It is recognized that offshore wind farms must be to a proper scale and properly sited to avoid unacceptable impacts on the coastal environment (Marine Conservation Society, 2013). The outdated and undemocratic legislation (Foreshore Act 1933) governing construction in Irish waters, together with inadequate regulation, has led to developers being awarded foreshore leases by the Minister for the Marine for construction of massive developments which are out of line with best European practice in terms of turbine size, number of turbines and distances from shore.
Offshore wind farms are vast industrial complexes. Typically they involve the following:
- Turbines: Large-scale wind turbines, up to 150 metres/ 500 feet high ( as high as a 30 storey building) mounted on huge monopile foundations. See Fig 1 below.
- Foundations: Each monopile foundation is a steel pile, around 60m long and 5m wide, weighing around 400/600 tones. This is drilled, hammered or vibrated into the seabed to a depth of around 32M (105 feet).
- Scour Protection: Wind turbine foundations change water flow patterns leading to “scour” or a lowering of the seabed immediately around them. To try and prevent this, large quantities of rocks are dumped on the seabed at each turbine site, before and after the foundations are installed
- Offshore Substations: Large substations mounted on platforms fixed to sea bed are installed to collect power from groups of wind turbines before feeding it to shore
- Cables: The turbines are interconnected with 33kV power cables which are connected to the offshore substations. Here the voltage is transformed from 33kV to 110kV and one or two export power cables bring the power to shore. All the cables are buried to a depth of at least 1m using trenching equipment
OFFSHORE WIND TURBINES - HEIGHT FROM SEA LEVEL to BLADE TIP
Particularly striking is the number of massive 5MW turbines permitted and proposed in Ireland’s near-shore zone. These mega turbines (160m / 524 feet high), are still largely at the pilot stage. They are designed primarily for use in locations far from shore where visual impact is not an issue. At end 2009, just six of these 5MW turbines were installed worldwide - at the Alpha Ventus test site, 43km off the German coast.
In Ireland, hundreds of these huge turbines have been permitted and proposed, 5km to 13 km off Ireland’s scenic coastline. These developments are almost all targeted at shallow coastal sandbanks, because they are cheaper to develop than deeper water further offshore. (Sandbanks are an important marine Annex 1 habitat, protected under EU legislation) There has been no independent, professional assessment of the visual impact of these large scale industrial developments on Ireland’s scenic coastline. The wild life impact of such extensive development is unknown.
It is worth noting that the two foreshore leases for offshore wind farms in Irish waters awarded by the Minister for the Marine are for 99 years. The European norm is 30/50 years. This again contributes to the value of the Irish leases.
INTERNATIONAL COMPARISON - 2009
Further details on the discrepancy between Ireland and the rest of Europe are contained in CCA's Global Offshore Windfarms - Comparison with Ireland, 2012. This is presented as a chart which sets out the name of the wind farm, distance from coast, number of turbines, turbine size, capacity in MW, status of projects and additional remarks. Based largely on the OSPAR database on offshore wind farms, CCA’s chart shows that in 2012 Ireland was out of line with good international practice in terms of size and number of turbines permitted and proximity to shore.
In the intervening years there has been increased emphasis on the need to conserve sensitive inshore habitats and coastal landscapes.
Ireland needs to develop alternative sources of energy to meet our climate and energy objectives. Development of ‘green’ energy should not come at the expense of our near shore marine environment. This country should follow good international practice in countries such as Germany, Belgium, and more recently USA, and protect our coastlines and seas by introducing buffer zones. Netherlands has adopted a policy of ‘free horizon’ to 22km+. The average distance from shore of offshore wind farms under construction in the EU in 2017 was 40km. This compares to 10/12 km for developments proposed and permitted in Irish waters between 2002 & 2008.
Irish regulation with regard to key regulatory parameters was, and still is, much more lax than in other countries. This poses a very serious threat to Ireland’s sensitive habitats, marine wildlife and coastal landscapes, important aspects of natural heritage and quality of life.