Wind Power

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German wind power output reached a new record this week, peaking above 33 GW overnight Tuesday, but dropped to just 1 GW by Friday, with coal and to a lesser extend also gas-fired power plants providing the flexibility needed to keep the system balanced, a Platts analysis of hourly generation profiles shows.


Windpower program

There is a considerable interest in wind power as a contributor to reducing our dependence on fossil fuel power sources. Unfortunately, the whole area is bedevilled by misunderstandings about precisely how much power can be obtained from wind turbines of all sizes and what exactly is their economic value. The WindPower program is aimed at clarifying some of these uncertainties. It is intended for both individuals and organisations.
The UK Wind Speed Database program is intended to present the Department of Energy and Climate Change's database in a more user-friendly form and to give users a better feel for the link between wind speed profiles and topography. Clearly, it is of use mainly to those concerned with UK wind power.
In addition to the WindPower and UK Wind Speed Database programs, this website covers a number of general issues associated with wind power such as wind statistics, the calculation of mean power, maximum turbine efficiency and the intermittent nature of wind power. The web pages on these topics can be navigated to from the technical webpage menu on the left. There is a also a reference library web page from which various publications and papers on wind power can be downloaded. This web page also gives access to accreditation test reports on a number of small turbines. Finally, there are a few videos on wind power which visitors to this site may find useful.

Wind Power (Technology and Economics) Electropaedia - Battery and Energy Technologies

Though modern technology has made dramatic improvements to the efficiency of windmills which are now extensively use for electricity generation, they are still dependent on the vagaries of the weather. Not just on the wind direction but on the intermittent and unpredictable force of the wind. Too little wind and they can't deliver sufficient sustained power to overcome frictional losses in the system. Too much and they are susceptible to damage. Between these extremes, cost efficient installations have been developed to extract energy from the wind.

capacity factor

Calculating the mean power

"It should be noted that there is never a practical circumstance where the mean power output reaches anything like the rated power output. It is therefore a very misleading practice when the rated output of a wind turbine is quoted as if this was the available power from an installation. It has caused great confusion in discussions about the power contributions that wind turbines can make."

The capacity factor of wind John Morgan; Brave New Climate; 8 Nov 2015

Australian wind fleet data

The capacity factor of wind John Morgan; Brave New Climate

Australia wind fleet data

UK offshore wind capacity factors – a semi-statistical analysis Roger Andrews; Energy Matters; 6 Oct 2017

The average capacity factor at 28 operating UK offshore wind farms is 33.6% (most recent 12-month average) and 34.5% (lifetime), increasing to 36.1% and 37.5% when four demonstration projects are discarded. There is a dependence of capacity factor on age, with older farms showing capacity factors of around 30% and younger ones factors of around 40%. This is interpreted to be a result of increased turbine sizes, with taller modern turbines accessing higher wind speeds at higher elevations. There is no evidence for significant degradation of turbine performance with time. A “generic” UK offshore wind farm coming on line in 2017 can be assumed to have a capacity factor of around 41%, although projections indicate that the turbines planned for the Hornsea II farm discussed in previous posts could have capacity factors exceeding 60%.
The data used in this post are from Energy Numbers. I have no way of verifying these data but have assumed them to be correct.

UK offshore wind capacity factors Andrew; Energy Numbers; 27 Jan 2017

Here are the average capacity factors for offshore wind farms in UK waters, newly updated to include data to the end of December 2016. And you might be interested in comparing these with the capacity factors and load-duration curves for Belgium, Denmark and Germany.


