Faculty of Engineering

MSc. in Environmental Engineering

Life Cycle Assessment of SDU’s TEK building and Carbon

footprint account on a consumer product – TimberNest bench

Supervisors: Marianne Wesnaes & Birgitte Lilholt Sørensen

Author: Silviu Moga

1
Contents
Abstract ............................................................................................................................................ 3
Acknowledgment .............................................................................................................................. 4
1. Introduction .............................................................................................................................. 4
1.1 SDU’s TEK Building ................................................................................................................... 4
1.2 Hypotheses and research questions ......................................................................................... 5
2. Literature review ....................................................................................................................... 6
3. Methodology ............................................................................................................................. 9
3.1 Life Cycle Assessment methodology ................................................................................... 9
3.2 Inventory Analysis ............................................................................................................ 10
3.3 Process flow diagram ....................................................................................................... 12
3.4 Life Cycle Impact Assessment ........................................................................................... 13
3.5 Scenario Development ..................................................................................................... 14
3.6 Assumptions for SimaPro ................................................................................................. 15
4. Results ..................................................................................................................................... 17
5. Discussions and limitations ...................................................................................................... 23
5.1 Limitations ............................................................................................................................. 24
6. Conclusions ............................................................................................................................. 25
7. Appendix ................................................................................................................................. 26
References ...................................................................................................................................... 29

Table of figures

Figure 1 Framework of an LCA [12] .................................................................................................... 9

Figure 2 Process flow diagram of the TEK building ........................................................................... 12
Figure 3 Endpoint Impact indicators (Larsen, 2017) ......................................................................... 13
Figure 4 Comparison of the totals from all three scenarios .............................................................. 17
Figure 5 Freshwater ecotoxicity totals ............................................................................................. 18
Figure 6 Land use totals ................................................................................................................... 18
Figure 7 Climate change totals ......................................................................................................... 19
Figure 8 Freshwater ecotoxicity scenario comparison ...................................................................... 19
Figure 9 Land use scenario comparison ........................................................................................... 20
Figure 10 Climate change scenario comparison ............................................................................... 20
Figure 11 Freshwater ecotoxicity for the end-of-life stage (Recycling and avoided products) ........... 21
Figure 12 Land use for the end-of-life stage (Recycling and avoided products) ................................. 21
Figure 13 Climate change for the end-of-life stage (Recycling and avoided products)....................... 22
Figure 14 TEK building SimaPro model inputs .................................................................................. 26
Figure 15 TEK building SimaPro model outputs ................................................................................ 27
Figure 16 TEK building SimaPro model Outputs – waste and emissions to treatment ....................... 28

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Thesis structure

The following study is made out of two different parts as follows: The first part is a Life
Cycle Assessment of the SDU’s TEK building (faculty of engineering) where the full life
cycle of the building was analysed starting from raw material extraction to the end-of-life
stage. The assessment was done for a better understanding of the environmental impacts that
the building has during its lifetime. The second part consists of a CO2 footprint account of a
company product. The company is TimberNest, a Danish start-up company which is
producing a bench for socializing. This CO2 footprint account was made to see what are the
CO2 emissions that the bench is emitting during its life cycle and to help the company in
becoming a CO2 neutral business in the future.

Abstract

Worldwide, the building industry accounts for approximatively 40% of energy consumption
and 33% of carbon dioxide emissions, making it one of the most demanding industries in the
world. Denmark has increased its building sector in the past years and is a leader in eco-
innovation and sustainable construction projects, therefore one of the best countries to invest.

This study thrives to analyse a particular building in Odense, the SDU’s faculty of
engineering (TEK building) which is part of the SDU’s campus in Odense. It was built in
2015 by C.F. Moller architects company and it is stated to be a self-sustainable building made
with long lasting materials and eco-friendly. The study is performed using a life cycle
assessment method (LCA) to determine the environmental impacts over the whole life cycle
of the building from raw material extraction to its end-of-life stage. In order to perform the
Life Cycle Assessment, SimaPro software is used and the consequential approach is chosen
for it.

Three scenarios are modelled along the way to understand which one has the less impacts
over the environment and the results are showing three impact categories that stood out to be
the most important ones.

3
Acknowledgment

Firstly, I want to thank Birgitte Lilholt Sørensen and Marianne Wesnaes for their guidance
and help in conducting this Life-Cycle-Assessment. Furthermore, I would like to thank Teis
Lenz for his help with data collection that made this study possible.

1. Introduction

1.1 SDU’s TEK Building

The Faculty of Engineering (TEK) is part of the University of Southern Denmark, in Odense
and is located in the south-eastern corner of the campus where the heating plant was
previously located. The total size of the building is 20.000 m2 with an area of 6.000 m2 for
laboratories. The new building connects the other parts of the University and the Mærsk
McKinney Møller Institute.

The architects company that built TEK, C.F. Moller states that “the building is designed as
one big envelope consisting of 5 buildings connected by bridges at multiple levels crossing
the heart of the complex, a "piece of furniture" containing common functions, meeting-rooms
and café/lounge areas. The many connections allow for more fluid boundaries, and more
community and knowledge sharing.
The unusual appearance is a result of both adaption and distinctiveness in relation to the
existing campus, which is a unique 1970s structuralist design by architects Krohn & Hartvig
Rasmussen characterized by its linear layout and brutalist use of fair-faced concrete and
weathered cor-ten steel cladding.”

In the same document from C.F. Moller, it is said that “the building is designed as a glass
house with an external screen or veil revealing and shading the glazing. The elegant and
seemingly weightless screen is made from pre-fab panels of white CRC concrete (Compact
Reinforced Composite, a special type of Fibre Reinforced High Performance Concrete with
high strength) featuring circular openings with an underlying solar screen and natural
ventilation. The eye-catching screen reflects the innovation and creativity that characterises
the various institutes which the building unites, including institutes for diverse research on

4
the subject of construction technology and industrialization. Here, the fiber-reinforced
concrete architecturally demonstrates the possibilities of new materials.”

According to the engineers and C.F. Moller company, the “TEK building at SDU meets the
requirements for low energy class 2015 according to the strict Danish building codes. This
means minimal energy consumption, good indoor climate and use of materials with a low
environmental impact in a life cycle perspective. The composition of the façade screen is
created from only seven different types of concrete panels, and the different diameters and
layouts of the panels’ perforation patterns have been optimized to act as a solar screen and
glare protection, reducing direct sunlight by up to 50 percent, while still allowing
unobstructed views from all interior spaces to the green surroundings.” [1]

Even though the TEK building connects four other buildings, the one that will be dissected in
this study for analysis is O42, the one with the concrete façade. The aim of this thesis is to
assess the veridicality of the above said words, to see if the TEK building indeed is or not
self-sustainable and built with good materials in order to meet the low energy standards stated
by the Danish building regulations.

1.2 Hypotheses and research questions

Two hypotheses have been formulated for this thesis:

H1: Based on the fact that it is a new building constructed with the aim of being
environmentally friendly, the TEK Building is sustainable in terms of energy consumption.

H2: TimberNest has the potential to become a CO2 neutral company by improving their
production methods.

In order to support the hypotheses, the following research questions have been formulated:

RQ1: In what degree do the materials used for the TEK building impact the building’s life
cycle?

RQ2: Does the fact that SDU’s TEK is a new building have a significant impact on its
sustainability?

