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ZEB Deinition – An Ongoing Theme Throughout the Eight Years | 57

What role will the ZEB deinition have in the future? Experience has

shown that a well-deined goal for the environmental ambition is

crucial for the success of zero emission building projects.

Due to different boundary conditions, it may be difficult to buildings and the market gains from the economic benefits of
achieve a full life cycle ZEB for all buildings. For example, scale, costs will decrease. There have already been dramatic falls
reaching a high ambition level may be less challenging for small in the cost of PV, and other technologies are gradually becoming
buildings such as single-family residential buildings, because less expensive as they develop. In addition, there are potential
the areas available for energy generation (e.g. solar modules) benefits of high-performance ZEBs which have not been taken
per heated floor area are larger than in more compact high- into account in traditional LCC (life cycle cost) analyses, such as
rise commercial buildings. Moreover, local climate conditions higher renting values, higher residual values, and productivity
and contextual boundaries such as urban density may limit values.
the possibilities of reaching a full Zero Emission Building. The In the next revision of the building regulations (TEK20), the
Norwegian ZEB Centre has therefore developed a hierarchy of ZEB-O÷EQ ambition level could well be implemented since it fits
ambition levels for zero emission buildings, to allow flexibility well with the EU requirement of “nearly zero energy buildings”.
for different types of buildings and local boundary conditions. However, since the analyses of the ZEB pilot buildings show that
The defintions include detailed descriptions of a number of emissions from production of materials may constitute about
criteria such as system boundaries and calculation procedures, 50% of total life cycle emissions, it is strongly advised that
and it addresses all the life cycle stages as defined in EN 15978 some requirements with respect to materials be included in the
on Sustainability of construction works . future building codes. In order to simplify the procedure, this
could be enforced through a requirement to document parts
The main ambition levels applied by the ZEB Centre are of the building structure. The calculation methodology has
described as follows, starting with the lowest level: already been developed in ZEB and can be used as a basis for
ZEB-O÷EQ: Emissions related to all energy use for operation the documentation procedure.
“O”, except energy use for appliances/equipment (EQ), should The higher ZEB ambition levels can provide a basis for
be compensated for with renewable energy generation. additional future regulations, as well as being useful for
ZEB-O: Emissions related to all operational energy “O” current developers and governmental institutions that want
should be compensated for with renewable energy generation. to be frontrunners and to promote buildings that contribute
ZEB-OM: Emissions related to all operational energy to a low carbon society.
“O” plus embodied emissions from materials “M” should be
compensated for with renewable energy generation.
ZEB-COM: This is the same as ZEB-OM, but also takes
into account emissions relating to the construction “C” phase. Further reading: Andresen I, Hegli T. (2017). Integrated Energy Design,
in Zero Emission Buildings, A.G. Hestnes and N.L. Eik-Nes, Editors.
The additional phases included are transport of materials and Fagbokforlaget: Bergen, Norway.
products to the building site and construction installation
processes. Fufa SM, Schlanbusch RD, Sørnes K, Inman M, Andresen I (2016). A
Norwegian ZEB Deinition Guideline, ZEB report 29. Trondheim, Norway:
These ambition levels have all been applied and tested in the Sintef Academic Press; 2016.
nine Norwegian pilot building projects described in research
section in this report. The ZEB Defintion also includes two Kristjansdottir T, Fjeldheim H, Selvig E, Risholt B, Time B, Georges
higher ambition levels (ZEB-COME and ZEB-COMPLETE ), L, Dokka TH, Bourelle J, Bohne RB, Cervenka Z. A (2014). Norwegian
1
ZEB Deinition Embodied Emissions, ZEB report 17. Trondheim: Sintef
but these levels have so far not been applied in any building Academic Press; 2014.
projects in Norway.
Experience from the pilot building projects suggests that Solli J, Berker T (2016). Economic Feasibility and Zero Emission
Buildings. A state-of-the-art report. ZEB report 19. Trondheim, Norway:
it is possible to reach the lowest ambition level for most new Sintef Academic Press; 2016.
building projects with little extra cost, and that this can
potentially yield a positive cost-benefit ratio in a life cycle 1
ZEB-COME is the same as ZEB-COM but also takes into account
perspective. emissions relating to the end-of-life phase. ZEB-COMPLETE takes into
As the building industry gains experience with such account all emissions related to all life cycle stages.