ENVIRONMENTAL NOISE ASSESSMENT CERRO DE HULA WIND PROJECT ENERGÍA EÓLICA DE HONDURAS, S.A. (EEHSA)

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1 -----CERTIFIED TRANSLATION----- I, the undersigned, Patricia Andrés-Carmona, Official Translator of the Ministry of Foreign Affairs of the Republic of Costa Rica, appointed by Agreement No AJ of April 15, 2002, certify that in English, the document to be translated reads as follows: IAS INGENIERÍA ACÚSTICA SPECTRUM, S.A. DE C.V. Gustavo A. Madero Mexico, D.F. Phone: Phone/Fax: FINDINGS REPORT IRA2-11-PE/hon/F EXECUTIVE ENVIRONMENTAL SUMMARY 1 ENVIRONMENTAL NOISE ASSESSMENT CERRO DE HULA WIND PROJECT ENERGÍA EÓLICA DE HONDURAS, S.A. (EEHSA) Municipalities of Santa Ana and San Buenaventura NOVEMBER 2011 NOVEMBER 2012 The digital version of this result report may not be modified. The client is hereby authorized to print it, and it will only be valid if complete. If more than one copy is needed, please get authorization from Ingeniería Acústica Spectrum, S.A. de C.V. to keep control of the number of copies. Translation into another language using any means is hereby forbidden Last line page

2 2 0. OVERVIEW 0.1 Company: Energía Eólica de Honduras, Sociedad Anónima ( EEHSA ) 0.2 Name of wind park: Cerro de Hula Wind Project 0.3 Final Report User: Scarleth Núñez-Castillo 0.4 Aerogenerators (AE): Brand Gamesa. Model G87. Number: Objective: To summarize the main aspects included in the environmental noise assessment at the Wind Park and present their findings. 1. METHODOLOGY 1.1 International References: Adaptation to the Official Mexican Standard NOM-081-SEMARNAT Which sets the maximum allowable limits of noise emissions from fixed sources and their measuring method to assess Wind Parks. The maximum allowable limits of noise emission are not applied. 1.2 Sampling Characteristics Sampling periods: November 2011; April, August, and November Location of the metering points: After the sensory recognition carried out in November 2011 and based on the technical meeting with EEHSA personnel, it was agreed to locate the sampling points in all areas of the AE groups, as well as to locate other points in the surrounding communities to collect field evidence. In other words, this allowed having evidence from all sound fields including those produced by the Wind Park and the various human activities in the area Meteorological conditions: During the assessment and acoustic data sample gathering period, the region presented varying climate conditions, temperature, relative humidity, rain, and wind speeds. Therefore, the findings take them into account, especially the primary energy source of the Wind Park, i.e., the wind speed. Four random samples designated by their climate conditions on the dates they were taken allow determining both the behavior of the noise emission on the basis of the wind speed Assay laboratory: The measurements and assessment of the noise emitted in the environment by the Wind Park was done by our Assay Laboratory which is accredited according to the Mexican Standard NMX-EC IMNC-2006 (ISO/IEC ) Last line page

3 1.2.5 Assessment method: The NOM 081 standard describes in general the methodology to assess noise emissions from a specific fixed source. In the case of a Wind Park, it is necessary to adapt the sampling times and the location of the metering points Two sampling periods, called Daytime from 07:00 to 20:00 hours and Nighttime from 20:00 to 7:00 hours, were set The main variable identified is the Equivalent Continuous Noise Level (Leq) with different sampling times. 1 10log m N 10 Leq 10 m 3 Where: Leq = Equivalent level per metering point (dba) N = Sound level A recorded at the i-th sample (dba) m = Number of samples per point In order to reduce the influence of wind speed in the Leq values, the values listed below were set for each metering point per run, metering period, sample number, sampling time, and total number of data set. DATE Nov. 11 Apr. 12 Aug. 11 Nov. 12 Number of Samples DAYTIME Sampling Time Sample Total (s) (min) METERING PERIOD Number of Samples NIGHTTIME Sampling Time Sample Total (s) (min) Because of security reasons for the Assessment Team and the Support Team, the sampling time was shorter at nighttime Sampling records were done automatically by the metering teams by saving them directly in the storing memory Last line page

4 Instruments used EQUIPMENT BRAND MODEL Series No. Real Time Analyzer (RTA), Class Integrating Sound Level Meter, Class Acoustic Calibrator, Class 1 1 LARSON-DAVIS CAL Acoustic Calibrator, Class 1 1 CAL Equipment with calibration certificate traceable to a national standard (Mexico) Instruments configured to simultaneously record: Acoustic Sound Level (ASL) Equivalent Continuous Noise Level (Leq) N 10, N 33, N 50, N 90 Acoustic Pressure Level (APL), (1/1 eighth band) Maximum Level, Minimum Level [sic] The AE groups are located as shown below. GROUP AE No. LOCATION Santa Ana, to the west of southbound road CA5 Nueva Arcadia, to the south of the road to San Buenaventura and to the west of the town of El Horno To the east of the southbound road CA5 and the west of the town of El Horno To the east of San Isidro de Hisopo In November 2011 and April 2012, the distribution of the metering points was as follows. Zone 1: At the perimeter of the AE base: 51 Zone 2: Close to the nearby receptors: In August and November 2012, given the increase in sampling time, the number of metering points decreased as follows. Zone 1: At the perimeter of the AE base: 12 Zone 2: Close to the nearby receptors: Last line page

