GRID INTEGRATION OF WIND POWER: A CASE STUDY OF TAMIL NADU Mel George Prof. Rangan Banerjee melgeorge@iitb.ac.in rangan@iitb.ac.in Abstract: As the worldwide use of renewable energy in utility scale applications continues to increase, it is important to assess the impact on the grid and conventional generation. This report combines analysis of load and generation characteristics, generation adequacy and base and peak load variations to gain insights into the future role of wind generation. A simulation of Tamil Nadu state in India, which has a high penetration of wind power (27% by installed capacity), has been presented here. The savings achieved in conventional generation due to installation of wind power are quantified as the capacity credit, using a power system reliability based approach. A new approach based on the annual load duration curve has been proposed for generation expansion planning with higher penetration of wind. The potential savings in base and peak capacity required with increasing wind power have been quantified. Also, a future scenario for the year 2021 has been illustrated and it was found that 5500 MW of wind power can save about 3200 MU of peak energy required or an average peak capacity of 2400 MW and 1100 MW of base capacity. This analysis would be useful for power planners to assess the future impacts of increasing renewable energy capacity in the grids and design appropriate strategies for capacity expansion planning. Keywords: Wind Energy, Capacity Credit, Load Duration Curve 1. Introduction India has about 8,700 MW of installed wind power capacity [1], and it is growing at an average rate of 27% per year (2001-2008). Wind accounted for 6.2% of the installed capacity and about 2% of the electricity generation in 2007 [2]. Due to the large potential of wind energy in India, it is necessary to analyse the impacts of integration of wind power within the Indian power system. Conventional power planning offers techniques for fossil fuel power and hydro power plants. The output of a wind power plant has daily and seasonal variations, depending on the site wind regime and machine characteristics. As the share of wind energy increases and becomes significant, issues related to capacity expansion planning and dispatch become important. The impact of wind energy in the grid has been studied in terms of the capacity credit. The capacity credit of wind power has been defined as the level of conventional generation that can be replaced with wind generation [3]. This concept has been explored by several researchers [4 -9]. It has been shown that calculating the capacity factor of the resource (wind) over a relevant time period usually provides a good estimate of capacity credit [7, 10]. Another method is to compute the wind power generation for time periods corresponding to high systems risk hours or approximate the system LOLP (Loss of Load Probability) curve so that high risk hours receive more weight than other hours. Most methods to assess the capacity credit of a wind power plant are based on a related reliability measure called the Loss of Load Expectation (LOLE) [4, 7]. The capacity credit goes into the long term adequacy considerations for the power system.