Problem based learning and design thinking methodologies for teaching renewable energy in engineering programs: Implementation in a Colombian university context

Abstract The rapid depletion of fossil fuel reserves, population growth, and increasing environmental pollution have forced a change in the search for alternatives to produce and use energy. Currently, renewable energies (RE) have achieved more efficient advances to produce energy from non-conventional and inexhaustible sources, which can meet the basic needs of society and whose environmental impact is a door of opportunities for all. For this reason, academia has a preponderant role in ensuring that engineers are fully equipped with the necessary skills to provide feasible and contextualised solutions for this era of energy transition framed by the UN Sustainable Development Goals (SDGs). This article explores the impact on the development of the necessary skills for engineers in the renewable energy sector by tracing a route towards the acquisition of renewable energy knowledge with strategically organised work teams of undergraduate students, where two methodologies that are gaining ground in engineering education programs are applied: Problem Based Learning(PBL)and Design thinking (DT).After the validation of these techniques, it is concluded that bringing engineering students closer to real contexts related to renewable energies and above all with an objective of impact on communities, it is the right way to build knowledge in teams, in an immersive and committed way with the institution, which has developed and implemented an innovative pedagogical method based on the application of a critical educational model focused on the development of competencies, where the union of new technologies with the teaching processes on which this research is based is envisioned for the future.


Introduction
Education in Engineering faces enormous challenges arising from the fact that the world is experiencing highly diverse and challenging environmental threats, where climate change is one of those.Also, energy plays an important role in the economic growth of a country, since it is key to the production of almost all goods and services (Mahalik et al., 2017).Rapid economic growth in many countries has generated an increasing demand for energy (Hussaini & Majid, 2015).According to the International Energy Agency (IEA), the annual growth of world energy demand between 2010 and 2030 will average 1.7% per year.Countries in transition will demand more than 30% of this increase and it is estimated that by 2040, CO 2 emissions could increase by 46% in relation to 2010, in the business-as-usual scenario (Irena et al., 2019).The need to accelerate the speed of the CO 2 emissions reduction to achieve a maximum of 1.5°C increase in the global average temperature was extensively discussed during the COP26, and one of the conclusions is that it requires enormous efforts worldwide in at least four areas which include additional advances in clean electrification (International Energy Agency, 2021).The preponderant role to play of next generations of engineers in the UN 2030 agenda accomplishment, who are called for understanding and developing technologies that will improve the communities living conditions, is calling for speed up the changes needed in the way engineering faculties around the world are educating their students (Romero et al., 2020).
Therefore, the need for a pertinent education in engineering that provides the future professional with the necessary skills for this energy transition is a must for the universities, this, as mentioned by the author Casimiro Urcos et al. (2019), is due to a large gap between the knowledge and skills of HEI graduates and the needs demanded by today's society.In that context the pedagogics and didactics necessary in the education of engineers must be aligned to develop in the students the competences that are required.This is, engineering students need to learn how to analyse and solve complicated and complex problems, be able to collaborate in a variety of teams and clearly understand the societal needs they are solving.These challenges require triggering a student centre and problem-based learning (PBL) approaches and to develop a more complex engineering curriculum (UNESCO, 2021).
Based on a study made by Wu et al. (2019) proposes a differential strategy depending on the complexity of the problem to be solved and considering the trust of social behaviour factor, to reduce the complexity of the problem, and group decision-making problems on challenges.From their analysis, the authors Kelley et al. andandOdell et al. (2019, 2019) concluded that the teaching and learning methods needed to solve challenges is Problem Based Learning.Research conducted on the application of PBL indicates that it reinforces motivation for learning, decreases dropout rates, increases the development of competencies, increases student participation, and positively impacts the application of prior knowledge.The application of PBL requires teamwork, which is a common challenge in many industries, although it is well known that the decisionmaking process usually yields better results when carried out in a well-formed team.
In the same way, it is also studied Design Thinking (DT), which is a process based on the needs of people and the way in which problems can be solved, this methodology aims to understand the real needs and problems of people to generate ideas that can give an effective solution totally oriented to what people want to solve.In this way, the most important point of DT is the creation of empathy to understand the problems of the people to whom the problem needs to be solved (Dotson et al., 2020;Linton & Klinton, 2019;O'Toole & Kelestyn, 2021).Additionally, this allows the development of skills, knowledge and even the entrepreneurial and business spirit in the students (Lynch et al., 2021).
On the other hand, the Universidad Cooperativa de Colombia began to work in a curricula reform in the year 2015 and has implemented a competences curriculum based on the development in three dimensions of the skills in each course.The dimensions are to know, to do and to be (Unigarro-Gutierrez, 2017).In such a context all the courses in the engineering curriculum are designed to contribute towards the development of a macro-competence which is defined for the whole program, a competence named as a unity of competence and some elementary competences defined for each course.In research such as the one by the author Llorente et al. (2019), it is pointed out that students demand more flexible, active and participative teaching proposals, adapted to their needs, that encourage collaborative learning and the development of different competencies and skills.
In such context, the present article is the product of a research that started with a systematic review carried out using different databases during the 2010-2021 period on 3 methodologies for teaching renewable energies in engineering, i.e., Problem/Program Based Learning (PBL) and Design Thinking (DT).Then, it describes a case of study where PBL was implemented in a secondyear course for industrial engineering in the Universidad Cooperativa de Colombia, specifically in the Thermodynamics course.The article presents some results obtained in terms of the competence development, motivation, and early knowledge retention, and gives an inside how to fully implement a PBL in teaching renewable energies for the education in engineering.
The research presented was done in the project named "Sustainable Development Goals challenges-based learning in engineering curricula at the Universidad Cooperativa de Colombia: enhancing the engineering skills in a developing country".

