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Archive for the category “offshore”

Sif – The Wind Tower Company

In February 2015 Port of Rotterdam and Sif Group met during an exhibition in Hamburg. In June of that year the two parties signed a contract for the construction of the 500 meter long assembly- and the 120 meter long coatinghall from Sif.

October 24, 2015 the first pile of the hall and in April 2016 the first pile of the deep sea quay was driven into the ground. The construction of the halls went smooth so the first cans and cones from Roermond were delivered in September for assembly. In December, the 200 meter deep deepsea quay was finished and in January 2017 the first load-out of monopiles took place.

Thanks to the excellent cooperation between the Port of Rotterdam and Sif Group we realized a new production facility in just 14 months. Through this production expansion Sif is perfectly equipped to produce 4-5 monopiles per week with a diameter up to 11 meters.

That would be 5 x 6 MW = 30 MW per week or 1.5 GW per year or 50 GW until 2050, when Europe needs to be fossil free. Companies like Sif exist in Germany, Denmark and Spain, see below for an overview of the European (=global) offshore wind foundation industry.

Current Dutch electricity production capacity is 28,7 GW. Assuming a capacity factor of 50% of North Sea offshore wind, this current Sif production capacity would suffice to achieve electricity independence for The Netherlands in 2050. The European monopile market in 2015 was 385 and 560 in 2016. In 2018, Sif alone will be able to produce ca. 250 monopiles. It is likely however that Sif will continue to expand far beyond that number in the coming years.

[sif-group.com] – Company site [Google Maps]
[energieoverheid.nl] – Nederland heeft voorlopig genoeg elektriciteit beschikbaar
[sif-group.com] – De razendsnelle realisatie van Sif op de Maasvlakte 2
[ewea.org] – The European offshore wind industry – key trends and statistics 2015
[windeurope.org] – The European offshore wind industry 2016
[tube-tradefair.com] – FA 07 Monopiles – gigantic pipes for offshore wind farms

European offshore foundation market 2016

References to the producers listed in the diagram according to production capacity:

[de.wikipedia.org] – Erndtebrücker Eisenwerk, Erndtebrück, Germany [Google Maps]
[steelwind-nordenham.de] – Steelwind Nordenham, Germany [Google Maps]
[ambau.com] – Ambau, Mellensee, Germany [Google Maps]
[bladt.dk] – Bladt Industries, Aalborg, Denmark [Google Maps]
[navantia.es] – Navantia, Ría de Ferrol, Spain [Google Maps]

Read more…

Lowering Maintenance Cost – Energy Islands in the North Sea

On March 23, 2017 an agreement was signed for the development of an artificial energy island in the middle of the North Sea intended to ease maintenance effort to keep potentially tens of thousands of offshore wind turbines running and to distribute power to neighboring countries.


Energy Island to be built in the Dutch part of the Doggersbank. Because of Brexit, Britain is an unlikely candidate to host this island and in case of a hard-Brexit will go it alone anyway.

[independent.co.uk] – North Sea island: Danish, Dutch and German firms launch bid
[tennet.eu] – European Operators to develop North Sea Wind Power Hub
[arstechnica.com] – North Sea: A giant wind farm to power all of north Europe
[deingenieur.nl] – Gigantisch Stopcontact op Eiland Doggersbank

World’s First Offshore Windfarm Vindeby Decommissioned

Reason decommissioning: end of economic life
Installation date: 1991
Decommissioning date: March 2017
Turbines: 11 of 450 kW
Water depth: 4 m
Capacity factor: 22.1%
Installation cost: 10 million euro
Cumulative lifetime power: 243 GWh
Danish electricity price consumers: 30 cent/kWh
Turnover consumer price: 79 million euro

The capacity factor was extremely low. More recent Danish offshore wind farm typically have an average capacity factor of 41.5%

[wikipedia.org] – Vindeby Offshore Wind Farm
[Google Maps] – Vindeby, Denmark
[energynumbers.info] – Capacity factors at Danish offshore wind farms
[deepresource] – Nuon Dismantles Offshore Wind Farm in the Netherlands

Sandbank Offshore Wind Farm Cabling

After the wind tower monopiles are installed, they need to be connected with cables. In the video it is done by offshore wind cabling market leader VBMS.

