Simulation of electricity generation by marine current turbines at Istanbul Bosphorus Strait Hasan Yazicioglu a , K.M. Murat Tunc b , Muammer Ozbek b, * , Tolga Kara b a Technical University of Denmark, Department of Wind Energy, Denmark b Istanbul Bilgi University, Faculty of Engineering and Natural Sciences, Turkey article info Article history: Received 9 July 2015 Received in revised form 29 October 2015 Accepted 17 November 2015 Available online xxx Keywords: Renewable energy Marine current turbine Energy yield simulations Cluster/farm optimization Offshore engineering Dynamic interactions abstract In this work, several simulations and analyses are carried out to investigate the feasibility of generating electricity from underwater sea currents at Istanbul Bosphorus Strait. Bosphorus is a natural canal which forms a border between Europe and Asia by connecting Black Sea and Marmara Sea. The differences in elevation and salinity ratios between these two seas cause strong marine currents. Depending on the morphology of the canal the speed of the flow varies and at some specific locations the energy intensity reaches to sufficient levels where electricity generation by marine current turbines becomes economi- cally feasible. In this study, several simulations are performed for a 10 MW marine turbine farm/cluster whose location is selected by taking into account several factors such as the canal morphology, current speed and passage of vessels. 360 different simulations are performed for 15 different virtual sea states. Similarly, 8 different configurations are analyzed in order to find the optimum spacing between the turbines. Considering the spatial variations in the current speed within the selected region, the analyses are performed for three different flow speeds corresponding to ±10% change in the average value. For each simulation the annual energy yield and cluster efficiency are calculated. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction The growing world population and rapid industrialization seen in developing countries cause a continuous increase in the global energy demand. Today the major source of energy comes from fossil fuels such as oil, coal and natural gas. However, considering the rate of increase in the consumption, it can easily be realized that these limited sources cannot be a long term solution to satisfy the global energy demand and are definitely bound to run out. Besides, using fossil fuels as primary source of energy has irreversible negative impacts on the environment which force many countries to seek for alternative environmental friendly renewable energy sources. Turkey, as a rapidly growing economy with very limited national hydrocarbon resources, is also heavily dependent on fossil fuels (e.g. natural gas) imported for electricity production [1]. However, some recent political instabilities in the supplier countries, the heavy economic burden of importing these resources and the most importantly, the increasing awareness of environmental issues have been encouraging policy makers to increase the use of renewable energy sources. Indeed, very detailed investigations and analyses were performed to determine the wind, solar and geothermal energy capacity of the country [1]. However, the po- tential of harnessing some other renewable sources, particularly sea current energy has not been fully realized yet. Compared to the other types of renewable energy such as wind and solar, current energy can still be considered in development phase and is not commercially available in large scales. Existing marine turbine systems are mostly in prototype testing stage. Although initial results are quite promising [2e9] some further verification for long term performance and durability under severe environmental conditions is still required. The average current speed needed for most commercial turbines is approximately 4e5 knots (2e2.5 m/s). Areas that typically experience high marine current flows are in narrow straits, be- tween islands and around headlands. Entrances to lochs, bays and large harbors often also have high marine current flows. Generally the resource is largest where the water depth is relatively shallow and a good tidal range exists [10]. * Corresponding author. E-mail address: muammer.ozbek@bilgi.edu.tr (M. Ozbek). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy http://dx.doi.org/10.1016/j.energy.2015.11.038 0360-5442/© 2015 Elsevier Ltd. All rights reserved. Energy 95 (2016) 41e50