RQ3: Which are the most important aspects that TimberNest should focus on, in order to
become a CO2 neutral business?

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 2. Literature review

In literature, there are many studies conducted on different buildings using Life Cycle
Assessment (LCA). Regarding energy consumption, a study was made by Rachel Elizabeth
Tapper Spiegel (2014) using Life Cycle Assessment on school buildings, based on two
Norwegian building standards: The Passive House Standards (NS3701 – Norsk
passivhusstandard for yrkesbygninger) and TEK10 Standard (Byggteknisk forskrift –
TEK10). [2]
On the other hand, the term of “passive house” was developed in the 1980s by Professor Bo
Adamson and Dr. Wolfgang Feist at The Passive House Institute, Germany. The term of
passive house refers to the building design. A passive house should be designed based on the
reduction of heat loss to minimum. To be sustainable, it should adopt some measures, such as
extra insulation, airtightness and heat recovery. [2]
By comparing a school built as a passive house based on Passive House Standards, with the
same school built based on TEK10 standards, the difference in life cycle performance for
these two schools can be seen. After assessing and comparing both schools built as passive
house in comparison with conventional building, the ones built with passive house standards
are more efficient regarding energy consumption, but requires more materials and energy in
the construction phase than the school built based on TEK10 standards. [2]
Another LCA study was conducted by the Concrete Innovation Centre (COIN Project report
36, 2011), on concrete used in building construction, focusing on the rooftop of passive
houses. The aim was to find the best material used, considering some criteria: aesthetics,
functionality, sustainability, energy efficiency, indoor climate and cost efficiency. The
passive house roof construction assessed was made from concrete, vapour barrier, mineral
wool insulation and bitumen welding. [3]
By using LCA as a tool assessment for buildings, in Spain, a survey by Zabalza et. al. (2013)
was conducted based on eco-design building, with the aim to demonstrate how energy
savings in construction and operation of buildings can be achieved, based on life cycle
assessment techniques in designing buildings and refurbishment. Here, it an LCA was made
on Valdespartera eco district, Zaragoza, Spain, where all the life cycle building stages were
analysed in terms of Cumulative Energy Demand (CED) and Global Warming Potential
(GWP). [4]

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Further studies based on the design of buildings were made, one of them being conducted by
Vaculikova et.al., (2014) They performed a Life Cycle Assessment of a Building
Replacement with Re-use of selected materials, where the focus was on the renovation of the
existing building stock in a sustainable stock. Here have been two scenarios developed,
where an old house was replaced by a new one using new materials and second scenario
where a new house was built by re-using old materials from demolition and extra material.
LCA results demonstrate that the impact of material used can be marginal. [5]

A further study was made on Building Materials and Services in Hong Kong by Leung et.al.
(2007) where 28 commercial buildings in Hong Kong were assessed, with the aim of finding
the scale of materials and service systems which contribute the most to the environmental
impacts. There were twenty material types identified and concrete, rebar, plaster, render and
screed represented the dominant materials, together with 40 types of service systems where
the most common were Heat, Ventilating and Air-conditioning Systems (HVAC). [6]

Gonçalves de Lassio et. al. (2016) performed a life cycle assessment of different building
construction materials from a housing complex. The materials included cement, steel, wood
and ceramics. The study highlighted the environmental impacts of these materials and the
consumption of non-renewable energy and fossil fuels. As the authors concluded in their
study, there is a need in acting over the production chain of building materials but also on the
end-of-life stage to avoid landfilling and promote recycling. In the end, the study stated that it
would be a good idea to look for other materials when it comes to buildings, materials like
glass or plastics which have a higher recyclability rate. [7]
Ghose A. et. al. (2017) conducted a study on the environmental impacts that arise from the
refurbishment of the building sector in New Zealand with a consequential life cycle
assessment approach. They compared building refurbishment strategies in order to minimize
the waste quantities on the construction site with the use of materials that can be recycled at
the production site. The outcome revealed that recovery and re-use of materials can decrease
the environmental impacts by around 20% compared to the strategies that used recycled
materials. Here the decrease in impacts was of 5%. [8]

Another study was made in Finland by Miimu Airaksinen et. al. where they analysed an
office building, performing a CO2 footprint of it. As nowadays office buildings are more and
more energy efficient, the heating use is going down, while the electricity use is increasing.
While performing the CO2 footprint, it came out that the materials play a huge role in the

7
energy efficiency of a building and those should be considered, not only the use phase of the
building. The results of the study showed that the lowest CO 2 emissions were achieved when
renewable energy or nuclear power was used for electricity and heat production. [9]

In his doctoral thesis in 2001, Jacob Paulsen discussed the significance of the use phase for
different building products. As in the European Union, the building sector accounts for about
40% of the energy use and generates around 40% of the total waste it is imperative to
approach the building industry in a sustainable way by reducing the amount of resources for
one product. Therefore it is crucial to consider the use phase of buildings. He concluded that
in order to perform a comparison between building products, the choosing of materials has to
be done in the planning phase of the building and then, the products can be compared in the
use phase from an environmental point of view if life cycle inventory data exists, building
data like lifetime or maintenance intervals exists. [17]

Moreover, Stefania Butera in her doctoral thesis studied the potential environmental impacts
of construction and demolition waste (C&DW) in Denmark. The findings showed that
C&DW has a variability when it comes to leaching mostly because of the ageing level of the
chemicals or the source segregation. Leaching of chemicals like selenium or antimony is
critical for C&DW and Polychlorinated Biphenyls (PCBs) are still present in C&DW
nowadays even if not in critical amounts. The study speaks about the use of C&DW in road
sub-bases and from an LCA perspective the waste stream does not provide any environmental
benefits because there are environmental impacts related to leaching or transportation. Even
though, C&DW has less impacts than landfilling but excluding toxicity impacts. Regarding
the leaching from C&DW, the oxyanion leaching is responsible for the environmental
toxicity impacts and it should be minimised. [10]

Gong et. al. (2011) conducted a comparative study on life cycle energy consumption and CO 2
emissions for three different residential building designs in Beijing. One is made out of
concrete framework (CFC), the other is steel framework (SFC) and the last one is made out
of wood framework (WFC). The study showed that over the whole life cycle of the buildings,
the energy consumption of the CFC building is almost the same as the SFC one but both of
them are 30% higher than the wood-made building. In terms of CO2 emissions, the CFC
building is 44% higher than the steel framework building and 49% higher than the wood
framework one, making the CFC, the least environmentally friendly. The main contributor to
these CO2 emissions is the use of electricity. Summed up, the WFC building is the most

8
environmentally friendly one and in order to have energy savings and less CO2 emissions it is
imperative to use energy-saving materials like natural wood. [11]

3. Methodology

3.1 Life Cycle Assessment methodology

The main method used in this thesis is the LCA method for assessing the environmental
impacts of the TEK building. The figure below, shows the main steps that every LCA study
must contain. This illustration is for a consequential LCA as the main approach for this study
is the consequential one for understanding the different consequences of the environmental
impacts involved. In the beginning the goal and scope of the study are defined, after that an
inventory analysis is made and this includes all the processes and materials used in order to
conduct the LCA. After the inventory analysis is done, it is followed by the impact
assessment showing the environmental impacts of the product assessed, in this case the TEK
building and after that, the last step is the interpretation of results.

