Friday, January 17, 2014

Principles for nearly zero energy houses

The recast of the Energy Performance of Buildings Directive (EPBD) introduced, in Article 9, “nearly Zero -Energy Buildings” (nZEB) as a future requirement to be implemented from 2019 on wards for public buildings and from 2021 onwards for all new buildings. The EPBD defines a nearly Zero-Energy Building as follows: [A nearly Zero-Energy Building is a] “building that has a very high energy performance… [ ]. The nearly zero or very low amount of energy required should to a very significant extent be covered by energy from renewable sources, including renewable energy produced on-site or nearby.”
Acknowledging the variety in building culture and climate throughout the EU, the EPBD does not prescribe a uniform approach for implementing nearly Zero-Energy Buildings and neither does it describe a calculation methodology for the energy balance. To add flexibility, it requires Member States to draw up specifically designed national plans for increasing the number of nearly Zero-Energy Buildings reflecting national, regional or local conditions. The national plans will have to translate the concept of nearly Zero -Energy Buildings into practical and applicable measures and definitions to steadily increase the number of nearly Zero-Energy Buildings. 
Obviously the qualitative nature of criteria in the above-mentioned nZEB definition leaves room for interpretation. While illustrating the major pillars of future nZEB – drastically reduced energy demand and a major share of renewable energy supply - the terms “nearly zero or very low amount of energy”, “very significant extent” (to which the energy required should be covered by renewable energy sources), and “renewable energy produced on-site or nearby” require further examination and definition.
In addition to the flexibility of the general EPBD definition for nZEB, several questions arise concerning the practicalities of a nZEB definition:
how to keep the nZEB definition sufficiently flexible so as to build upon existing low-energy standards and enable energy-positive buildings? 
how to properly define and set the share of renewable energy?
how to determine the optimal balance between energy efficiency and renewable energy?
how to forge the nZEB definition as a ‘silver bullet’ for reaching the same levels of energy and GHG reduction?

Related Posts

Principles for nearly zero energy houses
4/ 5

Subscribe via email

Like the post above? Please subscribe to the latest posts directly via email.