Hardly any other building material combines technical innovation, design potential and ecological challenges as clearly as glass. In this interview, Dr Anna Braune, Head of Research & Development at the German Sustainable Building Council (DGNB), talks about the role of glass in resource-conserving construction – between energy-optimised use, recyclability and take-back systems.
What importance do you attach to glass as a building material in the context of sustainable construction – particularly with regard to energy efficiency, life cycle and recyclability?
Dr Anna Braune: Glass is absolutely at the heart of the sustainability requirements and plays a versatile role in the context of climateconscious construction. When used as a material in façades, glass has great potential to improve the energy efficiency of buildings. With the further technical development of its products and systems, the industry has been focussing on this point for many years and has already made good progress, which should be continued. In times of continuously rising temperatures due to climate change, thermal insulation in summer is also becoming extremely important in our latitudes. The effort required to cool buildings is not only expensive and energy-intensive, but also harmful to the climate. Thermal insulation glazing can make an important contribution here.
Although glass is a durable material, there is still room for improvement when it comes to handling, reuse and subsequent utilisation over the life cycle. Highly specialised solutions often only provide for the one-off use of the products, and take-back systems are still the absolute exception. For many practitioners, reuse only seems possible in exceptional cases. Yet there are already examples that show how well the reuse of entire glass elements can work. I expect much more commitment and product responsibility from the manufacturing companies in this area.
What needs to happen for the glass industry to make an active contribution to the transformation of construction? What are the biggest obstacles currently - and where are new opportunities opening up?
Dr Anna Braune: Fundamentally, as in all areas of construction product manufacturing, those responsible must finally implement a genuine circular economy. This begins with the recycling of the material, continues with the development of the necessary logistics and ends with the introduction of take-back systems. Although glass is 100 per cent recyclable, it is only gradually being recognised as a recycling material. Due to its physical properties and recyclability, the material has great potential to be recycled in a closed loop without any loss of quality. This is not only an important contribution to climatefriendly construction, but can also ensure long-term economic availability.
The glass industry must take responsibility for its products throughout their entire life cycle and offer recyclable solutions for the future. Transparent information on circularity is just as crucial as the provision of EPDs (Environmental Product Declarations). These standardised documents provide detailed information on the environmental impact of a product throughout its entire life cycle.
The obstacles to decisive further development appear to be mostly within the companies themselves. Securing the necessary resources in the long term is currently just as irrelevant as the very high, environmentally and climate-damaging energy and CO₂ intensity of their products during manufacture. Customers, on the other hand, have long been ready for more sustainable solutions. Many have realised that even more sophistication, technology and effort will not produce a product for their future-proof buildings. The big exception in terms of technology is façade-integrated photovoltaics as a forward-ooking approach that integrates energy production directly into the architecture of buildings and will also gain in demand due to the solar obligation in the European Energy Performance of Buildings Directive (EPBD).
What impetus did you take away from glasstec 2024 – and what contribution can the leading trade fair make to driving the change towards sustainable and circular construction across all sectors?
Dr Anna Braune: At glasstec 2024, it was positive news to me that it is finally technically possible to recycle. Due to the above-mentioned, this process urgently needs to be taken seriously and scaled up by the industry. Like all other resources, glass is too valuable and energy-intensive to waste.
In general, the organisers of trade fairs should make sustainability and resource conservation prominent key topics and encourage exhibitors to take an honest look at these issues in their own field of activity. In addition, particularly committed exhibitors should be labelled in the run-up to and during the trade fair. The German Sustainable Building Council, for example, can serve as a point of contact for visitors to provide a general and independent overview of the issues surrounding sustainable building. In addition, the stands of manufacturing companies that are demonstrably serious about sustainability could be labelled accordingly. These measures have proved successful at trade fairs in which the DGNB regularly participates.
In general, trade fairs and exhibitions have a high social value. They impart knowledge, encourage dialogue and create space for encounters.
