*1.1. PESTEL*

PESTEL analysis has been evolving through the years as an integrative approach and can be found in different forms of literature. The origin of this approach is considered to be the book "Scanning the Business Environment" by Francis J. Aguilar [5], where the concept of economic, political, social and technological analysis (EPST) was first introduced. The acronym was later changed by Arnold Brown, becoming STEP, which was a rearrangement of the order of the words. The environmental factor was added subsequently becoming then social, economic, technical, political, and environmental (STEPE) factors. In general terms, the concept of environment involves far, near, and internal environments, including all types of factors related to the activities of the company [6]. The last addition to the acronym was the legal dimension, solidifying the concept of PESTEL that we have today. Even though the acronym can vary in the literature, the main idea behind it remains the same: provide the underlying structure for macro external environment analysis. PESTEL is commonly used for business and marketing research, being particularly useful to structure data and information that enables the company to predict situations and circumstances that it might encounter in the future [6].

Throughout the years, PESTEL has been adapted into different fields and its use has been expanded, even reaching the renewable energy sector. When it comes to the marine energy sector, the ocean energy converters have not fully reached market viability and are mostly in the research & development (R&D) stage. Thus, we are still not fully aware of the potential obstacles that are expected in new environments where ocean energy research does not exist. For this reason, there have been studies in the marine renewable energy field that incorporate the structure of PESTEL to conduct resource and feasibility analysis. Examples include the analysis done by Sandberg et al. [7] in 2016 regarding critical factors for wave energy converters in off-grid luxury resorts and small utilities, as well as a study on risk identification for the tidal industry using PESTEL by Kolios and Read [8] in 2013. Both papers utilize the PESTEL approach, however, the topics of interest are specific parts of the marine energy industry, and the outputs also differ. Sandberg et al. focused on the scenario of luxury resorts and small utilities and how viable wave energy would be; by contrast, Kolios and Read chose to focus on a literature review and a case study-oriented approach on the risks for the tidal industry.

#### *1.2. SWOT and the PESTEL-SWOT Approaches*

SWOT Analysis is a simple but powerful tool for sizing up an organization's resource capabilities and deficiencies, its market opportunities, and the external threats to its future [9]. It is a strategic planning framework that stands for strengths, weaknesses, opportunities, and threats. Strengths and weaknesses are internal factors and attributes

of the organization, while opportunities and threats are external factors and attributes of the environment [10]. Heinz Weihrich [11] first introduced the concept of a matrix that identifies threats, opportunities, weaknesses, and strengths, naming it the TOWS matrix. Even though the matrix name varies in the literature, SWOT is a very well-known strategic and flexible framework that identifies key issues affecting business. Its adaption to different fields has been broadened, and it is possible to find studies applying SWOT to healthcare, agriculture, and tourism, among others. Within the marine energy field, Stingheru et al. [12] conducted a SWOT analysis of the European marine energy sector; this study highlighted positive and negative influences of harnessing marine energy at a European level to promote marine renewable energy.

It is also possible to combine PESTEL and SWOT to create a matrix that finds the strengths, weaknesses, opportunities, and threats by going through the external factors associated with PESTEL elements. Since the SWOT itself is a general matrix, the structure provided by PESTEL is useful for finding relevant external factors. The combined analyses of PESTEL and SWOT have not been adapted to marine energy technologies, nevertheless, they have been used for other renewable energy studies in the past. Damasceno and Abreu [13] created a PESTEL-SWOT evaluation method for the wind energy sector that assessed the favorable conditions and challenges for the wind energy market to expand in Brazil. Moreover, there is a study from Shadman et al. [14] utilizing stakeholder engagement, PESTEL, and SWOT analysis to assess the role of renewable energy for energy security in Malaysia. Finally, Islam and Mamun [15] have researched the possibilities and challenges of implementing renewable energy in island countries by utilizing both the PESTEL and SWOT approaches; their study did not focus on any particular region or technology, instead providing a broad view on the strengths, weaknesses, opportunities, and threats for renewable energy in developing and developed nations.