Figure 1 Framework of an LCA [12]

The TEK building is part of the SDU campus in Odense and it was built in 2015 which makes
it a new building in accordance with the Danish building regulations. The building it is stated
to be a self-sustainable one and environmentally friendly. The goal of this master thesis is to

9
assess the materials used for the construction, the electricity and heat used during its lifetime
in order to see the environmental impacts of TEK and if the building is self-sustainable in
terms of energy consumption. This study is an internal one and will not be disclosed to the
public, the results being communicated to the university staff only for internal use.

The scope definition determines what product systems are to be assessed and how this
assessment should be done. [13] This is a stand-alone LCA study where the SDU’s TEK
building will be analysed based on data collected from stakeholders (university’s technical
service, companies providing the electricity and heat). The whole LCA study has a cradle-to-
grave approach where all the life cycle stages are considered from the extraction of raw
materials to the end of life stage of the building where the waste amounts are recycled,
incinerated or landfilled.

The functional unit used in every LCA it is used to describe and quantify the function or
performance of a product system. This is done to create a reference unit for the comparison of
the product systems. [12] For this study, the functional unit used is 1 year of service for the
TEK building, meaning the energy used in one year for electricity, water and heating
systems.

The system boundaries used in this study are intended to set a more accurate approach over
the LCA. The spatial boundary is Denmark, more explicitly Odense city while the temporal
boundary is set by the functional unit – 1 year of service. These boundaries can be found in
the process flow diagram (figure 2).

3.2 Inventory Analysis

In this chapter collected data as the basis of the assumptions for the calculation of
environmental impacts in SimaPro is presented. Data from different sources from all
processes of the studied product are listed in the following and compile an inventory of
elementary flows. [12] The calculation of the environmental impact is made with SimaPro
version 8.5.0, which is build up on the Database Ecoquery Ecoinvent 3.4.

The data for the study was obtained from the university’s technical department and it includes
quantities for the materials used during the building process, electricity, heat and water
consumption for one year of service. The materials considered in this study are as follows:

10
concrete, wood, glass, ceramics, gypsum for plasterboards, stone wool for isolation, metals
(steel, iron, aluminium, nickel), plastics (polyethylene and polystyrene) and a tank of 5000l
of propylene glycol. Data collected will be afterwards divided for every life cycle stage. In
the use stage of the building, electricity, heat and water will be used, while for the
construction and end-of-life stages the building materials are used to make the model.

11
3.3 Process flow diagram

Below, the Process flow diagram (PFD) of the TEK building is shown for a better
understanding of the life cycle of the building which goes from cradle-to-grave.

Figure 2 Process flow diagram of the TEK building

Figure 2 illustrates the PFD of the TEK building with all the life cycle stages included from
extraction of raw materials to end-of-life stage “Demolition of TEK building”. As the
functional unit is 1 year of service, all the weights of the materials are divided by 50, this
being the lifetime of the building. For the construction of the building there was no energy
consumption considered as it is too small to be relevant.

Considering the use phase, here the numbers for the use of electricity, heat and water are
presented as follows: 1.042.044 KWh/year for electricity, 994.900 KWh/year for the heating
system and 2907 m3 of water, this water being tap water used in bathrooms and kitchens. The
water used in the heating system is recycled over the whole heating system so it is not
considered in the study.

12
For the demolition process an assumption was made regarding the demolition period in hours
and fuel consumption. After this, there is a sorting process where all the materials are sorted
to be either recycled, incinerated or landfilled. According to the Danish statistics on
construction and demolition waste from 2015, 87% of the waste is recycled, while 7% is
landfilled and the rest of 6% is sent for incineration. [13]

3.4 Life Cycle Impact Assessment

The life cycle inventory´s information on elementary flows is converted into scores of
environmental impacts. The software SimaPro 8.5.0 is used to conduct the Impact
Assessment. The setting “ILCD 2011 Midpoint+” with EC-JRC Global, equal weighting is
used. The results of the assessment with the above-mentioned method can afterwards be
allocated to areas of protection. Typically, these areas are human health, ecosystems &
species (natural environment) and resources.

Figure 3 Endpoint Impact indicators (Larsen, 2017)

According to ISO 14040/14044 from 2006, characterization is a mandatory step in every

LCA study alongside with classification. There are also optional steps in an LCA like
normalization, weighting and grouping. For this particular study, characterization and
normalization were chosen to be assessed. Characterization is about how much each impact
indicator contributes to the overall assessment. Normalization is expressing the life cycle
impact results which are relative to a reference system (person equivalent). [14]

13
In the characterization step, all the flows from the life cycle impact assessment are calculated
according to how much they contribute to a certain impact. Then, all the elementary flows are
multiplied with their characterization factor and then summed over all emissions to get an
impact score for a specific impact category. [12] Concerning normalization step, this is done
after the characterization and expresses the results using a common reference impact. As of
this, normalization shows the total impact for a certain region (Demark for this study) and for
a certain impact category e. g. climate change. [14] The final aim of this optional step is to
reveal the environmental impacts which are associated with the European production and
consumption, including impacts from trade. [14]

3.5 Scenario Development

In order to build the model for the TEK building in SimaPro, three scenarios were developed.
The first one is the actual scenario where the building materials are considered with the actual
energy, heat and water consumption in the use phase, the reference year being 2015-2016.
Also, during the disposal stage, the data used is from the Danish statistics on construction and
demolition waste from 2015. Here 87% of the waste is recycled, 7% is landfilled and 6% is
incinerated. For the other two scenarios, the use stage of the building was modified as it
follows: the electricity and heat consumption processes were modified.

Considering that for the actual scenario, the production of electricity is made up from 85%
electricity mix for Denmark which has wind power, solar power, hydro power, coal and
biomass. The rest of 15% is covered by solar power as they use solar panels on the building’s
roof. In the future scenarios, the percentages are changed being first 50% wind power and
50% solar power and then 100% wind power for the electricity production.

For the heat production, the actual scenario has a mix of coal (33%), wood chips (34%) and
waste (33%) because the TEK building is taking its heat from Fjernvarme Fyn A/S, the
district heating company in Odense and according to their data, they use three Combined
Heat and Power (CHP) plants to produce heat. [19]

On the other hand, for the future scenarios, heat production is modelled as it follows: firstly,
there is a share of 50% wood chips and 50% waste and then, in the last scenario there will be
100% waste used for heat production.

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3.6 Assumptions for SimaPro

In order to build the model for SimaPro, assumptions were made. Firstly, the lifetime of the
TEK building is considered to be 50 years for the structure materials like concrete, steel or
iron. For the rest of the materials, an average of 25 years was considered as their lifetime.
[17] For the calculations in the SimaPro software, regarding the functional unit of 1 year, the
total amounts of building materials (BM) were divided by the lifetime of the building (LB) –
50 years, respectively 25 years.

𝐵𝑀 (1)
𝐿𝐵

For the electricity consumption over one year of service, an assumption was made as in
Denmark most of the electricity is produced by renewable energy like windmills, solar or
hydro power and biomass, around 60% and the rest of 40% being coal (30%) and natural gas.
[18]

Although, because TEK was built in 2015 it has on the roof solar panels for electricity
production. According to the data collected from the university regarding the amount of
electricity produced by the solar panels on roof, they produce 15% of the total energy
requirement for one year, the rest of 85% being covered by an electricity mix.

