Optimal sizing methodology for a stand-alone and grid connected PV-biomass hybrid energy system that is serving the electricity demand for a complete village is discussed in this paper. The least levelised cost of energy while minimising annualised cost of system is done using BAT algorithm. This method is ascendable which can be used in any test system. It is proved from the results that grid connected hybrid PV-biomass energy system is cost effective and better choice when compared with stand-alone hybrid PV-biomass energy system. The proposed system is giving more reliable and affordable results for electrification of a village from its natural resources. The comparison of results for ABC algorithm with BAT algorithm is done in this paper. In this paper it is concluded that BAT algorithm is giving best results when compared with ABC algorithm alone. Keywords: ACS (Annualised Cost of System), NPC (Net Present Cost), LCOE (Levelised Cost of Energy) ABC (Artificial Bee Colony) Algorithm, Bat Algorithm I.INTRODUCTION The National grid of India has an installed capacity of 331.11GW as on 31 October 2017 [1]. In the total installed capacity around 31.7% is generated through the renewable resources. The average electricity usage is around 1,122KWh per capita for the year 2016-17. A total of 12288.83MW of solar power and 8182MW of biomass power is generated up to March 2017. Around 8846 remote villages were electrified using renewable energy systems by MNRE [2].Punjab shares only 1.4% of total geographical area of India but produces 17% of wheat, 11% of rice of India's total production. It also produces 12% of cereals produced in the country [3][4][5][6][7]. It can generate a total of 3172MW of biomass power through crop residues and 36.9MW through forest residue. This not only generates less pollution emitting biomass fuel and also reduces the air, soil pollutions along with human health hazards due to burning of crop residues in open farm lands [9,19].Power management, reliability and economic cost of energy are the three main issues while designing a renewable based hybrid system. For planning an effective and economic hybrid system the designed system should be optimal in terms of sizing and controllability. For rural electrification solar and biomass are having greater advantage when compared with other sources of energy. Various solar and biomass energy based systems are explored by various researchers. Off-grid renewable hybrid energy sources is one of the most adopted techniques. Because of the intermittent nature of the renewable energy sources integration to grid is a difficult task. But when connected it discards the usage of batteries and diesel generator [20].The authors [21][22][23][24] proposed different nature inspired algorithms for distributed generation placement. The mathematical modelling of the grid connected PV-biomass system is done in this paper and provides the cost analysis for the system. Bat inspired algorithm is a meta heuristic optimization algorithm developed by Xin-She Yang ...