The Key Strategies to Implement Circular Economy in Building Projects—A Case Study of Taiwan

Abstract

The building industry is blamed for consuming enormous natural resources and creating massive solid waste worldwide. In response to this, the concept of circular economy (CE) has gained much attention in the sector in recent years. Many pilot building projects that implemented CE concepts started to appear around the world, including Taiwan. However, compared with the pilot projects in the Netherlands, which are regarded as the pioneer ones by international society, many CE-related practices are not implemented in pilot cases in Taiwan. To assist future project stakeholders to recognize what the key CE-related practices are and how they could be implemented in their building projects in Taiwan, this study has conducted a series of case studies of Dutch and Taiwanese pilot projects and semi-structured interviews with key project stakeholders of Taiwanese pilot projects. Thirty key CE-related practices are identified via case studies, along with their related 5R principles (Rethink, Reduce, Reuse, Repair, Recycle) and project phases. Suggestion on CE-related practices, their 5R principles, project items, and phases to implement in building projects in Taiwan is also proposed while discussion on differences between two countries’ pilot projects is presented.

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sustainability
Article
The Key Strategies to Implement Circular Economy in Building
Projects—A Case Study of Taiwan
H.-Ping Tserng 1, *, Cheng-Mo Chou 1,2 and Yun-Tsui Chang 1


Citation: Tserng, H.-P.; Chou, C.-M.;
Chang, Y.-T. The Key Strategies to
Implement Circular Economy in
Building Projects—A Case Study of
Taiwan. Sustainability 2021,13, 754.
https://doi.org/10.3390/su13020754
Received: 14 December 2020
Accepted: 12 January 2021
Published: 14 January 2021
Publisher’s Note: MDPI stays neu-
tral with regard to jurisdictional clai-
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Copyright: © 2021 by the authors. Li-
censee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and con-
ditions of the Creative Commons At-
tribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
1Department of Civil Engineering, National Taiwan University, Taipei 106, Taiwan;
audi@tecg.com.tw (C.-M.C.); ytchang@caece.net (Y.-T.C.)
2Taiwan Engineering Consultants Group (TECG), Taipei 114, Taiwan
*Correspondence: hptserng@ntu.edu.tw
Abstract:
The building industry is blamed for consuming enormous natural resources and creating
massive solid waste worldwide. In response to this, the concept of circular economy (CE) has
gained much attention in the sector in recent years. Many pilot building projects that implemented
CE concepts started to appear around the world, including Taiwan. However, compared with the
pilot projects in the Netherlands, which are regarded as the pioneer ones by international society,
many CE-related practices are not implemented in pilot cases in Taiwan. To assist future project
stakeholders to recognize what the key CE-related practices are and how they could be implemented
in their building projects in Taiwan, this study has conducted a series of case studies of Dutch and
Taiwanese pilot projects and semi-structured interviews with key project stakeholders of Taiwanese
pilot projects. Thirty key CE-related practices are identified via case studies, along with their related
5R principles (Rethink, Reduce, Reuse, Repair, Recycle) and project phases. Suggestion on CE-related
practices, their 5R principles, project items, and phases to implement in building projects in Taiwan
is also proposed while discussion on differences between two countries’ pilot projects is presented.
Keywords: circular economy in construction; strategic implementation; 5R principles
1. Introduction
Building industry consumes enormous natural resources and creates massive solid
waste around the world. For example, according to the new Circular Economy Action Plan
released by European Commission, it accounts for about 50% of all extracted materials and
over 35% of the total waste generation in Europe [
1
]. It is also responsible for about 50% of
raw materials and 40% of solid waste in the Netherlands [2]. In Taiwan, it has used about
25 million tons of raw materials and generated nearly 2 million tons solid waste yearly
based on the estimation of the Environmental Protection Administration, placing much
pressure on this small island country that lacks many natural resources and facilities to
deal with construction and demolition waste [3].
To tackle the challenging environmental problems that the building industry has
brought, the concept of circular economy (CE) has gained its popularity by public and
private sectors around the globe. For instance, European Commission will launch a
new comprehensive Strategy for a Sustainable Built Environment in 2021, integrating CE
principles in its policies including addressing the sustainability performance of construction
products, improving the durability and adaptability of built assets, etc. [
1
]. The Government
of the Netherlands has proposed a roadmap to implement CE in its construction industry in
2016, executing actions including adding substance to innovative and circular construction
projects, developing a circular construction assessment method, etc. [
2
]. The government
of Taiwan has also highlighted construction industry as one of its major focus in its CE
implementation roadmap in 2018, promoting measures including enhancing front-end
classification and recycling efficiency, encouraging partnerships and collaborations between
different sectors, etc. [
4
]. However, CE implementation in the building industry globally is
Sustainability 2021,13, 754. https://doi.org/10.3390/su13020754 https://www.mdpi.com/journal/sustainability

Sustainability 2021,13, 754 2 of 16
just at its initial stage, facing many barriers such as unproven business cases of requiring
manufacturers to be responsible for their products once they reach their end of life [5].
Meanwhile, several CE-focused pilot building projects have started to appear around
the world to test and demonstrate the robustness of CE concepts for building [
2
,
6
–
8
]. For
example, Park20|20 in the northern Netherlands is famous for implementing the C2C
principles in a holistic and multilevel way since the 2010s. The Amsterdam Schiphol
airport is recognized for adopting new CE-related business models such as product as a
service for their lighting system since 2015. The new pavilion built by the Dutch bank
ABN AMRO in 2017 is noted for its innovative financial model. The Dutch pilot projects
are regarded as the pioneer ones by the international society [
2
,
9
]. However, limited
research has conducted case study on these cases [
6
], and none has delivered overview and
comparison of their adopted CE-related practices between these cases in a systematic way,
hindering the international society to learn and utilize the CE implementation experience
from these cases comprehensively.
Meanwhile, following the global trend of CE adoption, several building projects in
Taiwan are also proposed to implement CE principles in recent years. Many of them
are public housing projects, highlighting the CE-related practices including modular and
flexible units, recycled materials and sharing space, etc. However, compared with the pilot
cases in the Netherlands, many CE-related practices seem to not be implemented yet in
ones in Taiwan [
10
]. Further investigation on the differences between the two countries’
pilot cases and the reasons behind them are critical for Taiwan’s building industry to
propose suitable CE implementation strategies and international society to see how CE
concepts are implemented in building projects in different countries.
The main objectives of this study are to identify the key CE-related practices from
the Dutch and Taiwanese pilot building projects, the differences between them and the
reasons behind those, and to propose an implementation framework for building projects
in Taiwan. The key research questions include: What are the key CE-related practices
implemented in these pilot projects and how to understand them? What are the different
practices adopted in these projects and the reasons behind them? How can the building
industry in Taiwan implement the practices learned from the Dutch cases?
To answer these research questions, this study carried out a series of case studies of CE-
focused pilot projects both in the Netherlands and Taiwan and semi-structured interviews
with key project stakeholders of Taiwan projects. Thirty key CE-related practices are
identified in five pilot projects and noted. Their related 5R principles (Rethink, Reduce,
Reuse, Repair, Recycle), project phases, items, and implementation time are also noted by
the authors and interviewees. Suggestions on implementing CE in building projects in
Taiwan are proposed, and discussion on difference between practices in the Netherlands
and Taiwan are also made in this study.
The key contributions of this study include presenting a case study of CE-focused
pilot building projects in the Netherlands and Taiwan in a systematic way by marking
their CE-related practices, related 5R principles, project phases, and items for international
society to see how CE concepts are implemented at project level in different countries.
Furthermore, based upon the identification of these key CE-related practices and other
essential information to consider before implementation in building projects in Taiwan (i.e.,
related project phases, items, 5R principles, and implementation time), an implementation
framework is proposed for future Taiwanese building project stakeholders. For countries
whose building industry is at the similar CE implementation stage as Taiwan, similar
methods can be applied for them to identify suitable strategies to implement these CE
practices.
This paper is structured by the following sections: in Section 2, literature review on
circular economy, its concepts, and research for building industry is presented, along with
the 5R principles and its applications in building projects, and the CE-focused pilot building
projects both in the Netherlands and Taiwan. Section 3reveals the methodology adopted
in this study to deliver a series of case studies of the chosen Dutch and Taiwanese pilot

