-connected, solar-powered building. Three different battery modelling scenarios are proposed in terms of battery ageing and lifetimes, internal states, and control strategies. Each proposed scenario consists of a set of specific methods for the estimation of battery voltage-current characteristics, capacity degradation, remaining lifetime, states of charge, states of health, and states of power. A criteria-based operational strategy linked to a nondominated sorting genetic algorithm (NSGA_II) is constructed for the simulation and multiobjective optimization of the system. The self-sufficiency ratio and life-cycle cost of a battery are considered the technical and economic goals, which are influenced by the capacity degradation and achievable lifetime of the battery. Moreover, the annual battery degradation cost and self-consumption ratio are calculated over the project lifetime. The comparison between the techno-economic optimization results obtained under three battery modelling scenarios indicate that a more realistic design and a superior techno-economic assessment are obtained under Model 3, which is able to simulate battery degradation considering all ageing influence parameters under real operational conditions. In comparison with Model 3, Model 1 which neglects the battery degradation, techno-economically leads an overly optimistic result and also Model 2, which was based on linear capacity degradation regardless of the observed dynamic operational conditions, leads an excessively pessimistic result, implying that applying several simplifying assumptions for a battery operation simulation in a real-life application greatly affects the resulting battery state of charge, state of power, and state of health estimations, leading to an improper battery management system and consequently to the misestimation of techno-economic objective functions. The results prove that the real design and techno-economic assessment of a battery in a solar-powered application highly depend on battery operations in which the seasonal photovoltaic (PV) power production affects the rates of calendric and cyclic battery degradation. 

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Energiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Energy Engineering (hsv//eng)

Nyckelord

Battery ageing models

Battery sizing

Distributed renewable energy

Photovoltaic

Stationary battery storage

Techno-economic optimization

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