An energy paradigm transition framework from negative towards positive district energy sharing networks: Battery cycling aging, advanced battery management strategies, flexible vehicles-to-buildings interactions, uncertainty and sensitivity analysis

In response to the clean power production with large-scale deployment of renewable systems, technical challenges are proposed, including the resilient and smart building system design, cycling aging of battery storages, energy congestion between renewable and flexible grid energy, the flexible micro-grids to energy supply fluctuations in multi-energy systems, and so on. In this study, a series of technical solutions, including the integration of plug-in vehicles (under multi-directional energy interaction paradigms), the Vehicles-to-Buildings interaction levels, and the grid-responsive control, were proposed, studied, and discussed to promote the resilient and smart energy systems from district levels in subtropical regions. Dynamic battery cycling aging and advanced modelling tool in this study outperforms traditional rough battery cycling aging approaches, and correct conclusions on battery and vehicle-to-building interaction, to avoid the battery performance overestimation. Novel energy management strategies advance traditional power flow strategy, in terms of the off-peak grid electricity
shifting, the enhancement of renewable penetration, and the deceleration of battery cycling aging. Technoeconomic performances have been investigated, including net present value (NPV), the discounted payback time (DPT), and the net direct energy consumption (DEC). Furthermore, the energy paradigm transition from negative to positive building–vehicle systems outperforms single case study in academia for carbon-neural transition. The research results showed that, with the energy paradigm transition from the negative to the positive system, the net present value increases from 􀀀 7.182 × 107 to 5.164 × 108 HK$, and the average annual net DEC decreased from 249.1 to 􀀀 343.3 kWh/m2.a. Furthermore, compared to Control Strategy 2 (gridresponsive control strategy), the proposed Control Strategy 3 (battery-protective control strategy) can improve the net present value, and the increasing magnitude is dependent on the specific energy paradigm. Furthermore, compared to the positive buildings-vehicle system, the impact of the vehicle-to-building interaction on the decreasing magnitude of the net present value is more prominent for the negative system. The uncertainty and
sensitivity analyses indicate that the net present value of the positive energy paradigm as compared to the negative energy paradigm is more sensitive to the battery cost. This study demonstrates the techno-economic performance of district building–vehicle systems with the energy paradigm transition from the negative to the positive, together with a series of effective solutions. The research results can provide multi-dimensional effective approaches for district energy sharing systems in subtropical regions.