Sustainability 2021,13, 754 3 of 16
projects and interviews with key stakeholders in Taiwanese pilot projects. Section 4presents
the results gained by case study and interviews, which are the identified key CE-related
practices in pilot projects, their related 5R principles, project phases and implementation
time for building projects in Taiwan. Section 5delivers discussions on research results
by comparing differences between two countries’ pilot projects and by organizing the
CE-related practices with their related project categories and items. An implementation
framework is developed based upon these discussions and contained in Section 5. In the
end, Section 6summarizes the conclusion and limitation of this study and some ideas on
future research directions.
2. Literature Review
2.1. Circular Economy, Its Concepts, and Its Research for Building Industry
Since the Second Industrial Revolution more than a century ago, mass production
and rapid economic growth have been seen in human history, as well as the enormous
resource harvesting and severe environmental pollution. This is resulted from the current
economic model, known as a “linear model,” which is mainly composed of three parts,
“take-make-waste,” referring to the linear process of modern product life cycle, from
harvest, manufacture, usage, then to disposal [
11
]. In response to this situation, the concept
of “circular economy (CE)” has arisen since half a century ago and gained tremendous
attention in the past half decade [
12
]. In contrast to linear models, CE creates loops in the
product life cycle to retain the value of resources (i.e., products, components, materials) in
every stage and thus avoiding generating waste [11].
To implement a circular economy, many frameworks and approaches have been
proposed. Two of the most referred frameworks are ReSOLVE [
13
] and the “butterfly
diagram” [
11
] proposed by Ellen MacArthur Foundation. The former one aims to assist
businesses and countries in generating circular strategies, while the latter one portraits
various approaches of CE in both biological and technological systems, guiding researchers
and practitioners to understand CE. Similar to the butterfly diagram, the R-Imperatives
are also widely used for conceptualizing CE and systematic thinking [
14
]. Among them,
even though the 3R framework (reduce, reuse, recycle) seems to be the most prominent
one [
14
], 5R is the most utilized one in CE-related literature [
15
]. This is recognizable,
since 3R is obviously insufficient in representing various loops that CE emphasizes, while
9R is detailed, specific, and might not be applicable to different kinds of industries [
16
].
In this study, the 5R framework is chosen to understand CE concepts and their practices in
building industry.
The trend of CE has also aroused much attention from the building industry around the
world. Research on this theme is growing rapidly, with the number of publications doubling
each year from 2016 to 2019 [
17
]. Among them, research on recycled/reusable materials
and circular transition are the major parts, followed by tools and assessments to support
circular buildings, CE-related product and building design, and stock and flow analysis
of resources and materials [
17
]. Several research have summarized CE-related practices
for building projects throughout life cycle through literature review [
18
,
19
]. However,
study on CE-related practices on pilot projects is yet to be found. Some case studies on
pilot projects have been conducted in countries like the Netherlands and Taiwan [
6
,
9
,
10
],
yet their focuses are not on their CE-related practices, but on developing collaboration
tools for stakeholders [
6
], exploring successful paths of knowledge transition of CE [
9
],
and disclosing current status and barriers of the building industry [10].
2.2. The 5R Principles and Its Applications in Building Projects
Several research have categorized CE-related practices by different phases in building
life cycle [
17
,
18
] and ReSOLVE framework proposed by Ellen MacArthur Foundation [
20
].
However, study on utilizing R-Imperatives to review CE-related practices in building
projects are yet to be seen. To systematically understand CE-related practices in building
projects, the 5R framework is utilized in this study. As mentioned in Reike et al.’s work [
15
],

Sustainability 2021,13, 754 4 of 16
there is no consensus on what R-Imperatives stand for, even the most prominent 3R
framework. The combinations of R-Imperatives are chosen according to the application
scenarios and best interests of applicants. In this research, the 5R principles set to be
utilized are Rethink, Reduce, Reuse, Repair and Recycle, since they are identified to be
more relevant to building projects [
14
]. The definitions, objectives, and their applications
in building projects of these 5R principles are shown in Table 1.
Table 1. Definitions, objectives of 5R principles and their applications in building industry (summarized by the authors).
5R
Principles Definition Objective Examples in Building Industry
Rethink
•To make a product use-intensive
(e.g., by sharing products or by
creating mufti-functional
products) [21]
•To replace parts as a service [22]
•To recreate ideas, processes,
dynamics of a product [23]
To achieve maximum resource
efficiency through innovative
model [23]
•Sharing space, sharing
ownership
•Pay per lux or pay per scan [24]
•Material passport [25]
Reduce
•To use fewer natural resources,
and therefore fewer inputs of
energy, raw materials, and waste
[23]
•
To dematerialize (i.e., to substitute
a product by a nonmaterial
alternative with the same utility
for users) [15]
To achieve minimum resource
usage through production and
consumption [23]
•
Energy-saving and water-saving
system
•Lightweight design [26]
•Prefabricated module [27]
Reuse
•To use a product again while
retaining it function and identity
[23]
To achieve maximum usage of
a product through relocation
or resell [23]
•Reuse of structural component
[28]
•Material bank [29]
Repair
•To repair and maintain a product
to be used with its original
function [23]
To achieve maximum lifespan
of a product through repair
and maintenance [23]
•Design for disassembly [30]
•Smart facility management
system [31]
Recycle
•To process materials to obtain the
same or quality of materials (e.g.,
shredding, melting) [23]
To achieve minimum usage of
newly mining resources by
reprocessing materials [15]
•Electric arc furnace steel, fly ash
cement
•Cradle to cradle design [32]
2.3. Circular Economy Focused Pilot Building Projects
The Netherlands is considered to be a pioneering country in implementing a circular
economy. Its government proposed an ambitious plan in 2016, aiming to achieve a circular
economy by 2050 in its five major industries, including construction [
2
]. Several pilot
projects in the Netherlands also become well known by the international society for case
study [
18
]. In this study, three Dutch pilot projects are chosen for case study because of
their wide variety of CE-related practices: Park20|20, Venlo City Hall, ABN AMRO CIRCL.
Here are some brief introductions of these three Dutch pilot projects. First of all, Park
20|20, adjacent to Schiphol Airport in the northern Netherlands, is the first full-service
Cradle to Cradle (C2C) office park in the world, synthesizing access and mobility, passive
design, and integrated energy, water and waste management systems etc. Since 2007,
Delta Development Group and William McDonough + Partners have been working closely
together to create a new model of sustainable development that implements the C2C
principles in a holistic and multilevel way, and until now, it is still a successful case to
which many researchers refer [
33
]. Second, Venlo City Hall, located in the southeast of

