<strong>Wind</strong> <strong>Energy</strong> <strong>Resource</strong> <strong>Atlas</strong> <strong>of</strong> <strong>the</strong> <strong>Philippines</strong> These reports represent a good starting point in understanding <strong>the</strong> wind resource in <strong>the</strong> <strong>Philippines</strong>; however, <strong>the</strong> studies do have some significant limitations: • The conclusions are based on <strong>the</strong> data from only 35 stations. • There is no information on <strong>the</strong> exposure <strong>of</strong> <strong>the</strong> instruments at <strong>the</strong>se 35 stations. This type <strong>of</strong> knowledge is extremely useful in judging <strong>the</strong> quality <strong>of</strong> <strong>the</strong> data used in <strong>the</strong> study. • There is no information regarding <strong>the</strong> quality <strong>of</strong> <strong>the</strong> measurements at each <strong>of</strong> <strong>the</strong> sites. Failure to properly maintain <strong>the</strong> anemometer, location changes, urbanization, and vegetation changes surrounding <strong>the</strong> anemometer site affect <strong>the</strong> measurements. • The analysis did not take into account <strong>the</strong> topography <strong>of</strong> <strong>the</strong> archipelago or o<strong>the</strong>r factors that may accelerate or retard <strong>the</strong> wind. 5.2.2 National Power Corporation NPC conducted a wind-resource-measurement program by placing towers with wind-speedmeasurement equipment at various sites in Luzon, Batanes, Catanduanes, Romblon Island, Cuyo Island, and Guimaras Island. These were <strong>the</strong> general locations <strong>of</strong> <strong>the</strong> better wind resource areas from <strong>the</strong> previous PAGASA studies. At nine <strong>of</strong> <strong>the</strong> sites, <strong>the</strong> wind-resource-measurement equipment consisted <strong>of</strong> NRG Systems 30-m-tall towers, NRG Systems 9200 data loggers, Maximum #40 wind speed sensors, and #200P wind direction sensors. The general location <strong>of</strong> <strong>the</strong> monitoring sites is presented in Figure 5-4. Two levels <strong>of</strong> wind speed and two levels <strong>of</strong> wind direction (20 m and 30 m) were installed on each tall tower. The sampling rate was every 2 seconds, and <strong>the</strong> data were averaged into hourly values. For <strong>the</strong> o<strong>the</strong>r five sites, we used a shorter tower, ei<strong>the</strong>r 12-m or 15.5-m, and <strong>the</strong> data acquisition equipment is not identified. The monitoring sites are installed in eight specific areas: Ilocos Norte (7 sites), Mountain Province (1 site), Guimaras Island (1 site), Romblon Island (1 site), Catanduanes (1 site), Cuyo Island (1 site), and Batanes (1 site). A description <strong>of</strong> each site is presented in Table 5-2. Seven <strong>of</strong> <strong>the</strong> sites are in <strong>the</strong> northwestern portion <strong>of</strong> Luzon, along <strong>the</strong> coast and in <strong>the</strong> coastal hills. The hourly wind speed and wind direction data were available for Bayog, Pagali, Saoit, Agaga, Bangui, Caparispisan, Subec, Sagada, and Guimaras. <strong>NREL</strong> processed <strong>the</strong>se data to produce estimates <strong>of</strong> monthly average power and monthly average wind speed, as well as average speed and power by hour <strong>of</strong> <strong>the</strong> day, and joint frequencies <strong>of</strong> wind speed and wind direction (see Appendix A). The annual average wind speed and power for <strong>the</strong> 30-m sites are presented in Table 5-3. The monthly average wind speed and wind power for three sites—Pagali, Sagada, and Guimaras Island—are presented in Figures 5-5 to 5-7. Due to <strong>the</strong> short collection period at all NPC sites, some months are underrepresented relative to o<strong>the</strong>rs (see plots <strong>of</strong> ‘Observations by Month’ in Appendix A). Averaging all records can bias <strong>the</strong> average towards those months with more records. To eliminate this bias, all annual averages reported here were computed by averaging <strong>the</strong> 12 monthly values. Some <strong>of</strong> <strong>the</strong>se monthly values may have been derived from data from 2 years, while o<strong>the</strong>rs represent only a single year. The sites at Bayog, Pagali, and Saoit are located on <strong>the</strong> northwest coast <strong>of</strong> Luzon near <strong>the</strong> town <strong>of</strong> Burgos. The site maps provided by NPC indicate that Bayog and Pagali are along <strong>the</strong> coast, while Saoit is located on <strong>the</strong> inland hills. Annual wind speeds at 30 m above ground level were 5.6 m/s at Saoit, 6.9 m/s at Bayog, and 7.2 m/s at Pagali. There are significant differences in <strong>the</strong> magnitude <strong>of</strong> <strong>the</strong> wind speed between <strong>the</strong> months with <strong>the</strong> highest and lowest average wind speeds. For example, at Bayog <strong>the</strong> highest monthly average wind speed is 12.4 m/s (December), while <strong>the</strong> lowest value is 4.0 m/s (June). At Saoit, <strong>the</strong> highest value is 9.0 m/s (December), and 20
21 <strong>Wind</strong> <strong>Energy</strong> <strong>Resource</strong> <strong>Atlas</strong> <strong>of</strong> <strong>the</strong> <strong>Philippines</strong> <strong>the</strong> lowest is 3.7 m/s (June). At Pagali, <strong>the</strong> highest value is 11.9 m/s (December), and <strong>the</strong> lowest is 3.6 m/s (June). For Bayog, Pagali, and Saoit, <strong>the</strong> annual average wind powers are 510 W/m 2 , 569 W/m 2 , and 266 W/m 2 , respectively, with <strong>the</strong> highest values occurring in December and <strong>the</strong> lowest values in June. The sites at Agaga, Caparispisan, and Subec are also located in northwestern Luzon, north <strong>of</strong> <strong>the</strong> town <strong>of</strong> Laoag. The Agaga and Subec sites are located on interior hills, while Caparispisan is on Figure 5.4 General location <strong>of</strong> <strong>the</strong> National Power Corporation monitoring sites in <strong>the</strong> <strong>Philippines</strong>
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