Wind power, solar power and water power are technologies that can be used as the main sources of renewable energy so that the target of decarbonisation in the energy sector can be achieved. However, when compared with conventional power plants, they have a significant difference. The share of renewable energy has made a difference and posed various challenges, especially in the power generation system. The reliability of the power system can achieve the decarbonization target but this objective often collides with several challenges and failures, such that they make achievement of the target very vulnerable, Even so, the challenges and technological solutions are still very rarely discussed in the literature. This study carried out specific investigations on various technological solutions and challenges, especially in the power system domain. The results of the review of the solution matrix and the interrelated technological challenges are the most important parts to be developed in the future. Developing a matrix with various renewable technology solutions can help solve RE challenges. The potential of the developed technological solutions is expected to be able to help and prioritize them especially cost-effective energy. In addition, technology solutions that are identified in groups can help reduce certain challenges. The categories developed in this study are used to assist in determining the specific needs and increasing transparency of the renewable energy integration process in the future.

Critical thinking skill is an important tool used by students to solve the common problems either internal problem or problems that are found in school. This research aimed at indicating the influence of problem-based learning model implementation accompanied with the virtual laboratory to students’ critical thinking skills and learning achievement. The method was a true experiment and the sample was taken by using the true experiment technique, where grade ten-two class was selected as the experimental class and grade ten-three class as control class. Each of the classes consisted of 30 students. The experimental class was taught using PBL accompanied by the virtual laboratory. The collected data were analyzed by studying the comparison of improvement from a result of pretest and N-Gain and continued by using the t-test. The findings showed that there were no differences between students’ average scores between the experimental class and control class. N-Gain showed the real differences between the two classes. Overall, N-Gain for critical thinking skill function analysis revealed better results in experimental class than control class. It can be concluded that problem-based learning model implementation accompanied with virtual laboratory effectively increases students’ critical thinking skills and learning achievement.

Sulfur dioxide (SO 2 ) and trace metal such as mercury emission during combustion of low-rank coal cause a significant impact on the environment and health. Flue gas at coal-fired power stations is one of the main sources for the emissions of SO 2 and mercury metal. Low-cost and sustainable technologies for the removal of SO 2 and mercury from flue gas have become increasingly important nowadays. This paper presents the study of simultaneous removal of SO 2 and mercury over natural zeolite as an adsorbent in briquette and pulverized. The research is focused on evaluating adsorbent to coal optimum ratio towards adsorption performance on SO 2 and mercury removal. The experiments on the removal of SO 2 and mercury were carried out using horizontal electric furnace with different combustion temperature and adsorbent ratio. SO 2 in the flue gas as the result of the combustion process which exits from the outlet was analyzed using Gas Combustion and Emission Analyzer (E4400, E-Instrument). Mercury metal residues in the bottom ash were analyzed using NIC Mercury SP Analyzer. An increasing zeolite adsorbent SO 2 content in flue gas decreased. The optimum SO 2 removal was determined on 4% zeolite adsorbent ratio. It also has been found that 8% natural zeolite ratio to low-rank coal show optimum condition to adsorb mercury for all temperature condition for both briquette and pulverized conditions.

Energy demand from the community, which continues to increase has resulted in depletion of petroleum (fossil) energy in recent years. Many researchers have sought to find alternative fuels to replace dependence on conventional energy. The mixing of alcohol into diesel fuel has also been carried out by several previous researchers. The main focus of this research is to investigate the combustion performance of diesel engines using a mixture of biodiesel-butanol-water and diesel (B5Bu5W5). This research experiment used a single-cylinder diesel engine with different speeds at 25% and 50% engine load. The experimental results show that the maximum cylinder pressure reaches 72.32 bar when the engine load reaches 50%. While at 25% engine load press the maximum cylinder 33.62 bar. The heat dissipation for 50% engine load is also higher than the engine load 25% respectively 34.39% and 33.62%. Overall results show that cylinder pressure increases when the load and engine speed increase. However, the combustion time is a little slower than when using pure diesel fuel.

It is necessary to find appropriate learning solutions to solve students’ misconceptions on the human reproductive system concepts. This study aims to determine whether learning through the implementation of a constructivist module influences the reconstruction of students’ knowledge about the human reproductive system. The method used in this study was experimental with one group pre-test and post-test design. The population consisted of 272 students from science class XI of SMAN 10 Fajar Harapan Banda Aceh and SMAN Modal Bangsa Aceh Province. A total of 107 students were chosen by random sampling. The study was carried out over four months from March to July 2019. The supporting instruments used were the learning media and the data collection instruments in the form of multiple-choice test questions with Certainty of Response Index (CRI). The data collected through a pre-and post-test were analyzed using percentages. The results show that the number of students who understand certain concepts rose by 52.36%, the number of students who had misunderstandings decreased by 43.58%, and the number of students who had misconceptions fell by 9.94%. So, it is concluded that learning through the constructivist module is effective in improving concept reconstruction and students’ learning outcomes.