Wind power in Denmark, 2006. ©

By Dr V.C. Mason (March 2007 )

Almost a fifth of the electricity produced annually in Denmark is generated by wind, yet only about 6% of the country’s electricity demand is satisfied directly from this source. Possibly two-thirds of its wind power output cannot be used to satisfy domestic needs at the moment of generation, and has to be exported (often at reduced prices) to preserve the integrity of the grid. Savings in carbon emissions are minimal. Public opposition and reduced subsidies have halted the deployment of on-shore wind turbines for the time being, but political and commercial interests are pressing to integrate much larger amounts of wind power into radically altered domestic and international transmission systems.

1. Background

With no nuclear power stations of its own, Denmark (pop. c. 5.4 million) generates the bulk of its domestic electricity by burning fossil fuels at its c.16 central and 728 local combined heat and power (CHP) plants. These are modern installations, capable of operating at up to 85-90 percent efficiency ( 75). In 2003, Denmark was the world’s seventh biggest consumer of imported coal per head of population ( 32). Its gas requirements are currently met by its North Sea reserves.

The country’s state-owned (Energinet.dk) electricity transmission system consists of unconnected grids located west and east of the Great Belt, respectively. These serve not only domestic needs, but they also help in the transfer of hydro-, nuclear- or coal-based electricity between neighbouring countries via long-established inter-connectors (total capacity to Norway, Sweden and Germany: 5.19 GW) ( 25). When water levels in the Norwegian and Swedish hydro-reservoirs are adequate, the international transfer of power is usually in a southerly direction, but when extended dry periods prevail in Scandinavia the net movement of electricity is typically northwards.

To reduce its reliance on fossil fuels, over 20 years ago Denmark initiated a very comprehensive programme to develop different sources of renewable energy. Today, its domestic wind industry employs about 20,000 people and satisfies a major part of the world market for wind turbines ( 48). In 2005, the country operated 5,267 wind turbines (total capacity: 3.126 GW) ( 21), including about 200 (i.e. 0.42 GW) offshore machines ( 27) . About 77 percent of these are located in the western region where their concentration per head of population is amongst the highest in the world.

2. Features of Danish wind power production

Spacing and turbine size

To prevent the turbulence of air from adjacent machines reducing the output and economy of wind electricity production, turbines must be separated by more than 7 to 10 times their rotor diameter (current spacing: 550 - 750 metres at Horns Rev and Nysted offshore windfarms). At Nysted Offshore Wind Park, it has been found that with some wind directions, production falls from 100 to 60 percent from the first to the last turbine in a row. A reduction in wind speed of 1 m/s has also been observed about 2 km down-wind of the wind park ( 10). One consequence is that Danish turbines are widely dispersed, and most land-based machines are embedded in distribution networks of under 100 kV (i.e. beyond the direct control of grid operators ( 03)). Horns Rev is connected via 150 kV sea and land cables.

Economy and productivity are also sensitive to turbine height. At average onshore locations, a free-standing 100-metre-high 2MW wind turbine can currently produce electricity for about DKK 0.49 / kWh, whereas a 144-metre-high 3.6 MW turbine at the same site can more than double the annual output at DKK 0.43 / kWh ( 14). For this reason turbines are getting bigger.

Load factors

Danish wind conditions are comparable to those found in most of England and Wales, but are somewhat inferior to those of western Scotland ( 73). During 2005, the annual load factor for Denmark’s carpet of wind turbines was about 24 percent (see 21). This is close to values of between 20 and 24 percent estimated for turbines in western Denmark in the previous five years. Such factors are of the same order of magnitude as those recently recorded onshore in most of England and Wales, but are lower than those found in Scotland or at offshore sites ( 50). Clearly, load factors are very sensitive to local wind conditions, turbulence, breakdowns, and blade accumulations of midges or salt, and have a big effect on turbine economy.

Variability of wind power production

Wind turbines operate ‘as the wind blows’, their productivity being related to the cube of prevailing wind speeds ( 35) up to about 13 metres / second. For Denmark’s carpet of turbines, production starts at about 4 m/s (Beaufort Force 3: Gentle breeze) and increases more or less linearly as the speed increases to 13 m/s (Beaufort Force 6/7; Strong breeze / Near gale). Above this, output is designed to level off, and at about 20 m/s (Beaufort Force 8; Gale) many machines trip out. Most modern turbines can operate above this wind speed with 20 percent lower output, but even these have to cease production at about 25 m/s to avoid structural damage in high winds ( 63; 66).