Literature review
It is important to define the methodologies used in the study and for this reason a review of the literature shows that it is a crossed opinion from different authors is that a natural, efficient, and innovative way of teaching, considering: the complexity, the inter and multidisciplinary approach involved in renewable energy for engineering education, and a highly changing world, is the application of problem-centred activities that motivates students to learn actively and to bring the real professional world and requirements closer to the students, therefore closing the gap between theory and practice.One of the methodologies is the PBL, which relies on CDIO (conceive, design, implement and operate) that encourages students to: consider the whole system, rather than the individual parts of the problem and to gain practical experiences.PBL also promotes the development of soft skills, and the ability to transfer the acquired knowledge to other situations and contexts.In addition, this methodology helps to raise awareness of the sustainability issues facing the planet (Belu, 2019;Belu et al., 2017;Leite, 2017;Mayasari et al., 2019;Rumler et al., 2016;Taheri, 2018;Verbič et al., 2017).
As mentioned in the previous section, the PBL methodology requires teamwork, in this sense, Srinivasa et al. (2022) indicates that teams have an intrinsic ability to solve complex problems, and their cognitive skills include planning (problem analysis, goal setting and resource management), implementing systemic solutions and monitoring progress.The authors Sun et al. (2020) tells us that team members must therefore identify the structure and procedures of the problem, collect, and evaluate the information needed to construct solutions, and engage in strategic problem solving.Team formation dynamics has been the subject of various research.Gutiérrez et al. (2016) in their research tells us that in the team formation problem, the assignment of multiple individuals matching a required set of skills as a group should be chosen to maximise one or more positive social attributes.It is important to point out that according to the results of the author Gil-Galván et al. (2020) in his Research on the students' perception of the PBL methodology, they show a generally positive attitude of the students towards the application of PBL.Giving them a medium-high valuation of the acquired competences.It is also observed that the participatory and personal competences are those that have been acquired to a lesser degree.Among the conclusions, it is worth highlighting the effectiveness of PBL in the acquisition of competencies compared to other traditional methodologies.
On the other hand, Fatahi and Lorestani (2010) exposes that many more practical models have been presented which were introduced by Dr. M. Belbin.who proposes to classify individuals into nine team roles.This model helps them to recognize their position in the team and to increase their effectiveness.In this line, Moreno et al. (2012), tells us that group formation is one of the key processes in collaborative learning, and proposes a method based on a genetic algorithm approach for the achievement of inter-homogeneous and intra-heterogeneous groups.The main feature of such a method is that it allows considering as many characteristics of the learners as desired, translating the clustering problem into a multi-objective optimization problem.The simplest methods are random and voluntary grouping, however, Liu et al. (2022) tells us how the incorporation of new team members is considered a way towards team creativity.
In this sense, the Belbin Test constitutes a method focused on the examination of the roles needed in a team and the individual strengths to facilitate the conformation of a successful and well-balanced team.For that, Belbin Test considers the following roles of shaper, co-ordinator, plant, resource investigator, monitor evaluator, implementer, team worker, completer finisher, and specialist (Flores-Parra et al., 2018).
