Penggunaan bahan bakar fosil, seperti batubara, masih dominan dalam Pembangkit Listrik di Indonesia namun berdampak pada peningkatan emisi Gas Rumah Kaca (GRK) yang mempengaruhi perubahan iklim. Biomassa, sebagai sumber energi terbarukan dapat mengurangi emisi GRK. Rencana Umum Ketenagalistrikan Nasional (RUKN) mencantumkan rencana PLN untuk mengimplementasikan Co-Firing pada Pembangkit Listrik Tenaga Uap (PLTU) dengan subtitusi batubara pada rasio tertentu dengan bahan biomassa seperti wood pellet, cangkang sawit dan serbuk gergaji. Penelitian ini fokus pada metode direct Co-Firing menggunakan 95% batubara dan 5% serbuk gergaji, bertujuan menilai pengaruhnya terhadap efisiensi Boiler. Analisis menggunakan perangkat lunak Microsoft Excel, dimana parameter operasi kinerja Boiler berdasarkan ASME PTC 4 pada pengoperasian skema Co-Firing biomassa dibandingkan dengan data benchmark atau commissioning. Hasil penelitian didapatkan, peningkatan persentase komposisi biomassa hingga 5%, menyebabkan konsumsi bahan bakar meningkat 1,19% (ton/jam) dan menurunkan efisiensi Boiler sebesar 0,9894% pada LHV basis dan sebesar 0,9647 pada HHV basis dibandingkan dengan skema operasi 100% batubara. Namun bertambahnya persentase Co-Firing cenderung menurunkan emisi gas buang SO2, NOx dan partikulat dan tetap dalam batas baku mutu KLHK.

The use of fossil fuels, such as coal, remains dominant in power plants in Indonesia, but it leads to increased Greenhouse Gas (GHG) emissions that affect climate change. Biomass, as a renewable energy source, can reduce GHG emissions. The National Electricity General Plan (RUKN) includes PLN’s plan to implement Co-Firing in Steam Power Plants (PLTU) by substituting a certain ratio of coal with biomass materials such as wood pellets, palm kernel shells, and sawdust. This study focuses on direct Co-Firing with 95% coal and 5% sawdust, aiming to assess its impact on Boiler efficiency. Analysis using Microsoft Excel software, with Boiler performance parameters based on ASME PTC 4, compares the Co-Firing biomass scheme with benchmark or commissioning data. The study finds that increasing the biomass composition to 5% results in a 1.19% increase in fuel consumption (tons/hour) and a reduction in Boiler efficiency by 0.9894% on an LHV basis and 0.9647% on an HHV basis compared to a 100% coal scheme. However, increasing the Co-Firing percentage tends to lower SO2, NOx, and particulate emissions and does not exceed the maximum quality standards set by the Ministry of Environment and Forestry (KLHK).