Solar PV scale smart battery systems


A technical solution to demonstrate and monitor the combination of solar PV panels and battery systems in large residential buildings and to develop design criteria for such combined systems. Further, the solution focuses on architectural aspects, economical aspects, and dialogues with authorities.


The electricity consumption in housing blocks has its peak in late afternoons and evenings. The production of solar electricity, however, peaks during daytime. Therefore, it is important to store solar electricity from daytime to late afternoons and evenings. Without batteries, the excess produced solar electricity has to be sold to the public grid for a low price 0.08 Euro per kWh. If the solar electricity can be stored in batteries and used in the evenings, tenants will be able to save 0.35 Euro per kWh, which is the normal price for electricity in Denmark (2023). Installing batteries in combination with solar PV also contributes to reducing the peak load demand on the public grid.
SAB Department 22 with roof integrated solar cells
15 kWh battery unit and battery inverter for 1 of the 19 housing blocks


The demonstration project includes 19 apartment blocks of 3 floors, in total 432 apartments with a floor area of 32,000 m2, located in Sønderborg, Denmark. Battery storage solutions combined with solar PV panels are still under technological development. Lithium batteries are available on the market, and commercial activities are ongoing. Materials used for manufacturing lithium batteries, however, are in the category “products with low sustainability”. Alternative battery solutions are in a beginning development phase, especially the so called “flow batteries” based on more sustainable materials instead of lithium batteries. As soon as new and more sustainable materials are available for batteries, the market for combined solar PV and battery systems is expected to grow noticeably, because this solution will be economical feasible.


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