Sustainability 2021,13, 754 5 of 16
the Netherlands, is another famous C2C building project, emphasizing a comfortable and
healthy working environment with innovative sustainability. Built in 2016, this new city hall
has become a sign of excellent service to residents and businesses, exuding the important
features of municipal organization: open, transparent, and accessible [
34
]. Last but not the
least, ABN AMRO CIRCL, set in the heart of Amsterdam’s Zuidas business district, is a
multipurpose circular pavilion, centering on high-quality recycling of materials, energy-
neutral consumption, and minimum of waste. Open to the public in 2017, Circl represents
ABN AMRO’s sustainability ambitions and its commitment to finance sustainable homes
and offices in order to contribute to a future-proof society [
35
]. A brief comparison of these
three cases are shown in Table 2to have more understanding on their attributes.
Table 2. Basic information of circular economy (CE)-focused pilot projects in the Netherlands.
Park20|20 [33]1Venlo City Hall [34]1ABN AMRO CIRCL [35]1
Picture
Sustainability 2021, 13, x FOR PEER REVIEW 5 of 16
design, and integrated energy, water and waste management systems etc. Since 2007,
Delta Development Group and William McDonough + Partners have been working
closely together to create a new model of sustainable development that implements the
C2C principles in a holistic and multilevel way, and until now, it is still a successful case
to which many researchers refer [33]. Second, Venlo City Hall, located in the southeast of
the Netherlands, is another famous C2C building project, emphasizing a comfortable and
healthy working environment with innovative sustainability. Built in 2016, this new city
hall has become a sign of excellent service to residents and businesses, exuding the im-
portant features of municipal organization: open, transparent, and accessible [34]. Last but
not the least, ABN AMRO CIRCL, set in the heart of Amsterdam’s Zuidas business dis-
trict, is a multipurpose circular pavilion, centering on high-quality recycling of materials,
energy-neutral consumption, and minimum of waste. Open to the public in 2017, Circl
represents ABN AMRO’s sustainability ambitions and its commitment to finance sustain-
able homes and offices in order to contribute to a future-proof society [35]. A brief com-
parison of these three cases are shown in Table 2 to have more understanding on their
attributes.
Table 2. Basic information of circular economy (CE)-focused pilot projects in the Netherlands.
Park20|20 [33]
1 Venlo City Hall [34] 1 ABN AMRO CIRCL [35] 1
Picture
Use type Commercial (office) Specialty (government) Specialty (pavilion)
Built year 2012~2 2016 2017
Level NA 11 floors 2 floors
Site area 114,000 m2 27,700 m2 NA
Floor area NA 13,500 m2 3300 m2
1 Refs [33–35] are sources of pictures and numbers in Table 2. 2 This development project is still on going.
In this study, two pilot cases in Taiwan are chosen to reflect the current implementa-
tion status of CE in building projects in the country because of their more mature project
phases. The first project is known as Shalun circular housing project (also known as
Taisugar’s circular village) in southern Taiwan. Proposed by Taiwan Sugar Corporation
and designed by Bio-architecture Formosana, this project introduced many CE concepts
such as flexible configuration and building as materials bank, etc., combined with other
features including smart electricity, water network, self-cultivated food, etc. (see Figure 1)
[36]. The second project is called Nangang public housing project in Taipei. Proposed by
Taipei City Government, this project also integrates many CE concepts such as modular
spatial unit planning and product as a service model etc., joined by other practices includ-
ing smart home appliances and sharing space, etc. (see Figure 1) [37]. More information is
conveyed in Table 3 to gain more understanding on these two projects.
Table 3. Basic information of CE-focused pilot projects in Taiwan.
Shalun Circular Housing [36] Nangang Public Housing [37]
Picture
Sustainability 2021, 13, x FOR PEER REVIEW 5 of 16
design, and integrated energy, water and waste management systems etc. Since 2007,
Delta Development Group and William McDonough + Partners have been working
closely together to create a new model of sustainable development that implements the
C2C principles in a holistic and multilevel way, and until now, it is still a successful case
to which many researchers refer [33]. Second, Venlo City Hall, located in the southeast of
the Netherlands, is another famous C2C building project, emphasizing a comfortable and
healthy working environment with innovative sustainability. Built in 2016, this new city
hall has become a sign of excellent service to residents and businesses, exuding the im-
portant features of municipal organization: open, transparent, and accessible [34]. Last but
not the least, ABN AMRO CIRCL, set in the heart of Amsterdam’s Zuidas business dis-
trict, is a multipurpose circular pavilion, centering on high-quality recycling of materials,
energy-neutral consumption, and minimum of waste. Open to the public in 2017, Circl
represents ABN AMRO’s sustainability ambitions and its commitment to finance sustain-
able homes and offices in order to contribute to a future-proof society [35]. A brief com-
parison of these three cases are shown in Table 2 to have more understanding on their
attributes.
Table 2. Basic information of circular economy (CE)-focused pilot projects in the Netherlands.
Park20|20 [33]
1 Venlo City Hall [34] 1 ABN AMRO CIRCL [35] 1
Picture
Use type Commercial (office) Specialty (government) Specialty (pavilion)
Built year 2012~2 2016 2017
Level NA 11 floors 2 floors
Site area 114,000 m2 27,700 m2 NA
Floor area NA 13,500 m2 3300 m2
1 Refs [33–35] are sources of pictures and numbers in Table 2. 2 This development project is still on going.
In this study, two pilot cases in Taiwan are chosen to reflect the current implementa-
tion status of CE in building projects in the country because of their more mature project
phases. The first project is known as Shalun circular housing project (also known as
Taisugar’s circular village) in southern Taiwan. Proposed by Taiwan Sugar Corporation
and designed by Bio-architecture Formosana, this project introduced many CE concepts
such as flexible configuration and building as materials bank, etc., combined with other
features including smart electricity, water network, self-cultivated food, etc. (see Figure 1)
[36]. The second project is called Nangang public housing project in Taipei. Proposed by
Taipei City Government, this project also integrates many CE concepts such as modular
spatial unit planning and product as a service model etc., joined by other practices includ-
ing smart home appliances and sharing space, etc. (see Figure 1) [37]. More information is
conveyed in Table 3 to gain more understanding on these two projects.
Table 3. Basic information of CE-focused pilot projects in Taiwan.
Shalun Circular Housing [36] Nangang Public Housing [37]
Picture
Sustainability 2021, 13, x FOR PEER REVIEW 5 of 16
design, and integrated energy, water and waste management systems etc. Since 2007,
Delta Development Group and William McDonough + Partners have been working
closely together to create a new model of sustainable development that implements the
C2C principles in a holistic and multilevel way, and until now, it is still a successful case
to which many researchers refer [33]. Second, Venlo City Hall, located in the southeast of
the Netherlands, is another famous C2C building project, emphasizing a comfortable and
healthy working environment with innovative sustainability. Built in 2016, this new city
hall has become a sign of excellent service to residents and businesses, exuding the im-
portant features of municipal organization: open, transparent, and accessible [34]. Last but
not the least, ABN AMRO CIRCL, set in the heart of Amsterdam’s Zuidas business dis-
trict, is a multipurpose circular pavilion, centering on high-quality recycling of materials,
energy-neutral consumption, and minimum of waste. Open to the public in 2017, Circl
represents ABN AMRO’s sustainability ambitions and its commitment to finance sustain-
able homes and offices in order to contribute to a future-proof society [35]. A brief com-
parison of these three cases are shown in Table 2 to have more understanding on their
attributes.
Table 2. Basic information of circular economy (CE)-focused pilot projects in the Netherlands.
Park20|20 [33]
1 Venlo City Hall [34] 1 ABN AMRO CIRCL [35] 1
Picture
Use type Commercial (office) Specialty (government) Specialty (pavilion)
Built year 2012~2 2016 2017
Level NA 11 floors 2 floors
Site area 114,000 m2 27,700 m2 NA
Floor area NA 13,500 m2 3300 m2
1 Refs [33–35] are sources of pictures and numbers in Table 2. 2 This development project is still on going.
In this study, two pilot cases in Taiwan are chosen to reflect the current implementa-
tion status of CE in building projects in the country because of their more mature project
phases. The first project is known as Shalun circular housing project (also known as
Taisugar’s circular village) in southern Taiwan. Proposed by Taiwan Sugar Corporation
and designed by Bio-architecture Formosana, this project introduced many CE concepts
such as flexible configuration and building as materials bank, etc., combined with other
features including smart electricity, water network, self-cultivated food, etc. (see Figure 1)
[36]. The second project is called Nangang public housing project in Taipei. Proposed by
Taipei City Government, this project also integrates many CE concepts such as modular
spatial unit planning and product as a service model etc., joined by other practices includ-
ing smart home appliances and sharing space, etc. (see Figure 1) [37]. More information is
conveyed in Table 3 to gain more understanding on these two projects.
Table 3. Basic information of CE-focused pilot projects in Taiwan.
Shalun Circular Housing [36] Nangang Public Housing [37]
Picture
Use type Commercial (office) Specialty (government) Specialty (pavilion)
Built year 2012~22016 2017
Level NA 11 floors 2 floors
Site area 114,000 m227,700 m2NA
Floor area NA 13,500 m23300 m2
1Refs [33–35] are sources of pictures and numbers in Table 2.2This development project is still on going.
In this study, two pilot cases in Taiwan are chosen to reflect the current implementation
status of CE in building projects in the country because of their more mature project
phases. The first project is known as Shalun circular housing project (also known as
Taisugar’s circular village) in southern Taiwan. Proposed by Taiwan Sugar Corporation and
designed by Bio-architecture Formosana, this project introduced many CE concepts such
as flexible configuration and building as materials bank, etc., combined with other features
including smart electricity, water network, self-cultivated food, etc. (see
Figure 1)
[
36
]. The
second project is called Nangang public housing project in Taipei. Proposed by Taipei City
Government, this project also integrates many CE concepts such as modular spatial unit
planning and product as a service model etc., joined by other practices including smart
home appliances and sharing space, etc. (see
Figure 1)
[
37
]. More information is conveyed
in Table 3to gain more understanding on these two projects.
Table 3. Basic information of CE-focused pilot projects in Taiwan.
Shalun Circular Housing [36] Nangang Public Housing [37]
Picture
Sustainability 2021, 13, x FOR PEER REVIEW 5 of 16
design, and integrated energy, water and waste management systems etc. Since 2007,
Delta Development Group and William McDonough + Partners have been working
closely together to create a new model of sustainable development that implements the
C2C principles in a holistic and multilevel way, and until now, it is still a successful case
to which many researchers refer [33]. Second, Venlo City Hall, located in the southeast of
the Netherlands, is another famous C2C building project, emphasizing a comfortable and
healthy working environment with innovative sustainability. Built in 2016, this new city
hall has become a sign of excellent service to residents and businesses, exuding the im-
portant features of municipal organization: open, transparent, and accessible [34]. Last but
not the least, ABN AMRO CIRCL, set in the heart of Amsterdam’s Zuidas business dis-
trict, is a multipurpose circular pavilion, centering on high-quality recycling of materials,
energy-neutral consumption, and minimum of waste. Open to the public in 2017, Circl
represents ABN AMRO’s sustainability ambitions and its commitment to finance sustain-
able homes and offices in order to contribute to a future-proof society [35]. A brief com-
parison of these three cases are shown in Table 2 to have more understanding on their
attributes.
Table 2. Basic information of circular economy (CE)-focused pilot projects in the Netherlands.
Park20|20 [33]
1 Venlo City Hall [34] 1 ABN AMRO CIRCL [35] 1
Picture
Use type Commercial (office) Specialty (government) Specialty (pavilion)
Built year 2012~2 2016 2017
Level NA 11 floors 2 floors
Site area 114,000 m2 27,700 m2 NA
Floor area NA 13,500 m2 3300 m2
1 Refs [33–35] are sources of pictures and numbers in Table 2. 2 This development project is still on going.
In this study, two pilot cases in Taiwan are chosen to reflect the current implementa-
tion status of CE in building projects in the country because of their more mature project
phases. The first project is known as Shalun circular housing project (also known as
Taisugar’s circular village) in southern Taiwan. Proposed by Taiwan Sugar Corporation
and designed by Bio-architecture Formosana, this project introduced many CE concepts
such as flexible configuration and building as materials bank, etc., combined with other
features including smart electricity, water network, self-cultivated food, etc. (see Figure 1)
[36]. The second project is called Nangang public housing project in Taipei. Proposed by
Taipei City Government, this project also integrates many CE concepts such as modular
spatial unit planning and product as a service model etc., joined by other practices includ-
ing smart home appliances and sharing space, etc. (see Figure 1) [37]. More information is
conveyed in Table 3 to gain more understanding on these two projects.
Table 3. Basic information of CE-focused pilot projects in Taiwan.
Shalun Circular Housing [36] Nangang Public Housing [37]
Picture
Sustainability 2021, 13, x FOR PEER REVIEW 5 of 16
design, and integrated energy, water and waste management systems etc. Since 2007,
Delta Development Group and William McDonough + Partners have been working
closely together to create a new model of sustainable development that implements the
C2C principles in a holistic and multilevel way, and until now, it is still a successful case
to which many researchers refer [33]. Second, Venlo City Hall, located in the southeast of
the Netherlands, is another famous C2C building project, emphasizing a comfortable and
healthy working environment with innovative sustainability. Built in 2016, this new city
hall has become a sign of excellent service to residents and businesses, exuding the im-
portant features of municipal organization: open, transparent, and accessible [34]. Last but
not the least, ABN AMRO CIRCL, set in the heart of Amsterdam’s Zuidas business dis-
trict, is a multipurpose circular pavilion, centering on high-quality recycling of materials,
energy-neutral consumption, and minimum of waste. Open to the public in 2017, Circl
represents ABN AMRO’s sustainability ambitions and its commitment to finance sustain-
able homes and offices in order to contribute to a future-proof society [35]. A brief com-
parison of these three cases are shown in Table 2 to have more understanding on their
attributes.
Table 2. Basic information of circular economy (CE)-focused pilot projects in the Netherlands.
Park20|20 [33]
1 Venlo City Hall [34] 1 ABN AMRO CIRCL [35] 1
Picture
Use type Commercial (office) Specialty (government) Specialty (pavilion)
Built year 2012~2 2016 2017
Level NA 11 floors 2 floors
Site area 114,000 m2 27,700 m2 NA
Floor area NA 13,500 m2 3300 m2
1 Refs [33–35] are sources of pictures and numbers in Table 2. 2 This development project is still on going.
In this study, two pilot cases in Taiwan are chosen to reflect the current implementa-
tion status of CE in building projects in the country because of their more mature project
phases. The first project is known as Shalun circular housing project (also known as
Taisugar’s circular village) in southern Taiwan. Proposed by Taiwan Sugar Corporation
and designed by Bio-architecture Formosana, this project introduced many CE concepts
such as flexible configuration and building as materials bank, etc., combined with other
features including smart electricity, water network, self-cultivated food, etc. (see Figure 1)
[36]. The second project is called Nangang public housing project in Taipei. Proposed by
Taipei City Government, this project also integrates many CE concepts such as modular
spatial unit planning and product as a service model etc., joined by other practices includ-
ing smart home appliances and sharing space, etc. (see Figure 1) [37]. More information is
conveyed in Table 3 to gain more understanding on these two projects.
Table 3. Basic information of CE-focused pilot projects in Taiwan.
Shalun Circular Housing [36] Nangang Public Housing [37]
Picture
Use type Residential (apartment) Residential (apartment)
Current Phase Construction Construction
Level 8 floors 26 floors
Site area 13,994 m278,811 m2
Floor area 28,580 m2141,850 m2
Refs. [36,37] are sources of pictures and numbers in Table 3.

