Guide to Climate Positive Building Stock
The construction and real estate industry plays a key role in achieving climate neutrality targets. Transforming the building stock in a climate-positive way is an ambitious task. It cannot be delayed and can only succeed if all stakeholders work together.
Four strategic goals with 15 fields of action and 50 top measures show the way to a climate-positive building stock. The following publication are available on this topic:
Background knowledge
The effects of climate change are already perceptible to many people and they affect billions of people worldwide. Stabilizing the climate is the major task of this decade: rapid and far-reaching measures are needed in all sectors in order to achieve "climate neutrality". Greenhouse gas emissions must be reduced immediately and effective greenhouse gas sinks established. Society must be involved in the process of making the necessary changes.
How can a climate-positive building stock be achieved?
In its final report in March 2023, the Intergovernmental Panel on Climate Change issued an urgent warning about the devastating consequences of climate change. The scientists call for the immediate implementation of measures that can be implemented quickly and on a large scale to ensure that the effects of climate change on all of our lives remain manageable.
In the new version of the Climate Protection Act of June 2023, the German government's declared aim is to achieve greenhouse gas neutrality in Germany by 2045 at the latest. However, calculations show that the sooner we bring our greenhouse gas emissions and greenhouse gas sinks into balance, i.e. achieve "climate neutrality", the lower the impact on our planet and thus the subsequent costs.
The pressure to change is increasing: The "climate transformation" must be implemented before the end of this decade, i.e. in the 2020s, and should - according to Johan Rockström's "Carbon Law" - end with at least a halving of greenhouse gas emissions compared to the beginning of this decade. So time is of the essence. We are all called upon - collectively and individually - to take and implement immediate measures to achieve greenhouse gas neutrality as quickly as possible.
In the case of upstream measures for greenhouse gas neutrality, the downstream measures can already be prepared and initiated now. If there are still obstacles to some measures, these must be removed immediately.
Four strategic goals. Concrete measures at a glance
With the current energy consumption of the building stock, a 100% supply of renewable energy sources could only be achieved at enormous cost, with very high space requirements and with gigantic infrastructure projects. The proportion of renewable energy used to operate existing buildings is currently around 12 percent. That is more than modest. It is true that the existing building stock still has a very high proportion of inefficiently operated buildings. However, the envelope surfaces and external areas of buildings offer enormous potential for energy activation, even beyond their own requirements. So far, this has been underutilized.
Prerequisites for successful energy activation of existing buildings:
- Create full transparency about energy performance and planned measures
- Create all the capacities required for the energy transition of existing buildings
The energy transition for buildings means - Massively reducing the real energy and heat consumption of the building stock as quickly as possible
- Switching the supply completely to renewable energy sources
- Where possible: activate the building stock to produce energy beyond its own requirements and have a grid-supporting effect, e.g. through load management or energy storage
The amount of space required per person has risen sharply in recent decades. At the same time, we have an average vacancy rate of around 3 per cent in Germany. Around 5,300 residential buildings were also completely demolished in 2020. At the same time, the number or area of extensions or additions to buildings has been negligible over the years. Another aspect that needs to be changed is that construction activities are now carried out almost exclusively with a high demand for primary raw materials. The utilisation of secondary raw materials and reuse is currently very low. At the same time, the amount of material used in German residential buildings per inhabitant is over 100 tonnes. A further 80 tonnes are required for all other buildings per inhabitant.
This must change:
- Preserve and upgrade the building stock
- Utilise the building stock efficiently
- Activate or repurpose vacant buildings
- Utilise the full potential of redensification and adding storeys
- Do not demolish existing buildings worthy of preservation without quality in order to erect "replacement new buildings" in their place
The sooner we bring our greenhouse gas emissions and greenhouse gas sinks into balance, i.e. achieve "climate neutrality", the lower the impact on our planet and thus the subsequent costs.