UK Wind Constraint Payments Euan Mearns; Energy Matters; 5 Sep 2016

Electricity generation from wind power has grown dramatically in the UK in recent years (Figure 2) and so has the challenge to balance the grid, especially when it is very windy. One of the balancing tactics deployed by National Grid is to pay wind farms to switch off when it is windy. This cost, borne by the consumer, is called a constraint payment. In 2015, UK consumers forked out £90 million to pay subsidy driven wind farms to switch off. The amount of UK wind that is constrained is growing with the level of penetration. At 10% wind penetration, 6% of the wind power available is constrained.

wind drought

‘Wind drought’ may have long-term implications for US energy power generation

Drop in wind levels affected states from Washington to Florida, caused wind power output to fall dramatically short of expectations – Rife


U.S. Offshore Wind Power Industry Emerges Off Rhode Island Bloomberg

The U.S. Energy Department has invested more than $300 million in offshore wind research, development, and demonstration projects. The U.S. has more than 4,000 gigawatts of potential offshore wind capacity located within 50 miles (80 kilometers) of U.S. coasts, Jose Zayas, office director for the Wind and Water Power Technologies Office at the U.S. Energy Department, said by e-mail.

Eight-MW giant makes offshore wind power cheaper Christine Rüth;; 5 Sep 2016

A new offshore wind turbine from Siemens is set to lower the cost of wind power generated on the high seas. Siemens believes it is well on the way to reaching its goal of producing offshore wind energy at a total cost of less than ten euro cents per kilowatt-hour (kWh) by 2020. In fact, it expects that generation costs for offshore wind power plants will decline to less than eight cents per kWh by 2025. Siemens and other companies in the wind energy business agreed on this target at the beginning of June 2016. Siemens' new wind turbine can generate eight megawatts (MW) of electrical power – previous systems were capable of no more than seven MW. The new turbine has a rotor diameter of 154 meters, which is the same as its predecessor model, but it can generate up to ten percent more energy per year, depending on its location. That is enough to supply 8,000 households with electricity.

Offshore wind turbine system that can be completely pre-assembled and pre-commissioned in controlled harbour conditions; 18 Oct 2016

Thanks to an innovative offshore wind turbine construction process developed by the ELISA project, this traditional barrier to the use of wind energy has finally been overcome. This innovation, the ELISA technology 5MW fully operational prototype, is located in the Canary Islands and is the first bottom-fixed offshore wind turbine completely installed without the need for costly and scarce heavy-lift vessels.


Floating wind-farms – unlocking energy on the ocean Stephen Tindale; Climate Answers; 15 Aug 2016


Giant Wind Turbines Now At Eight Megawatts, And Getting Larger Peter Kelly-Detwiler; Forbes; 1 Jan 2017

News arrived in late December from the waters off the United Kingdom that the first of MHI Vestas (a joint venture between Vests and Mitsubishi Heavy Industries) 8.0 megawatt (MW) turbines is now delivering commercial power to Dong Energy’s Burbo Bank Extension. The entire 258 MW project – to be completed in Q1 of 2017 – will need only 32 such turbines. This is a significant milestone, as wind turbines have become increasingly more powerful over a relatively short timeframe. This 8 MW machine is currently the largest commercial turbine in the world. Less than ten years ago, at the original Burbo Bank project, a 3.6 MW turbine was inaugurated, the largest in the industry at the time.
As large as they are, turbine expansions have not yet fully maxed out. The industry is already eyeing machines in the 10-12 MW range in order to future cut costs. And while MHI Vestas is the first out of the block with its deployment of an 8 MW machine, two other manufacturers have 8 MW machines in the offing. Meanwhile, here in the U.S., Deepwater Wind just energized five of its 6 MW GE turbines. So the big machines are not just limited to offshore Europe.

Researchers' idea will blow you away: 656-foot long blades on wind turbines Rob Nikolewski; Los Angeles Times; 13 Mar 2016

Efforts to increase wind power mean that turbine blades are getting bigger and bigger. But a new design in the works takes the idea to levels most people can barely imagine: Blades up to 656.2 feet long — more than two football fields. Today's longest blades are 262.5 feet. The blades at Imperial County's Ocotillo wind farm, which sends electricity to San Diego, are 173.9 feet long.