Sustainability 2021,13, 754 6 of 16
Sustainability 2021, 13, x FOR PEER REVIEW 6 of 16
Use type Residential (apartment) Residential (apartment)
Current Phase Construction Construction
Level 8 floors 26 floors
Site area 13,994 m2 78,811 m2
Floor area 28,580 m2 141,850 m2
Refs. [36,37] are sources of pictures and numbers in Table 3.
(a)
(b)
Figure 1. Description on CE-related practice of Taiwanese pilot projects (a) Shalun Circular Housing [36]; (b) Nangang
Public Housing (drawn by the authors).
3. Methodology
The research process of this study is as following (shown as Figure 2): first, the key
CE-related practices of the selected three Dutch pilot building projects were identified
through reviewing their related literature and publications (shown as Table 4), and noted
with related project phases by the authors, along with the related 5R principles (Rethink,
Reduce, Reuse, Repair, Recycle) based on definitions identified through literature review
of related academic publications (see Section 2.2). A table containing these three sets of
information of three Dutch pilot projects was generated. Second, the key CE-related prac-
tices of the selected two Taiwanese pilot projects are identified by their key project stake-
holders, which are the two interviewees in this study. They were asked to mark the CE-
related practices in their projects based upon the table generated in step one. Third, the
interviewees were asked to mark the expected implementation time of each key CE-re-
lated practice for building projects in Taiwan by short term (i.e., becoming common prac-
tice within a five-year time period) or long term (only after a ten-year time period) or both
scenario (i.e., being implemented within a five-year time period, but only becoming com-
mon practice afterwards). Fourth, the interviewees are asked to discuss the differences of
Figure 1.
Description on CE-related practice of Taiwanese pilot projects (
a
) Shalun Circular Housing [
36
]; (
b
) Nangang
Public Housing (drawn by the authors).
3. Methodology
The research process of this study is as following (shown as Figure 2): first, the key
CE-related practices of the selected three Dutch pilot building projects were identified
through reviewing their related literature and publications (shown as Table 4), and noted
with related project phases by the authors, along with the related 5R principles (Rethink,
Reduce, Reuse, Repair, Recycle) based on definitions identified through literature review
of related academic publications (see Section 2.2). A table containing these three sets
of information of three Dutch pilot projects was generated. Second, the key CE-related
practices of the selected two Taiwanese pilot projects are identified by their key project
stakeholders, which are the two interviewees in this study. They were asked to mark the
CE-related practices in their projects based upon the table generated in step one. Third,
the interviewees were asked to mark the expected implementation time of each key CE-
related practice for building projects in Taiwan by short term (i.e., becoming common
practice within a five-year time period) or long term (only after a ten-year time period) or
both scenario (i.e., being implemented within a five-year time period, but only becoming
common practice afterwards). Fourth, the interviewees are asked to discuss the differences
of CE-related practices between pilot projects in two countries and the reasons behind them
based upon the notation results in previous steps. Information on interviewees are shown
in Table 4and interview questions in Tables 5and 6.

