Flow acceleration by converging nozzles for power generation in existing canal system Abid A. Khan, Abdul M. Khan, M. Zahid * , R. Rizwan National University of Science and Technology, Islamabad, Pakistan article info Article history: Received 15 January 2013 Accepted 7 June 2013 Available online Keywords: Run-of-river Small hydro power Convergent nozzles Open flow channels Ghazi-Barotha canal abstract Small-scale hydro or micro-hydro power has been increasingly used as an alternative energy source, especially in remote areas where other power sources are not viable. In the larger hydro projects po- tential energy of the water is converted to electrical power, whereas such small-scale hydro power systems utilize kinetic energy of the flow. These systems can be installed in small rivers or streams with little or no discernible environmental effects. Usually, these systems do not require a huge infrastructure like dam or major water diversions, rather use water wheels with least environmental impacts. This paper presents a report on how flow can be accelerated through convergent nozzles for run-of-river turbines in open flow channels. An existing canal in Pakistan has been used for the analysis based on its easily accessible data. The analytical and computational work presented here converts kinetic energy of water flow to electric power. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction The availability of energy in any country not only reflects its economic growth but also reflects strength of other development indicators such as social, economic, environmental, and security issues like poverty, jobs and income level, access to social services, population growth, industrial and agricultural production. The relation between energy availability and country’s development indicators has been discussed in detail by Bhutto et al. [1]. Several countries in the past have faced the economic crisis due to power shortages. Sri Lanka is one such example which faced the severe economic crisis in 1996 due to shortage of electricity [2]. Hydro power generation due to its low environmental effects is consid- ered best among all energy sources. The environmental effects of different energy generation technologies have been compared by Felix et al. [3] and energy generation from hydro source has been shown to have minimum environmental effects. Hydro power is the leading source of renewable energy with inherited advantage of fuel cost elimination [4]. Hydro power, large or small, remains the most important source for electrical power production worldwide. This source generates 19% of the planet’s electricity [5]. In spite of numerous benefits of hydro power gen- eration through large reservoirs they have multitude adverse effects discussed in details by Berkun [6]. As a result of these adverse factors small-scale hydro projects such as “run-of-river” are mostly preferred. It does not have a requirement of dam or water storage making it cost-effective and environmental friendly, thus small hydro power is considered to be one of the most promising renewable energy source [7]. Mini-hydro power generation can be planned in small-scale on existing rivers; canals etc., as it utilize existing water reservoirs and streams to generate hydro power which is renewable in nature. Such projects do not necessitate the rehabilitation of people and environmental problems associated with the large hydro power plants [8]. Small-scale hydro power systems do not require a large infrastructure; rather use water wheels with least environmental impacts. Numerous inborn benefits of small hydro power genera- tion projects are making them extensively acceptable worldwide. In India alone a potential of 15,000 MW has been estimated in small hydro sources, out of which 611 plants having 2045 MW capacity were reported to be operational whereas 225 plants with another 669 MW were under various stages of construction [9]. Another significant benefit associated with such small projects is provi- sioning of electricity to those small isolated communities where power production through other sources is not viable. Brazilian Amazon region is one such example discussed by Blanco et al. [10]. Flow in hilly areas usually has rapids thus offering few feasible locations for such projects whereas, in the plains numerous feasible locations may exist but low velocity of flow may pose problems. Flow acceleration in the existing canals and streams is therefore an * Corresponding author. E-mail address: zahidm56@gmail.com (M. Zahid). Contents lists available at SciVerse ScienceDirect Renewable Energy journal homepage: www.elsevier.com/locate/renene 0960-1481/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.renene.2013.06.005 Renewable Energy 60 (2013) 548e552