Palm Trees Inspire UVA Team’s Revolutionary Design for Offshore Wind Turbines Elizabeth Thiel Mather; University of Virginia; 11 Dec 2015

In 15 years, a forest of giant wind turbines – able to protect themselves in severe weather by folding in their rotor blades like palm trees in a hurricane ­– could be planted off the coast of Virginia, delivering enough energy to power as many as 500,000 homes, thanks to research that has earned a $3.56 million federal grant for the University of Virginia School of Engineering and Applied Science.
A large offshore wind farm has been commissioned for construction beginning in 2016 off the southern coast of the United Kingdom, and is planned to have 32 turbines sized at 8 megawatts each, equivalent to the power needed for 180,000 homes.

Watch MidAmerican build tallest wind turbine in the U.S. Donnelle Eller; The Des Moines Register; 29 Jun 2016

It took about 30 weeks, but MidAmerican Energy has built the tallest land-based wind turbine in the nation in southern Iowa.The Des Moines-based power company captured construction of the 379-foot concrete turbine in a video posted on YouTube
The foundation alone required about 70 trucks of concrete and 90 tons of steel rebar. Altogether, the tower has about 80 miles of reinforcing steel running through it. The 2.4-megawatt wind turbine weighs an amazing 1,200 tons.


Try not to jiggle while watching these amazing bladeless wind turbines Jon Comulada; UpWorthy; 12 May 2016

A startup in Spain has created a wonderfully innovative alternative to traditional wind turbines.

New Whirlwind-Attracting Bladeless Micro Wind Turbine Gets Harvard Cred Tina Casey; CleanTechnica; 1 May 2015

The startup Vortex Bladeless is developing a — you guessed it — bladeless micro wind turbine shaped like a super-long popsicle stick only rounder, like an ice cream cone without any ice cream. From a distance it looks like a pole stuck in the ground, so at first glance you might thing that there isn’t anything there. However, the technology does generate electricity, and it has attracted interest from Harvard University as well as SunEdison’s TerraForm Power renewable energy unit and Dat Venture, a startup incubator recently launched by the IT consulting firm Efron Group, so you’re probably going to start hearing more about Vortex Bladeless sooner rather than later.

Windstalk concept is a wind farm without the turbines Darren Quick; gizmag; 13 Oct 2010

Devised as a potential clean energy generation project/tourist attraction for Abu Dhabi’s Masdar City, the Windstalk concept consists of 1,203 carbon fiber reinforced resin poles, which stand 55 meters (180 feet) high and are anchored to the ground in concrete bases that range between 10 and 20 meters (33-66 ft) in diameter. The poles, which measure 30cm (12 in.) in diameter at the base, tapering up to a diameter of 5cm (2 in.) at the top, are packed with a stack of piezoelectric ceramic discs. Between the discs are electrodes that are connected by cables that run the length of each pole – one cable connects the even electrodes, while another connects the odd ones.

Bladeless Wind Turbine — Reality Check guest contributor; CleanTechnica; 21 May 2015

The Vortex Bladeless wind turbine ... is, unfortunately, yet another example of an impractical, uncompetitive wind turbine that is getting too much hype for its extremely weak results and potential. The Vortex Bladeless wind turbine has essentially the same problems that all micro-wind turbines have. Wind non-experts don’t seem to understand these well enough to avoid big mistakes in their coverage ...

Bladeless Wind Turbines May Offer More Form Than Function Phil McKenna; MIT Technology Review; 27 May 2015

Startup Vortex Bladeless makes a turbine that looks intriguing, but it may not solve wind power’s challenges.

kite power

Kite power - notes by David MacKay 14 Dec 2008 (updated 21 Apr 2011) PS copy

High Altitude Wind Power Reviewed Euan Mearns; Energy Matters; 4 Jul 2016

This post reviews the weird and wonderful world of high altitude wind power. It looks into the reasons for wanting to go high, explains tethered flight and explores the main competing technologies of
1) airborne generation (Google Makani) and
2) ground based generation (KiteGen) and compares their strengths and weaknesses.

