Optimized Energy Management of a Solar and Wind Equipped Student Residence with Innovative Hybrid Energy Storage and Power to Heat Solutions

Grid-connected Energy Storage Systems (ESS) are vital for transforming the current energy sector. Lithium-Ion Battery (LIB) technology is presently the most popular form of ESS, especially because of its fast response capability, efficiency,
and reducing market prices, but is not always preferred for long-term storage, due to its relatively shorter lifetime. A Redox Flow Battery (RFB) on the other hand has a higher lifetime and better long-term storage capability, but has a higher upfront cost and reduced round trip efficiency. A Hybrid ESS (HESS) consisting of LIB and RFB offers the advantages of both technologies, thus making the ESS more economical and flexible to use while also improving the cycle lifetime of individual ESS. Such a grid-connected HESS is planned and installed for a student residence at Bruchsal having 126 apartments for 150 students and equipped with 220 kWp photovoltaics and 10.5 kWp wind-power. Real-time high-resolution data of the residence’s electrical load and energy generation are collected and used to optimally control the HESS. Additionally, the RFB is also used as heat storage, which supports partial heating requirements of the residence. ... mehr

In the present work, an Energy Management System (EMS) is deployed which not only controls this conglomerate but also optimizes its operations in real-time. Additionally, an in-house built independent controller for the power-to-heat operation is installed, which works together with EMS to store and extract heat from the RFB. The EMS aims at running the whole system at the lowest operational cost, while also reducing the aging process of the HESS. The EMS is also backed up with energy generation and consumption forecasting algorithms, which enable it to intelligently predefine not only the energy flow, but also the ratio of the energy form, i.e. electrical and thermal.