Windy Wednesday: Some Windfarms

Below I have picked out four wind farms and listed their specifications. I have also added my own notes as to why they are of interest in the case of the wind farms planned for the Copper Coast, three of which I have listed below for comparison

Energia’s North Celtic Sea Project (5-10km offshore) proposes a 600-800MW(approx.600,000 homes) wind farm and suggests that between 40-60 turbines are the usual amount (many factors will determine that, geography, turbine type and height, distance from shore. For example the London Array at 600MW has 175 turbines).

ESB/Equinors’ Celtic Offshore Wind proposal (10km offshore) is also for 600MW (approx. 600,000 homes) and has no mention of the amount of turbines.

SSE Renewables floating wind farm The Celtic Sea Array(25km offshore) proposes an 800MW wind farm with no turbine estimate.

Beatrice

Beatrice. Irish Independent June 2020.

Beatrice Up to 2007, wind farms were only built in depths of 20 metres and less. Then came the experimental two turbine Beatrice wind farm off the east coast of Scotland (25km from shore and at a 40 metre depth). Beatrice has since been expanded closer to shore. What’s interesting to note is that Beatrice powers homes in southern Scotland via a 160km long subsea cable and underground cables to Blackhillock Substation in Northern Aberdeenshire via underground cables. This required the construction of two new converter stations, one at Blackhillock, which, at the size of 24 football pitches, is now the largest substation in the UK.

Of added interest re:the length of this cable to us on the Copper Coast is that the governments of the UK, Northern Ireland and Ireland commissioned a study about a decade ago which concluded that the development of an offshore interconnected grid would provide the UK with an increase of imports in the form of renewable generation from the Irish market and improve the interconnector capacity between both markets (Aoife Foley, Paraic Higgins, The evolution of offshore wind power in the United Kingdom, 2013). Could the power generated on the Copper Coast be used in the UK?

Distance from Shore: 13km

Area:131 square km

Water Depth: 56 metres.

Number of Turbines: 84

Turbine Height:188 metres (maximum pile depth to the highest point of the blade sweep up to 288)​

Turbine Type: Siemens Gamesa 7MW

Foundation: Jacket (with the jacket substructures up to 81m tall).

Operator: SSE on behalf of a joint venture partnership.

Electricity Generation: 400, 000 homes.

The London Array

London Array wind farm as viewed from the air in February 2019 Source:Bodgesoc

Once the biggest offshore wind farm in the world, the London Array is 20km off the Kent coast. Maintained and operated from the port of Ramsgate. Turbines are between 650 and 1200 metres apart. The blades have a swept area of one and a half times the size of Wembley Stadium’s football pitch. The turbines are designed to run for more than 20 years. That means basically that after two decades or so many wind farms will be decommissioned. Like our Metal Man and his pillars. Only eleven times taller. And more numerous.

Distance from Shore: 20km

Number of Turbines: 175

Turbine Height to tip of blade:147 metre

Turbine Type: Siemens 3.6MW

Water Depth: 25 metres

Foundation: Monopile (i.e. basically an extension of the turbine underwater)

Area: 100 square km

Operator: RWE, Orsted, Masdar & La Caisse de dépôt et placement du Québec (CDPQ)

Electricity Generation: 500, 000 homes.

Hornsea 1 Image Credit: Volodimir Zozulinskyi/Shutterstock.com

Hornsea 1

Located off the Yorkshire coast, Hornsea One spans a huge area over five times the size of the city of Hull. The offshore wind farm uses 7 MW wind turbines, with each one 190 metres tall – larger than the Humber Bridge concrete towers.

Distance from Shore: 120km

Number of Turbines: 174

Turbine Height to tip of blade:190 metre

Turbine Type: Siemens Gamesea 7MW

Water Depth: 25 – 30 metres

Foundation: Monopile

Area: 407 square km

Operator: Orsted

Electricity Generation: 1 million homes.