[vbms.com] – VBMS (VolkerWessels Boskalis Marine Solutions), Papendrecht, the Netherlands
[vattenfall.com] – Offshore Wind Farm Sandbank
[4coffshore.com] – Sandbank Offshore Wind Farm

2-B Energy – Back To Two Blades

3-blade turbines have become the standard in present day wind energy development. The Dutch company 2-B Energy argues that for offshore, wind 2-blades could perhaps be a better design. First of all from a maintenance perspective: in case of a defect, nacelle and rotor can be lifted from the tower in one piece and brought to a maintenance location, onshore or nearby offshore. Furthermore the company claims to be able to realize lower production costs. A first 2-b wind turbine has meanwhile been installed in Eemshaven, in the North of the Netherlands, see video below. Installation rotor downwind and able to rotate freely around a vertical axis, ensuring automatic direction towards an orientation perpendicular to the wind flow. Dimension nacelle 17 m, large enough for a helicopter to be able to land on top of it. Gain: less material, easier maintenance. 2-B Energy is participating in the Methil offshore project off the coast of Scotland.

[2benergy.com] – Company site
[offshorewind.biz] – Forthwind Cleared to Install Two-Bladed Turbine Duo off Scotland
[wikipedia.org] – Methil Offshore Wind Farm

At [1:33] you can see the test-installation of the 2-B wind turbine in Eemshaven. Visually it is not a very attractive installation, but it is intended for offshore operation anyway.

EROI of Offshore Wind

There is a lot of confusion about the real value of the EROI of wind energy. Time for a back-of-an-envelope calculation.

By far the largest energy input in the construction of a wind turbine from iron ore is realized in the steel mill. How much energy does it take to produce 1 ton of steel? Here is an old Dutch study (1986) from the Energie Centrum Nederland:

[ecn.nl] – Energy Consumption For Steel Production

On p20 we see that the lowest value for steel production is ca 20 GJ/ton or 5555 kWh/ton. We can safely assume that in 2017 the amount of energy required is lower, but we will accept this figure anyway to be on the prudent conservative side.

A 6 MW offshore wind turbine has roughly the following weight distribution:

Part Weight [ton]
monopile 2200
tower 650
nacelle 350
Total 3300

Energy cost for the steel production: 3300 * 5555 = 18331500 kWh
In the North Sea this 6 MW wind turbine on average produces 144,000 kWh/day, see:

[deepresource] – Gold Mine North Sea

Payback time in energy terms therefore is: 18331500/144000 = 127 days

There are of course extra energy costs. Say you need to get the iron ore from Australia, the worst case in transport energy terms, from a Dutch perspective.

[withouthotair.com] – Sustainable Energy – without the hot air, David JC MacKay

This source claims a shipping transport cost for dry cargo: 0.08 kWh/ton-km

Australia-Rotterdam = 20,000 km, in other words: 1600 kWh/ton. Or 3300 * 1600 = 5280000 kWh for the entire wind turbine. Divide it again by the daily energy production of 144,000 kWh of our 6 MW turbine to arrive at 37 days extra work for the wind turbine to earn itself back.

Total energy payback time: 127 + 37 = 164 days.

In other words: the offshore wind turbine must work for less than half a year to “earn” itself back in energy terms.

The remaining items like rotor (3 * 25 ton), construction of the gear, generator, maritime handling, installation, etc, have far smaller energy cost. Add a 22 days (wet finger in the air) to conveniently arrive at exactly half a year.

Things get even better if it is realized that these days about 1/3 of the world’s steel production comes from scrap metal, which requires far less energy to turn into new steel than iron ore. If in the future the windturbine has arrived at end-of-life, you can reuse the steel of the old turbine. You don’t have to get the iron from Australia anymore and recycling of steel costs far less in energy terms than producing steel from ore.

Summarizing: assuming a very conservative [*] life cycle of 30 years for the turbine, EROI for our offshore 6 MW wind turbine is therefore 30/0.5 = 60 or higher.

[*] The Eiffel tower is around since 1887 or 130 years. Experts estimate that the tower can easily survive another 300 years. Likewise it is absurd to assume that an offshore wind tower will fall over after 30 years.