Another assumption was made on the end-of-life of the building where for one month of
work to dismantle the building are necessary 200 working hours and the work is done with
excavators, bulldozers and trucks for waste transportation. In total, three months is the time
for full dismantling so 600 working hours.

For the machinery used in the demolition process, the fuel consumption was considered and
assumed to be an average of 20l of diesel per working hour [18]. The total fuel consumption
is calculated by multiplying the working hours (WH) with the hourly fuel consumption
(FC/H)

𝑊𝐻 × 𝐹𝐶/𝐻 (2)

After the building is brought down, there is a sorting phase of the waste which takes place. At
this point, 1% of the demolition waste is loss and goes to landfill. After the sorting process is
done, 87% of the waste goes to recycling, 6% to incineration and 7% to landfill, in this 7%
the loss of 1% is included. [13]

15
When it comes to the avoided products due to incineration of wood, here electricity and heat
are the avoided processes. To model these processes in SimaPro an assumption was made as
it follows: for the reuse of electricity, the total amount of wood that goes to incineration is
multiplied with the percentage of wood that is incinerated (90%), the rest of 10% is
considered as loss. For the reuse of heat, the same amount of wood that goes to incineration
(W) is multiplied this time with the calorific value of wood, which is 18.5 MJ for dry wood.

𝑊 × 18.5 𝑀𝐽 (3)

Uncertainties:

Due to the fact, that an LCA is based on assumptions and estimations, uncertainties are
always present. Nevertheless, managing uncertainties allows to quantify and improve the
precision of a study and the validity of its conclusions. [12]

1) Demolition of the building:

Base scenario: 3 months used for the demolition of the whole building – 600 working
hours in total.
Sensitivity scenario: 6 months used for the demolition – 1200 working hours in total.
After making this scenario, the results were too small to be taken into consideration so
they are not presented in the report, as the only thing that was changed was the time of
the demolition process.
Sorting of the demolition waste:
Base scenario: 87% recycling, 7% landfilling and 6% incineration.
Sensitivity scenario could be: 95% of the waste goes to recycling and 5% to
incineration, in this case the landfilling is avoided.

2) Functional unit:
Base scenario: 1 year of service for the TEK building
Sensitivity scenario could be with the whole lifetime of the building which is assumed
to be 50 years.

16
 4. Results

In the following chapter, the results obtained from the SimaPro calculations are presented as
comparisons between the three scenarios modelled.

Figure 4 Comparison of the three scenarios

Figure 4 shows the comparison of all the scenarios assessed. It can be seen that the actual
scenario has impacts on seven impact indicators compared with the other two scenarios.
Comparing these three scenarios, the second one where TEK uses heat from Fjernvarme Fyn
made out of 50% wood chips and 50% waste is the one that has less impacts over the
environment for almost all the impact indicators.

17
 Freshwater ecotoxicity Totals (CTUe)

4057621 Freshwater ecotoxicity TEK

actual scenario
9005333 Freshwater ecotoxicity TEK
50% wood 50% waste
Freshwater ecotoxicity TEK
6782471 100% wind 100% waste

Figure 5 Freshwater ecotoxicity totals

Land use Totals (Kg of C deficit)

Land use TEK actual scenario

1735646
2705081 Land use TEK 50% wood 50%
waste
Land use TEK 100% wind
1874678 100% waste

Figure 6 Land use totals

18
 Climate change Totals (Kg of CO2 eq)

Climate change TEK actual

569939 scenario
716622
Climate change TEK 50%
wood 50% waste
Climate change TEK 100%
wind 100% waste
505874

Figure 7 Climate change totals

Figures 5, 6 and 7 illustrates, the total numbers for the freshwater ecotoxicity, land use and
climate change for all the scenarios. It can be seen that the actual scenario has the highest
numbers for freshwater ecotoxicity and land use with a share of around 45%. On the other
hand, climate change indicator has the highest share of around 40% for the third scenario.

Freshwater ecotoxicity scenario comparison

7000000
6000000
5000000
4000000
CTUe

3000000
2000000
1000000
0
TEK actual scenario TEK 50% wood 50% TEK 100% wind 100%
waste waste
Freshwater ecotoxicity Freshwater ecotoxicity Freshwater ecotoxicity

Concrete Metals (iron, steel, nickel) TEK electricity TEK heat

Figure 8 Freshwater ecotoxicity scenario comparison

19
 Land use scenario comparison
1800000
1600000
1400000
Kg of C deficit

1200000
1000000
800000
600000
400000
200000
0
TEK actual scenario TEK 50% wood 50% TEK 100% wind 100%
waste waste
Land use Land use Land use

Concrete Metals (iron, steel, nickel) TEK electricity TEK heat

Figure 9 Land use scenario comparison

Climate change scenario comparison

600000
500000
Kg of CO2 eq.

400000
300000
200000
100000
0
TEK actual scenario TEK 50% wood 50% waste TEK 100% wind 100%
waste
Climate change Climate change Climate change

Concrete Metals (iron, steel, nickel) TEK electricity TEK heat

Figure 10 Climate change scenario comparison

Figures 8, 9 and 10 above are showing the comparison of the scenarios for every impact
category. Here electricity and heat have the highest impacts over all the impact categories.
For climate change, the shares for heat over the scenarios are almost the same with a slight
change for the last scenario where the heat production has around 80% from the total. The
detailed figures regarding the modelling in SimaPro can be found in the appendix – figures
14,15 and 16.

20
 Freshwater ecotoxicity CTUe
-7119.331987
-1115.850575 -15430.74569
Avoided gypsum mineral
-15256.39177
Avoided electricity
-7000.559984
-72617.80943 Avoided heat

Avoided glass cullet for

stonewool
Avoided gravel crushed
-116918.7133
-59587.84628
Recycled aluminium

Recycled Plastics (PS&PE)

Recycled metals
-71273.2507

Recycled glass

Figure 11 Freshwater ecotoxicity for the end-of-life stage (Recycling and avoided products)

Land use kg C deficit

-4299.490697 -1582.475173
-85.27844571 -10081.48342
Avoided gypsum mineral
-19804.18504 -3310.695642

-4278.777739 Avoided electricity

Avoided heat
-20177.06435
Avoided glass cullet for
stonewool
Avoided gravel crushed

Recycled aluminium

-157016.6701 Recycled Plastics (PS&PE)

Recycled metals

Recycled glass

Figure 12 Land use for the end-of-life stage (Recycling and avoided products)

21
 -38.83028441
Climate change kg CO2 eq
-155.5547272
-3625.372528
-1498.147955 Avoided gypsum mineral

-9034.358433 Avoided electricity

Avoided heat
-12986.01537
Avoided glass cullet for
stonewool
Avoided gravel crushed
-26426.27831 -7521.711843

Recycled aluminium

Recycled Plastics (PS&PE)

-18731.76577
Recycled metals

Recycled glass

Figure 13 Climate change for the end-of-life stage (Recycling and avoided products)

Finally, figures 11, 12 and 13 show the values for the TEK building materials that are
recycled and the ones that are avoided to be used in other products. The amount of concrete
after demolition is used as gravel crushed for road sub-bases or pavements and “avoided
gypsum mineral” refers to the gypsum that is avoided after the recycling of gypsum
plasterboards. The processes “Avoided electricity” and “Avoided heat” refer to the avoided
electricity and heat due to wood incineration. After the demolition of the building, the wood
products are assumed to be incinerated.

