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Plus minus zero: carbon dioxide emissions of plus energy buildings in operation under consideration of hourly German carbon dioxide emission factors for past, present and future

Studniorz, Alexander; Wolf, Daniel; Kiessling, Niklas; Fahrich, Raik; Banhardt, Christoph; Tsatsaronis, George

FG Energietechnik und Umweltschutz

The energy supply of private household buildings accounted for 16 % of the total German CO2-emission in 2020. To fulfil the targets of a climate neutral building sector in 2045, both, energy efficiency as well as on-site use of Renewable Energies in buildings are needed. One concept of a climate neutral building is the so-called Efficiency House Plus, that features large photovoltaic systems making it seemingly energy self-sufficient and CO2-negative by feeding in more electric energy into the grid than needed for its operation on a yearly basis. In fact, houses of this type are highly grid dependent especially during winter months due to their solely electrically based energy supply and a missing long term energy storage. This paper analyses the CO2 -emission of Energy Efficiency Plus houses more in detail on a timely resolved basis for the German electric supply system of the year 2013, 2021 and a perspective one 2030. An alternative calculation approach for simplified normative evaluation of such buildings is proposed.