The Winds of Change: What are Turbines made of?

Today we’ll look at the turbines. For the purpose of this post, I’ll divide turbines into three components: Foundation, Tower, Blades. But first here’s an image showing the overview of an offshore wind farm which I thought might be useful.

Overview of a wind farm from On the Use of Scaled Model Tests for Analysis and Design of Offshore Wind Turbines – Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/publication/323118519_On_the_Use_of_Scaled_Model_Tests_for_Analysis_and_Design_of_Offshore_Wind_Turbines [accessed 5 Nov, 2021]

Foundations take up a quarter to a third of the cost of constructing a wind farm and their feasibility is the making or breaking of a project. There are several types of Foundations – Gravity bases, Suction Bucket Bases, Monopile, Tripod, and Floating (which SSE and DP energy are planning for Waterford and Cork respectively). Today I’ll cover Monopile Foundations in a little detail as they are most likely for near shore turbines in Waterford. I include a little on Jacket Foundations too as they can act as artificial reefs which is often cited as an advantage. The floating systems we will leave for another time.

Different foundations to support offshore wind turbines based on water depths. Reference same as previous image.

Monopile is a single foundation inserted into the ground or seafloor and are roughly the same diameter as the tower. They are used closest to shore and will likely be what Energia and others are considering for the Waterford Coast. Monopiles have a simple design that installs quickly. Disadvantages are that installation noise can disorient, injure or kill marine life sensitive to pressure waves and wind, wave and seismic loading can cause early fatigue damage to the structure if it is not accounted for during installation.

Jacket foundations are used for turbines further offshore and I don’t believe they are proposed for any Waterford wind farms. The larger surface area of the lattice configuration may provide an artificial reef location, providing a new habitat for local species though it also may allow invasive species to establish and spread. Installation requires pile drivers the noise of which may injure or kill some marine life. Changes to local water patterns may be detrimental to native marine ecosystems.

Towers: Turbine towers are made from tubular steel and come in sections, usually three. They are easy enough to recycle. There. That was fast.

Blades: The bigger the blades are the more energy they generate. GEs Haliade X, which is likely to be considered for Waterford, is now being fitted with blades (made in Cherbourg) over 100 metres long. Turbine blades are made from fibreglass (older blades) or carbon fibre (newer blades). This means they are light and strong but it also means they are hard to recycle. This is becoming an issue now as the first generation of wind farms reach the end of their lifespan (wind farms currently last 20-25 years before they are decommissioned). There are experiments with converting the blades into useable substances, for instance into pellets to use in concrete or as glue, but the energy required for such transformations can be an issue.

Some people are getting creative. In Denmark, bike shelters are being made from turbine blades as are a number of playgrounds in the Netherlands. However, a lot of old blades are buried in places like the turbine graveyard, by the North Platte River in Casper, Wyoming in the U.S. Between last September and this March, it became the final resting place for 1,000 fibreglass turbine blades. Here in Ireland, UCC are looking at using parts of turbines for a Greenway bridge but how many old blades a country the size of Ireland can dispose of may be an issue. Perhaps we could live in them? As a non-home owner I would certainly consider it!

I have read elsewhere that there are experiments with lighter fabric-based skin on frames but I am not sure how that is developing. I’ll look at alternatives to the traditional windmills on which the turbine is based – which having been in use for 1000s of years are not really as innovative as they are made out to be – in another post.

I think I’ll start looking at impacts on wildlife, what they are and how they are measured, next Saturday…

Other posts in the series are

The Winds of Change: Introduction to a series

Windy Wednesday: The distance to the horizon for Dummies

The Winds of Change: The Proposal(s)

Windy Wednesday: Some Windfarms

The Winds of Change: Block Island

Windy Wednesday: An Artist’s Impression in Progress

Links and References

https://www.windpowerengineering.com/comparing-offshore-wind-turbine-foundations/
https://www.designboom.com/design/denmark-repurposing-wind-turbine-blades-bike-garages-09-27-2021/
https://www.bbc.com/news/business-51325101
https://www.researchgate.net/figure/Different-foundations-to-support-offshore-wind-turbines-based-on-water-depths_fig5_323118519

Windy Wednesday: An Artist’s Impression in Progress

When I started looking into wind farms a few months ago, I wanted to visualize them. The developer’s artists impressions aren’t exactly telling us anything. So I set about making images. It turned out to be more complicated than I thought.