22
 5. Discussions and limitations

As Denmark is a country where the building sector is more and more eco-friendly and with
low carbon emissions every year, the TEK building is not an exception. Three scenarios were
modelled for the use stage of the building, focused on the use of electricity and heat inside the
building in one year, in order to see which one is more convenient to be used in the future.

Overall the use of electricity and heat have the highest impacts over the environment due to
the processes included in the production of these two. For the actual scenario, the electricity
is made up from a country mix of renewable energy, coal and natural gas and the heat is
provided by Fjernvarme Fyn also with a mix of waste, wood chips and coal. The impacts are
comparable within the three scenarios with small differences for electricity and heat.

On the other hand, the production of concrete has a considerable impact as it is the material
that has the highest share (Kg) in the construction stage of the building with 18072 m3 which
is around 43.372.280 Kg used for the whole building.

After assessing the TEK building scenarios using the SimaPro software, the results shown
that three impact categories came out to be more important than the others. These impacts are
Climate change, Freshwater ecotoxicity and Land use.

Climate change is one of the most important environmental impact indicator because of the
CO2 emissions that goes into the atmosphere and heats the planet. This impact is measured in
Kg of CO2 and in SimaPro the unit represents also the other greenhouse gases (CH4, N2O,
CHF3, SF6, CCl2F2). Many of the greenhouse gases are present in the Earth’s atmosphere
contributing to the greenhouse effect (CO2, CH4, N2O) alongside with water vapour.

The results show that the electricity and heat used by the TEK building in one year have the
biggest impacts over climate change. Overall, the CO2 emissions globally for electricity and
heat production account for 25% of the total CO2 emissions on the planet. [12]

The other impact, land use is present in the graphs with a share of around 20%. Land use
refers to all anthropogenic activities for a given area, these activities include agriculture,
forestry, mineral exploration or others. As the soil is a finite resource on Earth, the soil
formation rate is substantially lower than soil depletion rate. [12]

The processes that have the biggest impacts on land use are electricity and heat, both due to
the production of these two. As Denmark uses a mix of renewable energy and coal and

23
biomass for the electricity production, all these processes have an impact on land use. The
same happens regarding heat production. TEK building takes its heat from a local district
heating plant in Odense (Fjernvarme Fyn) and this one is producing the heat with a mix of
coal, wood chips and municipal waste. Here, the impact on land use is due to the coal mining,
forestry for wood and onshore gas production.

Although, the model for land use in an LCA is still extensively discussed and not yet settled
as the first operational models came out in 2010, until that year, land use was only an
inventory flow. [12]

The last impact indicator to be discussed is freshwater ecotoxicity as this one has the highest
impact over the three scenarios. Like for land use, the processes that are mostly affected are
electricity and heat. This time, the freshwater ecotoxicity impact is due to the waste treatment
of lignite or coal for heat production alongside with wood from forests. While the wood is
burned for heat production, residues may end up in the nearby streams or lakes, polluting
them.

5.1 Limitations

As in every LCA study, limitations are present regarding either data availability or its quality.

In this case, the main limitations were regarding data availability for the energy used during
the construction of TEK. There was no data available for the energy consumption in this
stage and the whole model would have been more accurate in terms of energy consumption to
see if the building meets the Danish building regulations and if it is self-sustainable or not.

Another limitation that was important when the model was built it was about the end-of-life
stage of the building. Here also, the data availability was the problem as assumptions had to
be made in order to understand the potential waste quantities and energy usage during the
demolition of the building. The transportation of materials from factory to construction site
was not considered in the study as the data was not available, this being another important
limitation in terms of energy and fuel consumption for a better assessment of the
environmental impacts.

24
 6. Conclusions

In the beginning of the study, two research questions regarding TEK building were addressed
to be answered:

Firstly, in what degree do the materials used for the TEK building impact the building’s life
cycle?

The materials used for the construction of TEK are mainly concrete and glass. Concrete has
the highest impact on the environment as its quantity is around 18.000 m3. Other materials
used in the building like iron, steel or gypsum for plasterboards are present in big quantities.
Due to the recyclability of these materials, the impact over the life cycle of the building is not
very high. The concrete can be reused after the demolition as gravel crushed for road
pavements or sub-bases, avoiding the production of new gravel.

Secondly, does the fact that SDU’s TEK is a new building have a significant impact on its
sustainability?

The TEK was built in 2015 and the materials used are of a high quality to comply with the
Danish and European regulations regarding environment and sustainability. Electricity and
heat used in the building have the biggest share over the environmental impacts as TEK uses
an electricity and heat mix during the use stage. The materials used have a significant impact
over the sustainability of the building but considering that TEK is built with high quality
materials like CRC (Compact Reinforced Composite) concrete or glass, it makes it more
environmentally friendly than using other materials due to the high recyclability of concrete
and glass.

25
 7. Appendix

Figure 14 TEK building SimaPro model inputs

26
Figure 15 TEK building SimaPro model outputs

27
Figure 16 TEK building SimaPro model Outputs – waste and emissions to treatment

28
References

[1] C. F. M. D. A/S, “SDU TEK Building,” 2015. [Online]. Available:

https://www.skyfish.com/p/cfmollerarchitects/1472116?predicate=label&direction=desc.
[Accessed: 14-May-2019].
[2] R. Spiegel, “Life Cycle Assessment of a new School Building designed according to the Passive
House Standard,” no. June, p. 85, 2014.
[3] T. E. Kalbakk, “LCA on case study – concrete,” 2011.
[4] I. Zabalza, S. Scarpellini, A. Aranda, E. Llera, and A. Jáñez, “Use of LCA as a tool for building
ecodesign. A case study of a low energy building in Spain,” Energies, vol. 6, no. 8, pp. 3901–
3921, 2013.
[5] M. Vaculikova, M. Stepan, J. Hodkova, and A. Lupise, “Simplified and Detailed Life Cycle
Assessment of a Building Replacement with Re-use of Selected Materials,” vol. 15978, no. 2,
2014.
[6] W. LEUNG and W. K. TAM, “Developing a Life Cycle Assessment Tool for Commercial Builidngs
in Hong Kong,” pp. 1057–1062, 2007.
[7] J. G. Gonçalves de Lassio and A. Naked Haddad, “Life cycle assessment of building
construction materials: case study for a housing complex,” Rev. la construcción, vol. 15, no. 2,
pp. 69–77, 2016.
[8] A. Ghose, M. Pizzol, and S. J. McLaren, “Consequential LCA modelling of building
refurbishment in New Zealand- an evaluation of resource and waste management scenarios,”
J. Clean. Prod., vol. 165, no. September 2018, pp. 119–133, 2017.
[9] M. Airaksinen and P. Matilainen, “A Carbon footprint of an office building,” Energies, vol. 4,
no. 8, pp. 1197–1210, 2011.
[10] S. Butera, “Environmental Impacts Assessment of Recycling of Construction and Demolition
Waste,” 2015.
[11] X. Gong, Z. Nie, Z. Wang, S. Cui, F. Gao, and T. Zuo, “Life cycle energy consumption and
carbon dioxide emission of residential building designs in Beijing: A comparative study,” J.
Ind. Ecol., vol. 16, no. 4, pp. 576–587, 2012.
[12] M. Z. Hauschild, R. K. Rosenbaum, and S. I. Olsen, Life Cycle Assessment: Theory and Practice.
2017.
[13] Danish Environmental Protection Agency, Affaldsstatistik 2015 [Waste statistics 2015], no.
1955. 2017.
[14] L. Benini, L. Mancini, S. Sala, E. Schau, S. Manfredi, and R. Pant, Normalisation method and
data for Environmental Footprints. 2014.
[15] N. Østergaard et al., “Data Driven Quantification of the Temporal Scope of Building LCAs,”
Procedia CIRP, vol. 69, no. May, pp. 224–229, 2018.
[16] M. Klanfar, T. Korman, and T. Kujundžić, “Fuel consumption and engine load factors of
equipment in quarrying of crushed stone,” Teh. Vjesn. - Tech. Gaz., vol. 23, no. 1, pp. 163–
169, 2016.
[17] Jacob Paulsen, "Life Cycle Assessment for Building Products - The significance of the usage