Regardless of the use of Design Thinking (DT) in the sector of renewable energies or sustainability and engineering education.Sullivan (2019) mentions that providing students with opportunities to learn to respond creatively to uncertainty will help them, building on their prior knowledge, to prepare for the kinds of real-world challenges they face now and will face in the future.Sullivan and Léger et al. (2020;Sullivan 2019) points out that the link between the exploitation of prior knowledge and creativity allows the students to engage in a discussion around the possible solutions having in mind the restrictions of the context where the design needs to be applied, which makes it possible to generate collective intelligence.In turn, Milovanovic et al. (2021) points that through design thinking, creativity and innovation, sustainable engineering solutions can be developed, and that active learning increases the students interest in designing solutions related to energy sustainability.It is recognised that design is a critical element for engineering thinking, therefore it is essential to spend significant time gathering information of the client voice, problem scoping, brainstorming to evaluate different alternatives as solutions (Jackson et al., 2016).
In this order of ideas, it is possible to mention some similar methodologies applied to the teaching of renewable energies in engineering programmes in various parts of the world.On the one hand, there is the work done by Pastor et al. (2020) who use a methodology of virtual laboratories to train students in renewable energy issues in some universities in Jordan, resulting in an increase in the effectiveness of learning, represented by the increase in the quality of teaching of virtual courses.
On the other hand, the authors Belu et al. (2021) conducted a study where they implemented the Project Based Learning methodology for teaching engineering courses related to energy and power.They show that the experience motivated students to acquire new skills and technical knowledge to face the industry and develop professional experience.It is also possible to highlight that in this experiment there was evidence of the development of teamwork and individual work skills.
Next, there is also the work done by Ulazia and Ibarra-Berastegi (2020) in which they use a Problem-Based Learning methodology for the study of renewable energy laboratories (specifically with Windpump), this was done in Eibar (Spain) and resulted in a much more motivated work environment that allowed students to think in a cooperative way to solve problems in a more efficient way.
It is worth noting that, according to the author Latorre-Cosculluela et al. ( 2020), in his paper on Design Thinking at the University, the most outstanding advantage that students perceive the Design Thinking approach is, with absolute clarity, the possibility of developing their creative and imaginative skills.The majority of them note the benefits it provides them not only in stimulating their creativity in the creation of the innovation project, but also in their ability to express themselves and reflect multiple ideas and thoughts.
Finally, it also highlights the work done by Al-Qaralleh et al. ( 2021) who integrated the Design Thinking methodology in an engineering curriculum at a university in Jordan, where students were given a problem and from there, they went through all the stages to reach a solution.On the other hand, based on DT, the students were asked to design a solar car and, according to the interview with the students, more than 80% of them think that it is a good methodology to increase their development skills and that implementing this methodology allows them to face problems from different points of view.Although there are different models for applying DT, there is a shared relationship between divergent and convergent thinking, in which it can be seen how both the logical and the creative allow significant improvements in the learning process (De Paula et al., 2022).

