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Figure 5: Operation energy and embodied energy share of total energy for the Minergie-A buildings
(top) and the adapted net zero energy buildings (bottom).
3.1 Life Cycle Energy
Life cycle energy (LCE) includes the net-operational energy and the embodied energy.
Due to the differences between the boundaries of net zero energy balance, the life cycle
energy of a Minergie-A and a Net ZEB must also differ. Based on the Minergie-A
buildings three different building configurations are considered:
•
the buildings are recalculated with no PV (low energy building)
•
the buildings are recalculated with enough PV to meet the Minergie-A balance
•
the buildings are recalculated with enough PV to meet the Net ZEB balance.
Figure 6 shows the life cycle energy of a low energy building (without PV), a Minergie-A
building and a Net ZEB. The net-operational energy includes the electricity for plug loads
and lighting in all three cases. The increase of embodied energy from a low energy
building to net zero energy building is about 25%. However, per definition, the net-
operational energy is reduced to zero. The net zero energy balance of Minergie-A
buildings and Net ZEBs clearly outweighs the increase in embodied energy for additional
materials. This shows that the Net ZEB has the lowest life cycle energy. It is 60% lower
than the life cycle energy of a low energy building. Therefore, a Net ZEB is preferable.