P.S. After writing this post we discovered this calculation by Jan-Pieter den Hollander:

[duurzaamgebouwd.nl] – Energiebalans van een windmolen

Embodied energy

Onshore wind turbine: 0,6MW, height = 50 m, rotor diameter = 40 m

Part Energy in GJ
Production 1900
Installation 495
Maintenance (20 year) 774
Total 3169

Generated energy

Energy yield per year: 5015 GJ
Energy payback time: 7-8 months

In essence a comparable value to ours. In the example of Jan-Pieter den Hollander we are dealing with an onshore machine with less yield than offshore. Although it must be said that in his calculation there are counter-intuitive high values for installation and maintenance. Perhaps we will update this post in the future to have look at those.

Offshore Wind in Japan

Youtube text: “A number of projects are under way around Japan’s coast to develop offshore wind power Japan has developed an advanced form of this platform that it expects will create demand in the rest of the world.

Sandbank Offshore Wind Farm Inaugurated

Map with all German offshore wind farms, planned, under construction or realized. Click to enlarge.

Swedish company Vattenfall completed the installation of the Sandbank offshore wind farm in the German part of the North Sea. The plant went operational on July 23. 288 MW worth of wind power was installed with 72 Siemens turbines. A Munich-based utility company Stadtwerke München also participated (49%). Investment volume 1.2 billion euro.

[vattenfall.com] – Offshore wind farm Sandbank now officially inaugurated
[4coffshore.com] – Sandbank Offshore Wind Farm

Offshore Wind Impressions

Read more…

Baltic Wikinger Offshore Wind Farm

Spanish developer Iberdrola, 350 MW, 70 turbines, area 34 km2, water depth 37-43 m, distance to German shore 39 km.

[4coffshore.com] – Wikinger Offshore Wind Farm

Hywind Scotland Floating Wind Turbines Pilot Completed

A small 30 MW wind farm has been completed in the waters of Stord, Norway and will be towed to Scotland. The project consists of five 6 MW wind turbines. What makes the project unique is that the turbines are floating, ensuring that shallow water is no longer necessary for offshore wind to work.

[gamesacorp.com] – Innovation in world´s largest floating wind farm by Siemens Gamesa can open new offshore areas
[wikipedia.org] – Floating wind turbine
[wikpedia.org] – Hywind
[fastcompany.com] – Scotland Will Be Home To The World’s Largest Floating Wind Farm
[spiegel.de] – Schottlands schwimmende Windkraftwerke

German Gode Wind 1 and 2 Offshore Wind Farms Go Live

DONG Energy has officially inaugurated the German Gode Wind 1 and 2 offshore wind farms, together 582 MW.

Next DONG projects in the North Sea: 240 MW OWP West, 240 MW Borkum Riffgrund West 2 and the 110 MW Gode Wind 3, total 590 MW.

[wikipedia.org] – Gode Wind Farm
[windpoweroffshore.com] – Gode Wind construction starts
[4coffshore.com] – Gode Wind 1 and 2 Offshore Wind Farm

[4coffshore.com] – OWP West
[4coffshore.com] – Borkum Riffgrund West 2
[4coffshore.com] – Gode Wind 3

TFliner XL

It is possible to install an offshore wind-turbine without the use of a sophisticated but expensive self-lifting sea-jack ship, like the Aeolus (see video at the bottom of this post). During installation the ship is held in place with the DP-2 dynamic positioning system.

[wikipedia.org] – Dynamic positioning

Fourfold functionality TFliner XL for offshore wind turbine installations:

1. installing monopile foundation
2. installing transition pieces
3. installing jacket type foundations
4. reel-lay spread

The ship can handle 75 m monopiles of max. 900 ton, jacket type foundations of 600 ton and transition pieces of 300 ton.

[dutchoi.com] – TFliner XL data sheet

Suction Bucket Foundation Offshore Wind Turbines

Advantages 8 m deep suction buckets over 25-30 m deep hammered monopiles: no noise, easier to decommission. Suitable for water depths of 30-60 m and larger wind-turbines like 10 MW.

