The largest offshore windfarms to date have cost multi-billion euro’s. Wind Farm Layout Optimization Problem or WFLOP is an important consideration. Can we build random numbers of large wind turbines in the North Sea without harvesting substantial lower energy per turbine?
Gemini wind farm data: 150 turbines of 4 MW each, area 68 km2 or 0.453 km2/turbine, total weight heaviest wind tower 1.347 ton (monopile, transition piece, nacelle and rotor with blades), rotor diameter 130 m. Assuming a layout with square cells, this would correspond with a rib of 673 m or 5 rotor diameters (5D).
But for very large grids with a size much larger than the height of the atmosphere other rules of thumb apply:
For realistic cost ratios, we find that the optimal average turbine spacing may be considerably higher (∼ 15D) then conventionally used in current wind-farm implementations (∼ 7D).
[kuleuven.be] – Optimal turbine spacing in fully developed wind-farm boundary layers
If we were to expand the Gemini wind farm over the entire North Sea, in so far it is suitable for monopile construction (200,000 km2), we would arrive are a grid of squares with a rib of 15 * 130 m = 1950m or an area of 3.8 km2/turbine. Total turbine in the North Sea: 200,000/3.8 = 52,631 turbines of 4 MW each or 211 GW in total.
[researchgate.net] – The Wind Farm Layout Optimization Problem
hindawi.com] – Wind Turbine Placement Optimization (Monte Carlo Simulation)
[fenix.tecnico.ulisboa.pt] – Offshore Wind Farm Layout Optimization Regarding Wake Effects and Electrical Losses
[geminiwindpark.nl] – Gemini wind park feiten | cijfers
[youtube.com] – Berlin – Take My Breath Away
The world’s largest wind turbine manufacturer Vestas wants to add storage facilities to its wind farms, hence the new relationship with battery manufacturer Tesla. With an ever increasing installed base of wind power, with a supply of electricity that is inherently variable, storage is becoming increasingly important.
Tesla wants to expands its customer base and move beyond car batteries and home powerwalls.
Inspired by the success of offshore wind in the North Sea, prospects for offshore wind to take off in the North Atlantic and Gulf of Mexico look good.
This push may be enough to usher a multi-gigawatt surge in US offshore wind development, led by the first commercial wind farm off Block Island, Rhode Island, commissioned in December 2016. With well-capitalized and experienced offshore wind developers such as Dong Energy, Statoil and Iberdrola eager to demonstrate their 15 years of European offshore wind know-how, it is likely that positive offshore wind market forces can be sustained in the US in the upcoming years… there is a potential capacity for more than 14GW of offshore wind in sites already leased on the US outer continental shelf, which could spark investments of up to $50bn if fully developed.
[rechargenews.com] – Gulf of Mexico will benefit from coming wave of US offshore
A wind tower is essentially a support structure to carry the nacelle and rotor. The wind turbine company Lagerweij conceived that a large crane used to build up the huge wind power structure is not necessary at all, but that the wind tower under construction can serve as its own crane. This reduces the construction cost of a wind turbine considerably. Additionally, more areas become suitable for placement of wind towers that were inaccessible for heavy cranes before, like dikes, mountain ridges or draughty terrain.
Giant cranes like the one here in Austria won’t be necessary anymore [1:29].
In a move that could be interpreted as a clear sign of confidence in its own renewable energy strategy, Denmark’s Maersk sold its oil and gas division A.P. Moller-Maersk A/S to French oil giant Total. Three months earlier the Danish company Dong Energy (Danish Oil and Natural Gas) sold its North Sea oil and gas production to German-based Ineos AG. Dong apparently wants to concentrate on its offshore wind core business.
Currently Denmark produces 40% of its electricity from renewable energy and plans to achieve more than 50% in 2020. Paradoxically Denmark would not be a major player in offshore wind without the experiences gained in offshore oil first. It looks like Shell is going down the same path.
With the current alarming news coming in from the climate change front, the prospects for offshore wind look extremely good, especially in the North Sea, were 90% of the world’s offshore wind activities are centered. Only a sudden real breakthrough in the field of nuclear fusion could ruin the prospects for offshore wind business.
[bloomberg.com] – World’s Biggest Wind Turbine Maker Waves Oil Industry Goodbye
You can’t be a great power if you have no functioning efficient energy base. In the 20th century that #1 power was the United States and its oil-based economy. In the 19th century that #1 power was Britain and its coal and steam-engine. In the 17th century the #1 power was the Netherlands and its windmill-based economy. Thousands of windmills were used to pump water away to claim new land and sawmills produced the planks with which the Dutch could build a fleet of 30,000 ships, three times more than the rest of the world combined, used to set up a global empire and en passant to keep the English away.
The lesson for the 21st century is that again that political unit will be the geopolitical “top dog” who embraces a new energy base first. That energy base can only be a renewable energy base, born out of the necessity to combat fossil fuel depletion and climate damage. A united Europe is well-placed to be that political unit and the only one with a coherent renewable energy policy (“completely fossil free by 2050”), but China is taking renewable energy serious as well. And although Washington has no real renewable energy policy worth mentioning, on a state level, like Texas and California, successful initiatives do exist. It is too early for anyone to claim victory.
