potential impact of wood building on ghgs...2012/10/15 · tn tn/building kg/brm2 kg/brm3 scenario...
TRANSCRIPT
Potential impact of wood
building on GHGs
Green Life of Wood LCA Workshop
Geneva 15.10.2012
Tarja Häkkinen, Antti Ruuska, VTT
2 15.10.2012
Objectives
To assess the potential impact
of the use of wood in
multi-storey residential
buildings in Finland on the
GHGs until 2030
To assess the significance of
building materials on GHGs of
buildings
Funding
Ministry of Ministry of employment
and the economy
Ministry of Environment
Methods
Case study
Model building
Parametric assessment
3 15.10.2012
GHGs caused by all building materials
Construction + renewals 50 / 100 years. A1, A2, A3 (EN 15978)
Construction of site: GHGs 12-360t
When site ground needs to be stabilised (cement + lime): GHGs 1100 – 1400 t
Basic case
t (1000 kg)
Range, min…max
t
Construction materials
970 540… 1400
Renewals, 50 a
300 200… 400
Total, 50 a
1300 740… 1800
Extreme values: 750 t CO2e / 3600 t CO2e
4 15.10.2012
Total GHGs (tonnes). Passive level building in Helsinki. Time frame 50 years.
(calculated considering the predicted change in GHGs of H&P)
0
200
400
600
800
1000
1200
Materials fornew
construction
Materials forrenovation
Construction,renovation,demolition
Heating,spaces
Heating, water Use ofelectricity
5 15.10.2012
Model building
5-storey residential building
Building volume 6100 m3
Gross area 1800 m2
Structures included
Exterior walls
Roof
Base floor
Intermediate floors
Environmental data for building
materials
From cradle to gate
Transportation, assembly, loss –
not considered
Finnish environmental
declarations + VTT assessments
6 15.10.2012
Building level results (in 1000 kg/building or GJ/building)
Building Weight
CO2e
Re-
new-
able
RM
Non
renew-
able
RM
Re-
new-
able
energy
GJ
Non-
renewa
ble
energy
GJ
CO2
abs.
Wood
Concrete 1900 360 10 2100 120 3500 0 0
Timber-framed 600 120 180 610 520 1800 240 150
CLT-based 910 180 500 700 1300 3400 580 390
Average wooden
(75% TF,
25% CLT)
680 130 260 630 720 2200 320 210
7 15.10.2012
Annual building volumes were assumed to be equal
as in average in in 2000 – 2008
Building volumes in 2000 - 2008 9 310 000 gross m2
Model building’s area 1800 m2
Annual number of buildings 571
Share of buildings
Scenario
Concrete Wood
1 98 % 2 %
2 78 % 22 %
3 48 % 52 %
4 18 % 82 %
11
126
297
11
468
0
100
200
300
400
500Number of buildings
Annually built wooden residential multi-storey buildings, 2010-2030 … Scenario 1
Scenario 2
Scenario 3
Scenario 4
8 15.10.2012
Estimated GHGs (residential blocks of flats) in 2030
Annual GHG-emissions from construction of new residential blocks of flats
in 2030 (25% of wooden buildings CLT based)
CO2-equ CO2-equ CO2-equ CO2-equ
tn/total tn/building kg/brm2 kg/brm3
Scenario 1 (2%) 200 000 350 190 58
Scenario 2 (22%) 180 000 310 170 50
Scenario 3 (52%) 140 000 240 130 39
Scenario 4 (82%) 99 000 170 95 28
9 15.10.2012
Assessment of wood products’ carbon footprint on LC bases
Problematics:
Carbon up-take during growth
Land use
Carbon storage
End-of-life carbon emissions - allocation
Time frame
Relevant (draft) standards
prEN 16485 Round and sawn timber - Environmental Product Declarations -
Product category rules for wood and wood based products for use in construction
ISO DIS 14067 Carbon footprint of products – Requirements and guidelines for
quantifications and communication
EN 15804 Sustainability of construction works - environmental product
declarations - Core rules for the product category of construction products
EN 15942 - Sustainability of construction works - Environmental product
declarations - Communication format business-to-business
EN 15978 Sustainability of construction works - Assessment of environmental
performance of buildings - Calculation method
10 15.10.2012
Guidelines for long / short term impact assessment
Standards give guidelines for long-term impact
assessment
Guidelines for the shorter term estimation are
inadequate.
prEN 16485:
as the formation of wood in the forest is based
on the absorption of CO2 from the atmosphere,
the amount of biogenic C in the wood product
is counted as a removal of CO2
all other natural processes related to the forest
are outside the system boundary of the LCA
temporal changes in forest C pools due to
forestry operations can be disregarded for
sustainably managed forests and for forests
where overall biogenic C stored in forest C
pools is stable or is increasing.
