Korean government made “Act on the Promotion of the Development, Use and Diffusion of New and Renewable energy” and enforce to new and renovation buildings of governments and those subsidiary agencies as a duty from 2004 [1], because Korea has imported more than 97% of fossil energies from overseas for decades. As the result of this act, many facilities which utilize the various renewable energies have been installed and are successfully in operation. The 3 top renewable resources to have been used are solar heat, solar photovoltaic and wind [2]. It is reported that solar heating system is normally installed in individual buildings, especially residential buildings, and the solar photovoltaic and wind power generation systems are normally being operated based on commercial profits with huge power generation capabilities per site.

But even though Korea is surrounded by ocean and there are over 3,100 islands in Korea, the voices from islands’ and coastal areas’ habitants are out of concerns for this business, because the electric loads are too small comparing to urban. And also the energy supply networks from the mainland to the islands are very simple and unique. Therefore, to make the energy supply network multiple and improve the habitants’ living conditions, it can be an option to design and install any kinds of renewable energy facilities on these areas. Because the islands and coastal areas are fully exposed to nature, the conditions of wind and solar are evaluated as better qualities than elsewhere and very good to introduce the facilities.

On the other hand, the time-based variations of wind and solar radiation cannot be predicted and the patterns of 2 resources are quite different [3], so the hybrid power generation system will be a good proposal.

The purpose of this case study is to build up a set of database of wind and solar radiation, which will be used for hybrid power generation system design. To build up a set of the database and estimate the effectiveness, not only the wind and solar radiation resources but also the power generation quantities are measured, respectively.

Figure 1 
Location of Yeongdo and KMOU in Busan, Korea [4]

Although Yeongdo is a district of Busan metropolitan, Korea, she is an island connected with mainland with only 3 bridges as shown in Figure 1. Figure 2 shows the location where the measurement equipment is located, where is 2^nd campus of Korea Maritime and Ocean University (hereafter, abbreviated as KMOU). This place is selected because there are no obstacles like buildings or artificial structures around the equipment, as partially shown in Figure 4.

From June to July of 2013, the measurement was conducted. The following items were measured by 1 minute intervals.

- Outdoor weather conditions: dry temperature, relative humidity, rainfall etc.

- Renewable energy resources: wind, solar radiation

- Generated power: wind power, solar photovoltaic

As the wind and solar radiation is seriously and mutually affected by the outdoor weather conditions, the outdoor weather conditions were also measured on real time base. To monitor and get the outdoor weather conditions, wind and solar radiation, Vantage pro2 Weather Stations [5] was used.

The hybrid power generation system for experiment is installed the above mentioned place as shown in Figure 4 and Figure 5. The circled numbers in Figure 5 represents ①Data Acquisition (Graphtec GL820), ②Control panel, ③Inverter, ④Weather monitor, ⑤Storage battery.

Figure 2 
Location of measuring place at second campus of KMOU [4]

Figure 3 
Parts of Weather Station [5]

The hybrid power generation system has totally 660W capacity, which consists of 2 units of 130W solar photovoltaic and 300W wind turbine. The single unit of solar photovoltaic weights 12.3kg and 1,500mm×680mm×38mm size, and it has 36 cells in 49 matrix connected in series. The rated voltage of the wind turbine is 12/24volts (selectable option). The wind turbine has 3 blades of which the rotating diameter is 1,200mm and starts up from 1.5 m/s at least.

The generated power, voltage and current of wind power and solar photovoltaic are monitored by data acquisition system after transformed by the inverter, respectively.

Figure 4 
External appearance of hybrid power generation system

Figure 5 
Internal appearance of hybrid power generation system

The purpose of this case study is to build up a set of database of energy resources, especially focused on the wind and the solar radiation, for the first step to be used as a hybrid power generation system design. Some results from this study can be summarized as followings.

1) The wind mainly flows from southwest and at the average speed of 2 m/s during June and July 2013. Because the wind velocity was low, the wind quality to generate the power seems not so good at this island.

2) Solar radiation was measured every day time (6:00~19:00) and the peak solar radiation occurred around 12:00~14:00.

3) It is clear that the quantity of wind power generation vs. wind velocity, the quantity of solar photovoltaic vs. solar radiation were proportional each other, respectively.

4) The patterns of each power generation are very different. This means that these 2 natural energies can be combined as sources of a hybrid system, because these 2 patterns are not overlapped so much on time base.