Kite Power Solutions

Has 2 kites on single generator shaft

Kite Power Solutions website

One of world's first kite-driven power stations to open in Scotland Ian Johnston, Environment Correspondent; Independent; 6 Oct 2016

One of the world’s first commercial-scale, kite-driven power stations is set to be created near Stranraer in Scotland
Kite Power Systems has already demonstrated a small kite-driven power station in Essex. now plans to build a 500-kilowatt system at the Ministry of Defence’s West Freugh Range near the southern Scottish town after securing planning permission. This will be the first of a significant scale in the UK and only the second in the world after a research project in Italy. The kites fly to heights of up to 450m in a figure-of-eight pattern, pulling a tether as they rise which turns a turbine that produces electricity. By having two kites working in tandem, one going up as the other floats back down, electricity can be generated continuously. David Ainsworth, business development director at Kite Power Solutions, the firm behind the system, told The Independent that the system was mainly designed to be used offshore with the West Freugh power station designed to demonstrate its capabilities. “Our systems basically float and the cost of the mooring is much lower than a wind turbine,” he said. He said traditional offshore wind turbines needed to be kept upright in the sea, so the mooring had to be quite rigid, adding to the cost. “They are talking about 10 euro cents per kilowatt-hour [for the electricity produced], we’re basically going to halve that,” he said. “We’re very optimistic we’ll have several hundred megawatts installed by 2025.” A full-sized kite will be 40 metres wide and be capable of generating two to three megawatts of electricity, about the same as a 100m conventional turbine.
“The number of days we won’t be generating is very few, less than 10 days a year,” Mr Ainsworth said. “The number of really, really still days you get offshore is very small.”
On the rare still days, a small fan is used to keep the kite aloft so it can start generating as soon as the wind picks up. The project has received backing from oil company Royal Dutch Shell and the UK Government.

Kite Power Systems

Kite/wing with single tether Kite Power Systems website


Flying wing, 2 tethers. Aerodynamic Lift – something for nothing? Euan Mearns; Energy Matters; 10 Oct 2016

Discussion of Mearns' work with KiteGen, principles and projected performance of their product etc

High Altitude Wind Power Reviewed Euan Mearns; Energy Matters; 4 Jul 2016

Euan Mearns' post about high altitude wind power generally also has more information on the Kite Gen approach

Tethered helicopter

Flying Electric Generators Sky Wind Power

Many means have been proposed for capturing the energy available in high altitude winds, but only those people who have not carefully considered the state of current technology doubt that capturing this energy should be achievable now. After much study on the various methods for capturing high altitude winds, we settled on a “Flying Electric Generator” (FEG), or a “rotorcraft”, for addressing the world’s major energy and global warming problem objectives. This was first proposed by Bryan Roberts. In the mid-2000s, he obtained a patent for a “Windmill Kite”, a variation of which we call a flying electric generator. We believe the FEG technology will lead the way in capturing the energy at these truly high altitudes where the very high altitude wind energy exists.
We submitted a peer reviewed paper “Harnessing High-Altitude Wind Power” of the IEEE Transactions on Energy Conversion, Vol 22, No.1, in March, 2007. It was co-authored by Ken Caldeira and Elizabeth Cannon, Dean of the Schulich School of Engineering, University of Calgary.

Balloon / Aerostat mounted turbines

Altaeros Energies

Helium-filled Buoyant Airborne Turbine

Introducing the Altaeros BAT: The Next Generation of Wind Power altaerosenergies; YouTube; 20 Mar 2014

Altaeros Energies is announcing the first planned commercial demonstration of its BAT (Buoyant Airborne Turbine) product in partnership with the Alaska Energy Authority. The Alaska project will deploy the BAT at a height of 1,000 feet above ground, a height that will break the world record for the highest wind turbine in the world. Altaeros has designed the BAT to generate consistent, low cost energy for the remote power and microgrid market, including remote and island communities; oil & gas, mining, agriculture, and telecommunication firms; disaster relief organizations; and military bases. The BAT uses a helium-filled, inflatable shell to lift to high altitudes where winds are stronger and more consistent than those reached by traditional tower-mounted turbines. High strength tethers hold the BAT steady and send electricity down to the ground. The lifting technology is adapted from aerostats, industrial cousins of blimps, which have lifted heavy communications equipment into the air for decades.