Suction caissons (also referred to as suction anchors, suction piles or suction buckets) are a new form of fixed platform anchor that have a number of advantages over conventional offshore foundations, mainly being quicker to install than deep foundation piles and being easier to remove during decommissioning. Suction caissons are now used extensively worldwide for anchoring large offshore installations, like oil platforms, offshore drillings and accommodation platforms to the seafloor at great depths. In recent years suction caissons also see usage for offshore wind turbines in more shallow waters.

[youtube.com] – how the ‘suction bucket’ technique works (Guardian)

[wikipedia.org] – Suction caisson

Read more…

Sif Awarded Trianel Windpark Borkum II Monopile Contract

Sif Group in Roermond, the Netherlands, has been awarded to deliver all required 32 monopiles of 1,000 ton each, carrying 6.2M152 turbines. The new windpark Borkum-II will be located in the German sector of the North Sea and will have a nameplate power of 203 MW.

1 monopile: think 1200 cars worth of steel.

[offshorewind.biz] – Sif-Smulders Team Bags Trianel Windpark Borkum II Contract
[subseaworldnews.com] – Sif to Build Trianel Windpark Borkum II Monopiles
[wikipedia.org] – Trianel Windpark Borkum
[sif-group.com] – Company site

Sif Group is expanding its offshore activities from Roermond in the East of the country to the newly build reclaimed land Maasvlakte.

Read more…

Floating Wind Turbines

For shallow waters like in the North Sea, fixed monopile-based wind turbines are preferred. But for deeper waters this option doesn’t exist. Nevertheless there are very lucrative wind locations, for instance between Britain and Norway or West of Ireland in the Atlantic and that’s just Europe. With floating wind turbines these wind resources can be utilized as well.

Currently many floating wind turbine projects are in the pipeline:

Floating Wind Projects

Project name Capacity Country Expected commissioning date
Hywind Scotland 30 MW Scotland 2017
Kincardine 48 MW Scotland From 2018
Dounreay Tri 2 x 5 MW Scotland 2018
WindFloat Atlantic 30 MW Portugal 2018-2019
French pre-commercial farms 4 x 25 MW France 2020
Atlantis/Ideol project 100 MW UK 2021
Gaelectic 30 MW Ireland 2021

[cleantechnica.com] – European Floating Offshore Wind Ready For The Big Time

[dnvgl.com] – Electrifying the future
[windeurope.org] – Floating Offshore Wind Vision Statement (pdf, June 2017)
[wikipedia.org] – Floating wind turbine

Veja Mate Offshore Wind Farm Installation

[wikipedia.org] – Veja Mate Offshore Wind Farm (402 MW)

Global Offshore Wind Speeds Ranking

[source]

Global data resource with more than 1,000 offshore locations that could be used for building wind farms. The data set is ordered after average wind speed. Every location links to information about the status of the wind farm, if any.

Spoiler: best location is Taiwan Strait.

[4coffshore.com] – Global Offshore Wind Speeds Rankings

Country Ranking Cumulative Offshore Wind

[gwec.net] – Offshore wind power

China Threatens Philippines With War Over South China Sea

[source] The near future, “People’s Liberation Army” storming the beaches of the Philippines?

China’s president warned the Philippines that it would go to war if Manila insisted on enforcing an international arbitration decision rejecting China’s claims over disputed areas of the South China Sea, the Philippine president said in a televised speech on Friday, May 19.

Xi’s threat was unmistakable. This was Xi’s message: “We’re friends as long as you accept the fact that the South China Sea is ours, all of it including the portion you call the West Philippine Sea. As long as you accept this, we will provide you with generous loans to fund your infrastructure projects. But if you drill for oil there, we will declare war on you.”

Philippines president Duterte going public and spilling the beans about Chinese threats, possibly in an attempt to seek international (read: American) help, after the UN has declared Chinese claims null and void?

The reason for this sudden aggressive tone could be the successful Chinese effort to begin to continuously mine methane hydrates, 9 days earlier in the South China Sea. Estimates of 150 billion cubic meters of natural gas equivalent, that is 50 years Chinese oil consumption equivalent. An additional advantage would be that China could shift from dirty coal to natural gas, alleviating Chinese cities pollution.

[nytimes.com] – Duterte Says Xi Warned Philippines of War Over South China Sea
[usa.inquirer.net] – Why China will declare war if PH drills for oil

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