Judul: Kajian Pengaruh Perubahan Iklim dan Tata Guna Lahan di Daerah Aliran Sungai (DAS) Citarum Hulu terhadap Pembangkit Listrik Tenaga Air Saguling
Abstrak: Saguling Hydropower has an important role in addressing electricity demand in Jawa-Bali region. To generate electricity, the hydropower utilizes storage water in Saguling Reservoir. However, due to rapid rate of deforestation, the hydrological cycle becomes uncertain as well as the water supply for electricity generation. The global climate change also affects local rainfall in the watershed. This research aimed to analyze the integrated impacts of landuse change and climate change in Upper Citarum Watershed on electricity generation of Saguling Hydropower. The SWAT model was applied to simulate hydrological cycle in the watershed while RegCM3 data simulated by CCROM-SEAP was used as climate data input. Statistical equation of inflowelectricity production based on different season (rainy and dry season) was also used to generate electricity data from inflow. It was predicted that between 2000 and 2025 deforestation will reduce about 38% forest cover in Upper Citarum watershed. This would lead to increasing runoff fraction and decreasing stream baseflow over subbasin scale. On the other side, climate change triggers rainfall alteration temporally and spatially that posses discharge input for hydropower. Collectively, climate and landuse change strengthen the risk of low inflow to Saguling reservoir, leading to lower electricity production.
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Judul: Evaluasi Produksi Energi Listrik di PLTA Saguling Menggunakan WEAP
Abstrak: Kebutuhan listrik masyarakat terus meningkat seiring dengan pertumbuhan ekonomi dan populasi masyarakat. PLTA Saguling merupakan salah satu pemasok listrik untuk Jawa dan Bali. Perubahan aliran sungai mempengaruhi produksi listrik di PLTA Saguling. Jumlah aliran tersebut dipengaruhi oleh curah hujan dan tidak selalu sama. Water Evaluation, Analisys and Planning (WEAP) digunakan untuk mensimulasikan dampak perubahan curah hujan dalam bentuk aliran masuk ke waduk terhadap produksi listrik. Aliran masuk waduk akan dianggap supply dan aliran keluar waduk akan digunakan sebagai demand waduk. Perubahan supply dilakukan dalam empat kondisi yaitu sebesar -25% dan -50% dan sebesar +25% dan +50%. Perubahan demand berupa aliran keluar juga dilakukan dengan persentase yang sama. Pengurangan suplai sebesar 50% mengurangi produksi listrik sekitar 90% dari kondisi awal. Penambahan supply sebesar 50% dapat meningkat produksi sebesar 111%. Penurunan dan peningkatan produksi listrik akibat perubahan supply lebih besar jika ada perubahan demand.
Keyword: Hydropower, listrik, Saguling, PLTA, WEAP

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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