Application of PBL for engineering teaching at UCC
Implementing the PBL methodology at the UCC consisted of a series of stages that will be described below.

Course selection and competences
The methodology applied for the implementation and study of PBL began with the selection of the course and competencies that met the following requirements: that sustainable development was part of the macro-competency and/or elementary competency/competencies of the course and that the teacher's willingness was sufficient to be able to implement a PBL during the course.Reviewing the courses that met these requirements, the course selection was made for the subject of Thermodynamics, a second-year course for industrial engineering students.Table 1 presents the competencies stated in this course.

Team role types and formation
With the purpose of promoting a balanced group formation, following the PBL approach (Virtue & Hinnant-Crawford, 2019) and considering that this study was performed after the closure during the COVID-19 pandemic and that the students had little or no exposure to work in teams with their mates, the first thing done was the identification of roles that each student could play when team working.Therefore, the first social activity was intended to break the ice.In this activity the Belbin Role Test was explained to the students and applied towards a self-perception inventory.For that a self-perception inventory was used which contained 7 sections related to: 1. Project general work, 2. Seeking Satisfaction through work, 3. Complex solving problem, 4. Work task and time, 5.
Approach to get unfamiliar and unknown information, 6. Sudden change of team or tasks and 7. Discussions contribution.This self-perception inventory was conducted based on what was mentioned by the author Flores-Parra et al. ( 2018) in his research on team formation, where he points out that an indispensable requirement is the ability to work in a team, especially in engineering, where the project member is expected to know how to collaborate with his/her peers.As a result of this team Role Types and Formation stage, 3 groups were formed.

Application of problem based learning (PBL) in engineering teaching
During the course, already selected, and the formation of teams, students worked in teams of 4 members, in the development of a renewable energy solution in a community where an implementation of such solution is needed and to be validated by someone from the community who could be interviewed, thus ensuring the correct development of the solution.This selection of communities to implement solutions was done in the first 4 weeks of the study.The groups selected the following type of communities with needs: Group 1: A rural and touristic community willing to contribute with environmental solutions and a reduction in the monthly electricity bill.
Group 2: A deprived and poor community located at the department of Cauca in a post-conflict zone.The community has access to limited electric energy, a maximum of 6 hours daily.Their economic activities are limited to these hours.The community is mainly conformed by Indigenous descendants.
Group 3: A deprived and very poor community located at the Pacific Colombian Coast that does not currently have access to drinkable water and electric energy.The community is mainly conformed by African Americans.
After this, the following 12 weeks each of the groups worked in: 1.The clear identification of the problem: This was perhaps the most important step, as the rest of the generated solution would depend on this step.
2. The development of a suitable technical solution using the concepts learned within the course and extending their knowledge through different sources of information such as people of the community, experts in the sector of renewable energies, etc.
3. An estimation of the costs for the proposed solution: As in all projects and solutions, the construction of the budget is of great importance, this allows the students to have an approach to the normal process of generating and studying a solution in economic terms.

A discussion of alternatives of funding for such solutions
5. Preparing a final presentation of their findings: to show communities and other stakeholders the solutions generated from the whole process.