Sustainability 2021,13, 754 7 of 16
Sustainability 2021, 13, x FOR PEER REVIEW 7 of 16
CE-related practices between pilot projects in two countries and the reasons behind them
based upon the notation results in previous steps. Information on interviewees are shown
in Table 4 and interview questions in Tables 5 and 6.
Figure 2. Description on research process (drawn by the authors).
Table 4. Reference of related literature and publications for case study of three Dutch pilot pro-
jects.
Project Name Related Literature & Publications
Park20|20 webpage [33,38], report [39]
Venlo City Hall webpage [34,40], report [41,42]
ABN AMRO CIRCL webpage [35], report [43]
Table 5. Basic information of two interviewees.
Interviewee A Interviewee B
Project Shalun Circular Housing Nangang Public Housing
Role Principal Architect Client Representative
Experience 15 years 25 years
Table 6. Basic information of interview questions.
Interview Questions
In your personal point of view,
1. What are the reasons behind different CE related practices adopted between your pro-
ject and the Dutch pilot ones?
2. What are the important aspects to consider when deciding the CE related practices for
adoption for your project?
The research methods adopted in this study can be regarded as two types: document
analysis for the proposed research process step one, and qualitative analysis of semi-struc-
tured interviews for steps two to four. A cross case analysis was done subsequently based
on the document study and the outcomes of the interviews for further research discussion.
Semi-structured interview was adopted for it is suitable for interviews with open-ended
questions requiring follow-up queries [44]. Similar research methods were adopted for
case study of CE implementation in the building sector [6]. These methods belong to the
methodology named as “Grounded Theory,” which allows theories to emerge from the
Figure 2. Description on research process (drawn by the authors).
Table 4. Reference of related literature and publications for case study of three Dutch pilot projects.
Project Name Related Literature & Publications
Park20|20 webpage [33,38], report [39]
Venlo City Hall webpage [34,40], report [41,42]
ABN AMRO CIRCL webpage [35], report [43]
Table 5. Basic information of two interviewees.
Interviewee A Interviewee B
Project Shalun Circular Housing Nangang Public Housing
Role Principal Architect Client Representative
Experience 15 years 25 years
Table 6. Basic information of interview questions.
Interview Questions
In your personal point of view,
1. What are the reasons behind different CE related practices adopted between your project and
the Dutch pilot ones?
2. What are the important aspects to consider when deciding the CE related practices for adoption
for your project?
The research methods adopted in this study can be regarded as two types: document
analysis for the proposed research process step one, and qualitative analysis of semi-
structured interviews for steps two to four. A cross case analysis was done subsequently
based on the document study and the outcomes of the interviews for further research
discussion. Semi-structured interview was adopted for it is suitable for interviews with
open-ended questions requiring follow-up queries [
44
]. Similar research methods were
adopted for case study of CE implementation in the building sector [
6
]. These methods
belong to the methodology named as “Grounded Theory,” which allows theories to emerge
from the data collected. It is known as a simultaneous process of collecting and analyzing
data by constant comparative analysis [
45
]. Its main issues regard precision and clarity. To
address these issues, this study used qualitative content analysis when explaining results.
A similar method was utilized to identify the strategic role of CE in other industries [
46
,
47
].

