Optimal Hybrid Power System Using Renewables and Hydrogen for an Isolated Island in the UK

摘要

A distributed electrical power system using renewable generations (RG) on an island was studied. The original system includes micro hydropower stations, wind turbines and solar PVs with a bank of batteries for storage of the extra power from the renewables; and two diesel generators were used as the back-up units. From the analysis of historic electricity generation and consumption data, it was found that the RG alone could not meet the total demand and the diesel generator(s) needed running occasionally in 8 months in one year. In order to make the electric power supply completely from renewables, one novel solution using hydrogen generated from extra renewable electricity to replace diesel as the fuel for the diesel generators was proposed, i.e. a sub-system of renewable hydrogen generation (RHG), which composed of extra wind turbines, a water electrolyser and a hydrogen storage tank, were added to the renewable system. A technical and economic performance evaluation of the RG system was carried out using HOMER software. The results showed that the RHG sub-system produced and stored enough hydrogen for the diesel generator(s) to generate electricity whenever needed. In this way, the power supply on the island will be completely from renewables and zero CO2 emission without using diesel. The cost of electricity (COE) of the new system was ￡0.776 per kilowatt hour.