Impact of STEM Project-Based Learning on research autonomy and engineering thinking in solar energy education

At the present stage, the development of renewable energy sources, particularly solar energy, is considered one of the key directions for ensuring energy security and sustainable development. In this context, training specialists with well-developed research and engineering thinking in the field of solar energy within the higher education system has become an urgent issue. The purpose of this study is to theoretically and empirically examine the effectiveness of developing students' research and engineering activities through the implementation of a STEM Project-Based Learning (PjBL) approach in solar energy education. The study was conducted using a sequential explanatory design, consisting of two phases. In the first phase, a systematic literature review and meta-analysis were carried out based on studies published between 2015 and 2025 and selected from Web of Science, Scopus, and Google Scholar in accordance with the PRISMA methodology. The meta-analysis was performed using Comprehensive Meta-Analysis 4.0 software and included 15 empirical studies. In the second phase, a pedagogical experiment was conducted at Khoja Akhmet Yassawi International Kazakh-Turkish University involving 88 students divided into control and experimental groups. An independent samples t-test was applied to analyze the collected data. The meta-analysis results indicated a large overall effect size (d = 1.75; 95% CI [1.29, 2.22]; p < 0.001), suggesting the strong potential of STEM-PjBL in enhancing students' research and engineering skills. The experimental results showed no statistically significant difference between the control and experimental groups at the pre-test stage (t = 0.1425; p = 0.887), while a significant difference was observed at the post-test stage (t = 5.8550; p < 0.001), with a large effect size (Cohen's d = 1.27). The findings suggest that the implementation of STEM Project-Based Learning in solar energy education can effectively support the development of students' research autonomy, engineering thinking, and their ability to connect theoretical knowledge with real-world applications.