Sustainability 2021,13, 754 8 of 16
4. Results
Thirty CE-related practices are summarized based on case study of three Dutch pilot
projects. To study these practices, they are matched with 5R principles and sorted by
different building life cycle: planning & design phase (P & DP), construction phase (CP),
operational phase (OP), destruction phase (DP), and whole life cycle (WLC). The majority
of practices (16) were implemented in P & DP, while some in CP and OP (5 & 5), and few
in DP and across WLC (2 & 2). In P & DP, Rethink and Reduce principles are highlighted,
related to 8 and 5 CE-related practices, respectively. Reduce and Recycle principles are
more common for practices in CP, while Reuse and Repair are for OP. CE-related practices
in DP and WLC are related to more than two 5R principles, indicating their importance
and challenge.
CE-related practices of two pilot cases in Taiwan, Shalun and Nangang Housing, are
marked by interviewees, which are 24 and 17, respectively. The potential implementation
time of these thirty practices for building projects in Taiwan are also noted by interviewees.
Many of them (14 out of 30) are expected to be commonly implemented in short term, i.e.,
within a five-year time period, while some (10) are to be implemented in short term and to
be common in long term, i.e., after ten years, and few (6) are to be implemented only long
term. These results are shown in Table 7.
Table 7.
Identification of CE-related practices of pilot cases in the Netherlands and Taiwan and their potential implementa-
tion time for Taiwanese building projects.
CE Related Practice 5R
Principle
Dutch Case Taiwanese Case Time to Implement
Park
20|20
Venlo City
Hall
ABN AMRO
CIRCL
Shalun
Housing
Nangang
Housing
Short
Term
Long
Term
1. Planning & design phases (P & DP)
1
Innovative business
model (e.g., material
ownership by supplier)
Rethink • • • N
2
Innovative financial
model (e.g., flexible
taxation)
Rethink •N
3
Passive/green/bio-
architectural
design
Rethink • • • • • N
4
People-oriented design
(e.g., good indoor
environment)
Rethink • • • • • N
5 Natural lighting system Reduce • • • • • N
6 Solar energy system Reduce • • • • • N
7 Heat recovery system Recycle • • • • • N
8 Water recycle system Recycle • • • • • N
9 Leftover recycle system Recycle • • • • • N
10
Urban agriculture Rethink • • • • • N
11
Lightweight structure Reduce • • • • N
12
Modular unit (e.g.,
modular
partition/exterior wall)
Reuse • • • • • N N
13
Flexible unit (e.g., design
for disassembly) Repair • • • • N N
14
CE related certification
(products/materials/
organization)
Rethink • • • N
15
Closed loops (e.g., on-site
resource circular flows)
Rethink/
Reduce • • • • N N
16
Zero waste/zero energy
consumption
Rethink/
Reduce •N

Sustainability 2021,13, 754 9 of 16
Table 7. Cont.
CE Related Practice 5R
Principle
Dutch Case Taiwanese Case Time to Implement
Park
20|20
Venlo City
Hall
ABN AMRO
CIRCL
Shalun
Housing
Nangang
Housing
Short
Term
Long
Term
2. Construction phase (CP)
17
Reusing green and
healthy materials Reuse • • • • • N
18
Using renewable or
recycled materials Recycle • • • • • N
19
Construction waste
recycling system Recycle • • • • • N
20
Prefabrication system Reduce • • • • N N
21
3D printing Rethink/
Reduce •N
3. Operational phase (OP)
22
Lifespan extension (smart
maintenance/repair/
renewal)
Reduce/
Repair • • • • • N
24
Building
materials/equipment
tracking (e.g., QR code)
Rethink/
Repair • • N N
23
Sharing space (e.g.,
co-working space)
Rethink/
Reuse • • • • • N
25
Sharing ownership (e.g.,
appliance, vehicle)
Rethink/
Reuse • • • • N N
26
Exchange platform (e.g.,
used goods, agricultural
products)
Rethink/
Reuse • • N N
4. Deconstruction phase (DP)
27
Quantifying residual
value of materials
Rethink/
Reuse/
Recycle
• • • N
28
Material bank
Rethink/
Reuse/
Recycle
• • • • N N
5. Whole life cycle (WLC)
29
Product as a service (e.g.,
lighting, elevator,
furniture, appliance)
Rethink/
Reduce/
Reuse/
Repair
• • • • N N
30
Material passport
Rethink/
Reduce/
Reuse/
Repair/
Recycle
• • • • N N
•is notation for project-related practices while Nhighlights expected implementation time for practices.
5. Discussion
5.1. Differences between Circular Economy Related Practices in Dutch and Taiwanese
Building Projects
Through comparing CE-related practices in Dutch and Taiwanese pilot projects, differ-
ences between these two countries are revealed. This is further discussed by highlighting
5R principles of these practices, noting their related project items and excluding the CE-
related practices that are common in pilot projects in both countries. As shown as Table 8,
many practices of Rethink principles have just started to develop in Taiwan (e.g., product
as a service, sharing ownership and material passport), and many are considered to be
implemented in ten years’ time (e.g., innovative business model and CE-related certifi-
cation). How key stakeholders as suppliers and policy makers in Taiwan can fasten the
implementation of these practices should be investigated in the future. As for the Reduce
principle, prefabrication system is still considered to be a CE-related practice that requires a
long period of time for common implementation in Taiwan by the interviewees, comparing

