Civil Engineering Reference
In-Depth Information
Table 3 (continued)
Operations and maintenance
uncertainties
Classification
Characteristics
Electrical and thermal
demands of building
occupants
Considerable differences in electrical and thermal
demands are expected due to the uncertain
occupant behavior (Masoso and Grobler
2010
)
Public policy
Sources of uncertainty are the availability of
governmental policy initiatives that promote
NZER and the future regulation of emissions
(Baden et al.
2006
)
Future value of the building
It is uncertain how the NZER refurbishments are
capitalized into the resale value of the building
(Brown
2008
)
Future supply and demand of
energy
The future supply and demand of delivered energy
are highly uncertain because it depends on
many unknown factors such as the future world
population, cost of fossil fuel and renewable
energy, and energy supply technologies (US
EIA
2012
)
during the design and construction phases. Many of these benefits were assumed
during the design phase, and now, the stakeholder can compare the predicted
benefits with the actual performance. However, these benefits will be perceived
differently by the occupants and by the building stakeholders. There is high
uncertainty in the non-energy cost savings and benefits due to the difficulty in
quantifying their return. Not only are the non-energy savings and benefits difficult
to quantify, but also the scale of their impact and success will depend upon whose
perspective is being considered. Occupants might not notice improvement in
building performance but will notice the improvement of the working environment
in the refurbished building. However, they might still be concerned about the
premium they are paying for these improvements and if it is balanced by the
perceived benefits of improved health and productivity. On the other hand, a
building owner might think the refurbishment was not successful because they did
not obtain the expected energy performance even though occupant satisfaction was
greatly increased. Quantifying the benefits of a NZER is another barrier. While
some benefits are easy to quantify (e.g., expected energy use), other benefits are
less tangible and more difficult to quantify, such as increased employee produc-
tivity, improved employee satisfaction, and the positive impact on the community
(Turner Construction
2010
; Menassa
2011
).
Furthermore, other uncertainties affecting the NZER operation and maintenance
are the future supply and demand of energy. The supply and demand of energy may
strongly affect the power quality at feeder level of an electricity distribution
network. As such, large-scale integration of NZER in particular and renewable
electricity generation in general will require well-developed solutions in the form of
energy storage, demand-side management, or both (Baetens et al.
2012
). In addition
to this, the available power for the NZEB could be limited in the future due to
