13. The wind industry maintains that ORE projects can have a positive impact on ecosystems and that using rock armour will create artificial reefs around turbine bases that will encourage/ increase new marine life. Is this true?

No, there is no reliable evidence to support this claim. An early study on small offshore wind turbine foundations suggests an increase in the variety of species present close to the turbine bases due to the introduction of hard substrata (rocks and concrete) around the turbine bases. This may be due to the fact that fishing is not allowed within the wind farm areas. It is known from a recently published long-term study carried out in Belgium that impacts change over time. After a ten-year period of monitoring, while initially it looked as if there might be some positive changes, the authors reported ‘slimeification’ and decline of the initial invasive species, effectively leading to significant deterioration of the original ecosystem. The study concludes that earlier reports on offshore wind turbines as potential biodiversity hotspots should be considered premature. In short, turbines and hard substrata do not belong in functioning, high biodiversity, sandy or soft mud ecosystems. Hard structures such as these facilitate the development and proliferation of different and potentially invasive species that will out-compete native species resulting in reduced biodiversity. Did you know that sand eels, on which whales and endangered bird species feed, require sand to survive and reproduce? Construction of windfarms on sandbanks would require the removal of 3-6 metres depth of sand, destroying this important sandy habitat. The International Union for the Conservation of Nature (IUCN) Red-listed Puffin and Kittiwake feed almost exclusively on sand eel, which means construction of wind farms on sandbanks has a direct impact on species protected under the Birds and Habitats Directive .

14. If ORE projects are given planning permission in ecologically sensitive areas, what do we have to lose?

Everything! Marine ecosystems depend on the food web, which starts with phytoplankton. Development of offshore wind is reported to have an impact on phytoplankton production. If we destroy phytoplankton, everything else dies. Ocean ecosystems provide 50-80% of global oxygen and are among the world's most effective carbon sinks. So, in short, these ecosystems are vital for regulation of climate, the air we breathe and life on earth. When the ocean breathes out, we breathe in! Areas containing natural reefs, seagrass, kelp forests and sea-pens, are examples of marine ecosystems that very efficiently capture carbon from the atmosphere. For example, seagrass beds capture carbon 35 times faster than a rainforest. Reefs give life to our seas providing shallow, light-filled waters for phytoplankton to bloom, fish to spawn, sharks and whales to feed. Protecting whales and allowing their numbers to increase is another really effective way to capture atmospheric carbon in the ocean. Phytoplankton captures carbon dioxide directly from the atmosphere through photosynthesis, just like trees. Unfortunately, if it is not consumed, phytoplankton can degrade and return the carbon dioxide to the atmosphere, rather than store it in the deep oceans. Whales, a vital part of the marine ecosystem, consume large amounts of phytoplankton (e.g. Blue whales feed on 16 tons per day), which they then defecate (poo out) onto the ocean floor, where it forms a stable carbon sink. In addition, the resulting release of inorganic nutrients (e.g. iron, nitrates, phosphates, silicates and calcium) from the faeces stimulates increased phytoplankton production (just like fertilising your garden). At the end of their lives, when whales die, their bodies fall to the ocean floor, resulting in even further carbon capture and storage (See image below). Excess carbon dioxide in our atmosphere creates global problems. Globally, 10 Gt would have to be removed annually to keep the global temperature increase to below 1.5 degrees, as committed to under the Paris agreement. However, because it is present in minute concentrations (approx. 419.08 parts per million) it very difficult and inefficient to remove using man-made systems. In contrast, marine and terrestrial ecosystems (e.g., oceans, bogs, rainforest) have evolved over millions of years to become exceptionally efficient at capturing and storing carbon. While there is much talk these days about carbon capture technologies, any technology developed by humans is going to be a highly inefficient and expensive alternative to the natural carbon capture provided by healthy functioning ecosystems.

15. What are the offshore elements of a wind development?

A typical wind development using fixed bottom foundations consists of wind turbine generators, associated foundations, offshore substations and associated foundations, inter-array cables linking each turbine to the substation and export cables which bring the power to an onshore substation. Construction of a typical wind farm requires hundreds of kilometers of electrical cabling and thousands of tons of steel, rock and concrete. Sites are prepared by clearing the natural seafloor. Turbines (up to 320m height above sea level) are then erected by embedding them deeply into the seabed. Various techniques may be used to drive these huge structures to depths that will ensure their stability, but irrespective of the technique used, none of the original seafloor integrity is likely to survive this operation. Similarly, a range of techniques can be used to embed and anchor the high voltage electrical cables into the seabed. Routes can be prepared by dredging, ploughing or trenching to some depth, then cables laid, sometimes on concrete 'matressing', and covered with concrete or rock that can be up to 5 metres wide. If cables are laid on sandbanks, prior to the cables being laid, 3-6 meters of the surface sand must be removed to create an appropriate base for the construction. This is the living layer of the ecosystem in which the sand eels live, so cable laying on sandy surfaces, effectively totally removes the functioning part of that important ecosystem.

