GRI 3-3, 301, 306
The term “grey energy” describes the amount of non-renewable primary energy that must be used to manufacture a product – whether it is a building material, a building component or even an entire building. This includes all the steps taken in extracting raw materials, manufacturing and processing as well as the transportation and tools needed for this process. Consumption of this primary energy generates CO2 emissions in turn (grey emissions).
Grey energy plays a key role in any consideration of sustainability. When constructing new buildings, it reaches far higher levels than the amount of operating energy consumed during the entire life of the building. The grey energy in a building can be reduced by up to 30% through specific designs and implementation measures. In many cases, this will also reduce building costs.
Ina Invest therefore focuses specifically on harnessing the existing potential to reduce grey energy. This starts with strategic planning, in which a compact building with the outer shell being as small as possible will generally perform better in terms of material input. The extent of foundations, excavation support and underground structures also has an impact. Grey energy can be further reduced by the choice of the load-bearing system (solid construction or lightweight construction), its design or the extent and type of building technology.
In accordance with our preferred decarbonisation strategy, we therefore set ourselves the target of using cubatures, structures and building materials with low levels of grey energy and grey emissions for each project. We also expect our partners that implement the projects to prioritise the criteria of regional procurement (short delivery routes), proportion of recycled materials and renewable materials in their choice of materials, and we expect them to be able to provide evidence of this.
Forecasts of the proportion of grey energy in our projects can be found in the portfolio analysis chapter