Dissemination of off-grid hybrid wind-diesel-battery power systems for electrification of isolated settlements of hot regions

Since the maturing of the wind farm industry, attention has been focused on the use of wind turbines for electricity production in remote areas. Generally, remote villages are driven by diesel generators. However, introduction/dissemination of wind energy conversion systems (WECS) into the existing diesel systems results in the reduction of the diesel fuel consumption and eventually allows atmospheric pollution to subside. A short-term energy storage integrated with wind-diesel system may compensate for fluctuations in the power output of the wind turbine and raise the fuel saving potential. The Kingdom of Saudi Arabia's (K.S.A) area is large, with large number of villages/settlements scattered all over the Kingdom. In the present study, hourly mean wind-speed data recorded at an airport, K.S.A., has been analyzed to investigate the technical and economic feasibility/viability of utilizing off-grid hybrid (wind-diesel-battery) power systems to meet the load requirements of a typical remote/isolated village with annual electrical energy demand of 13,244 MWh. The airport is located in the vicinity of the candidate settlement. The hybrid systems simulated comprise of various combinations (wind farms) of 600kW commercial WECS supplemented with diesel generators and a short-term battery storage. The amount of battery storage capacity has been varied from 0 to 60 load minutes (equivalent to 0-60 min of average load). National Renewable Energy Laboratory's (NREL's) HOMER software has been used to perform the technical and economic analysis of hybrid wind-diesel-battery power systems. The investigation indicates that for a hybrid system consisting of 3.6MW (six 600kW wind machines, 50m hub-height) wind farm capacity together with 4.5 MW diesel system (three 1.5 MW diesel units) and a battery storage of 30 load minutes (equivalent to 30 min of average load), the wind penetration is 24%. The cost of generating energy from the above hybrid configuration has been found to be 0.078 US$/kWh (assuming a diesel fuel price of 0.1 $/liter). The simulation results highlight that the number of operational hours of diesel generators in wind-diesel system decreases with increase in wind farm capacity. The study also illustrates that for a given hybrid wind-diesel system, the decrease in diesel run time is further enhanced by inclusion of battery storage capacity. An attempt has been made to address the effect of wind penetration, effect of hub-height on energy production, cost of wind-diesel-battery systems, cost of energy production, excess electricity, un-met load, percentage fuel savings and decrease in carbon emissions, etc (for different scenarios such as wind-diesel without storage, wind-diesel with storage, as compared to diesel-only situation).