5 Background noise: The background noise carried out by EEHSA before the assessment of the noise emitted by the Wind Park operation, allowed establishing a correlation between the metering point and the noise at the site, whether it is the natural site noise or that overlaid and generated by the interaction of the wind speed with the flora, the site topography, or intrinsic human activities [sic] The following values are considered to be background noise. Daytime Nighttime Location AE Group* (07:00-22:00) (22:00-07:00) Leq (1hr) L90 (10min) Leq (1hr) L90 (10min) M M M M M * Modification to the Original Table for the purpose of this Findings Report Field Calibration. The Integrating Sound Level Meter 831 and 824 were calibrated before and after each measurement at each metering point and sampling time. 1.2 [sic] Receptor Location Receptor location was determined using EEHSA s criteria. 2. FINDINGS 2.1 According to the objective of this Findings Report, only the findings about the Leq are included, but not those of the N 10, N 33, N 50, N 90, N max, and N min determined during the assessment of each of the sampling program stages of the Wind Park. 2.2 In order to validate the assessment, the sampling times in the runs in November 2011 and April 2012 were different from those of the runs in August and November In order to maintain a common referent in all stages, for the third and fourth stages a number of AE representing each Group were selected based on their closeness to the receptors. Thus, twelve AE were selected; using the same criteria, the metering areas at the receptors were selected Last line page

6 2.4 Table 1 [sic] [1.1 to 1.4] shows the Leq values determined during the four runs. Because of their closeness to the receptors zones, AE Groups 6 and 10 contributed two values each. Table 1.1 Daytime Leq AE Zone N AE Leq (dba) Group Nov. 11 Abr. 12 Aug. 12 Nov Table 1.2 Daytime Leq Receptor Zone N Receptor Leq (dba) Nov. 11 Abr. 12 Aug. 12 Nov Group NR Group Group 7 NR 49.3 NR Group Group Group Leq (dba) = Equivalent Continuous Noise Level in Decibels NR = No record -----Last line page

7 7 Table 1.3 Nighttime Leq AE Zone N AE Leq (dba) Group Nov. 11 Abr. 12 Aug. 12 Nov NR Table 1.4 Nighttime Leq Receptor Zone N Receptor Leq (dba) Nov. 11 Abr. 12 Aug. 12 Nov Group NR Group 3 NR Group 7 NR Group Group NR 49.7 NR Group NR Leq (dba) = Equivalent Continuous Noise Level in Decibels NR = No record 2.5 The wind speed in November 2011 and 2012 was similar and high. In April and August 2012, it was lower than in November. In April, it was higher than in August. This can be noticed in Table 2 [sic] [Tables 2.1 to 2.4]. 2.6 Graph U shows a comparison of the components of the Acoustic Pressure Level (APL, db) by frequency for a particular AE measured in the four runs Last line page

8 8 Table 2.1 Daytime Wind Speed. AE Zone No. AE Group Wind Speed S(m/s) Nov. 11 Apr. 12 Aug. 12 Nov NR NR NR NR NR NR 0.2 NR Average Table 2.2 Daytime Wind Speed. Receptor Zone No. Receptor Wind Speed S(m/s) Nov. 11 Apr. 12 Aug. 12 Nov Group NR 0.2 NR 14 Group Group 7 NR 2.5 NR NR 16 Group NR 17 Group NR NR Group NR 2.6 NR Average NR = No record -----Last line page

9 9 Table 2.3 Wind Speed Nighttime. AE Zone No. AE Wind Speed S(m/s) Group Nov. 11 Apr. 12 Aug. 12 Nov NR NR NR Average Table 2.4 Daytime [sic] [Nighttime] Wind Speed. AE Zone [sic] Receptor Zone No. Receptor Wind Speed S(m/s) Nov. 11 Apr. 12 Aug. 12 Nov Group NR Group 3 NR NR 15 Group 7 NR NR 16 Group Group NR NR 0.3 NR NR Group NR NR Average NR = No record 2.7 Graph V shows a comparison of the components of the Acoustic Pressure Level (APL, db) by frequency for the receptor area close to AE Group 10 measured in the four runs. 2.8 The metering of the Noise Level is the result of overlaying the noise generated by the AE and all other noise sources nearby which are natural and result from the impact of the wind on the flora and other obstacles as well as human activities Last line page

