Building as a Battery

On average every U.S. citizen experienced over eight hours of power outages in 2020, which has considerably increased from previous years (eia.gov, 2021). The increasing number of outages indicates the vulnerability of the utility grid to different natural and man-made disasters. There is an immediate need to reduce the dependency on the utility grid and increase the resilience of the buildings. As a result, stand-alone or building-scale solar panels are gaining popularity. However, states like California, which has a high number of rooftop solar panel systems, face challenges due to the diurnal cycle of sunlight, which creates a 'duck curve' and 'camel curve'. This is impacting both solar panel owners and utilities. (energy.gov, 2017). Moreover, many of the existing systems without batteries may cease to produce power due to safety & lack of batteries affect critical building function due to interruption and inconsistent power supply. (NREL, December 2014). This gap can be resolved by a holistic approach towards better integration of PVs, energy storage, and demand control systems to make any building self-sufficient and resilient. 

The research study was initiated by identifying strategies, cutting-edge technologies, and existing case studies for three types of energy load management systems: DER (Distributed Energy Resources), Energy Storage Systems (ESS), and energy hubs. The study focuses on on-site Renewable Energy (RE) generated through rooftop/ Building-Integrated PV (BIPV), Behind-The-Meter (BTM) energy storages, and ways to supply energy to other homes and EVs at a community level. Through a meta-analysis of these solutions, a toolkit of cost-effective, energy-efficient, and environmentally sustainable energy storage solutions was created. To apply this solution set, a site representing a diverse range of demographic and socio-economic conditions was selected, with the aim of minimizing equity and environmental issues at the community level. The study conducted a simulation analysis of two scenarios, one with the building connected to the utility grid alone and another where the building is grid-interactive, uses strategies from the solution set, and supports critical loads of four single-family detached homes. The comparative analysis of the results confirmed improvements in savings in the utility bill by $10,425/yr, energy support for 3 days of power outages, and lower carbon emissions by 12% in Scenario-II than the baseline model. Lastly, we determined the financial viability and policy support. The study led to the development of a scalable and adaptable module to make buildings self-sufficient and support critical loads of other buildings through intentional islanding. The study concluded the framework of ‘Building into a Battery’ can help to save the utility grid from DER fluctuations and promote renewable energy adoption for community-based solutions with a focus on equitable social sustainability