Economy & Jobs
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By Quentin de Hults | European Copper Institute
02-06-2022 (updated: 02-06-2022 )
arch-plans_ICA [Credits: European Copper Institute]
As highlighted by the REPowerEU Plan, energy efficiency is crucially important for addressing the energy and climate crisis: every opportunity to save energy must be considered. The energy efficiency potential of technical building systems is neither fully harvested by policies addressing individual products, nor by those focusing on the entire building. This gap can be rectified by the ongoing recast of the Energy Performance of Buildings Directive (EPBD).
Quentin de Hults is the Director of the Green and Healthy Buildings program at the European Copper Institute.
Is there anything more policymakers can do to reduce energy losses in buildings? The Ecodesign and Energy Labelling Directive has successfully removed ill-performing devices from the European market, the Energy Efficiency Directive (EED) has addressed industrial processes via energy-management systems, and the EPBD has set building-level efficiency requirements and certificates. Still, a gap remains.
Technical systems in buildings, such as space heating, ventilation or domestic hot water, combine different components interacting together. Just like a good team is worth more than the sum of its members, system performance is more than combining efficient components. Design, installation and control contribute to efficiency.
As this escapes the responsibility of manufacturers and is often dependent on a site-specific load profile, it is not tackled by Ecodesign. Building requirements do not tackle it either because they are based on a theoretically modelled performance with some limitations. Harvesting the full energy-efficiency potential requires a stronger focus on technical building systems within the EPBD.
Let’s take two examples.
Heat recovery in domestic hot water systems
Regarding domestic hot water, ecolabels and minimum energy performance standards are set for water heaters and storage tanks. Showerheads also have their ecolabel. These are the elements that can be regulated at product level, while optimizing the control and the hot water distribution should be done by installers. Annex 1 of the current EPBD frames the calculation methodology for the energy performance of buildings and states “The methodology shall be laid down taking into consideration at least the following aspects: (b) heating installation and hot water supply, including their insulation characteristics”.
While this is a start, it still lacks a fully holistic approach. This is demonstrated by the disregard of the energy-savings potential of heat recovery. A waste water heat recovery system (WWHRS) is a simple heat exchanger that uses the hot water drained from a shower to pre-heat the cold water flowing to the shower. As demonstrated by a recent study of University of Innsbruck, such systems can easily be integrated into any new shower and save up to 40% of energy on domestic hot water in a very cost-effective way.
If all new constructions and renovations triggered by the renovation wave implement this solution (6.25 million units per year), the yearly energy saving potential by 2030 would be 17.9 TWh. If the whole housing stock is equipped with WWHRS, the savings would be 100 TWh/year. This figure is high enough to explicitly include heat recovery in the forementioned Annex 1 of the EPBD.
Optimizing electrical installations
Another telling example is the case of the electrical installation, the system composed of all the fixed components (such as switchboards, electrical cables, earthing systems and sockets) aiming to distribute electrical power within a building to all points of use or transmit electricity generated on-site. The efficiency of this system can be optimized in different ways : positioning of switchboards to reduce cable lengths, sizing of conductors according to the load profile, load management and monitoring. Again, this optimization potential is highly site dependant.
Cable sizing is regulated through national wiring codes, but these only take safety and aspects of functionality into account, not energy efficiency. An Ecodesign impact assessment analysed the potential of optimal cable sizing.
The study shows about 2% of the electricity generated in the EU gets lost in the electrical installations behind-the-meter, predominantly in non-residential buildings and about half of these losses (approximately 32 TWh per year) could be saved by choosing the cable cross sections with the lowest life cycle cost. Since the optimal choice of cable depends on the site-specific load, the Commission decided not to address it at product level via Ecodesign.
An international standard on energy efficiency of low voltage electrical installations (IEC 60364-8-1:2019) is available but remains entirely voluntary. As a result, the energy efficiency potential of electrical installations is rarely considered. Electric vehicle charging points, heat pumps, on-site PV generation and home batteries rely on safe, efficient and smart electrical installations. Recognizing their importance becomes ever more urgent.
One solution would be to include electrical installations in the definition of ‘technical building system’ in the EPBD, next to space heating, space cooling, ventilation, domestic hot water, built-in lighting, building automation and control, on-site renewable generation, and storage, and to point to the existing standard for their dimensioning.
EPBD and systems approach
These examples show the importance of a holistic approach toward technical building systems that looks beyond the sum of the constituting components. The EPBD recast proposal, recital 15 made a good start by stating that “Energy performance requirements for technical building systems should apply to whole systems, as installed in buildings, and not to the performance of standalone components, which fall under the scope of product-specific regulations under Directive 2009/125/EC (Ecodesign).”
To reflect this recital, more amendments to the EPBD are needed, as demonstrated in the examples above. It also requires active market guidance at national level. As the responsibility for the optimisation of technical systems lies with the designers and installers, measures to facilitate their work will be needed. These can include training and education programmes, and the development of manufacturer independent design tools.
The ongoing recast of the EPBD presents the right opportunity to tackle the energy savings potential of holistically approaching technical building systems. Failing to do so would mean the inability to realise this potential for a long time. Given the current global context, leaving energy savings opportunities untapped is a luxury policymakers cannot afford. The systematic optimization of electrical installations and all other technical building systems should be a priority of the EPBD recast.
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