+ H Y T T E . a V e r s a t i l e C o n s t r u c t i o n S y s t e m
391
Accounting emissions.
Norway is an integral part of the European electricity networks. Simulations conducted
by I. Graabak, N. Feilberg collected in the document "CO
2
Emissions in different
scenarios of electricity generation in Europe" showed that it is possible to achieve a 90%
reduction of CO
2
emissions by 2050. This is "verified" by the EU program "A roadmap for
moving to a Competitive low carbon economy in 2050". Quantitatively speaking that
means moving from the 357 gCO
2e
/KWh of 2004 - European OECD nations factor
(Selvig & Zdena, 2008) - to 35,7 gCO
2e
/KWh within the next forty years.
Operational emissions due to the use of the building for 60 years can thus be calculated
as:
)
(
60
y
y
OE DE
OE
⋅
=
∑
,
KWh
g
e
CO
2
(1)
Where:
60
OE
_ 60 years’ operational emissions.
y
DE
_ Delivered Energy of the year
y.
(Assumed constant in the 60 years)
y
OE
_ Operation emissions of the year
y
(variable from 357
KWh
g
e
CO
2
to 35,7 in a 40
years time span and then constant on the value of 35,7 for the remaining 20 years).
The formula (1) is mathematically equivalent to consider 132 g/kWh in a 60 years lifetime
of the building (stationary factor commonly used in ZEB at NTNU) (I. GRAABAK, N.
FEILBERG). Considering the delivered energy of 37,75 KWh/m
2
(table 4) thus it results:
[
]
4,91
1000 /
7800 75,37
130 60
60
=
⋅
= ⋅
⋅
=
DE
OE
2
2
m
Kg
e
CO
(2)
That means a total operational CO
2
footprint of:
CO
2
operational footprint: 4,91 x 106,38= 522,08
e
CO
Kg
2
Preliminary calculations recently conducted inside the ZEB centre showed that it is
possible to contain the embodied annual emission to 5,0 kg/m
2
y assuming a 60 year
lifetime of the building. This value will be taken in this paper as a hypothesis to be
validated during the next stage of development of the project. Under this condition
operational and embodied emissions will have an impact of around 50%+50% on the
total CO
2
footprint of the building with a total of:
CO
2
total footprint: 5,0*106,38+522,08= 1054
e
CO
Kg
2
In order to balance 1054 KgCO
2e
/y of emission, the necessary yearly PV production of
electricity will be of:
1054/0,13=8109,4 kWh/y
This is based on the premise that a kilowatt-hour of energy exported to the grid reduces
the central production of a kilowatt-hour and associated CO2 emissions (same
conversion factor of 132 g/kWh= 0,13 Kg/KWh).
