SUMMARY OF WIND TURBINE ENVIRONMENTAL IMPACT ASSESSMENT
INTRODUCTION
This report focuses on the environmental issues related to the construction of a 600kW class wind turbine on Lamma Island by Hong Kong Electric Corporation (HEC). The main source of information is the Environmental Impact Assessment (EIA), which was went online on 14th September 2004.
The EIA covers the choice of location, noise, ecology, dust, visual impact, wastewater, reduction of pollution from the main plant, permitting process and public information process. This report does not review technical issues or finance.
Construction of the wind turbine is scheduled to start in early 2005 and will last about 1 year. The design life is 20 years, which is only half that of the coal plant and gas turbines.
The wind turbine capacity was chosen as 600kW because it is a proven design, there are a large number of installed machines internationally of this class, it is the smallest size that is widely available and it is the maximum size that complies with the height restriction.
A study was undertaken which commenced in 1999 to determine the optimum location for the turbine. Initially both Po Toi and Lamma were reviewed, however the technical and environmental concerns related to Po Toi ruled out this option.
Although most sites with high wind levels are found on South Lamma, HEC did not consider constructing the turbine on the south side of Lamma because it is classified as a Site of Special Scientific Interest (SSSI) and is a potential country park. There are also problems with exporting power from this area.
Six sites were reviewed on North Lamma, with the optimal choice being Tai Ling, which is located on the north end of the easterly cable road, locally known as Cable Road 2. This location was selected because of its proximity to the existing cable road, ground conditions plus noise and visual impact.
NOISE
The noise produced by the wind turbine will be a low, constant and predictable sound. At the wind turbine the noise will be a pure, tone free 100dB(A). However 250m away the noise level will be less than 45dB(A), at this distance the noise created by the wind turbine will not be noticeable against the background noise, which is confirmed by the website.
According to the website http://www.lhh.org/noise/decibel.htm, 100dB(A) is equivalent to a motorbike, whilst 45dB(A) is barely louder than the noise in a quiet library.
Noise monitoring will not be performed during the construction phase although the installation equipment will be audited to ensure that it complies with the EIA assumptions.
For the first six months of operation, noise monitoring will be conducted once every fourteen days. Noise monitoring will be performed at night to reduce the background interference and only when the wind speed is greater than 5m/s.
The wind turbine location has been classified as having low ecological importance. The area is mainly shrubland with a small amount of shrubby grassland, which were observed as having been disturbed by human activity, with littering, dumping and the effects of hill fires being noticeable. No tree felling will be required during the construction period.
There are 14 species of conservation interest – 5 birds, 8 uncommon butterflies and 1 frog.
Three birds (Black Kite, Barn Swallow and Little Swift) were observed flying at a height of 10-100m in the turbine area during the site investigation. However the turbine location will not be in a main food area or on a migration path. International experience indicates that the birds will alter their habits to keep away from the blades.
The turbine is not expected to affect the butterflies, whilst no substantiation was provided it is assumed to be because they generally fly lower than the blades and will alter their habits.
The key land animal in the area is the Romer’s Tree Frog, which is only found in Hong Kong, primarily at Chep Lap Kok, Po Toi and Lamma, further information is provided at http://www.afcd.gov.hk/conservation/text/con_new/frog.htm However the poor vegetation and general dryness of the area make this a less desirable location for the frogs. The frogs will be relocated to a more suitable area before the start of construction.
There are four streams near the site with a total length of 1.1km. During the site investigation, little to no water was found in the streams, which indicates that they are of limited ecological importance.
There will be no monitoring during the construction phase, although installation activities will be audited to confirm they comply with the EIA assumptions.
Monitoring for bird collision will be performed during the operational phase on monthly intervals for 12 months. If there are 3 events of bird collisions during this period HEC will work with the government to implement remedial actions.
Dust will be the main pollutant during the construction phase, however during the operational phase the turbine will displace power generated by the power plant and the associated dust emissions. Dust will be produced during construction through excavation work and storage of materials at site.
The following measures will be implemented to minimize dust generation during construction:
No monitoring will be conducted, however weekly site audits will be undertaken to ensure that the mitigation measures are implemented.
The visual impact of the wind turbine has been minimized through site selection, however the residual impact can be summed up as “beauty is in the eye of the beholder”.
