Download Reducing the Carbon Footprint of Canadian Infrastructure

Reducing the Carbon Footprint of
Canadian Infrastructure
Jamie Meil, Research Principal
Introduction: Construction and Climate Change Policy
Climate change mitigation and a major infrastructure initiative are the
foundation of the newly elected federal government’s platform.
Canada’s renewed commitment to reducing its carbon footprint by 2020
or even 2030 may be difficult to achieve if new and rehabilitated
infrastructure isn’t managed for environmental sustainability.
The “embodied” carbon emissions due to new construction are
substantial. That is, materials matter.
Fortunately, we have the tools and data in hand to bring evidence-based
decision-making to infrastructure projects for a lighter carbon footprint.
Total GHGs over 60 years for a typical building
Over the life of a
building, emissions
from building
operation are the
largest part of its
carbon footprint
and need to be
addressed.
Operating
Embodied
But let’s not
forget about
these carbon
emissions.
Especially with a shorter time perspective
These are the carbon
emissions from operating
the building – mostly
fossil fuel burned for
heating, cooling, lighting
and ventilation. These
emissions slowly
accumulate over time.
Reducing these emissions
is recognized as important
but is a long term climate
change strategy.
These are the carbon emissions from constructing the building – mostly
due to materials manufacturing. Reducing these emissions is a near term
climate change strategy with immediate benefit, yet there are no policies
in place to encourage this.
Source: an extensive Athena Institute LCA study of mid-rise concrete buildings
(see “Life cycle assessment for sustainable design of precast concrete
commercial buildings in Canada,” M. Marceau et al, 2012), which is highly
conservative as it is strictly core and shell and does not include finishes,
furnishings, HVAC and so forth. This is the carbon footprint for a typical new
5-storey building in Toronto.
Embodied Carbon Really Adds Up
For Example:
Total embodied carbon footprint
of annual Canadian new nonresidential construction is over
2,300,000 metric tons CO2e.
That’s 487,000 cars driving for a
year or equivalent to 25% of all
cars purchased in 2015 by
Canadians.
Or about $46 million in carbon
offsets @$20/tonne of CO2.
Over the next 20 years, the world is projected to build 80 billion square meters
of new buildings in cities worldwide, an area equal to 60% of the entire current
global building stock (Architecture 2030)
Calculations are based on the following sources. Average non-residential starts floor area is derived from CanaData as cited
in a 2011 blog post by Alex Carrick of CMD (formerly Reed Construction Data). Average carbon footprint per square foot of
construction is derived from an extensive Athena Institute LCA study of mid-rise concrete buildings (see “Life cycle
assessment for sustainable design of precast concrete commercial buildings in Canada,” M. Marceau et al, 2012), which is
highly conservative as it is strictly core and shell and does not include finishes, furnishings, HVAC and so forth. Car
equivalencies per USEPA GHG equivalencies on-line calculator. Carbon cost calculated at $20 per metric ton, per
offsetters.ca.
Typical Embodied vs. Operating
GWP GWP per year, typical commercial building
2,000,000
1,800,000
Embodied
1,600,000
Kg CO2e
1,400,000
Operating
1,200,000
1,000,000
800,000
Embodied=Operating @ 8.5 yrs
600,000
400,000
200,000
0
0
1
2
3
4
5
6
7
8
9
10
Year
11
12
13
14
15
16
17
18
19
20
High Performance Design Approach
GWP per year, Enermodal office building
600,000
Embodied
500,000
Operating
Kg CO2e
400,000
300,000
Embodied = Operating @ 17.5 years
200,000
100,000
0
0
1
2
3
4
5
6
7
8
9
10
Year
11
12
13
14
15
16
17
18
19
20
Twice as efficient as the
typical design
• Better insulated
• Employed passive
design techniques
Relative to our 2030
climate policy window,
materials are equally
important
Issue:
considerable legislation
around operating energy
use via codes.
No climate policy dealing
with materials use
So where is the embodied carbon?
Montreal suburban Condo
8 story, cast in place building
64 units - 10,000m2 gross floor area
Parking garage 48 spaces
Core and Shell account for 80% of the
initial embodied carbon
Services and fit-out accounts for 20%
C/S Embodied GWP (kg CO2e) =
1,720,404
% Embodied CO2 by Assembly
Roof Assembly
Above Grade Walls/Partitions
Concrete Floor Slabs
Concrete Columns & Beams
Below Grade Concrete Walls
20% of the carbon
is below grade
Footings
Excavation & Fill
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
Strategies for Reducing Embodied Carbon
• Reduce material use – eliminate some or all of the parking garage,
eliminate balconies, leave concrete floors unfinished (polish)
• Optimize material use – optimize spans/bay sizes for material, specify
lower burden concrete – use Portland limestone cement in place of
regular Portland cement, employ more SCM’s in concrete mix designs
• Explore material use & operating energy trade-off – e.g., leave concrete
exposed on the interior to maximize thermal mass effects
• Design for deconstruction and reuse – explore using precast panels in
place of CIP so panels may be recovered and reused
• Plan for durability and resiliency – 500 yr. event is the new baseline
• Climate adaption is the new reality
Advocate the use of tools to explore “what if” scenarios during the design
process ….