Tethers and airspace

Airspace concerns StratoSolar

The platforms at 20 km altitude (65,000 feet) are far above commercial aircraft, in unregulated airspace and present no hazard to aviation. The main airspace concern is the potential hazard of tethers to aviation.
Background: High altitude tethered aerostats are not new. There have been tethered aerostat radars suspended almost permanently at 4.8km altitude along the southern US border since 1980. The company TCOM provides a wide range of tethered aerostat solutions, primarily to the military. TCOM aerostats have flown as high as 10km.
What is new is:
  • the tethered platform altitude of 20km which places tether hazards in Class A airspace
  • the permanent nature of the platform and tethers
  • a potential increase in the number of systems deployed.


Germany Faces Huge Cost Of Wind Farm Decommissioning

In Germany, more and more wind turbines are being dismantled. The reason: subsidies are running out, the material is worn out or it is simply more profitable to replace old wind turbines with new ones. The dismantling, however, is extremely complex and expensive.

rare earth production

Big Wind’s Dirty Little Secret: Toxic Lakes and Radioactive Waste

safety / failures

Forget Eagle Deaths, Wind Turbines Kill Humans James Conca; Forbes; 29 Sep 2013

comparison of safety of wind, coal and nuclear, with suggestions for improving the former
humans need about 3,000 kWhrs per person per year to have what we consider a good life (United Nations Human Development Index). In the old days, you generally needed to own a few people to get that much energy. The advent of coal, followed by hydro, gas and nuclear, changed all that, and raised 4 billion people up out of abject poverty, saving billions of man-years, perhaps more than offsetting these other collateral deaths.

Wind Industry In Freefall: Wind Turbines Keep Dropping Like Flies & Hard Hats Won’t Help StopTheseThings; 7 Jan 2015

list of wind turbine collapses from an anti-wind power site whose byline is "We're not here to debate the wind industry, we're here to DESTROY IT!", which also dubs itself "THE TRUTH ABOUT THE GREAT WIND POWER FRAUD".


Bat Killings by Wind Energy Turbines Continue Amy Mathews Amos; Scientific American; 7 Jun 2016

A research review published in January of this year found that wind turbines are, by far, the largest cause of mass bat mortality around the world. White-nose syndrome, the deadly fungal disease that has decimated bat populations throughout the northeastern U.S., came in second. Biologist Cris Hein of the nonprofit group Bat Conservation International says that if the current industry practices continue and wind turbine installation grows, bat populations already weakened by the fungus will crash. Industry has balked at holding the blades still at higher wind speeds, however, saying the energy loss will be larger than scientists claim


Factcheck: Whale strandings and offshore windfarms Simon Evans; Carbon Brief; 26 May 2017

Last Saturday, two dead whales washed up on the coast of Suffolk, in eastern England, and a third was spotted floating at sea.
What happened next illustrates how news can spread and evolve into misinformation, when reported by journalists rushing to publish before confirming basic facts, or sourcing their own quotes.
The death of the whales generated a lot of media attention in the UK. However, much of the coverage was based on the speculation of one volunteer coastguard. The three whales became a “family”, even though they were each from a different species. And their deaths were pinned on noise from offshore windfarm construction, even though pile-driving at a nearby site finished two months ago.
Carbon Brief has spoken to half a dozen experts on whales and underwater noise to try to get to the bottom of the story. Our findings cast huge doubt over whether offshore windfarms were to blame for the whale deaths, as implied by much of the media coverage.