**2. Methodology**

The research is based on quantitative and qualitative research methods, including a literature review and assessment on the circular economy and industrial symbiosis. The methodology includes conceptual research including analysis of normative, jurisprudence, doctrinal, theoretical, and scientific sources. It reflects on different theories of change relating to ethical behavior, social responsibility, and sustainability transformations. According to Mileva (2018), the method of triangulation (also known as qualitative-quantitative method) was applied to ensure the validity of the study. Meaning that the data obtained from seven industrial symbiosis cases from literature reviews, empirical data, and empirical data were assessed from articles with interviews of those who work with the practical aspects of IS. A theoretical framework which stemmed from the literature review on IS, frameworks the data collection and assessment in all parts of the study [39].

Various methods have been used to measure the actuality of the topic. In this case, we used the current keywords and their application over time, see Figure 2. The Google Ngram Viewer demonstrates how user-selected words or phrases (Ngrams) have appeared in a corpus in a graph over the selected years 1990–2019. It is easily and transparently perceived because the graph on the *x*-axis shows the year in which the selection group was published, while the *y*-axis shows the frequency with which the searched keyword was found in the publications.

A search for the term "industrial symbiosis" revealed that the number of publications was rising moderately since 1992 until a significant surge began in 2006 but since 2018 onwards a decline was observed.

Observing the frequency of the term "green deal", in a separate graph, it can be concluded that the insignificant increase was from the mid-1990s until 2005, when it rose sharply, to 0.000000300% in 2013, followed by a slight decline and a rise again, starting with the year 2016. Unfortunately, due to the scale, it does not stand out significantly in the overall schedule.

**Figure 2.** The frequency of using the terms "industrial symbiosis", "green deal", "circular economy", "eco-innovation" (Ngram Viewer). Reprinted from Ngram Viewer [40].

In describing the frequencies of the term "circular economy", the term has been used moderately but dynamically since 2001 but has been growing rapidly since 2012. A clear increase starts in 2013 when it reaches 0.0000350% in 2019.

Surprised by the graphic representation with the search for "eco-innovation", the frequency of the term has been increasing moderately from 1992 to 2004. Since 2006 there has been a sharp increase to 0.00000400% in 2012, then a decrease again until 2015, when the frequency increases again, to 0 00000550% in 2019.

Ngrams showed a dynamic development in publications, according to the search term "sustainability". This is not included in the graph, as it differs sharply from the ones described above—from 0.00024% in 1990 to 0.0140% in 2019. After identifying keywords and the evolution of domains of the literature, the authors analyzed articles and relevant documents. The analysis determined the application of the keywords based on their relevance to the research topic. Results were used to build a theoretical framework and identify a research problem statement, which has created the basis for the critical literature review [40–42].

The main purpose for the authors was to assess the Baltic University Program membercountries and on a benchmark of the European members, to develop a set of recommendations for development and improvement possibilities within SDGs (in particular focusing on SDG No. 8, 9, 11, and 12) and circular economy for the BUP non-EU member countries.

The research was focused on benchmarking the following countries: Czech Republic, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Slovakia, and Sweden. Figure 3 depicts the theoretical framework that served as a basis for the research. Nowadays the EU produces more and more ambitious documents and the business-as-usual path will no longer be valid, sooner than one could have imagined some five years ago.

This is why businesses, as well as entire country economies, must look for ways to adapt to changes more efficiently. Common projects by region of industrial symbiosis in the EU are presented in Table 1.

The development of industrial symbiosis is associated with risks that can be caused both at the national and cross-country levels, which are associated with the impact on the competitiveness of its participants as well as on the state of the environment (Table 2).

Despite the systematic development of industrial symbiosis, policy and economic are identified as the most influential risks and the main obstacles (Table 3).

**Figure 3.** The theoretical framework of the research.



After an extensive literature research, analysis of existing case studies and relevant information, including PESTLE, the authors developed the dependent variable "Industrial symbiosis on a cross country/regional level". The independent variables are namely: PESTLE, Circular economy, and Waste management. The Circular Economy here includes as well national or regional strategies and supply chains [43]. The Waste management independent variable focuses on waste prevention and waste management proximity principles as well as on the idea to re-capture all the valuable resources from waste.


**Table 2.** Risk assessment and mitigation for industrial symbiosis establishment.

**Table 3.** Obstacles for development of industrial symbiosis.


The Authors developed the following research questions:

RQ1. Can industrial symbiosis on a cross-country level improve the resource consumption ratios?

RQ2. What are the main obstacles to the implementation of industrial symbiosis on a regional and cross-country level?

The design of the theoretical framework also leads to the definition of a research gap: lack of a harmonized method towards reaching a circular economy approach through IS. This gap is identified both on cross-country and even regional level within one country and leads to a significant obstacle for transition towards circular economy on the EU scale.

In the subsequent sections of the research the authors provide an overview of the conducted research, revealing the main results and findings as well as the most significant conclusions.

## **3. Results**

The assessment of development and sustainable development by EU Member States is carried out using the Eco-Innovation Index (Eco-IS), the results of which allow a comprehensive approach to the use of the benefits of eco-innovation and processes [44–46].

