Civil Engineering Reference
In-Depth Information
Rules and definitions for near zero-energy buildings or even zero-energy
buildings are still subject to discussion at the international level (Dall'O et al.
2013
).
Some authors (Adhikari et al.
2012
) use ZEB as ''net zero-energy buildings''
and NZEB as ''nearly zero-energy buildings''. ''Net'' refers to a balance between
energy taken from and supplied back to the energy grids over a period of time.
Therefore, net ZEB refers to buildings with a zero balance as well that the NZEB
concept applies to buildings with a negative balance.
The European Energy Performance of Buildings Directive 2002/91/EC (EPBD)
has been recast in the form of the 2010/31/EU by the European Parliament on 19
May
2010
.
One of the new aspects of the EPBD is the introduction of the concept of
NZEB. Of all the new aspects set out by the new directive, this one seems to be the
one with most difficult enforcement member states. The article 9 of the European
Directive establishes that, by the 31 December 2020, all new constructions have to
be NZEBs; for public buildings, the deadline is even sooner—the end of 2018.
Article 2 of the EPBD recast states that '''NZEB' means a building that has a
very high energy performance, as determined in accordance with Annex I. The
nearly zero or very low amount of energy required should be covered to a very
significant extent by energy from renewable sources, including energy from
renewable sources produced on-site or nearby''. The directive does not specify
what is the concept of ''low amount of energy''. The EPBD is also dubious on the
meaning of ''nearby'' renewable resources. This broad definition could encompass
1 km or even 10 km and even any national energy grid in countries where the
majority of the energy supply comes from renewable resources.
Since in the preliminary drafts, the directive was referring to ''net zero-energy
buildings'', some authors (Adhikari et al.
2012
) believe that the global economic
crisis of recent years has prompted lawmakers to scale back targets due to the fact
that evidently that a ZEB (net zero) would be too expensive.
Although each EU member state need to transpose into national laws, the
directive's provisions to account to its specific situation (climate conditions,
economic aspects, building practices, etc.) so far only three countries had already
made that transposition (Denmark, Sweden and Ireland). Therefore, in 21
September 2012, infringement procedures were started on 21 September 2012,
against the 24 member states that did not declare full transposition.
This is the best proof of the difficulties felt by the different EU members in the
transposition of such ''unspecified'' and ''dubious'' regulation.
Another novelty of the EPBD recast that can complicate transposition into
national laws is the cost-optimality requirement. According to the Article 4 (1),
Member States shall take the necessary measures to ensure that minimum energy
performance requirements for buildings or building units are set with a view to achieving
cost-optimal levels. The energy performance shall be calculated in accordance with the
methodology referred to in Article 3. Cost-optimal levels shall be calculated in accordance
with the comparative methodology framework referred to in Article 5 once the framework
is in place.
