Wind Energy Resource Atlas of the Philippines - NREL

Wind Energy Resource
Atlas of the Philippines
These reports represent a good starting point in understanding the wind resource in the
Philippines; however, the studies do have some significant limitations:
• The conclusions are based on the data from only 35 stations.
• There is no information on the exposure of the instruments at these 35 stations. This type of
knowledge is extremely useful in judging the quality of the data used in the study.
• There is no information regarding the quality of the measurements at each of the sites.
Failure to properly maintain the anemometer, location changes, urbanization, and vegetation
changes surrounding the anemometer site affect the measurements.
• The analysis did not take into account the topography of the archipelago or other factors that
may accelerate or retard the 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 the general locations of the better wind resource areas
from the previous PAGASA studies. At nine of the sites, the wind-resource-measurement
equipment consisted of NRG Systems 30-m-tall towers, NRG Systems 9200 data loggers,
Maximum #40 wind speed sensors, and #200P wind direction sensors. The general location of
the monitoring sites is presented in Figure 5-4. Two levels of wind speed and two levels of wind
direction (20 m and 30 m) were installed on each tall tower. The sampling rate was every 2
seconds, and the data were averaged into hourly values. For the other five sites, we used a shorter
tower, either 12-m or 15.5-m, and the 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 of each site is presented in Table 5-2.
Seven of the sites are in the northwestern portion of Luzon, along the coast and in the coastal
hills. The hourly wind speed and wind direction data were available for Bayog, Pagali, Saoit,
Agaga, Bangui, Caparispisan, Subec, Sagada, and Guimaras. NREL processed these data to
produce estimates of monthly average power and monthly average wind speed, as well as average
speed and power by hour of the day, and joint frequencies of wind speed and wind direction (see
Appendix A). The annual average wind speed and power for the 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 the short collection period at all
NPC sites, some months are underrepresented relative to others (see plots of ‘Observations by
Month’ in Appendix A). Averaging all records can bias the average towards those months with
more records. To eliminate this bias, all annual averages reported here were computed by
averaging the 12 monthly values. Some of these monthly values may have been derived from
data from 2 years, while others represent only a single year.
The sites at Bayog, Pagali, and Saoit are located on the northwest coast of Luzon near the town of
Burgos. The site maps provided by NPC indicate that Bayog and Pagali are along the coast,
while Saoit is located on the 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 the
magnitude of the wind speed between the months with the highest and lowest average wind
speeds. For example, at Bayog the highest monthly average wind speed is 12.4 m/s (December),
while the lowest value is 4.0 m/s (June). At Saoit, the highest value is 9.0 m/s (December), and
20