[wikipedia.org] – Energy policy of the European Union
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]
[sif-group.com] – Sif projects
[energieoverheid.nl] – Nederland heeft voorlopig genoeg elektriciteit beschikbaar
[sif-group.com] – De razendsnelle realisatie van Sif op de Maasvlakte 2
[offshorewind.biz] – Dutch Steel: Manufacturer Geared Up for Offshore Wind
[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
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]
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.
[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
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
[source] Amsterdam Airport is the home of KLM
It all began with Dutch Rail, but now Schiphol Airport near Amsterdam wil also run entirely on renewable electricity as of 2018. For that purpose the energy producer Eneco for the next 15 years will deliver 200 GWh annually to Schiphol (64m), the third airport in Europe after London (76m) and Paris (66m) in terms of passengers and surpassed Frankfurt (61m) last year. The electricity will be entirely sourced from ‘Hollandse wind’.
The amount of electricity equals the consumption of a town like Delft (100,000) and will mostly be used for cooling and airconditioning. With 64 million passengers annually, each producing 120 Watt (or 150 Watt if the suitcase is very heavy) at a temperature level of 37 Celsius, there is very little need for space heating. Where Dutch Rail invested in 8 windparks all over Europe, Schiphol will be provided with electricity from new Dutch wind parks only.
Comment: this is exactly what you want to see happening, major top notch companies setting the tone in the energy debate. After Dutch Rail, Schiphol is yet another Dutch company that switches to 100% renewable energy for its (on-the-ground) operations. Expect other major companies not wanting to stay behind and provide themselves with a “green image” as well, creating a run on renewable energy.
This creates a new “problem”: there is not enough supply of renewable energy. However this “corporate green pull” will greatly stimulate offshore installation companies to expand their businesses, backed by fat, multi-year contracts with large companies, eager to show the world how green they are.
[schiphol.nl] – Royal Schiphol Group draait vanaf 2018 volledig op Hollandse wind
[parool.nl] – Schiphol stapt volledig over op Nederlandse windenergie
[wikipedia.org] – List of the busiest airports in Europe
[nos.nl] – Schiphol nu derde luchthaven van Europa
[deepresource] – Contracts Signed for 752 MW Offshore Wind of Dutch Coast
[deepresource] – Dutch Rail Runs 100% on Wind Power
[deepresource] – 100+ Companies Committed to Corporate Renewable Energy
[deepresource] – Electric Flying
[4coffshore.com] – Ports in NW-Europe with offshore wind facilities
Inventory of North Sea ports that function as hubs in the offshore wind construction boom. Esbjerg in Denmark is no doubt the #1 in scale. Other important hubs in no particular order:
Orange Blue Terminal, Eemshaven in The Netherlands.
Offshore Wind Port Bremerhaven in Germany.
Cuxhaven, Germany offshore terminal
[source] La Mancha, Don Quixote and Windmills. Nobody fighting the Spanish wind mills this time around.
The wind is blowing in the right direction for the European wind industry these days. 3 giant 1.2 GW wind projects have been given the green light, one Spanish onshore in North-East Aragon and two offshore in the North Sea off the coast of England: Hornsea I and East Anglia III, the first with 7MW Siemens wind turbines. The British projects are supposed to be completed by 2020 and 2025 respectively.
[wikipedia.org] – Hornsea Wind Farm
[wikipedia.org] – East Anglia Array
[reuters.com] – ScottishPower Renewables gets planning approval for 1.2 GW offshore windfarm
[genewsroom.com] – Forestalia Selects GE Renewable Energy to Provide 1.2 GW Wind Power in the Largest European Auction to Date
[renewablesnow.com] – Dong makes final investment decision on 1.2-GW wind project off UK
[ge.com] – Generation Next: Wind Already More Powerful Than All Nuclear Plants Combined
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.
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.
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.
[source] 350-mile dedicated power line will connect a substation at the wind farm with a substation near Tulsa to deliver the wind energy to customers.
Will be the largest in the US and 2nd largest in the world. Invenergy will cooperate with General Electric on The Wind Catcher project and install 800 GE 2.5 MW turbines. Operational mid-2020. Cost: $4.5 billion, including 350 miles of dedicated, extra-high-voltage power lines.
[invenergyllc.com] – Invenergy and GE Renewable Energy Announce America’s Largest Wind Farm
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:
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
Onshore wind turbine: 0,6MW, height = 50 m, rotor diameter = 40 m
|Part||Energy in GJ|
|Maintenance (20 year)||774|
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.
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.”
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.
Statoil of Norway busy constructing floating wind turbines for the Scottish Hywind projects.
Scotland makes impressive progress with installing renewable power. During the first half of 2017 124% of Scotland’s electricity needs were met from wind power alone. According to a report, Scotland could be fossil-free by 2030.