Stimulation of sustainable development based on the country's Eco-IS can be distinguished by certain factors (Figure 4) [47–49]. The economic system is posed to extract as much value from given resources as possible [50] and the key point here is to make this process as much eco-efficient as possible and to enhance regional cooperation where possible. However, at the same time, the main barriers to regional cooperation in the field of eco-innovation are namely: institutional barriers; fiscal restrictions; imbalance between the technosphere and the biosphere associated with regional differences in the industrial sector.

**Figure 4.** Eco-innovation index of BUP EU-Member States. Reprinted with permission from [51].

Solving the problem of climate change mitigation in the direction of counteracting carbon dioxide emissions and rational environmental management is possible thanks to the development of climate-regulated ecosystems and the mechanism for ensuring the development of a circular economy at the state and regional levels. This is because at the regional level, local authorities form the demand for waste processing products (for example, secondary processing or biogas) and track the carbon footprint in urban areas.

In any case, business models of the circular economy are local because of the following: products for recycling (e.g., waste) are predominantly generated in a certain area (the need to reduce their transportation costs and reduce CO2 emissions); sharing mainly uses products that are locally located due to the impracticality of their delivery (the same costs, emissions, and additional waiting time for delivery) from other regions. The above indicates that the development of a circular economy is possible with the ability of regional cooperation (organs of local government, business, and the population). The clusters help understand the status of eco-innovation in EU countries and identify possible cooperation partners.

As the authors chose to analyze only the BUP EU member states, represented in Figure 4, they can be clustered as follows:


Here it is necessary to mention that the EU-28 average Eco-innovation index is 109 (based on the ratio over the time frame 2021–2021), meaning that we have Cluster 2 with the Eco-Is reaching the EU average and Cluster 3 with three countries which significantly over performed the average figures and which thus can be motivators for others to catch up.

Further on, when turning to industrial symbiosis, it is necessary to assess one of the Eco-IS composing indicators, i.e., resource efficiency. Eco-innovation is expected to have a positive influence on resource efficiency in two ways: it can boost the economic value, and lead to a decrease in the pressure on the environment [44].

It is notable that the resource indicator is also covered by the circular economy indicators and the demand for material extractions due to consumption in the public sector, households, and businesses in the EU [44,52,53]. Figure 5 gathers three indicators and shows that the leader in resource productivity in terms of Eur/kg is Germany, followed by Sweden.

**Figure 5.** Material Footprint of BUP EU-Member States [44,52,53].

The concept of sustainable competitiveness is to find a compromise approach in order to balance economic growth, environmental issues, and the sustainability of society [54,55].

The efficiency of the development of the country and its industries is mainly expressed in terms of economic production, but for a deeper analysis, indices are used that allow a balanced approach to assess the competitiveness of the national economy (Figure 6). The countries are grouped because it is the BUP of the EU-Member States for which the analysis is being carried out. In this regard, it is rational to use a competitiveness model based on the sustainable competitiveness index, which allows for a more comprehensive coverage of all indicators and an assessment of the effectiveness of economic development (the root) (Figure 7) [56].

**Figure 6.** Indicators of economic efficiency in sustainable development of BUP EU-Member States [44,52,53].

**Figure 7.** Sustainable Competitiveness Index 2020 of BUP EU-Member States [44,52,53].

Industrial symbiosis is not only a technological or logistical system; it transcends the boundaries of various systems, and it is also a social system [39]. Businesses that have successfully shifted to sustainability have encouraged participation in industrial symbiosis [57]. Industrial symbiosis allows businesses to maximize the use of resources by recycling [58] and in particular by diverting waste from landfills, reducing its generation, and seeking alternative application to production residuals or by-products, which will

lead to increased efficiency of resource use and reducing greenhouse gas emissions in industries [59].

It is quite notable that according to research carried out by Domenech et al. (2019) [57], the mapping of industrial symbiosis in Europe revealed the absence of any type of network in parts of the countries analyzed in the present research. In particular it tackles such countries as the Czech Republic, Poland, Lithuania, Latvia, and Estonia. This is why the authors consider it even more evident that such networks need to be developed in the near future (Figure 8).

**Figure 8.** Benefits of cross-country industrial symbiosis and potential funding sources.

Sustainability and value creation are significant challenges for businesses' analysis of IS on a regional basis [58]. According to recent research [57,59], there were no industrial symbiosis networks reported in Slovakia, Poland, Lithuania, Latvia, or Estonia in 2018. It has to be noted that in Poland and Slovakia there have been some attempts, but mostly short-term, using H2020, Interreg or other European, national, or regional financing and they did not manage to commercialize after the termination of the projects.

It is vital to mention that the lack or the availability of industrial symbiosis networks is surely also dependent on a range of issues like political will, cooperation of the countries on a range of other issues, availability of resources, the willingness of the industries to undertake such start-up projects, and the willingness to continue any grant-based projects in order to develop them in the long-run. Another important aspect is the geographic location of different facilities and distances between them, as geographic proximity is said to be a key characteristic of resource reuse and recycling practices in terms of industrial symbiosis.