29
 phase", Doctoral Thesis, 2001
[18] Electricity sector in Denmark, Accessed 14 May 2019,
https://en.wikipedia.org/wiki/Electricity_sector_in_Denmark
[19] Fjernvarme Fyn heat mix, Accessed 14 May 2019, https://www.fjernvarmefyn.dk/viden-om-
fjernvarme/?

30
TimberNest Bench CO2
footprint account

31
Contents
Abstract .......................................................................................................................................... 33
1. Introduction ................................................................................................................................ 34
2. Methodology ............................................................................................................................... 36
2.1 Emissions scopes ................................................................................................................... 36
2.2 ISO Standards/CO2 footprint of a product .............................................................................. 38
2.3 Life Cycle Assessment Approach ............................................................................................ 40
2.4 Goal Definition....................................................................................................................... 40
2.5 Scope Definition and Functional Unit ..................................................................................... 40
3. Results......................................................................................................................................... 43
4. Discussions/Limitations ............................................................................................................... 45
5. Conclusions ................................................................................................................................. 46
6. Appendix ..................................................................................................................................... 47
References ...................................................................................................................................... 49

Figure 1 TimberNest bench [9]......................................................................................................... 34

Figure 2 GHG emissions scopes [14] ........................................................................................... 38
Figure 3 Process flow diagram for the incineration scenario ............................................................ 41
Figure 4 Process flow diagram for the recycling scenario ................................................................. 42
Figure 5 Climate change chart for all scenarios ................................................................................ 43
Figure 6 Climate change chart with all processes included ............................................................... 48

32
Abstract

In the last decades, one of the biggest challenges of the humankind is related to environment
and the protection of it. Greenhouse gas emissions are a concerning problem with every day
that passes for the generations to come, so the main objective is to keep track of these and
lower them as much as possible. The scope of this report is to evaluate the CO2 footprint of a
given product, in this case a wooden bench. The company interested in this footprint account
is TimberNest, a Danish start-up company which, like many other companies in the market,
they want to become a CO2 neutral firm as soon as possible. To assess the carbon dioxide
emissions for this bench, a Life-Cycle Assessment (LCA) approach was chosen. By doing
this, a certain environmental impact indicator was considered (Climate change) as being the
most important one. The software used for this paper is SimaPro where all the processes from
raw material extraction to disposal stage were considered. In order to do this assessment, we
created four scenarios. The first two scenarios are represented by the benches made out of
Douglas Pine and Oak, both having the same disposal procedures: incineration of wood and
recycling of screws. The other two scenarios have just recycling as the main disposal type,
resulting in less greenhouse gas emissions.

33
1. Introduction

Nowadays, environmental care is an important topic in the industry due to global climate
change, which already has considerable effects on our planet. The consumer behaviour has
changed in the recent years in terms of consumption, how they should treat the waste or what
they should buy or consume. Many people start to realize that global warming is a bad thing
for our living having many side effects such as: glaciers are melting, rising temperature,
accelerated sea level and so on. All these side effects occurred due to greenhouse gases
produced especially by the industry.

For our Master thesis we are making a CO2 footprint account of a company product and by
that, we want to present the environmental impacts caused by producing, utilization and the
post-consumer usage related to that product.

The company Is called TimberNest, a Danish start-up company located in Odense. Their first
concept was created in 2016 as a university project in collaboration with the Danish music
festival Tinderbox. Since then, more social furniture has been developed for an even greater
audience including other
Danish festivals, companies,
municipalities, and private
people.

TimberNest’s vision is to create

value and empathy for humans,
adults and children alike,
through the creation of relations
through the physical meeting. Figure 17 TimberNest bench [9]

We believe that the physical meeting and social recognition is more important than ever. The
company’s products therefore live up to the requirement for creating a frame for being
together in a natural way.

The analysed product is an innovative bench as in the figure up. The product has been
evaluated throughout the life-cycle stages, from the raw material extraction stage, to
production, use and disposal stage. The bench is made from Douglas Pine or Oak, used for
the sitting planks, purchased from another company in Denmark and then just assembled and

34
painted in the company’s factory. The provenience of wood is from Danish forests, so, in this
way the transportation distances are avoided, having less impacts on the environment. Beside
of the wood used for sitting planks, in the construction of the bench they use for the sides of
the bench Plywood, which is imported from Finland. Moreover, they also use two types of
stainless-steel screws and two types of water-based paint for the preservation of wood.

The lifespan of one bench is 5 years, according to the company, and then as disposal types
are mostly incineration for wood, and recycling for screws.

The CO2 footprint account will help the company to improve the design, materials used in
construction of the bench, types of treatment of the product and developing a sustainable
business plan towards a lower environmental impact. The aim of the company is to become a
CO2 neutral company. Regarding this, in the following steps, different scenarios were created
in order to find solutions to lower the environmental impacts and reduce the greenhouse gas
emissions.

35
2. Methodology

In this section are described the methods and principles used to measure the Greenhouse
gases produced by the wooden bench. Our aim is to provide a comprehensive carbon
accounting for TimberNest, following the right standards guide related to CO2 footprint for a
product, and help them to develop a sustainable product.

2.1 Emissions scopes

In order to do this CO2 accounting, first we must identify and categorize the Greenhouse gas
emissions released by the company product. The emissions are classified in three scopes [14]

Scope 1 – Direct Greenhouse emissions, which came from company activities and resources
they own. The emissions are classified as following:

• Production of electricity, heat and steam by combustion of different fuels through

furnaces, boilers, turbines and so on.
• Different kind of transportation, materials, products, waste or employees. Emissions
are released by combustion of fossil fuels using ships, trains, trucks, airplanes, cars or
buses.
• Physical or chemical processing – when the company is producing different kind of
products as aluminum, cement, ammonia, adipic acid or they are treating the waste.
• Fugitive emissions consists in different types of releases, intentional or unintentional.
Some examples could be emissions from mines, different leaks during transportation
of different good by sealing etc. [14]

In this first scope of emissions TimberNest does not fit due to its activity: they do not
produce electricity or other activities presented above. Regarding the first scope, it
was presented anyway for a better understanding of the emissions that are emitted by
a company.

Scope 2 – Electricity Greenhouse gas emissions, are released by a company which purchase
electricity from the grid or independent power generators and then resell to consumers. These
emissions appear in the atmosphere through transmission and distribution of the electricity.
[14]

36
As a company, TimberNest produces emissions by consumption of electricity. They are using
electrical screw drivers to assembly the bench, but moreover, they are using electricity for
lighting or other daily uses.