Results of the case study: Thermodynamics course
All the final projects were proposed rationally.Some of the photos taken in the last session are presented in Figure 1.
Group 1 developed a hybrid system based on the climatic conditions of the community and wind speed officially reported.The community was framed to one house.The interviews showed that one of the families in the community has a strong interest in investing in a renewable energy system.Their electricity monthly consumption was estimated as an average of the six latest electricity bills as 139kWh.The system proposed was composed by of six five monocrystalline solar panels generating 120 W, one 6 blades wind turbine with a 400 W power, and one power 200 W converter.
Group 2 developed a solar system for one family composed by 5 members in the described community.Their approach was to calculate the electricity that was not supplied given the interruptions of the supply and considering the appliances that the family has, since that community does not receive a monthly electricity bill.The estimated monthly consumption was 129.09 kWh.They also contrast this data with that produced in a commercial software that was tested during 15 days of free access (i.e., 19.09 vs 130.2 kWh/month).They considered the solar radiation of the area and proposed a photovoltaic solar system.
Group 3 developed a solution for the provision of drinkable water powered through a photovoltaic system.Their field recognition evidenced that the community has a scarce drinkable water only Model developed for providing drinkable water (Group 3) Model developed for providing electricity by a hybrid system (Group 1) 3 hours every 48 hours.Nevertheless, the rain varies throughout the year in the range of 65 to 166 mm.Their approach was based in designing a process composed of a filter, a sedimentation tank, and a flock system for the community of 197 persons.After that they estimated the consumption of the whole system as 72Wh/day.
Once the 3 groups had developed the solutions, a questionnaire was applied to each member of each group with the purpose of testing how they felt during the application of PBL in their project development.The questionnaire was designed to analyse the different steps considering the CDIO methodology (Conceptualization, Design, Implementation), In addition, it was done on Office forms and applied to the 12 students who participated in the methodology.The questions, the answers and the results obtained in percentages are presented below: The first question was related to the conceptualization stage: Thinking about the CONCEPT stage, which aspects were considered by you during the stage of selecting the problem and community addressed.The students could select more than one option.
Results are presented in Figure 2, which shows a total of 17 answers given the possibility of multiple selection.The awareness about the importance of providing a solution to the problem was considered as the main motivation in the conceptual stage in 70% of the answers provided.
The second question was related to the Design step, and in this case the question was: thinking in the DESIGN stage what aspects you consider to be the most relevant.You can choose several of the answers.The students could select more than one option.
In this case, a total of 20 answers were obtained, the responses show that the technical knowledge either learned during the course (30%) or during the degree (35%) were considered substantial for the designing step.The previous community approach also played a role since 20% of the answers (please refer to Figure 3).
The third question deals with the implementation stage.In this sense, the question raised was: thinking about the IMPLEMENTATION stage, what aspects would you consider taking the proposal developed during the THERMODYNAMICS course to an implementation stage?Again, the students could select multiple options.
Results are presented in Figure 4.In this case a total of 19 answers were obtained, in which institutional support was considered in 36.8% of the cases as the main source for the implementation stage, followed by closeness to the community (31.5%) and the information to relevant calls (26.3%).The four question was formulated to see the perception of the PBL as valid methodology for the learning process as a future engineer.In this case, the question raised was: Do you consider that the PBL methodology applied to the development of the project was adequate for your training process as a future Engineer?The student could select just one of the options.
In this question a total of 12 answers were obtained as shown in Figure 5.In this case 70% of the students considered that PBL was adequate for the preparation as future engineers whereas the rest 30% is not sure yet.

Discussion of the implementation in the UCC
The implementation at the UCC of the PBL and DT has been an answer to the innovative educational model where an active and centred learning approach is hoped to be applied in different areas within the university (Unigarro-Gutierrez, 2017).In engineering, these techniques are starting to be actively applied in a few courses such as physics and thermodynamics to mention some.Also, the students enrolled in extracurricular teaching seminars and groups (e.g., BERSTIC undergraduate students' group) have been exposed to PBL and DT, and have reported substantial improvements in learning and practice, a process that has been done through 1. immersive workshop experiences where the students started listening to the voice of the customer (e.g., community, public company, etc) and proposed a feasible solution following an iterative process where understanding the client's opinion played a highly important role; 2. a competition supported by a company, where the students presented along the process, to a panel of experts, different components of their project.For that, they received specific training in areas such as market and needs potential, conceptual design, economic and social costs/return of the project, etc; 3. workshops and lecturers with international experts in areas such as aquatic and biomass renewable energies where the students were exposed to these emerging technologies and their substantial role in the energy transition and climate change (publication not yet available).
The concrete overall results are very promising: 1. some of the ideas designed for the students have received the recognition of companies and institutions, 2. Some of the students are now developing their engineering studies at international institutions to further develop their ideas.Results that evidence that the application of the PBL and DT are highly increasing both the competences and interest of the students towards the generation of applicable and feasible engineering solutions in the subject of renewable energies.
These results clearly show the positive impact that the implementation of these methodologies has had on the students, they have increased their interest in learning not only about their careers but also about complementary careers, they consider the opinion of the communities to offer the right solutions, they work efficiently in groups to find a solution to a problem, among other findings.

