Judul: Potential Greenhouse Gas Reduction and Financial Feasibility of Co-composting Project (Case Study: KUD Langgeng Organik Fertilizer Factory, Riau)
Abstrak: Peningkatan Gas Rumah Kaca (GRK) yang signifikan dalam seratus tahun terakhir telah menyebabkan terjadinya pemanasan global. Salah satu kegiatan yang menimbulkan GRK adalah pengelolaan limbah. Praktik pembuangan Sludge Palm Oil Mill Effluent (POME) dan kotoran sapi yang tidak tepat dapat menimbulkan bau dan mengeluarkan gas metana. Kedua jenis limbah ini bisa dimanfaatkan kembali sebagai bahan baku pengomposan bersama (Co-composting). Daur ulang limbah organik ini dapat mereduksi jumlah emisi GRK, sehingga Co-composting berpotensi mengurangi emisi GRK pada sektor limbah. Namun terdapat isu bahwa usaha ini tidak menguntungkan karena kurangnya minat dan perhatian petani terhadap pupuk organik. Penelitian ini bertujuan mengestimasi potensi emisi GRK sebelum dan setelah adanya proyek Co-composting, serta menganalisis kelayakan finansial dari usaha pabrik pupuk organik. Penelitian ini menggunakan beberapa metode Clean Development Mechanism (CDM) yaitu AMS-III.D, AMS-III.H, AMS-III.F, dan analisis kelayakan finansial. Hasil penelitian menunjukkan emisi baseline sebesar 784,67 t CO2e/tahun dan potensi reduksi emisi GRK sebesar 293,78 t CO2e/tahun. Co-composting sludge POME-kotoran sapi layak secara finansial pada skema proyek 30 tahun., The significant greenhouse gas (GHGs) increase in the last hundred years has led to global warming. One of the activities that generate GHGs is waste management. Improper disposal practices of POME sludge and cow dung can be a problem for the environment. Both types of waste can be reused as raw materials for co-composting. Recycling organic waste can reduce the amount of GHG emissions. Co-composting has the potential to reduce GHG emissions in the waste sector. However, there is an issue that this business is not profitable due to farmers' lack of interest and awareness towards organic fertilizer. This study aims to estimate the potential GHG emissions before and after the Co-composting and analyze the financial feasibility of the organic fertilizer plant. This research uses several CDM methods, namely AMS-III.D, AMS-III.H, AMS-III.F, and financial feasibility analysis. The results showed baseline emissions of 784.67 t CO2e/year and GHG emission reduction potential of 293.78 t CO2e/year. Co-composting POME sludge-cow manure is financially feasible in a 30-year project scheme.
Keyword: CDM, Co-composting, Financial Feasibility, GHG, Waste Sector

Judul: Methane Emissions Reduction from Palm Oil Mill  Effluent through a Biogas Plant (Case Study: Tungkal Ulu Biogas Plant, Jambi)
Abstrak: Mayoritas industri kelapa sawit di Indonesia mengolah limbah cairnya atau Palm oil Mill Effluent (POME) menggunakan sistem kolam terbuka yang melepaskan gas metana dan berpotensi meningkatkan Gas Rumah Kaca (GRK). Salah satu upaya mencegah pelepasan gas metana dari sistem tersebut adalah pembangunan proyek methane recovery, melalui Pembangkit Listrik Tenaga Biogas (PLTBg). Proyek PLTBg mendukung target pemerintah dalam menurunkan emisi GRK dan menghasilkan energi terbarukan. Penelitian ini bertujuan untuk (1) mengestimasi potensi emisi GRK dari POME sebelum adanya proyek PLTBg, (2) mengestimasi reduksi emisi GRK dari POME setelah adanya proyek PLTBg, dan (3) menganalisis kelayakan finansial proyek PLTBg. Penelitian ini menggunakan metode Clean Development Mechanism (CDM) AMS III H dan analisis cashflow. Hasil penelitian menunjukkan bahwa PLTBg Tungkal Ulu mereduksi emisi GRK sekaligus menguntungkan perusahaan. Emisi sebelum adanya PLTBg yang diestimasi dari 106.267 m3 POME adalah 44.767,80 t CO2e. Potensi reduksi emisi setelah adanya PLTBg berkisar 66,64%-74,26% pada tahun 2021-2030. Pada kurun waktu tersebut, proyek PLTBg layak secara finansial pada harga CER rendah dan tinggi. Skenario CER rendah menghasilkan nilai NPV, BCR dan IRR sebesar Rp 18,55 miliar, 1,19 dan 11,46% sedangkan CER tinggi menghasilkan nilai NPV, BCR dan IRR sebesar Rp 19,65 miliar, 1,21 dan 11,69%., Most palm oil industries in Indonesia treat Palm Oil Mill Effluent (POME) by using an open lagoon system that releases methane gas emissions and potentially increases Greenhouse Gases (GHGs). Biogas plant, a methane recovery project, becomes one measures to reduce such emissions. Biogas Plant projects support the government's target in reducing GHGs emissions and produces renewable energy. By focusing on the Tungkal Ulu Biogas, this study aims to (1) estimate the potential GHGs emissions prior the implementation of biogas plant project, (2) estimate the GHGs emissions reduction after the project implementation, and (3) to analyze the financial feasibility of the project. This study employes Clean Development Mechanism (CDM) method (i.e. the AMS III H) and cashflow analysis. The results showed that Tungkal Ulu Biogas Plant project can reduce GHGs emissions and can benefit the company. Based on 106,267 m3 of POME, GHGs emissions prior the project implementatation is 44,767.80 t CO2e. The potential GHGs emissions reduction ranges from 66.64% to 74.26% during 2021-2030. Financial analysis indicates that the project is feasible, at both low and high CER market prices. The low CER results in NPV, BCR and IRR values of 18,55 billion IDR, 1,19 and 11,46%, respectively, while high CER results in NPV, BCR and IRR values of 19,65 billion IDR, 1.21 and 11,69%, respectively.
Keyword: cashflow, CDM, GHGs, PLTBg, POME

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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