The use of fossil fuels such as coal still dominates as fuel for power plants in the world. The use of fossil fuels in most power plants can increase Greenhouse Gas (GHG) emissions that affect climate change. Biomass is one of the renewable energy sources that is expected to reduce Greenhouse Gas emissions. The use of biomass energy sources as a mixture of fossil fuels known as co-firing in power plants has been widely done to reduce dependence on fossil fuels. In this research will be reviewed the influence of biomass mixture on the efficiency of coal power plant boilers. The composition of the mixture as well as the type of biomass used will greatly affect the efficiency of the Boiler. The percentage of biomass composition as well as the right combustion settings will be able to produce optimal boiler efficiency. From the study in this research, it is hoped that it will be able to provide an overview of the performance of a power plant that performs co-firing so that in addition to getting the benefits of reducing greenhouse gas emissions, good boiler efficiency is also obtained.

The performance of steam turbine is very important to know and analyze to understand the actual condition compared to conditions of commissioning. The purpose of this paper is to understand the performance by comparing the efficiency of the steam turbine in actual conditions based on  commissioning data in accordance with ASME PTC 6 rules. By doing this, it can be known the actual performance experienced by the steam turbine, the actual condition is what will be compared with the commissioning data so that later will be obtained performance differences that will be a concern in the continuous improvement of the steam turbine. The observations were made at Tarahan Power Plant Unit 3 regarding the condition of steam entering the turbine in this case the pressure and temperature, the condition of the extraction steam, and the condition of the exhaust side that will affect the performance analysis of the steam turbine.

The utilization of waste heat in a power plant system-which would otherwise be released back to the environment-in order to produce additional power increases the efficiency of the system itself. The purpose of this study is to present an energy and exergy analysis of Kalina Cycle System (KCS) 11, which is proposed to be utilized to generate additional electric power from the waste heat contained in geothermal brine water available in the Lahendong Geothermal power plant site in North Sulawesi, Indonesia. A modeling application on energy and exergy system is used to study the design of thermal system which uses KCS 11. To obtain the maximum power output and maximum efficiency, the system is optimized based on the mass fraction of working fluid (ammonia-water), as well as based on the turbine exhaust pressure. The result of the simulation is the optimum theoretical performance of KCS 11, which has the highest possible power output and efficiency. The energy flow diagram and exergy diagram (Grassman diagram) was also presented for KCS 11 optimum system to give quantitative information regarding energy flow from the heat source to system components and the proportion of the exergy input dissipated in the various system components. Abstrak Analisis Energi dan Eksergi Siklus Kalina untuk Pemanfaatan Limbah Panas di dalam Air Garam untuk LadangPanas Bumi Indonesia. Pemanfaatan limbah panas pada sistem pembangkit tenaga listrik, yang sebetulnya akan dikembalikan ke alam, untuk memproduksi tambahan tenaga listrik akan meningkatkan keefisienan sistem itu sendiri. Penelitian ini bertujuan untuk menampilkan analisis energi dan eksergi Sistem Siklus Kalina (Kalina Cycle System atau KCS) 11 yang kami ajukan agar dapat dimanfaatkan untuk menghasilkan tenaga listrik tambahan dari limbah panas yang terkandung di dalam air garam panas bumi yang terdapat di situs pembangkit listrik tenaga Panas Bumi Lahendong, Sulawesi Utara, Indonesia. Penerapan model sistem energi dan eksergi digunakan untuk mengkaji rancangan sistem termal yang menggunakan KCS 11. Untuk menghasilkan keluaran tenaga listrik yang maksimal dan keefisienan yang maksimal, sistem itu akan dioptimalkan berdasarkan fraksi massa cairan yang digunakan (air amonia) dan tekanan keluar turbin. Simulasi ini menghasilkan performa KCS 11 yang optimal secara teoretis, yang menunjukkan keluaran tenaga listrik dan keefisienan yang paling tinggi. Diagram aliran energi dan diagram eksergi (diagram Grassman) juga disajikan di dalam sistem KCS 11 yang telah dioptimalkan itu untuk menyediakan informasi kuantitatif tentang aliran energi dari sumber panas menuju komponen-komponen sistem dan tentang proporsi masukan eksergi yang tersebar di berbagai komponen dalam sistem itu.