Conclusions
The evidence presented above shows that approaches such as PBL and DT applied in the teaching processes have allowed us to favour the commitment and active motivation of engineering students in the face of various challenges that we as a society observe from the real world, where not only renewable energies are the focus of interest for teaching but a whole culture around science, technology, and innovation linked to this research, this is a very important step for us in the mission of adapting methodologies with extensive background and from which the best processes were executed to reach the proposed objectives in the face of a chaotic and unpredictable context such as the COVID-19 pandemic.Therefore, the application of these methodologies in the training of future engineers is essential and relevant, as they provide students with the necessary skills to face the enormous multidisciplinary and interdisciplinary challenges arising from the climate and environmental crisis facing the world.
The experience gained at UCC, using PBL and DT to reinforce the development of the necessary competencies in future renewable energy engineers, endorses these advantages, since, given the great demand for sustainable and efficient solutions by the energy, economic and social sectors, these results allow transforming a new mental model to face the current and future needs of those that UCC is committed to such change and be competent in the mentioned foci of this research, as well as in new foci that will be part of this type of projects in the future.
The positive impact of the DT and PBL methodologies in addressing renewable energy issues and finding a solution that is much more tailored to the requirements while also taking sustainability into account has been observed.Renewable energies are in a certain way novel and are in constant renovation and research, therefore it is important to be able to apply different techniques, beyond the traditional ones, to be at the same level as renewable technologies, and to respond to the requirements and problems related to them, in this way, these methodologies tested in this Colombian context demonstrate a great acceptance and results reflected in complete solutions to complex problems.Throughout this process, engineering students actively participated in different activities where PBL and DT were used, substantially developing their skills and interest in tune with the critical educational model with a focus on the development of competencies that flourished at UCC, such skills are encompassed in problem-solving, to be able to identify a need and trace a satisfactory solution route.
Finally, it should be noted that the technical-theoretical flexibility of these methodologies has a promising potential to teach materials related to sustainability in higher education institutions.

Recommendations
Recently we have witnessed the rise of a whole movement around virtual reality programs as an immersive learning alternative (Allcoat et al., 2021), which together with teaching methodologies such as PBL, Design Thinking, and gamification, it is possible to open a door to new spaces of cocreation between teams interconnectedly, this is a concept that is still taking shape in society and that will be the future of education, it is the metaverse, virtual worlds where you can work, study and perform various team activities.
As future work and recommendation, it is possible to apply the experience gained from this research for the formulation of a new model to motivate and enhance the skills of students through virtual and immersive training On the other side, also as future work, it is hoped to analyse the statistical part of the answers given by the students in the questionnaire, as part of an in-depth study of the techniques applied and the data generated.It is also hoped to carry out a study of other teaching methodologies in the context of the Universidad Cooperativa de Colombia.Verbič, G., Keerthisinghe, C., & Chapman, A. C. (2017) You are free to: Share -copy and redistribute the material in any medium or format.Adapt -remix, transform, and build upon the material for any purpose, even commercially.The licensor cannot revoke these freedoms as long as you follow the license terms.
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Figure
Figure 1.Presentation of final projects in the Thermodynamics course.
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