Zero CO₂ is no utopia

In order to contain global climate change to an acceptable level, we are called upon to achieve massive reductions in current CO₂ emissions. On the other hand, we must orient all future activities, including the construction, conversion, renovation and operation of buildings, at least to the climate protection targets contractually agreed in the Paris Agreement.

CO₂ emissions are the new target

The following therefore applies: if CO₂ emissions are to be reduced and limit values derived from scientific findings are to be adhered to, the requirements for new building construction and renovation must be geared towards these. Therefore, the primary energy demand of a building should no longer be the benchmark, as stipulated by the Building Energy Act (GEG). This way of thinking and calculating results from the oil crisis of the 1970s, when the main aim was to become more efficient. Today, it is about much more than energy efficiency. It is about climate protection, which consequently requires a different target figure: CO₂ emissions. This is the only way to give us the planning and design freedom for the right, sensible concepts and the necessary innovations.

Accounting for user energy during planning

It is not uncommon for an energy-optimized office building with a comprehensive IT infrastructure to have higher CO₂ emissions from user applications than from other building operations (heating, cooling, hot water). Consequently, these internal processes and equipment are part of the overall building system and should not be planned, optimized or operated separately. If only part of the energy flows and the resulting CO₂ emissions are considered, the supply of CO₂-free energy cannot be guaranteed and consequently it is not possible to speak of "CO₂ neutrality". For this reason, user energy must be taken into account in the climate protection-oriented planning of buildings.

CO₂ emissions over time

All processes that use energy from fossil fuels generate greenhouse gases. The most relevant greenhouse gas, accounting for over 80 percent of global emissions, is the climate-damaging CO₂. Depending on which energy source and which form of energy is used, the amount of CO₂ produced and used varies. This means that a building can only become or be mathematically climate-neutral by balancing on the time axis - by comparing the amount of CO₂ emissions caused by the building itself and the amount that is avoided by other users through CO₂-free energy generated and exported close to the building. For the operation of buildings, the period under consideration is defined as one calendar year.

Zero CO₂ is no utopia. A meaningful CO₂ balance for real estate is possible. And thus a basis for determining the specific need for action on the way to climate neutrality. In combination with a building-specific climate protection roadmap and the annual review of the carbon footprint, a solid basis for decision-making is created in order to optimally combine climate protection and economic efficiency.