In 2011, Skanska completed the West Coast’s first and the
world’s fourth certified Living Building in Seattle: The Bertschi School Science Classroom
addition. But Living Buildings—which must meet a series of
ambitious performance requirements, including net zero energy, waste and water,
over a minimum of 12 months of continuous occupancy—are still so rare that many
questions remain about how they compare financially to its next closest
neighbor, LEED Platinum.
So when the District of Columbia’s Department of
Environment was looking to understand the costs and benefits associated with
net zero energy, net zero water and Living Buildings, our team was eager to
help with this effort of quantifying the rewards of ultra-green buildings.
The District of Columbia’s Department of Environment had
two goals: first, to investigate the costs associated with upgrading existing
buildings from LEED Platinum to zero energy, zero water and Living Building.
And second, to collect data to advise policy makers on deep-green buildings and
incentives.
Their findings are published in: Net Zero and Living Building Challenge
Financial Study: A Cost Comparison Report for Buildings in the District of
Columbia. For the study, Skanska joined the New Buildings Institute
(NBI) and the International Living Future Institute (ILFI) to conceptually
transform three LEED v3 Platinum-designed buildings in the District to net zero
energy, net zero water and Living Buildings. Three reference buildings were
chosen to represent three of the most common developments in the District of
Columbia: new office construction, new multifamily construction and office
renovation.
NBI and ILFI determined the most appropriate energy
efficiency and renewable energy strategies for the buildings, while Skanska determined
the anticipated differential costs for the various energy strategies employed.
The team applied a set of energy efficiency measures to
each building’s envelope, lighting, HVAC, operations, occupancy and direct
loads, along with rainwater harvesting techniques in order to achieve reduced
energy and water usage before adding photovoltaics and water-reuse strategies.
The costs for getting to net zero are difficult to
distinguish from overall project costs. However, our team conducted an analysis
to identify costs connected to energy and water conservation, as well as the
photovoltaic and water reuse systems necessary for such a project.
SO WHAT'S THE ANSWER?
The initial cost for energy efficiency is approximately
1-12 percent higher, varying by the building type. This rises to 5-19 percent
in net-zero energy buildings when considering the added cost of photovoltaic
power supply. But the benefits make the added cost worthwhile: the energy
efficiency measures alone offer a return on investment of 6-12 percent. After
factoring current tax and renewable energy credits into these figures, the
return on investment in net zero building is approximately 30 percent.
That is not to say the net-zero goal is appropriate or
feasible in every case. When considered in isolation, even ultra-efficient
300,000-sf buildings with today’s onsite renewable energy technology cannot
generate as much energy or collect as much water as they consume over the
course of a year. In fact, these buildings would require up to seven
equivalent rooftop areas to achieve net zero. And achieving net zero is
not only a matter of design; it also requires careful attention in such areas
as operations and maintenance.
But ultimately, this project yielded valuable results
that will inform future design decisions on our journey to Deep Green. The largest
benefit: it raises the dialogue over the value of net zero to a new level.
Facility owners now have something tangible to consider
when looking at high-performance buildings. We’ve come a long way with Living
Buildings, but there is now a true framework to have meaningful conversations
shifting from first cost alone to life-cycle value, emboldening market leaders
to explore building solutions that push the envelope toward a more sustainable
future.
Source: BDC
Network
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