Delegates are invited to meet and discuss with the poster presenters during the poster presentation sessions between 10:30-11:30 and 16:00-17:00 on Thursday, 19 November 2015.
Lead Session Chair:
Stephan Barth, ForWind - Center for Wind Energy Research, Germany
Sílvia Mesquita (1) F Miguel Mascarenhas (1) Joana Marques (1) Ricardo Ramalho (2) Celso Costa (3) Miguel Ferreira (3)
(1) Bioinsight, Odivelas, Portugal (2) Bioinsight South Africa, Cape Town, South Africa (3) Megajoule, Maia, Portugal
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Presenter's biographyBiographies are supplied directly by presenters at EWEA 2015 and are published here unedited
Nuno Salgueiro graduated in Biology and holds a Post-Graduation in Environmental Sciences and Technologies. During his professional career, he has acquired large technical experience on ecological impact assessment and developed numerous ecological monitoring programs. Lately, his focus has been on project and team managing, seeking the best solutions for our client project development regarding ecological values. He joined Bioinsight in 2014 has production manager, contributing with his expertise on environmental consulting.
PosterDownload poster (9.02 MB)
Minimizing bat curtailment costs: an approached tailored to your investment
Despite the efforts one can make during the development phase of a wind project to avoid areas and/or habitats with high bat activity (micrositing), the high degree of uncertainty regarding the significance of the residual negative impacts frequently urges environmental authorities to request the implementation of operational curtailment of wind turbines when environmental conditions correlate with higher bat activity. And in fact, recent research has documented significant reduction of bat fatalities with specific operational curtailment by raising factory cut-in speed.
However these results have been interpreted ad hoc by environmental scientists, transposing these specific findings to their proposed wind projects with different environmental and ecological conditions. Given the unique conditions of each site, both from the environmental framework to the project technical specificities, ad hoc recommendations of operational curtailment often lead to unnecessary losses on productivity with little to no effectiveness in reducing negative impacts on bat populations.
Maximize sustainability of wind projects while mitigating negative impacts on bat populations is possible by designing site specific operational curtailment. To do so we optimized pre-construction bat monitoring programme experimental design and data collection, integrated our results with the wind resource assessment and determined site specific operational curtailment measures.
Main body of abstract
Through the analysis of the data collected during the pre-construction monitoring programme of a wind project near Durban, KwaZulu-Natal, South Africa, we were able to characterize bat activity and assess impact risk caused by the proposed implementation of 39 wind turbines with hub height between 95m and 120m and rotor diameter between 90m to 120m. During 1-year period bat passive detection was conducted at rotor height using automated ultrasound detection systems (Song Meter SM2BAT+© Wildlife Acoustics) installed at the two met mast available on site. Detectors were equipped with omni-directional weather resistant microphones and set to automatically record bat calls every day, from sunset to sunrise. Data collected was analysed using AnalookW 4.1d©. Bat activity was isolated from ambience noise through automatic filters in which the number of bat pulses and bat passes was quantified per unit of time (hour).
Based upon the wind speeds observed, in correlation to bat activity, season and hour of the day, two scenarios were established to study different curtailment strategies: i) night curtailment; ii) seasonal hour-specific curtailment. Additionally, a no-curtailment scenario was set as the benchmark. The long term representative wind distribution, obtained from local measured and modeled wind data, was divided in several periods according to the different curtailment strategies of each scenario. The production was estimated for each of these periods, applying an operation curtailment to the cut-in speeds of every wind turbine in the layout. Finally, the accumulated annual energy production was compared between scenarios, using the no-curtailment production estimate as the benchmark.
Simulations obtained showed a reduction in annual production losses up to 40% by implementing a site specific operational curtailment in comparison to general curtailment recommendations, safeguarding up to 90% of the bat activity detected on site throughout the year.
The most commonly proposed mitigation measure is the implementation of operational curtailment of wind turbines when environmental conditions correlated with higher bat activity. By relating bat activity to predictive environmental variables, such as wind speed, season and hour of the night, a simulation of the annual production losses was conducted by comparing a general operational curtailment scenario to a site-specific operational curtailment scenario. Simulations allowed us to choose as the most cost effective curtailment scenario the implementation of a season hour-specific curtailment with a bat activity safeguard up to 85% and an annual production loss of 2,4%.
A robust bat pre-construction monitoring programme combined with a co-relation analysis between bat activity and the predictive environmental variables can make a substantial difference when mitigation measures such as operational curtailment need to be accomplished. Our work shows that it is possible to simultaneously safeguard bat activity while minimizing production losses.