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What happens when a high-tech industry meets environmentalism? This seemingly intractable conflict is the challenge faced by those who support a global shift toward green energy.
As an abundant and inexhaustible natural resource, few question wind power’s status as one of the most sustainable ways to generate electricity. Yet the environmental impact associated with the industry remains a point of debate – especially the CO2 emissions during the extraction of raw material and turbine disposal. Improving the environmental performance of products and their impact throughout their entire lifecycle is one of Siemens’ main drivers.
Nature has been around forever and it will be here long after we are gone.
The environmental impact of Siemens wind turbines is calculated based on Lifecycle Assessments (LCAs). The LCA not only determines and evaluates the ecological footprint of our products and solutions, but also looks at every step from the raw material extraction and materials processing, from manufacturing, installation, operation, and maintenance to dismantling and end of life. In this way the LCA helps our experts identify areas of improvement.
The results of the LCAs are the basis of our environmental product declarations (EPDs) and support product development. Through this, we help our customers improve their current and future environmental impact. There are EPD examples for all turbine types – geared and direct drive for onshore and offshore: SWT-2.3-108, SWT-3.2-113, SWT-4.0-130, and SWT-6.0-154.
Electricity produced by wind turbines contributes significantly less to global warming than electricity produced by fossil fuels. To examine how much each stage of the wind power plant's life cycle contributes to global warming, we assessed their specific CO2 emissions.
payback time for a wind turbine
We collected data from Siemens’ own production sites and from main suppliers. Consumption data for manufacturing as well as waste and subsequent treatment is based primarily on annual manufacturing data from European production sites. Transport of materials to the manufacturing site is included in the data. Percentage of global warming contribution from this life cycle stage: 8%
On-site installation includes preparing the site, erecting the turbines, and connecting the turbines to the grid. These installation activities result in the consumption of resources and production of waste. Percentage of global warming contribution from this life cycle stage: 5%
The structural design lifetime of a Siemens 2.3 MW wind turbine is designed to last 20 years. Manpower, materials, and energy required for service and maintenance over the turbine’s lifetime are taken into account. There are almost no emissions during wind power plant operation. The percentage of global warming contribution from this life cycle stage is 2%.
At the wind power plant’s end-of-life the components are disassembled and the materials transported and treated according to different waste management systems. There is an offset to emissions at end-of-life because a large part of the materials is recyclable. The percentage of global warming contribution from this life cycle stage is -20%.
Effects on Wildlife
Next to the environmental impact associated with carbon emissions, wildlife topics are also heavily debated, since wind power plants often exist in animals’ habitats. Siemens is aware of – and takes very seriously – its responsibility to the environment. In close cooperation with customers, business partners, and federal governments, we are always on the lookout for innovative technology solutions to place us at the vanguard of environmental protection measures.
On some occasions, onshore wind power is blamed for the death of bats, birds, and other flying species – supposedly killed by turning rotor blades. But according to recent studies and research reports, the danger of turning rotor blades for most bird species is extremely low and the increasing death rate of birds is actually caused by climate change, human activity, or wild and domesticated predators. To ensure protection for birds and bats, Siemens turbines can be equipped with a special feature.
Depending on the time of day or the season, the wildlife bat schedule stops the turbine when there is an increased risk of, for example, bats flying in the turbines’ vicinity.
Offshore wind power is a cornerstone of the desired transition toward renewable energy. But nature conservation associations, foundations, and media refer to the possible risk to marine life from offshore wind power plants – especially to the harbor porpoises found in the North Sea, which are affected by noise from the pile drivers used when offshore wind power plants are installed, and any further noise pollution from machinery operations.
There are two different methods we use to ensure the reduction of noise pollution while installing offshore wind parks. The first option is the bubble curtain. This method uses two hoses with holes, laid out around a pile to be installed. A compressor pumps air into these hoses, so the bubble ascends – thus restricting sound emission. Based on this simple but effective idea, the hydro sound damper is another feature that reduces noise. It resembles a fishing net wrapped around a pile from the top down to the seabed. Inside this net are balloons and foam material pieces in various sizes and shapes. Due to their different characteristics, these elements soften the sound in different frequencies.
In addition to lowering the noise level when installing traditional offshore wind power platforms, which are mounted into the seabed, new ways to build the foundation itself have been developed: suction buckets and floating wind farms.
Suction buckets consist of a three-legged jacket structure standing on three giant buckets. Once the jacket has been lowered onto the seabed, pumps are used to create a pressure differential inside each bucket – and this, together with the weight of the structure, forces it into the ground. The jacket does not need to go as deep as the traditional piles, and the pumps used are much quieter than the sound that is usually generated by pile drivers. Suction buckets were successfully used for the Borkum Riffgrund 1 wind farm.
With floating wind farms, such as the Hywind projects driven by the Norwegian energy company Statoil, the concept is taken even further. Rather than bottom-fixed foundations, floating steel tubes are used. These tubes are filled with ballast and tethered to the seabed – the individual turbines are moored by catenary cables connected to a single spar buoy. In addition to softer volumes, floating wind farms enable the exploration of new offshore locations with even higher wind speeds – since great depth is no longer a problem for installing a farm at a particular location.
Effects on Humans
Even though society asks for more green energy, carbon footprints and threats to wildlife aren’t all that is discussed when the negative aspects of wind power are put forward. When it comes to installing wind turbines in their neighborhood, people often have a lot of prejudice and doubt. This is a topic that Siemens takes seriously.
There is a range of rules, restrictions, and administrative procedures that have to be taken into account even before a wind power project can start. In general, well-designed permit and siting procedures for the installation of projects keep costs down, allow for better return on investment, and drastically reduce the likelihood of conflicts with local communities.
National authorities are mindful of the development of wind farms in their planning policies for wind energy projects. The decisions on siting should always be made with consideration for and in consultation with other land users to avoid conflicts from the very beginning. Regional and local land use planners must decide whether a permit is compatible with existing and planned adjacent uses, whether a wind power project will negatively modify the overall character of the surrounding area, whether it will disrupt established communities, and how it will be integrated into the existing landscape. Phenomena like shadow flicker can be calculated prior to construction and turbines can be sited to minimize impacts on residences.
To make wind power more acceptable for people nearby Siemens offers, on top of optimized site layout, the capability to adapt turbine operation to fit noise requirements in a specific area. In this way, the neighboring environment will experience a noise level compliant with local regulations, without compromising power output. One way to achieve this is by noise-reduced operation, through which the optimization of rotor speed and pitch angle to maximize power output is subordinated to a control algorithm that maintains noise emission below certain thresholds.
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