4. Conclusions

turbine depends on the detailed wind data analysis of local site, which is beyond the

Finally, Table 7 shows the annual amount of pollutant gases emissions due to

Although the most optimal system solutions have already been explained in detail in above sections. But it is also of critical importance to briefly explain some

Multiple system solutions with LCOE superimposed over NPC (a) discount rate = 4% (b) discount rate = 6%

Figure 17 displays the graphical representation of power produced by PV panels in both cases. Both the images of Figure 17 indicate that summer is the ideal season for harvesting energy from sun in South Korea, as the average day-time is almost 14–15 hours in Deokjeokdo island. The average hourly power generated by PV panels in case of system A is 425 kWh whereas this value corresponds to 536 kWh

scope of current study; therefore not performed here.

Wind Solar Hybrid Renewable Energy System

operation of both systems.

for system B.

Figure 18.

178

(c) discount rate = 8%.

3.3 Sensitivity cases

The present study provides a basic information about the working methodologies of a hybrid renewable energy system (HRES) consisting of wind and solar as primary energy resources. Two case studies of HRES have also been included to further clarify the economic aspects of such energy systems.

First case study deals with the analysis of a small HRES consisting of wind turbines and PV panels with batteries as energy storage system (ESS). This small HRES is being installed at Deokjeokdo island in South Korea and its performance have been monitored for two consecutive years (2016 and 2017). Analysis showed that the prevailing wind direction at Deokjeokdo island is either north-east or south-west, with mean wind speed of 3.6 m/s at 10 m height. Similarly, average value of daily solar radiations was estimated to be 4.13 kWh/m2 with mean clearness index of 0.5. The total capacity of this small HRES is 6 kW; with two Darrieus VAWTs of 1.5 kW size each and 3 kW size of PV panels.

Second case study finds an optimum HRES to fulfill the yearly electricity demand of Deokjeokdo island, which corresponds to approximately 7.296 MWh/ year. Over 8760 simulations were performed to find out two optimum HRESs based on lowest NPC (system A) and lowest LCOE (system B), respectively. The overall NPC of system A was calculated to be 11.29 million USD, whereas for system B, it was 17.61 million USD. On the other hand, LCOE for system A was slightly higher than system B as it was 0.158 \$/kWh for system A and 0.123 \$/kWh for system B. Both systems can independently provide electricity to Deokjeokdo island throughout the year without any external assistance such as grid, etc.
