Enhanced Operational Flexibility of a Small Run-of-River Hydropower Plant

Over the last two decades, the public policies for promoting new renewable energies allowed the growth of such energies around the world. Due to their success, the policies are changing, forcing the producers to adapt their strategy. For instance, in Switzerland, the feed-in tariff system has been modified in 2018 to promote an electricity production from renewable energies that matches the demand. For small hydraulic power plants owners, such a change requires to increase the flexibility of their fleet. The SmallFLEX project, led by HES-SO Valais, aims at demonstrating on the pilot site of Gletsch-Oberwald owned by Forces Motrices Valaisannes SA, the possibilities to increase the flexibility of the power plant and to provide new services. The paper focuses on the methodology followed to warranty the use of the settling basin, the forebay tank, and the third upper part of the headrace tunnel as a new smart storage volume. By combining laboratory tests, numerical simulations, and on-site measurements, the new range of operating conditions has been defined. These data can be used to foresee economic gains. The methodology and the outputs of the project can be useful for performing such a study on other power plants.

PERANCANGAN PEMBANGKIT LISTRIK TENAGA MIKROHIDRO. STUDI KASUS DI CURUG CIGEUNTIS, KECAMATAN TEGALWARU, KABUPATEN KARAWANG, JAWA BARAT

This research aims to create a design model of microhydro powerplant, and implement that design model to particular location, which decided location in this research is Cigeuntis Waterfall. Output of this research can be utilized by microhydro power plant practitioners as a tool, and stakeholders to valuing natural resources potential in their area. Cigeuntis Waterfall is selected because it has sufficient water in raining season, and more important, in dry season. Analysis descriptive method is used in this research with qualitative approach. Technics of Engineering is type of this research, encompassing design formulation of microhydro power plant, formula validation by comparing design of microhydro power plant based on formula with existing microhydro power plant in PLN Laboratory, and designing microhydro power plant components like intake, settling basin, penstock pipe, turbine, pulley, and generator regarding water flow and net head of Cigeuntis Waterfall. Results of this research are if microhydro power plant build at Cigeuntis Waterfall with 0.55 m3/s water flow and net head is 25 m, the size of components must be 2.97 m2 for intake, 6.6 m x 0.83 m x 2.2 m for settling basin, 48 cm for penstock diameter and 0.17 cm for its thickness, 11.81 inch for turbine diameter and 3.8 inch for its length, 2.1 inch for blade turbine space, 18 blades turbine needed, 11.81 inch for pulley diameter which connected to turbine and 5.2 inch diameter which connected to generator, and capacity of generator is 104.1 kW. This formula created in Microsoft Excel format, and after validation with existing microhydro power plant, there is not any substantial difference as the result. Therefore, the conclusion is this design model of microhydro power plant able to be implemented. Abstrak Penelitian ini bertujuan untuk menghasilkan model perancangan PLTMH, dan mengimplementasikannya pada lokasi tertentu, yang pada penelitian ini ditetapkan lokasinya adalah Curug Cigeuntis. Model perancangan ini nantinya bisa digunakan oleh para perancang PLTMH sebagai observasi awal, dan juga digunakan oleh para pemangku kebijakan dalam melihat potensi sumber daya alam di daerahnya. Curug Cigeuntis dipilih menjadi lokasi pengujian sebagai contoh implementasi yang dari model perancangan yang dibuat karena ketersediaan air di sana boleh dikatakan tinggi akibat curah hujan yang besar. Penelitian ini menggunakan metode deskriptif analisis melalui pendekatan kualitatif. Jenis penelitian yang dipilih ialah rekayasa teknik dengan mencangkup pembuatan formulasi perancangan PLTMH, validasi formulasi perancangan PLTMH dengan acuan sistem PLTMH yang terpasang pada Laboratorium Tenaga Air Mini milik PLN, dan perancangan b agian PLTMH, yaitu saluran intake, bak penenang, pipa penstock, turbin, pulley, dan generator mempertimbangkan kondisi alam seperti debit air dan tinggi jatuh air pada Curug Cigeuntis. Hasil penelitian menunjukan bahwa Curug Cigeuntis dengan debit andalan sebesar 0.55 m3/s dan tinggi jatuh air sebesar 25 m, diperoleh ukuran intake 2.97 m2, ukuran bak penenang 6.6 m x 0.83 m x 2.2 m, ukuran diameter penstock 48 cm dan ketebalannya 0.17 cm, ukuran diameter turbin 11.81 inch dengan panjang 3.8 inch, jarak antara pisau 2.1 inch, dan jumlah pisau turbin sebanyak 18 buah. Ukuran pulley besarnya pada bagian diameter terhubung turbin adalah 11.81 inch dan diameter terhubung generator 5.2 inch. Kapasitas generator yang digunakan sebesar 104.1 kw. Formulasi perancangan yang dibuat menggunakan program Microsoft Excel, telah divalidasi dengan sistem PLTMH terpasang dan tidak didapati perbedaan yang substansial sehingga dapat disimpulkan perancangan PLTMH layak untuk diimplementasikan pada perancangan tertentu.

Flow control in a multichamber settling basin by sluice gates driven by a CFD and an ancillary analytical model

Unequal flow distribution between the chambers of a three-chamber settling basin causes its malfunction and endangers the turbines of a small hydropower plant. To equalize the flows, sluice gates are used. To find their positions, the following methodologies are considered: (1) measurements combined with trial-and-error method (TAE), (2) measurements with regression analysis (RA), (3) CFD model combined with TAE, (4) CFD model with RA, (5) CFD model supported by a one-dimensional flow model, and (6) CFD model with an analytical model. The additional models and RA are intended to speed up the solution finding. From the previous list, only the sixth methodology is applicable. The first four are not because of the weir design, and the fifth because of the three-dimensional flow character. Initially, the CFD model of the side-weir intake was developed and validated. Afterward, the analytical model, which consists of a system of three pressure drop equations for three parallel and partly imaginary streams, is formed. The local flow resistances in the analytical model are determined by the CFD model combined with RA. To equalize the flows, three solutions with (i) fix, (ii) fix in a range of flows, and (iii) variable positions of the sluice gates are analyzed.