The turbine will not be visible from most locations on Lamma, however it will be visible from the pier, Pak Kok, Long Tai Tsuen beach and Tai Wan To beache. The turbine will be visible from South Hong Kong including the Peak, Ap Lei Chau and Aberdeen. However the distance from South Hong Kong means that this will not be an obtrusive view, furthermore the turbine will be painted non-reflective light grey to minimize the visual effect, as this colour will blend into the background during periods of medium to low visibility. To further minimize the environmental effect, trees, shrubs and hydroseeding will be performed at the site.
The required land area is 3100m2 of which 1400m2 will be replaced after construction, leaving a permanent displacement of 1700m2 of land. The wind turbine will sit on a plinth 15m by 15m (225m2), with an area 20m by 30m (600m2) required as laydown during construction and operation phases and an area of 10m by 3m (300m2) housing a transformer, switchgear and cabling. Interestingly the diameter of the blades is 52m, which is longer than the wind turbine plinth.
Civil Aviation Department has decreed that structures on north Lamma must not be greater than 165m above Hong Kong Datum point. The turbine will be installed at a location 90m above HK Datum point, which means that the capacity of the turbine is restricted to the choice of machines with a maximum rating of 600kW to 850kW.
During the construction phase the primary source of wastewater will be from pollutants in site run-off. Pollutants, mainly suspended solids, may also enter receiving waters if any pumped groundwater is not adequately controlled on site. The key periods will be during excavation work, backfilling and underground cable laying.
To minimize the potential wastewater the EIA recommends the following:
Monitoring will only be performed if required under the terms of the relevant construction license.
Water will not be required or produced during the operational phase.
The wind turbine is expected to generate 700MWhr per year, which will save the annual burning of 240 tonnes of coal. The EIA calculates that the reduction in coal consumption is estimated to result in the following emissions reductions:
The above figures have not been verified.
The generation of electricity by burning coal requires a lot of cooling water to return the exhausted steam back into water and so in addition to the above there will be a reduction of approximately 1100MWhr of thermal energy released into the sea per year.
As the turbine capacity is low, it is not expected that the machine will have a material effect on the boiler load and so the concerns raised in the HKE (ash) report will not be exacerbated.
The environmental conditions existing before site work commences, have been measured and collated to produce the Baseline Monitoring Report. The information in this report will form the basis of future monitoring.
Upon approval of the EIA, HEC can apply for an environmental permit, which typically has conditions attached to it that HEC and the contractor must comply with in addition to all environmental legislation and guidelines.
HEC has also produced an Environmental Monitoring and Audit (EM&A) Report, which will be submitted with the EIA to the Environmental Protection Department. The manual defines how to implement environmental monitoring and auditing including frequency and resources. The results of monitoring will be used to produce a monthly EM&A report.
As part of the environmental compliance, the contractor is required to produce an Environmental Management Plan, to ensure that this is produced and of a suitable quality, HEC will require submission of a draft report as part of the tender process.
The Baseline Monitoring Report and Monthly EM&A reports will be available to the public on line via the Environmental Impact Assessment Ordinance (EIAO) Internet website and at the EIAO Register Office no later than 2 weeks after the monitoring data are collected or become available.
Due to the expected large amount of interest from the government, media and the public, HEC will set up special procedures to deal with the correspondence. A dedicated Environmental Team (ET) will be developed with a Team Leader, the process will be:
The above procedures appear to be a good method for dealing with complaints, however this will not be verified until the construction phase commences.
The EIA has thoroughly reviewed all environmental concerns related to the installation and operation of a 600kW class wind turbine. The findings of the review are that it will have minimal negative effect of the environment.
Whilst the noise level at the turbine will be high, it will quickly decrease to an acceptable level.
Sufficient measures have been developed to minimize wastewater and dust emissions during the construction phase and these will not be created during the operational phase.
The location, colour and landscaping measures mean that the turbine will not be obtrusive. Many residents are expected to consider that the wind turbine fits well with the environment.
Site investigations indicate that the turbine location is of low ecological value. Furthermore the site is not on a bird migratory path or a significant feeding ground. Therefore there is expected to be minimal negative impact on the local ecology.
The wind turbine will displace an equivalent quantity of coal-generated power with associated emissions, has minimal negative environmental impact, will provide the basis for additional renewable energy installation in Hong Kong and encourages greater environmental awareness. Therefore from a purely environmental perspective it is recommended that this project be advanced and that the Lamma residents support the project.