Sustainability 2021,13, 754 10 of 16
to the Dutch case, even though both pilot cases in Taiwan have adopted some prefabrication
systems for structural, exterior, and interior engineering. As for the Reuse and Repair
principle, modularity and flexibility of units and standardization of size of all building
components and products are still challenging for Taiwanese scenarios, according to the
interviewees. Lastly, as for the Recycle principle, its related CE practices are all identified
as to be implemented commonly in the short term, which is the same as the Dutch scenario
shown by its pilot cases.
Table 8.
Highlighting of the uncommon CE-related practices in Taiwanese building industry, their related 5R principles and
project items.
5R
Principle Category Item CE Related Practice Time to Implement
Short Term Long Term
Rethink
MEP Lighting & HVCA system Product as a service N N
F & A Furniture & appliance Product as a service N N
Other
Sharing ownership Vehicle, appliance N N
Exchange platform 1Used goods, agricultural products N N
Building information
modeling Material passport N N
3D printing 13D Printing structure, component N
Net zero buildings 1Zero waste/energy consumption N
Closed loops On-site resource circular flows N N
CE related certification BS 8001, Cradle to Cradle, etc. N
Innovative financial
models 1Flexible taxation, etc. N
Innovative business models Material ownership by supplier, etc. N
Reduce
Structural Structural system Prefabricated beam, column, etc. N N
Exterior Exterior system Prefabricated panel, facade, etc. N N
Interior Interior system Prefabricated panel, partition, etc. N N
Reuse All Building components,
products
Modularization of
unit/Standardization of size N N
Interior Spatial units Modularization of plane N N
Repair All
Building components,
products Flexibility of unit N N
Building materials &
equipment 1
Maintenance management system
with QR Code N N
1The highlighted items are CE-related practices that are not common among three Dutch cases.
5.2. Reflection on Research Results with Working Hypotheses and Past Research
Before interviewing the key project stakeholders of Taiwanese pilot projects, the
authors assumed that the 5R principles, project phases, and expected implementation
time (i.e., feasibility for implementation) of the identified CE-related practices are three
key information to consider for CE implementation for project stakeholders. Based upon
interviewees’ responses, these information are relevant to their considerations. However,
the information on relevant project items for CE-related practices is also critical. This set
of information is provided to propose the CE implementation framework for building
projects in Taiwan.
As mentioned in the literature review section (see Section 2.1), Chang and Hsieh [
10
]
have also conducted a case study of a CE-focused pilot project in Taiwan on industry
level. One of their key findings is that even though the Taiwanese government has high
awareness of CE implementation, the rest of the parties in the industry are still falling
behind, especially the manufacturers, who should be the core players in the industry for
CE. This finding is consistent with the discussion in the previous section (see
Section 5.1)
,
showing that many manufacturers-centered CE practices such as product as a service,
prefabricated system, and modular and flexible unit are still uncommon. In their findings,
the lack of incentive given by governments is the key challenge, while the establishment of

Sustainability 2021,13, 754 11 of 16
financial incentives and platforms for building material exchange are the key enablers for
CE in building industry in Taiwan.
5.3. Suggestion on Implement Circular Economy in Building Projects in Taiwan
As mentioned by the interviewees and discussed in the previous section (see
Section 5.1
),
identifying the suitable project items for CE-related practices is important for CE implementa-
tion in Taiwanese building projects. Therefore, the key CE-related practices summarized in
previous case study are further categorized not only by five types of building life-cycle and
5R framework but also by six common engineering categories of building project in Taiwan,
which are foundation and structure, exterior, interior, mechanical, electrical, and plumbing
(MEP), furniture and appliance (F & A), and other, and the CE-related practices that are noted
as not to be implemented in the short term by interviewees are excluded in this discussion.
An implementation framework is proposed based on this discussion and shown as Table 9.
When project stakeholders are considering which CE-related practices to implement, they can
review the relevant project items, phases, and 5R principles for implementation based on this
proposed framework.
Table 9.
Suggestion on CE-related practices, their related 5R principles, project items, and phases to implement in building
projects in Taiwan.
Category Item CE Related Practice 5R Principles Lifecycle
Rethink Reduce Reuse Repair Recycle
Foundation &
Structure
System
Lightweight
structure •P & DP
Prefabricated system
(prefabricated
staircase)
•CP
Steel 1
Electric arc furnace
steel
(recycled/upgraded
steel)
•CP
Standard length steel
bars •CP
Flexible frame •P & DP
Concrete 1
Recycled concrete
aggregates, fly ash
cement
•CP
Exterior
Components
Standardization of
sizes •P & DP
Prefabricated
panel/facade •P & DP
Materials
Reusing green
materials •CP
Using recycled
materials •CP
Interior
Components
Standardization of
sizes/ •P & DP
Modularization of
space •P & DP
Prefabricated
panel/partition •P & DP
Materials
Reusing green
materials •CP
Using recycled
materials •CP