The first image shows the height of the turbines proposed relative to Brownstown head, 5km away in this photo. I did this by finding out the height of the towers on Brownstown (c.20metres) and stacking up towers to the height of 250 metres at their very tip. I got a turbine graphic from Blue Horizon’s page. This gives a good impression of size and I know how big a turbine 5km from me – if I am standing 60metres above sea level – will look. (See post on elevation here). I measured the turbines at 10km using the container ship. But of course, the turbines are not going to be right next to Brownstown (I think I hope) so I figured I needed to create a more realistic view before causing a mad panic.

I tried some 3D modelling software but I didn’t last long at that because even if I got more ‘professional’ measurements, I still had some problems. How many turbines will there be? How far apart? And then how do I allow for rows of turbines moving diagonally away?They will appear closer together. I can place them on the horizon relatively correctly but what about the ones closer than the horizon? Or the ones beyond the horizon but still visible?

The second images show turbines a lot further out than the 5km or 10km that Energia and ESB are proposing and a lot less than the 60-80 turbines Energia are hinting at (they are a bit vague). It is an impression of 19 turbines in 2 rows, the first row about 22km away, the second row (every second turbine) further away. 22km is the minimum distance Blue Horizon are suggesting for the windfarms. I have also made them around 200 metres high rather than the max 260 metres. There is the issue that ships on the horizon will look bigger than they are…but then again so will the turbines. There is a larger version of the main image with one row of turbines at the end of the post.

I stress that this is a work in progress but I have erred on the smaller size and dulled the colour of the turbines (usually white) which I believe will be more visible in reality. And keep in mind images are not reality. In reality, the impact is usually much stronger.

I’ll work on a 10km wind farm impression next. See you Saturday with another post…probably on what turbines are made of.

Other posts on #windfarms on this blog: The Winds of Change: Introduction to a series Windy Wednesday: The distance to the horizon for Dummies Windy Wednesday: Some Windfarms The Winds of Change: Block Island

The Winds of Change: Block Island

The story of Block Island caught my eye. Block Island off Rhode Island is a permanent home to 1000 residents. In the summer times, daily visitors number between 10 to 20,000. Electricity supply has been problematic with some using generators and their own wind turbines. An application by the community for a grant for an undersea cable to connect to the mainland grid was rejected. The proposed wind turbines, 5 Haliade 6MW turbines, seemed a no-brainer for most though there were those who objected to it. But this small, private wind farm went ahead and began commercial operation in 2016. But there have been problems. Within a couple of years, the undersea cable connecting to the mainland (as part of the wind farm project) became uncovered at the island end for it had only been buried in places at four-foot depth to save money. Warning flags appeared on some beaches for a while and the cable had to be reburied at the cost of $31million. This reburial also has also problems with blockages and sediment.

There is some controversy over who paid for this reburial with claims that the National Grid profited by $46million from customer surcharges for maintaining the cable. The National Grid denies this.

The Block Island offshore wind farm  [FROM –  cleanpower.org/resources/offshore-wind-public-participation-guide]. Taken from Green City Times.

This June, 2021 it was noticed 4 out of 5 of the turbines had ceased operation. The community on the island struggled to get any information from the operators, the Danish-based Orsted, who claimed that the turbines were down for regular maintenance which was best performed in summer. Ignoring the fact that it is the summer when the island needs the power most, this caused a lot of frustration and the turbines were down for the best part of two months. It emerged then that stress fatigue was noted on the support structures of the “helihoist” platforms on some of GE Haliade turbines in the Merkur project in the German North Sea. Stress lines were subsequently found in Block Island’s turbines but a risk assessment has deemed them safe and repairs were also undertaken.

The Haliade turbines are the same turbines being considered for some of the Copper Coast windfarms – though likely they will be of more recent versions and of higher wattage – which will have well over 100 turbines if projected output is anything to go by.

In the end, the shutting down of the turbines caused no power interruption for the island as the cable, though still being reburied, continued to connect them to the national grid. As far as I know, the turbines are operational once again.

Block Island. Image GE/Sharon Radisch. Taken from Duke Energy/Illumination.

Previous Posts

The Winds of Change: Introduction to a Series, The Winds of Change: The Proposals, Windy Wednesday: Distance to Horizon for Dummies, Windy Wednesday: Some Windfarms

Links

https://www.blockislandtimes.com/article/national-grid-returning-finish-cable-reburial/59851

https://eu.providencejournal.com/story/news/2021/08/14/block-island-offshore-wind-farm-offline-two-months-due-to-maintenance-and-safety-concerns/8122841002/

https://electrek.co/2021/08/10/egeb-us-first-offshore-wind-farm-is-currently-offline-heres-why/https://splash247.com/turbine-stress-issues-bring-merkur-offshore-wind-farm-offline/

https://www.theday.com/article/20210807/NWS05/210809578

https://www.ge.com/renewableenergy/stories/block-island-construction-process