Comparison of battery storage strategies in combination of photovoltaics for SNHBM

Abstract

This master thesis is written in the frame of the implementation of photovoltaic cells on roof with combination of batteries and electric vehicles for single-family homes. The study begins by the study of the influence of household consumption on the size of a storage system. To do it, 24 household load profiles have been selected for a total consumption of 114.5 MWh. An assessment of a single-family home load profile is done comparatively to an aggregated combined load profile which is the load profile of the 24 households. According to the above, a theoretical techno-economic comparison between a decentralised battery storage system and a centralised one is done such as one could make a choice between the two storage systems. It appears that a centralised battery storage system is more advantageous theoretically than a decentralised one in reason of the cost and the technical management of the electricity demand. Afterwards, by using PV*SOL software, one should develop models of photovoltaic generation systems with grid as battery storage strategy will be simulated to know which model satisfy the most to technical, economic, and environmental criteria following the current legislations, the current behaviours of energy users. For that, a photovoltaic plant of 240 kWp (peak kilowatt) which corresponds to 10 kWp for each household, is designed. And the results of the simulations show that a photovoltaic production combined to centralised battery storage system is the model which guarantees a better self-sufficiency, a better self-consumption, and a profitability (the result of the net actual value which is positive) when the discount rate value is 5%. Moreover, other combinations with electric vehicle have been checked and mainly the profitability of a vehicle-to-grid process. It appears that, the use of electric vehicles increases the self-consumption and the profitability according to the different net actual value results as well as they are used for electricity storage. But, if the electric cars realize long travels, it could affect the rentability of the global system. By taking account of the competition between accumulators, fuel cells, and regenerative fuel cells (a combination of flow batteries and fuel cells technologies), a theoretical comparison of their storage cost has been done. Even if the Na-S battery appears as the most profitable, its field of application is not larger than the ones of a Li-ion battery and a regenerative fuel cell. Then, following the feasibility, Li-ion batteries are reliable as they are more mature than regenerative fuel cell. At the end of the study, it comes out that a centralised battery storage is the best strategy to adopt because it eases maintenance and the electricity management in terms of peak power and energy consumption. Concerning the photovoltaic production, the electricity storage should be a priority unless the self-consumption should be increased like by usage of electric vehicles for charging. Besides, public authorities should participate in improving legislations as they could be attractive and less worry for energy users like for the duration of feed-in tariff (15 years).