Construction activities in building construction, in particular the building materials industry and the energy sector, are a significant source of national greenhouse gas emissions. Added to this are foreign supply chains for raw material extraction and value creation, which are not included in the national balance. Emissions from the construction of infrastructure (civil engineering) such as roads, bridges, supply and disposal are also considerable.
The greenhouse gas intensities for most building materials and products are largely known, at least at a generic level. Manufacturer-specific EPDs (environmental product declarations) are currently available for around 1,750,127 building materials and products. Climate-positive building materials and products, i.e. CO2 sinks and CO2 reservoirs, are currently only available on the market on a very small scale.
The greenhouse gas intensity varies greatly depending on the building material, product and manufacturer and should be assessed in context and not in generalised terms. The standardised method of life cycle assessment or life cycle greenhouse gas calculation is used for an assessment. Based on the total number of sustainability certifications, it is estimated that several hundred greenhouse gas calculations are carried out each year during the planning phase or as proof during the execution phase. Unfortunately, construction site processes or project-specific transport are hardly ever taken into consideration.
Planners can develop very good climate-friendly solutions if they make use of all the optimisation options: from reducing demand to circular and long-lasting strategies to material-saving solutions and the use of materials and products with low greenhouse gas intensity.
Demands on manufacturers, planners and building owners:
- Materials must be produced in such a way that they cause little to no CO2
- Materials must be developed with a clear focus on subsequent refurbishment
- Planners must develop the skills to carry out life cycle CO2 balances and establish them as new normal planning parameters in their processes.
- Development of CO2 sinks and CO2 storage capacity of buildings. For most manufacturers, planners and building owners, this field is still far removed from the current discourse on solutions to the climate crisis.
The prerequisites for the successful development of CO2 sinks and CO2 storage capacity in buildings are - the identification of materials and processes for the construction sector that absorb and store CO2
- the development of "climate-positive" or "CO2-negative" products and their use in building renovations and necessary new constructions.
This is the legal situation: climate protection for the building sector has not been the focus of federal policy in recent decades. Rather, it was only about the rational use of energy for heating. The requirements have not been tightened since 2016 and the standard introduced at that time was declared a "near-zero energy standard" in accordance with the European Energy Performance of Buildings Directive (EPBD). It was only in 2020 that the Building Energy Act (GEG) brought the labelling of greenhouse gas emissions for the operation of buildings into regulation. The federal subsidy for efficient buildings (BEG), introduced in 2021, continued the previous energy-focused subsidy programme. It includes a new "sustainability class", one element of which is the requirement to limit life cycle CO2 emissions and which can be verified with a DGNB certificate, for example. More climate protection-orientated funding has been announced for 2023.
Since 2009, the BNB system (Assessment System for Sustainable Building) has been used for federal construction, which has also been introduced and applied in some federal states and includes climate protection aspects such as a life cycle carbon footprint.
At state level, there is a colourful patchwork of individual regulations via the state building codes and other regulations, as well as state funding programmes.
Some very good approaches are being pursued at city and municipal level, with ambitious statutes, guidelines, subsidies or requirements for municipal building companies.
The introduction of binding criteria for the ecological procurement of building construction measures is planned at European level. Climate protection, climate adaptation and the circular economy are likely to take centre stage.
With a few exceptions, the financial sector has paid little attention to the topic of sustainable property financing and sustainable portfolios in recent decades. Only recently has there been a great deal of activity, largely triggered by the "EU Action Plan on Financing Sustainable Growth" and its accompanying guidelines and projects.
Conclusion
The transformation needs clearly formulated government targets, as described in the Climate Protection Act (as of 2023). And it needs accompanying framework conditions that enable the transformation to take place as quickly as possible. These political and financial framework conditions must be created at all levels. This requires collaboration, foresight and ambition from the federal government, federal states, municipalities and cities. We also believe that banks and insurers have a duty to provide the financial resources required to mobilise the transformation. They, too, are called upon to make targeted climate goal-compatible offers or specifications for the allocation of funds.
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