Scope 3 – Other indirect Greenhouse gas emissions, results from production of materials
that are purchased by the company from a supplier and used in their activity or project. [15]

The company has its own suppliers for materials as: Oak and Douglas Pine for planks, birch
plywood for the sides, screws for assembling and paints for the preservation of wood. In this
way, they avoid emissions produced by using electricity, heat and fossil fuels in the following
product stages:

• extraction of raw materials (chopping down and logging the trees, extraction of iron
ore, extraction of materials for chemicals substances used for paints)
• production of the bench (sitting planks, sides, screws and wood preservation paints)
• transportation of materials to consumer.

Regarding Scope 3, this is an optional one, compared with the first two scopes, but it is very
helpful to account all greenhouse gas emissions related to activities of a company. [14]

In the figure below, are illustrated all these three scopes, describing the provenience of all
Greenhouse gas emissions emitted by the company activities and also the boundaries of all
scopes.

37
Figure 18 GHG emissions scopes [14]

2.2 ISO Standards/CO2 footprint of a product

International Organization for Standardization (ISO) represents a worldwide federation,
independent and non-governmental organization with a member agenda consists in 164
national standards bodies. In the ISO structure the members are classified in three categories:
member bodies, correspondent members and subscriber members. Every member ISO
represents its country and contribute with knowledge and skills to improve the International
Standards to support innovative solutions for actual and future global challenges [8].

International Standards provide a guideline with specifications applicable worldwide for

different products, services and systems, in order to ensure the quality, safety and efficiency.
Until this moment, ISO has published 22547 International Standards and related documents,
comprising all industries starting with technology, food safety, agriculture ending with
healthcare [8].

For this CO2 footprint account of the TimberNest bench it is used the ISO 14067:2018. This
ISO standard was developed by Technical Committee ISO/TC 207, Environmental
management, Subcommittee SC 7, Greenhouse gas management and related activities. The
ISO 14067:2018 is the revised version of the previous one ISO 14067:2013 and is the main
standard for quantification of carbon footprint of a product [3].

38
CO2 footprint of a product (CFP) represents the sum of all Green House Gases emissions
(GHG emissions) and GHG removals of a specific product. The results are expressed as CO2
equivalent per functional unit by doing a life cycle assessment using a single impact category
of climate change [3].

Green House Gases represent a large category of gaseous constituent in the atmosphere
which can be divided in natural gases or anthropogenic. These gaseous constituents can
absorb or emit radiations at specific wavelengths within the spectrum of infrared radiation
emitted by the Earth’s surface, atmosphere and clouds [3].

Carbon Dioxide (CO2) – it is released in the atmosphere especially through combustion and
from production of glass, cement, aluminium or steel.

Methane (CH4) – results from incineration and decomposing of biomass (e.g. wood) and from
fossil industry by refining of petrol and production of natural gas.

Nitrous Oxide (N2O) – spread in the atmosphere by combustion of solid waste, transport
sector and from agriculture by using of fertilizers.

Hydrofluorocarbon-23 (CHF3) – appears in form of by-product from industrials processes as

air conditioning, refrigeration and insulation

Sulphur Hexafluoride (SF6) – the main use in insulation and electronic systems. [15]

Chlorofluorocarbon-12 (CCl2F2) – the main uses in refrigeration, blowing agents, solvents

[13]

From all Greenhouse gases described above, for Climate Change is accounting just CO 2,
because the other gases contribute to other environmental impact categories.

Land Use (LU)

Refers to all human activities related to land use within a relevant range. [3]

Direct land use (dLUC)

Refers to change in using the land by humans throughout a relevant range. [3]

In this report, were not considered Land Use and Direct Land Use, because are very complex
and requires a lot of time of investigations to determine the environmental impacts caused by
the company activities.

39
2.3 Life Cycle Assessment Approach
The aim of this CO2 footprint is to approach the environmental impact of the TimberNest bench
but focusing only on the impact category of climate change, using a consequential Life-Cycle-
Assessment approach. Products play a key role in the attempts to reduce the total environmental
impact of human activities. All environmental impacts can be tracked to the consumption,
respectively need of products [1]. Life Cycle Assessment (LCA) is a standard method for
comparing the environmental impacts of providing, using and disposing of a product or
providing a service throughout its life cycle. LCA identifies the material and energy usage,
emissions and waste flows of a product, process or service over its entire life cycle to determine
its environmental performance [2]. An LCA can give an answer to the question if there is a
more environmentally friendly substitution for the ordinary product which fulfills the same
need. Meaning, it helps in decision making if the aim is to choose the most environmentally
friendly product. The software used for this report in order to assess the environmental impacts
(climate change) is SimaPro 8.5.0.0.

2.4 Goal Definition

Since its foundation in 2016, TimberNest wants to change the way of socializing by introducing
a new concept called natural socializing through their products which are benches. Those
benches are supposed to connect people and break the social media barriers nowadays.

With this CO2 footprint account, the company wants to know what are the CO 2 emissions of
their products in order to become a CO2 neutral company in the future. To do so, the company
has to be provided with information about the environmental impacts of their products and see
which are the alternatives for a better management of these emissions.

2.5 Scope Definition and Functional Unit

The scope definition determines what product systems are to be assessed and how this
assessment should take place [5]. The functional unit describes and quantifies the service
performance of the product systems. This is to create a reference unit to be able to compare
the product systems [1]. For this report, the functional unit is one bench, which is used either
by municipalities, rented for concerts or domestic use by individuals. It is also considered a
lifetime of 5 years before disposal.

40
 TimberNest
Bench
% Sent to % Sent to Incineration Recycling
Scenario Wood Type recycling incineration avoids avoids
Waste from
1. Oak Incineration Oak 0% 100% UK -
Waste from Gypsum
2. Oak Recycling Oak 80% 20% UK production
3. Douglas Pine Douglas Waste from
Incineration Pine 0% 100% UK -
4. Douglas Pine Douglas Waste from Gypsum
Recycling Pine 80% 20% UK production
Table 1. TimberNest bench scenarios

Figure 19 Process flow diagram for the incineration scenario

41
Figure 20 Process flow diagram for the recycling scenario

Figures 3 and 4 are illustrating the process flow diagrams for both the douglas pine and oak
benches. The full-line polygons represent processes, the dotted polygons are avoided
products that are avoided through recycling of materials and the arrows are flows. In the first
one is presented the incineration scenario cradle-to-grave with all the life-cycle stages from
extraction of raw materials until the disposal stage where the wooden materials are
incinerated and the screws are recycled. For the recycling scenario, the processes are almost
the same with the exception that here, the wooden parts from the benches are recycled. The
wood is recycled through post-consumer recycling, meaning that it is aged, its properties are
changed and the wood is biologically contaminated [18]. By doing this, not 100% of the
wood will be recycled since it can rot if it is left outside, an assumption was made where 80%
is recycled and 20% incinerated. [18]

42
3. Results

In the following chapter the results from SimaPro are assessed. These results express the CO2
footprint of the TimberNest bench through the impact category of Climate change. There
were assessed four scenarios for the bench, two of them regarding the actual disposal
situation where the wood is incinerated and the screws are recycled. The other two were
made to see what will happen if all the materials used for the bench will be recycled and how
the environmental impact of CO2 will look like.