11 15.10.2012
Short term assessment
Even sustainable forestry, where C balance of forest
land is basically neutral over the full rotation, cannot
be considered climate neutral.
Re-growth time typically much longer than the urgent
timetable of emission reductions (creating a C debt
with respect to the no-use baseline)
Dynamics of the terrestrial C is an issue to be
considered due to the urgency of emission reductions
To generate a reference scenario of not-harvesting
To estimate the difference of C balance over time
between scenarios.
12 15.10.2012
201
176
137
99
-4
-41
-96
-151
-200
-150
-100
-50
0
50
100
150
200
250
Scenario 1 Scenario 2 Scenario 3 Scenario 4
CO2-equ 1000 t/a
Residential multi-storey buildings GHG emissions and Carbon uptake, 2030
Stored carbon, total
Emissions, total
13 15.10.2012
Amount of annual green house gas emissions, in 2030, mineral wool insulation
CO2-equ CO2-equ CO2-equ CO2-equ
tn tn/building kg/brm2 kg/brm3
Scenario 1 200 000 350 190 58
Scenario 2 180 000 310 170 50
Scenario 3 140 000 240 130 39
Scenario 4 99 000 170 95 28
Amount of annual green house gas emissions, in 2030, cellulose insulation
CO2-equ CO2-equ CO2-equ CO2-equ
tn tn/building kg/brm2 kg/brm3
Scenario 1 200 000 350 190 58
Scenario 2 170 000 300 170 50
Scenario 3 130 000 230 130 37
Scenario 4 88 000 160 85 25
An additional maximum annual
saving of GHGs of 10 000 t in
2030 when wood based
insulation is used.
14 15.10.2012
Wood in exterior wall refurbishment
Assumptions:
Model building 1800 m2
Number of buildings 3681
Exterior wall will be refurbished (constant rate) until 2030:
a) 50% (880 buildings per year)
b) 75% (1400 buildings per year).
Refurbishment concepts:
a) additional heat insulation and rendering (U = 0,16W/m2K)
b) additional heat insulation and wooden cladding (light weight / +
wooden frame)
Share of wood in exterior wall refurbishment
2, 22, 52 or 82 % until 2030.
Starting point:
Residential blocks of flats during 1950 – 2000
Total gross area 66 800 000 m2
15 15.10.2012
0 1 3 5
12 10
6
2
0
2
4
6
8
10
12
14
Scenario1
Scenario2
Scenario3
Scenario4
Annual CO2-equ emissions, ktn/a Emissions,
Rendered
Emissions,Wooden
0 2 5 8
18 15
9
3
0
2
4
6
8
10
12
14
16
18
20
Annual CO2-equ emissions, ktn/a
Emissions,Rendered
Emissions, Wood
CO2-equ emissions from
refurbishments, when
50% or 75% of buildings
are renovated, in 2030.
Estimated maximum
annual saving of GHGs
roughly
11 000 t in 2030 when there
is an increased use of
wood in refurbishment of
exterior walls.
16 15.10.2012
19 17
14 11
-1
-12
-29
-45
-50
-40
-30
-20
-10
0
10
20
30
Scenario1
Scenario2
Scenario3
Scenario4
CO2-equ ktn/a
CO2-equ emissions considering carbon uptake. Refurbishment in 2030
Stored carbon, total
Emissions, total
17 15.10.2012
SUMMARY
The objective was to assess the potential
impact of wood building on GHGs
Time frame: until 2030
Alternative scenarios for the building of blocks
of flats in Finland:.
Share of wood buildings grows to:
22, 52 or 82 %.
The corresponding decrease of GHGs in
2030 would be
13 % (26 000 t) when the share is 22%
32 % (64 000 t) when the share is 52 %
52 % (102 000 t) when the share is 82 %
Compared to basic case.
The material use in building refurbishment is
considerably less; thus also the related
changes in GHGs.
18 15.10.2012
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