Wind resource assessment for urban renewable energy application in Singapore B.R. Karthikeya a , Prabal S. Negi b , N. Srikanth a * a Energy Research Institute @ Nanyang Technological University, #06-04,1 Cleantech Loop, Cleantech One, Singapore 637141, Singapore b School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore article info Article history: Received 10 February 2015 Received in revised form 5 August 2015 Accepted 7 October 2015 Available online 10 November 2015 Keywords: Urban wind potential Wind energy Wind speed Urban wind turbines Weibull distribution Resource assessment abstract In highly urbanized and energy intensive countries like Singapore all possible avenues for power gen- eration need attention. In this context, rooftop installations of both solar and wind energy are of particular interest for Singapore, especially because of Singapore's condition of land limitation. Decen- tralized and distributed energy sources such as rooftop wind and solar installations have numerous advantages. However, the potential for wind energy is not fully understood in built-up areas and thus not fully exploited. Hence it is important to study wind flow patterns in built-up areas and also develop technologies tuned for these conditions. The demand for technologies that deliver energy for low flow wind conditions is of paramount importance to Southeast Asia region and especially to Singapore. In this paper, two measurement systems, namely stationary rooftop wind mast and mobile Light Detection and Ranging (LiDAR) profiler, have been discussed. Measured wind data from various sites across Singapore using have also been presented. Wind roses, Weibull distribution, roughness lengths and other statistical analyses were carried out to understand the prevailing wind characteristic, which is used for evolving the basic criteria for economic viability of roof top wind turbines in the tropical conditions of Singapore. © 2015 Published by Elsevier Ltd. 1. Introduction Singapore's installed electricity generation capacity is 12.5 GW, which is almost entirely derived from fossil fuels [1]. Household electricity consumption is 15% of the total electricity consumption and consumption by commercial and services sector is 37%. Singapore is committed to reducing its emissions by 7%e11% below 2020 business-as-usual levels [2]. Hence, decentralized and distributed energy sources such as rooftop wind and solar in- stallations require due attention in terms of resource estimation and techno-economic evaluation. Based on the space availability in Singapore, maximum cumulative capacity of rooftop photovoltaic installations is estimated to be 5 GW p by 2030, with 80% of the installed capacity on rooftops and facades [3]. However, the po- tential for wind energy is not fully understood in built-up areas and hence not fully estimated. In order for Singapore to achieve this goal and to diversify the energy mix, several government agencies are working with Institutes of Higher Learning and local SMEs. National Environment Agency (NEA) owns and maintains several met masts that measure the surface wind across the island nation. But this data is inadequate to estimate the wind potential for the installation of rooftop wind turbines in densely urbanized Singapore. Housing Development Board (HDB) of Singapore, a government body responsible for public housing in Singapore, has been working with the Energy Research Institute at Nanyang Technological University (ERI@N) to study the feasibility of rooftop wind turbines in Singapore. Hence, ERI@N has developed two wind measurement systems for Singapore, namely remote sensing and mobile LiDAR measurement system and rooftop standard anemometry measurement system with wireless data transfer ca- pabilities. ERI@N is the first and so far the only institute in Singapore that conducts wind measurement campaigns in the re- gion using SODAR (SOnic Detection and Ranging) and LiDAR wind profilers. Singapore has a wet equatorial climate with fairly uniform mean monthly temperatures between 26  C and 28  C throughout the year [4]. Singapore's weather can be classified into four seasons. These four seasons are the Northeast Monsoon (December to early March), the Southwest Monsoon (June to September) and two relatively short inter-monsoon seasons. Singapore experiences light and variable winds during the transition between these * Corresponding author. E-mail address: NSrikanth@ntu.edu.sg (N. Srikanth). Contents lists available at ScienceDirect Renewable Energy journal homepage: www.elsevier.com/locate/renene http://dx.doi.org/10.1016/j.renene.2015.10.010 0960-1481/© 2015 Published by Elsevier Ltd. Renewable Energy 87 (2016) 403e414