Introduction

Solar power installed capacity has  increased from only 3.7 MW in 2005 to about 4060 MW in 2015.  Government of India has ambitious policy of solar expansion the capacity to 100 GW by 2022 through the implementation of solar parks,  ultra mega solar power projects, canal top solar projects and one hundred thousand solar pumps for farmers, solarisation of petrol pumps, etc. to minimize carbon emissions. Decentralised generation (DG) is the electric energy production at the distribution side of the power supply network or closer to the load center itself. Distributed energy generation can play pivotal role to meet the electricity demand in a reliable and environmental friendly way. Dispersed generation exploits locally available energy resources which will reduce the exploitation of conventional energy resources and also the congestion of generating units. DG based on RE sources promotes higher penetration of RE resources in the grid. DG plants have the unique advantage of operating in islanded mode (grid isolation mode), during the outage of the central grid. Grid connection can be restored as the grid is energized and electricity can either be transferred to the grid or drawn from the grid. Micro grids are the building units of dispersed generation, which essentially exploits locally available RE resources. Micro grid is an emerging technology and has evolved as smart grid with higher reliability, limited greenhouse gas (GHG) emission, reduced transmission and distribution (T & D) losses. Smart grid architecture is in the infancy stage, which integrates renewable energy based distributed generation with the conventional system using control strategies over a two-way communication link.

India has one of the biggest power supply networks, having the installed capacity of more than 243 GW. Though electricity is one of the cleaner energy forms, the generation is mainly dependent on thermal power plants (168.25 GW, 69%). Indian power sector recently witnessed one of the biggest blackouts (July 2012); peak power shortfall of 12,159 MW (9%) and energy shortage of 86,905 GWh (8.7%) during 2012-13 [1, 2]. Distributed electricity generation through renewable energy resources can help in strengthening the power system and also certainly reduces carbon footprint of energy generation. It reduces the line losses, improves the voltage profile, and enhances the system reliability, security and quality of power [3]. The associated economic benefits of DG are reduced operation and maintenance cost, increased productivity, reduction in fuel cost due to the exploitation of RE sources and increased efficiency. There are health benefits due to pollution control and the up-gradation of the current system can be avoided [4, 5].

India is blessed with very good renewable energy potential which is not exploited in large scale yet. Southern part of the country harvesting electricity mainly from hydro and limited coal resources (Navyeli in Tamil Nadu). The region has 3 metropolis (Bangalore, Chennai and Hyderabad) and many industrial, agriculture and commercial consumers, which are posing the higher peak load and energy demand to the grid. SRLDC is facing very high energy (59,297 GWh, 19.1%) and peak power (11,669 MW, 26.1%) crisis over the years, which led to decreased power quality and load shedding [2]. Many studies have described the application of renewable energy for decentralised generation [6, 7], as micro grid [8, 9] and standalone generation for remote area electrification [10, 11, 12]. Energy potential analysis using spatial data are also carried out by researchers which gave new avenue for energy research [13, 14]. However, most of the studies were done for a specified application in a region or for the cluster of villages. The present study analyses the solar energy potential for entire southern India, which contributes significantly in DG planning. Taluk wise RE resources assessment has been carried out considering the seasonal variability of the resources and clustering the high energy yielding regions. Solar energy potential of the region ranges from 5.2 to 6.0 kWh/m2/day annually. The excess electricity required in the region can be met using decentralised renewable energy based generation which also plays a significant role in energy independence and the region’s energy security.