Economic feasibility of a hybrid energy system for Kalpitiya peninsula from selected technologies

Abstract

Economic feasibility of having a grid connected hybrid energy system, consist of wind, solar, biomass (rice husk) & municipal solid waste (MSW) technologies for Kalpitiya peninsula was studied. Four (04) different microgrid configurations were simulated in HOMER Pro(Hybrid Optimization of Multiple Electric Renewables) for a project life time of 20 years and the economics of each case was compared with the base case, where Kalpitiya peninsula is fed from fossil fuel based (i.e.: diesel) power transmitted through main utility grid. Electricity demand data of Kalpitiya peninsula in every 30 minute interval throughout a day were obtained for the days in calendar year (2018) from Puttalam grid substation (feeder 03) to derive averaged hourly load profile and to study the daily, monthly variation. Average electricity demand in April was found to be the highest of all months in the year and average load in a typical day was 125056.52 kWh with a daily maximum of 8320.5 kW. Considering the recent global market costs trends of installation, operation and maintenance of renewable energy resources as well as the availability of resources, in Sri Lankan context four (04) different configurations of microgrids were simulated in HOMER Pro with the motive of ensuring 100% power supply throughout the project lifetime of 20 years. Most economical option in a private investors’ perspective was a microgrid with wind, solar, biomass (rice husk) & municipal solid waste (MSW) in the system which has a discounted payback period of 2.68 years. However, in the perspective of Ceylon Electricity Board, the most economical microgrid consist of wind, solar & biomass (rice husk), where annual cost saving against the base case of LKR 350.5 Mn equivalent to ‘stop running’ a 1 MW diesel generator for 353 days per year. Sensitivity analysis was performed limiting the grid sales for each microgrid configuration proved that net energy purchase was lowest when the grid sale capacity was 10000 kW. Any of microgrid combinations was not possible to operate in island mode due to the intermittency of renewable resources. However, it was evident that none of the configurations considered solar energy is significant due to the high dominance in wind, biomass & MSW resources.