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12 In addition to the information available about the background noise, in November 2011 additional measurements were carried out in several points; these values, which are similar to those determined earlier, are presented in Table 3. Table 3. Background Leq per Metering Period (November 2011) Place Leq (Daytime) dba Leq (Nighttime) dba G06--AE G09--AE Transformer CONCLUSIONS 3.1 The audible perception factor derived from the environmental conditions, especially in a mountainous area, creates an important subjective factor for the population that judges and interprets a clearly new and different sound in the area. Therefore, even when noise levels are relatively low, they are easily identified. 3.2 The Leq values obtained are considered representative of an extreme and random environmental condition, but their repetition is feasible. In other words, this is a situation of special subjective perception given the collateral effects of the wind speed. 3.3 The following Table shows the conclusions of the noise assessment. November 2011 April 2012 August 2012 November 2012 The modifications to the NOM 081 In order to validate the sampling technique methodology are adequate both the metering times were modified. As a operationally and technically to obtain field sampling data and to describe the noise level under the wind speed conditions result, the number of metering points was reduced both in the AE zone and the receptor zone. necessary to operate the fixed source. The methodology modifications used in the first and second run produced similar noise level values. High wind speed conditions produced noise values higher than those detected in April and August Leq values found are independent from the sampling time. Low wind speed conditions produced noise level values similar during all runs. ----Last line page High wind speed conditions produced noise values similar to those detected in November 2011.

13 13 The sample size of the data collected allowed reducing the variability between the maximum and minimum values obtained offsetting the effect of the wind on the microphone. The maximum values (Nmax) are not significantly different from the Leq values. The transient high speed winds, >10 m/s, generate peaks. When assessed as Leq, the resulting value prevails. In the receptor zone assessed, human activities generate noises with magnitudes above those recorded in the AE zone. The longest record time allows capturing transient events (for instance, the passing of a vehicle, voices, domestic animal noises, work activities, etc.) in such a manner that they become a sequence of values that influence the results. Sound Level (As average Leq) of the Noise Issued (dba) AE ZONE, DAYTIME AE ZONE, NIGHTTIME RECEPTOR ZONE, DAYTIME RECEPTOR ZONE, NIGHTTIME The values shown above are the averages of all of the points assessed per zone. Two zones were created, one at the AE base and the other in the various areas where receptors subject to assessment were located. The presentation allows making a direct comparison of them by period, zone, and season. At the AE zone in both periods, the average arithmetic value in November is 58.8 dba, and, in the other two seasons, it is 52.2 dba. At the receptor zone in both periods, in November the average arithmetic value is 56.6 dba and, in the other two seasons, it is 50.8 dba. The noise levels detected in the November runs represent the environmental conditions of the season and their values are the result of an increase in the natural background noise produced by the flow of wind that prevailed during the metering period. This occurred regardless of the zone where the assessment was done. Under low wind speed conditions, the values obtained differ in up to 6 dba. These values are within the same magnitude as the values determined in the region when the Wind Park did not exit. ----Last line page

14 Background Noise Level (dba) 45 < Leq > 50 The magnitude interval above is based on the values determined in 2009 and during the assessment runs, measured during AE shutdown conditions or at points where no AE exist. It should be pointed out that in 2009 and 2012 the measures were taken under low wind speed conditions and in 2011 under high wind speed conditions. The noise level values assessed in the month of April are of the same magnitude as the background noise levels assessed at different times (2009, 2011) while using different metering techniques and two evaluators external to EEHSA. These noise levels are a result of overlaying three types of noise: a) The site s natural noises (wind flow, geographic position, topography), b) Background noise (resulting from various human activities), and c) The noise issued by a particular AE. This acoustic energy is dispersed from its origin to the metering site or auditory perception in the case of the receptors zone. The CERRO DE HULA WIND PROJECT owned by Energía Eólica de Honduras, Sociedad Anónima, complies with the Allowable Noise Emission Limit as it does NOT exceed the site s background noise in 3Dba. The subjective interpretation of the assessment Group while gathering data at various receptors, both in populated or urban areas and uninhabited and mountainous areas allowed establishing the multiple noise generating sources with an impact on the metering site. This has a theoretical support in the low frequency content of the spectrum recorded at each site. The auditory perception of the inhabitants of the sites assessed clearly identifies the AE sound. The habitual condition is to listen to noises inherent to the region or those common noises derived from human activities; this subjectively prevents masking the [AE] sound as it is new and foreign to what they are used to. Maximum Allowable Noise Emissions 55 dba during the day (07:00 to 22:00 hours) 45 dba during the night (22:00 to 07:00 hours) The background noise level must not be exceeded in 3 dba Last line page

15 15 4. RESPONSIBLE FOR THE REPORT Assay Laboratory of Ingeniería Acústica Spectrum, S. A. de C.V. 4.1 Participants OBSERVERS Name JUAN PABLO ORTIZ-AVILA Position Technician Name YULIANA ELVIRA SAUCILLO Position Engineer B OBSERVER / SUBSCRIBER Name LEON RODRIGO PEREZ-SEGOVIA Position Enginee A SUBSCRIBER / RESPONSIBLE Name JUAN ANTONIO ORTIZ-GARCÍA Position Director *** END OF THE REPORT *** [Copy of Mr. Ortiz s membership card and permit to exercise his profession] [Signature] IN WITNESS WHEREOF this translation from Spanish to English and which consists of 15 pages is issued in San Jose, Costa Rica, on August 06, The corresponding legal stamps are affixed and cancelled. [Hardcopy signed and stamped] PATRICIA ANDRÉS-CARMONA