16. What is a wind turbine?

A wind turbine consists of a tall cylindrical tower with a nacelle (generator housing) on top which contains the functional components of the turbine. Attached to the nacelle are three blades which rotate, driven by the force of the wind. Turbine nacelles also rotate through 360 degrees in order to keep the blades facing into the wind. The specifications of turbines vary between manufacturers. Overall height from the sea level to the blade tip can reach over 300 meters (1000 feet). The turbine tower diameter is approximately 7-9 meters. Blade tips can reach speeds of 195 km/h when rotating.

17. What determines how close to the coast a wind turbine can be located?

In Ireland, the government has imposed no restriction on proximity of wind farms to shore. For this reason, developers have targeted sites that are significantly closer to shore than would be permitted in other EU countries. Turbine distance to shore has changed with advances in technology. The seven turbines that were constructed 20 years ago in Phase One of the Arklow Bank development are 124 meters high, while turbine height for proposed developments are over 300 meters. (To put this into context, the blade of proposed turbines would be similar in length to the Dublin Spire, 121 meters high). In the early stages of offshore wind development, it was a huge accomplishment to sink a turbine foundation into 10 meters of water. This explains why some early developments are located in shallow water relatively close to shore. Advancements in technology now allow turbine foundations to be installed in up to 70 meters of water and developers are already installing foundations at this depth. This, together with the introduction of floating turbine platforms, means that the majority of current EU and global offshore wind developments are located a minimum of 25 km from the shore.

18. What are fixed bottom wind turbines?

In simple terms fixed bottom wind turbines are turbines that are individually anchored to the sea bed: some are anchored using a structure called a monopile, others are fixed with what’s called a jacket foundation. Monopiles are hollow steel cylindrical tubes approximately 8 meters in diameter with wall thicknesses of 8-10cm (imagine a really massive steel drinking straw). Using a hydraulic device, monopiles are hammered into the seabed to depths of between 30-40 meters (or more, for bigger turbines). A turbine is then attached to the monopile via a transition piece. Each monopile requires thousands of tons of rock armour to protect the base of the turbine from hydrodynamic erosion. Jacket foundations are lattice structures consisting of three or four legs and are normally attached to the seabed by fixing each leg to a pre-driven monopile. Again, thousands of tons of rock are required to protect the base of each leg from hydrodynamic erosion. Current technology allows fixed bottom turbines (using either single monopiles or jacket foundations) to be installed in water up to 70 meters deep.

19. What is a floating wind turbine platform and does floating wind offer any benefits?

A floating wind turbine platform is anchored to the seabed and can carry a turbine in water depths of between 80-200 meters. While fixed bottom wind turbines are limited to being sited in waters of approximately 70 meters deep, floating wind turbine platforms allow developers to use deep water locations where wind speeds are stronger, visual impact is less and environmental impacts on the seabed are likely to be minimised, due to less invasive installation and operation phases. The Irish Government has stated that it will not provide any route to market for floating wind before 2030, although applications to develop floating projects are currently being made. No clear explanation has been given for this decision.

20. How high are offshore wind turbines?

Ireland’s only existing offshore wind turbines are situated on the Arklow Bank, approximately 12 km from the shore. The height from the surface of the sea to the tip of the turbine blade is 124 meters (407 feet). Turbine heights currently being proposed can extend 320 meters (1050 feet) from sea level to blade tip. It is difficult to imagine the scale of such a turbine, but if you have ever seen the Eiffel Tower in Paris, or can picture it in the Parisian skyline, you’re there: modern wind turbines are just four meters shorter than Gustav Eiffel’s tower! Closer to home, consider that the Dublin Spire is 121 meters tall: the same height as one blade on a modern turbine. Try imagining two Dublin Spires stacked lengthways to get an idea of the rotor diameter and then imagine these hoisted another 40-50 meters in the air to allow for clearance above the sea surface—that’s how big modern wind turbines are. Turbines of this size have not yet been installed en masse anywhere in the world, so it is understandable that people find it difficult to conceptualise the size and scale. Image

FAQs Archive - Page 2 of 4

Published: March 30, 2022

11. What are the greatest ecological impacts of offshore wind farms?
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Published: February 20, 2022

12. Could offshore wind affect bird species?
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Published: January 30, 2022

13. The wind industry maintains that ORE projects can have a positive impact on ecosystems and that using rock armour will create artificial reefs around turbine bases that will encourage/ increase new marine life. Is this true?
Learn More
Published: December 31, 2021

14. If ORE projects are given planning permission in ecologically sensitive areas, what do we have to lose?
Learn More
Published: December 5, 2021

15. What are the offshore elements of a wind development?
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Published: November 5, 2021

16. What is a wind turbine?
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Published: October 5, 2021

17. What determines how close to the coast a wind turbine can be located?
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Published: September 5, 2021

18. What are fixed bottom wind turbines?
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Published: August 5, 2021

19. What is a floating wind turbine platform and does floating wind offer any benefits?
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Published: July 5, 2021

20. How high are offshore wind turbines?
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