Climate change impact indicator chart

400.000
200.000
Kg of CO2 Equivalent

0.000
-200.000
-400.000
-600.000
-800.000
-1000.000
Incineration Incineration Recycling
Recycling Oak
Pine Oak Pine
Waste wood, post-consumer 0.000 0.000 -158.789 -211.719
Transport, freight, inland waterways,
29.120 39.127 0.000 0.000
barge
Production of Plywood sides -199.754 -199.754 -199.754 -199.754
Production of wooden planks -125.032 -125.032 -125.032 -125.032
Emissions of CO2 biogenic 32.844 43.860 164.220 219.300

Figure 21 Climate change chart for all scenarios

Figure 5 above, shows the most relevant SimaPro processes for all four scenarios considered.
The first three processes: “Emissions of CO2 biogenic”, “Production of wooden planks” and
“Production of Plywood sides” are the most important ones as they have the highest impacts
on environment. “Emissions of CO2 biogenic” it refers to how many Kg of CO2 are contained
in the wood used for one bench; therefore this amount can be emitted into the atmosphere.
“Transport, freight, inland waterways, barge” is the process selected in SimaPro to define the
transportation of waste from the United Kingdom to Denmark. For the incineration scenarios
considered, the assumption is that in Denmark, in order to fulfil the amounts for the
incineration plants across the country there is a need to import waste from the United

43
Kingdom by ship. [17] Even though, the numbers for “Transport, freight, inland waterways,
barge” from the incineration scenarios are very small compared with the other processes. For
the last line, “Waste wood, post-consumer” this process is used in SimaPro to define what
happens with the wooden materials from the bench when they are recycled. Post-consumer
recycling refers to the alternative of aging the wood with the side effect of changing inherent
properties. [18]

In the recycling scenarios there is also a line called “Gypsum, mineral” which refers to the
avoided amount of gypsum. According to Erlandsson and Sundquist, one of the best
alternatives to wood recycling is to replace the gypsum in particle boards as these are made
with gypsum, so the wood shavings can replace it in the future. The line “Gypsum, mineral”
is also not presented in the figure above because the results that came out for this process are
too small.

For all four scenarios, the other processes are too small to be taken into consideration and this
is the reason why they are not presented here. A more detailed figure with all the results
including the ones that are not here can be found in the appendix (Figure 6).

44
4. Discussions/Limitations

The overall assessment of the environmental impacts for both TimberNest benches made out
of Douglas Pine respectively Oak, shows that the oak and the douglas pine bench in the
recycling scenarios they have the same impact. For the incineration scenarios although, the
douglas pine bench is more environmentally friendly. An assumption was made considering
the difference between the recycling scenarios that the oak has a higher density and also the
energy content is higher and these could be the reasons why the other one is better.
Considering plywood which is used for the sides, this one is made out of laminated wood
(birch) and is harder to recycle but not impossible, therefore it is burned for now in the actual
situation of disposal. In the near future, TimberNest intends to recycle every single material
that they use for their benches.

The company also uses two water-based paints for their product both of them being for wood
preservation. The paints which are used for wood treatment are Flügger Impredur Træolie
and Flügger 04 Wood Tex Opaque. Regarding the calculations in SimaPro, we had some
limitations in finding the chemical substances from the paint in the software used. The
chemical components of these two paints are as follows: Hydroxyphenyl-benzotriazol
derivate, 3-Iod-2-propynylbutylcarbamat, Cobaltbis (2-ethylhexanoat), Kvaternære
ammoniumforbindelser, benzyl-C12-16-alkyldimethyl, chloride, 1,2-Benzisothiazol-3(2H),
5-Chlor-2-methyl-2H-isothiazol-3-on/2-Methyl-2H-isothiazol-3-on, 2-Methyl-2H-isothiazol-
3-on. [10] We tried to find in SimaPro a similar product which has in composition these types
of substances or at least some of them, but what we found is a product called “wood
preservative for outdoor use”. This product is water-based, we do not know the composition,
but we assumed that it is the same type as the product used for the TimberNest bench.
Furthermore, in what concerns the two types of screws used for the assembling process of the
bench, we could not find the exact material used, because they are made from steel and some
protection layer. For the calculations it was chosen two types of steel: chromium steel and
reinforced steel.
Finally, the TimberNest bench has two different designs, when the bench is placed directly on
concrete/bitumen or other hard surface, and when the base is soft as grass, sand etc. The
difference between these two situations is represented by using steel and rubber for the bench
sole when the product is placed on a hard ground, to protect the wood when is used, while in
the case of soft base the bench does not have any protection. In our calculations we did not

45
take in consideration the extra material used in bench composition, because having less
materials used for the product than wood and screws, the results will be better for Climate
Change.

5. Conclusions

In a nutshell, the findings relating the bench show that, the best solutions to become a CO2
neutral company are to improve the disposal solutions for their benches and this could be by
recycling all the materials contained in one bench. Moreover, regarding the materials which
are used in these benches, the plywood used for sides is a good material and it can be used in
the future as it can be recycled like the other materials. Plywood is made out of thin birch
wood layers that can be recycled afterwards. In addition, to have less greenhouse gas
emissions, it is recommended to recycle the wood, not just the screws.

To become a CO2 neutral company, maybe it is impossible, but at least it could lower the
emissions, by having a Circular Economy. Old components can be reused in other new
products, instead of making another by-product as wood pellets for example, and in this way
less energy is used in that specific process.

46
6. Appendix

Greenhouse gas Chemical formula Global Warming Atmospheric

Potential, 100-year lifetime (years)
time horizon
Carbon Dioxide CO2 1 100
Methane CH4 25 12
Nitrous Oxide N2 0 298 114
Chlorofuorocarbon- CCl2F2 10,900 100
12 (CFC-12)
Hydrofluorocarbon- CHF3 14,800 270
23 (HFC-23)
Sulphur SF6 22,800 3,200
Hexafluoride
Table 2. Principal Greenhouse gases [4]

47
 Climate change impact indicator chart

400.000
Kg of CO2 Equivalent

200.000
0.000
-200.000
-400.000
-600.000
-800.000
-1000.000
Incineration Pine Incineration Oak Recycling Pine Recycling Oak
Wood ash mixture, pure 0.000 0.000 0.310 0.413
Waste wood, post-consumer 0.000 0.000 -158.789 -211.719
Avoided Gypsum, mineral 0.000 0.000 -0.010 -0.010
Waste from UK 3.482 3.482 0.000 0.000
Waste from UK 0.000 0.000 0.000 0.000
Avoided steel production 0.000 0.000 0.000 0.000
Electricity, low voltage 0.191 0.191 0.191 0.191
Transport, freight, inland waterways, barge 29.120 39.127 0.000 0.000
Production of Wood Tex Paint 0.002 0.002 0.002 0.002
Production of Paint Impredur Tree Oil 0.005 0.005 0.005 0.005
Production of screws 0.000 0.000 0.000 0.000
Production of Plywood sides -199.754 -199.754 -199.754 -199.754
Production of wooden planks -125.032 -125.032 -125.032 -125.032
Emissions of CO2 biogenic 32.844 43.860 164.220 219.300
Total -127.765 -62.678 -320.037 -318.179

Figure 22 Climate change chart with all processes included

48
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49
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