Wind Turbines
The foundations of wind turbines have an impact on their local environment. Therefore, foundation selection is a primary consideration for developers and wind farm managers. Foundation selection is especially important for offshore wind turbines. The construction of turbine foundations and the use of scour protection materials have been notable impediments to shorebirds, seabirds, and the integrity of shallow water ecosystems including bedrock (Drewitt & Langston, 2006, p. 32). All wind turbines have an impact on birds, though, and the evidence suggesting that offshore wind turbines have a net worse impact on the avian community has been unsubstantiated (Fox et al., 2006). According to a Danish study, no more than two percent of total wind farm area is lost due to the turbine foundations or antiscour protection (Fox et al., 2006). The seabed habitat loss should, however, be monitored over time to provide more an accurate understanding of how foundation construction can be improved to minimize damage. One of the most notable problems with wind turbine environmental impacts is especially related to the foundation construction in both on shore and off shore settings. Madsen, Wahlberg, Tougaard, Lucke & Tyacke (2006) found that the construction of wind turbines for offshore turbine farms was more damaging to marine mammals than their ongoing operation, rendering the construction phase the most detrimental in terms of overall environmental impact.
One of the environmental concerns related to the foundations of wind turbines is how effective their siting is in reducing unwanted noise. This is especially true for marine mammals that rely on sound for their communications, which is why offshore wind turbine foundations have received the bulk of research funding in recent studies. However, land animals are also affected by the noise generated by wind turbines in the construction and operating stages. As the Wind Energy EIS (2014) points out, insulating materials can be installed in the base of the turbine construction to mitigate noise problems.
The foundations of wind turbines, whether shallow or deep, are not linked to significant damages in terms of leaking of toxic materials into surrounding earth. “Relatively small amounts of lubricating oils and hydraulic and insulating fluids” will be emitted, making “contamination of surface or ground water or soils is highly unlikely,” (Wind Energy EIS, 2014, p. 1). There are, however, some differences between the concrete and steel foundation types used in the erection of wind turbines. Traditionally, reinforced concrete is used as a foundation for high rise wind turbines and these leave a shallow footprint (Zygomalas & Baniotopoulos, 2014). Concrete foundations are known to be both effective and stable (Zygomalas & Baniotopoulos, 2014). However, the new steel micropile foundations that are driven deeper into the earth have become more common in recent years and these may have more serious and severe environmental impacts than their concrete predecessors (Zygomalas & Baniotopoulos, 2014). Steel foundations have a more severe and detrimental environmental impact for several reasons. First, they involve more building materials and are therefore more resource-intensive. Second, the steel foundations cause direct damage to the place in which they are situated due to their being driven deeper into the earth surface. Third, the steel foundations require greater use of fossil fuels (Zygomalas & Baniotopoulos, 2014). However, the concrete foundations are not without their problems. The release of dust, toxins, and possible carcinogens into the air results from the construction of concrete foundations, whether or not those foundations are shallow or deep and combined with steel (Zygomalas & Baniotopoulos, 2014).
Generally, and ironically, it has been found that the shallow foundations are responsible for relatively higher environmental impacts overall (Zygomalas, & Baniotopoulos 2013). This is due to the overall life cycle of the wind turbine and its foundation. Over the course of its life cycle, the shallow foundation may be more detrimental to the environment. These conclusions are based on several simultaneous assessments of steel micropile deep vs. concrete and shallow foundations (Zygomalas, & Baniotopoulos 2013). Issues such as the ability to recycle the materials used, and the cost of transporting materials all have an impact on how environmentally damaging the foundation will be.
Unfortunately, both concrete and steel foundations present particular problems with regards to environmental impact. During the construction phase, steel is more problematic but overall, concrete foundations may have the most impact. There are several different variables, though, and the impacts may certainly be different for different installation environments, sites, and settings. Whether or not the turbines are located on land, whether or not an economy of scale in the business leads to reduced fossil fuels in the transportation of the construction materials, and prevailing winds carrying dust are all mitigating factors that will impact how damaging the wind turbine foundation will be over the course of the life cycle. Finally, the differences with each situation also may differ based on the construction phase environmental damages vs. The overall life cycle environmental impact. Longitudinal studies need to examine the imact of the foundations on things like acidification of ground water (Zygomalas & Baniotopoulos, 2014). In the future, more environmentally sound materials and construction processes may be developed.
References
Drewitt, A.L. & Langston, R.H.W. (2006). Assessing the impacts of wind farms on birds. Ibis 48(1): 29-42.
Fox, A.D., et al. (2006). Information needs to support environmental impact assessment of the effects of European marine offshore wind farms on birds. Ibis 148(1): 129-144.
Razizadeh, S.B. (2014). Life cycle analyses of the foundation of onshore wind energy structures.
Wind Energy EIS (2014). Wind energy development environmental concerns. Retrieved online: http://windeis.anl.gov/guide/concern/
Zygomalas, I. & Baniotopoulos, C. (2013). Life cycle assessment of traditional shallow and steel micropile foundations for wind energy converters. 3rd International Energy, Life Cycle Assessment and Sustainability Workshop Symposium.
Zygomalas, I. & Baniotopoulos, C. (2014). Wind turbine steel towers environmental impact. Eurosteel 2014.