Sustainability 2021,13, 754 12 of 16
Table 9. Cont.
Category Item CE Related Practice 5R Principles Lifecycle
Rethink Reduce Reuse Repair Recycle
MEP
HVAC
Product as a service • • • • WLC
Smart energy saving
system • • P & DP
Lighting
Product as a service • • • • WLC
Smart energy saving
system • • P & DP
Mobility
Product as a service • • • • WLC
Smart energy saving
system • • P & DP
Electrical
Solar energy
system/heat
recovery system
•P & DP
Smart energy
management • • OP
Plumbing
Water recycle system
•P & DP
Smart water
management • • OP
F&A
Furniture Product as a service • • • • WLC
Modular furniture •P & DP
Appliance Product as a service • • • • WLC
Modular appliance •P & DP
Other
Landscape 1
Recycled pavement •CP
Urban agriculture • • P & DP
Leftover recycle
system •P & DP
Site 1
Modular formwork •CP
Modular site
office/reusable
construction rack
•CP
Waste recycling
system •CP
BIM 1
Material passport • ••••WLC
Material bank • • • DP
Management system
with QRCode • • OP
Sharing space (e.g., co-working
space) • • OP
Sharing ownership (e.g., equipment,
vehicle) • • OP
Exchange platform (e.g., used goods,
agricultural products) • • OP
Closed loops (e.g., on-site resource
circular flows) • • P & DP
1The highlighted items are added by interviewees during interviews.
For foundation and structure engineering, three items and six CE-related practices are
noted for implementation in Taiwanese building projects. Because the main structural type
in Taiwan is reinforced concrete (accounting for 70% of new buildings in 2016), practices
related to steel and concrete are emphasized by interviewees. For exterior and interior
engineering, the main items for implementation and CE-related practices are similar,
including standardization of component sizes, prefabrication of components, reusing green
materials, and using recycled materials. However, one more key practice needs to be

Sustainability 2021,13, 754 13 of 16
considered for interior engineering, which is modularization of spatial units to increase
flexibility of future usage. For MEP engineering, HVAC, lighting, mobility, electrical,
and plumbing systems are highlighted for CE implementation. For the former three
items, two CE-related practices are vital, which are product as a service and smart energy
saving system. For the latter two items, resource regeneration or recovery and smart
resource management system are crucial practices. For furniture and appliance, product
as a service and modular design are seen as critical CE-related practices. Last but not the
least, several other items are added by interviewees and should also be taken into account,
which includes landscape engineering with leftover recycle system and construction waste
recycling system. Modular formwork, reusable construction rack, and site office are
also regarded as important items for CE implementation by interviewees, which are not
underlined in Dutch pilot case study. Furthermore, building information modeling (BIM)
should also play an important part in building project, for it can enable CE-related practices
such as material passport, material bank and effective facility management system. To be
noted, CE-related practices including sharing space, sharing ownership, and exchanging
platforms should be taken into consideration in OP, and closed loop systems in P & DP.
5.4. Suggestions on Policy Implications
Further suggestions on policy implications are proposed by the authors based upon
responses of interviewees on expected implementation time of key CE-related practices for
building projects in Taiwan and research finding of past study [
10
]. In Taiwan, the relevant
regulations to CE for building projects include Resource Recycling Act, Building Technical
Regulations, and Government Procurement Act. Among them, the Resource Recycling
Act is under Taiwan’s Environmental Protection Administration, Executive Yuan, which
has not been revised since 2009. Building Technical Regulations are under Construction
and Planning Agency, Ministry of the Interior, which was revised in 2019 to increase the
mandatory proportion of green building materials used in buildings. The Government
Procurement Act is under Public Construction Commission, which was also revised in
2019 to improve the green procurement system. This shows that for building projects
in Taiwan to implement CE-related practices, problems including ununified responsible
government units and different paces of regulation revision will be faced. The former
should be included in the overall consideration of government organization re-engineering,
while the latter is related to further regulation revision. This research suggests the following
considerations for latter one:
1.
Article 12 of Resource Recycling Act: to add environmentally friendly design provi-
sions for building projects, including durability, upgradeability, repairability, ease of
remanufacturing and recycling.
2.
Article 321 of Building Technical Regulations: to include product certification (such
as Cradle to Cradle) that meets the principles of circular economy into the scope of
green building material certification in Taiwan.
3.
Article 26-1 of Government Procurement Act: to add supporting programs for green
procurement including related enforcement rules, bidding templates, demonstration
cases, and price databases that meet the principles of circular economy.
6. Conclusions
The main goal of this study is to identify the key CE-related practices for building
projects and to propose an implementation framework for building projects in Taiwan.
A series of case studies of CE-focused pilot projects in the Netherlands and Taiwan are
conducted along with semi-structured interviews with the key project stakeholders in Tai-
wanese pilot projects to achieve this goal. Thirty key CE-related practices are identified via
case study, along with their related 5R principles (Rethink, Reduce, Reuse, Repair, Recycle)
and project phases (Planning & Design, Construction, Operation, Deconstruction, Whole
Lifecycle), helping future project stakeholders to understand the concepts and features
these practices for their implementation. Further, the expected implementation time (short

Sustainability 2021,13, 754 14 of 16
or long them) of these CE practices and their relevant project items (categorized by six
different types) are identified via interviews. Moreover, an implementation framework of
key CE-related practices for building projects in Taiwan is proposed, providing essential
information of these practices including the related 5R principles, project items and phases,
and expected implementation time (i.e., feasibility for implementation) for project stake-
holders to consider. Also, differences between pilot cases in both countries are discussed
and presented, along with reflection on research results with past study and suggestions
on policy implications in Taiwan.
The main contribution of this study lies in a systematic analysis on CE-related practices
by highlighting their related 5R principles and project items via case study of two countries’
pilot building projects. More understanding towards CE implementation for building
industry at project level is fostered. Also, different CE implementation progress of different
countries can be seen via such case study. Furthermore, via semi-structured interviews
with key project stakeholders in Taiwan, the expected implementation time and relevant
project items of CE-related practices are identified, and an implementation framework is
proposed. Similar processes can be utilized for project stakeholders whose countries are
also at the initial CE implementation stage for building industry.
One of the key weaknesses of this study is the limited Taiwanese pilot cases and inter-
viewees. In the future, after more pilot cases have appeared, more in-depth investigations
and discussions on CE implementation roadmap for building projects in Taiwan can be
fostered with different sectors in the industry (e.g., manufacturers, demolishers, etc.). To
be noted, the CE-focused pilot projects in the Netherlands are commercial and special
types (i.e., office, government, pavilion) while the ones in Taiwan are all residential types.
How CE-related practices are affected by different building types should be investigated in
the future.
Author Contributions:
Conceptualization, H.-P.T. and C.-M.C.; methodology, Y.-T.C.; validation, C.-
M.C.; investigation, C.-M.C.; resources, C.-M.C.; data curation, C.-M.C. and Y.-T.C.; writing—original
draft preparation, C.-M.C. and Y.-T.C.; writing—review and editing, H.-P.T.; visualization, C.-M.C.
and Y.-T.C.; supervision, H.-P.T. All authors have read and agreed to the published version of the
manuscript.
Funding: This research received no external funding.
Informed Consent Statement: Not applicable.
Data Availability Statement: Data available in a publicly accessible repository.
Acknowledgments:
Much appreciation is given by the research team towards the Bio-architecture
Formosa (BaF) and Taipei City Government for the precious time and information shared for
this study.
Conflicts of Interest: The authors declare no conflict of interest.
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