Dogger Bank

Dogger Bank. Image Windpower Monthly

Dogger Bank Wind Farm is an offshore wind farm that will be the largest in the world when it’s finished, knocking Hornsea 1 off the top spot. It’s worth noting as it is located between 130km and 190km from the North East coast of England. Turbines are GE’s Haliade X 13 and 14 MW, over two and a half times taller than the Statue of Liberty and are likely to be considered by some developers for the Waterford coast. Dogger Bank will be capable of powering up to 6 million homes on completion in 2026. The subsea export cables will make landfall in Yorkshire, where around 30km of underground cables will take the electricity to converter stations near Cottingham before passing through the adjacent Creyke Beck substation onto the National Grid.

Distance from Shore: 130-190km

Number of Turbines: 600 (up to 200 for each phase).

Turbine Height: 260 metres

Turbine Type: General Electric’s Haliade X 13/14MW

Water Depth: 18-63metre.

Foundation: Monopile

Area: 8660 square km

Operator: SSE Renewables/Equinor/Eni

Electricity Generation: 6 million homes

Block Island Wind Farm ©John Supancic

BONUS Farm: Block Island off Rhode Island. America’s first offshore wind farm was operational in 2016 and its operation has since been taken over by the Danish company Orsted. Though it is a pilot windfarm – 5 Haliade 6MW turbines less than 5km offshore – this ‘little’ windfarm deserves its own post because for most of this summer the turbines were shut down and the island’s residents did not know why. I’ll post about it on Saturday and move the planned post for creating an artist’s impression of turbines further along.

Other Posts: The Winds of Change: Block Island, The Winds of Change: Introduction to a Series, The Winds of Change: The Proposals, Windy Wednesday: Distance to Horizon for Dummies,

Windy Wednesday: The distance to the horizon for Dummies

This is a mini-post ahead of Saturday’s. The distance to the horizon varies from where you are standing on land. There are any number of ways to estimate distance to horizon.

  • If you’re standing at sea level, divide your height in half. So if you’re 5’6″ (5.5 feet) tall, the distance to the horizon is only about 2.75 miles.
  • Use an online distance to horizon calculator (link below)
  • Use the AIS Marine Traffic website which will give the position of most vessels you can see out on the water.
  • Use geographical features e.g. far off headlands, a map and a piece of string

I whale watch, most often from Dunabrattin at Boatstand, from the first car park going west. This is 22 metres (72 foot) above sea level. (I can find elevation using free online elevation finders. There’s a link to one below). Helvick head is 20 km from Dunabrattin as the crow flies on a map. So I can see at roughly 20km from 22 metres above sea level at Dunabrattin.

For more accuracy we can use formulas. This is the most simple one:

Multiply your height in metres above the ground by 13**, and take the square root of that.

So for Dunabrattin…

  • Height above sea level = 22 metres
  • Add my height up to to eye level = 23.6 metres
  • Multiply by 13 metres** (1.5 foot if using imperial) = 306.8
  • Calculate the square root (a calculator or Google does this for you) = 17.5157072366

According to this the horizon from straight out from Dunabrattin is 17km distant.

From Gallwey’s Hill in Tramore the horizon is 19km distant

From the Tramore Racecourse roundabout the horizon is 23km distant

But… that’s just the horizon. At 190-260 metres above sea level, the height of the proposed turbines is no small consideration. It seems to me that even a windfarm at 22km will be well visible from much our coast. And at 5 km or 10 km distance?Yikes.

Many of you will also be aware that it’s possible to see things over the horizon due to effects of the light. That is why one far off container ship may seem tiny while the upper decks of another one even further over the horizon is five times larger.

See you on Saturday when I’ll try and describe the proposal for the Waterford coast in 500 words or less. Any corrections, – especially to my equation! – comments etc. can be sent via the contact form on this blog.

**I am not sure where the 13 comes from. I think its something to do with triangles and the radius of the earth but as I have an allergy to sums my head imploded before I could read much more.

Links

Elevation Finder https://www.freemaptools.com/elevation-finder.htm

Marine Traffic https://www.marinetraffic.com/en/ais/home/centerx:-12.0/centery:25.0/zoom:4

Distance to Horizon Calculator http://www.ringbell.co.uk/info/hdist.htm