The electricity produced by wind bears little relationship to public demand ( 35). Strong winds in western Denmark can generate up to about 2.3 GW of power for a system in which total demand ranges between about 1.3 and 3.8 GW. An increase in wind speed from 9 to 11.5 metres per second at the Horns Rev off-shore station can double production from about 80 to 160 MW within a few minutes ( 29). Conversely, adverse conditions greatly restrict production ( 18). Throughout February 2003, for example, wind speeds and the generation of wind power in western Denmark were very low ( 17); while in January 2005 a hurricane forced turbines to shut down within hours of running at near maximum output ( 08).

Life expectancy

The mechanical nature and physical exposure of wind turbines makes them susceptible to considerable wear and tear. In larger machines, gearboxes and roller bearings are particularly prone to damage ( 43), and harsh offshore environments have caused several very expensive breakdowns in transformers and the components of turbines at Horns Rev ( 04; 30; 55) and Middelgrunden ( 47). It is claimed that wind turbines have a life-expectancy of over 20 years, although most machines scrapped before 2002 operated for less than 16 years ( 16). Clearly, maintenance and scrapping policies make it difficult to predict the potential life of a turbine.

Economic support

For many years, the production of ‘environmentally friendly electricity’ by renewable and CHP plants was under-pinned by massive economic support paid via electricity and heating bills. In 2001, turbine owners received DKK 0.60 / kWh ( 72) when the market price for electricity was about DKK 0.15 / kWh (1DKK = c. 9p). The extra annual capital and operational costs for the combined conventional + renewable energy package to this small nation were about DKK 8-10 billion ( 45). In 2003, a question in Folketing first revealed that annual subsidies for ‘obligatory purchase electricity’, ‘environmentally friendly electricity [sold] under market conditions’, ‘connection of wind turbines and decentralised CHP plants’ and ‘R&D’ for the period 2001 to 2005 varied between DKK 3.40 and 3.85 billion ( 12). Between 2002 and 2004 new subsidy was offered to replace 1,200 older wind turbines (< 150 kW) by 300 bigger ones ( 48). Consumers were even taxed on the wind power used.

Following a change in government, policy started to change in 2002 with a view to reducing subsidies and exploiting free-markets for the sale of electricity ( 26). The obligatory purchase scheme was abandoned, but owners of existing wind turbines and some district heating plants continued to receive subsidy ( 05; 48). To reduce the production of surplus power, it was decided that in due course district CHPs of over 5 MW would switch from the guaranteed three-step tariff payment to electricity production under free-market conditions ( 22; 29; 48).

Today, established wind turbines receive market price plus a supplement of up to DKK 0.10 / kWh (according to market price). Only for turbines erected after 1 st January 2003 does the total supplement remain intact. It disappears when turbines reach 20 years of age ( 14).

In 2004, a second ‘re-powering’ scheme was proposed to replace 900 turbines of up to 450 kW with 175 much larger ones ( 41; 58). The incentive was a subsidy of up to DKK 0.12 / kWh for the first 12,000 full-load hours, this partly compensating for the purchase and removal of earlier turbines prior to the granting of planning permission. The scheme has been poorly utilised because county authorities have found it difficult to allocate appropriate sites for bigger machines ( 14).

New 200 MW offshore wind parks are being built at Horns Rev and Omø Stålgrunde, respectively ( 13). The former is guaranteed a total price of DKK 0.518 per kWh for 11-12 years, irrespective of market price and irrespective of whether the electricity can be used in Denmark or must be sold at a loss to neighbouring countries ( 75). Future changes in energy policy (including a re-construction of the grids) may cost an extra DKK 5 billion per annum (see below, and 39).

A major draw-back of the various Danish subsidy regimes has been their promotion of unpredictable surpluses of wind power and (until recently) electricity from local CHP plants ( 59). Since these surpluses cannot be stored on an industrial scale within national boundaries ( 77), they have been disposed of abroad at considerable cost to the nation ( 28; 44, 65). In 2003, for example, such exports cost Danish electricity consumers about DKK 1 billion (roughly £100 million) ( 64; 65).

3. Power transmission and balance

Denmark’s demand for electricity is about one tenth of that of the UK, yet the capacity of its international inter-connectors ( 25) is considerably greater than England’s 2 GW link to France, offering it much greater operational flexibility ( 76; 77).

Although the amount of wind power currently produced (c. 6.6 TWh) equates to almost a fifth of Denmark’s annual demand for electricity (just over 35 TWh ) ( 75 ), two studies ( 64 ; 75 ) suggest that at the moment of generation possibly two-thirds of this wind power cannot be integrated into the domestic system and has to be exported. Direct access to the much bigger power systems of neighbouring Norway, Sweden and Germany is thus crucial for the disposal of such surpluses and the maintenance of balance and quality in domestic grids.

With the build-up of wind power, this problem has increased ( 03). During 2003, close relationships were observed between the generation of wind power and net exports of electricity from West Denmark ( 49; 64). Possibly 84 percent of the annual output of wind electricity was surplus to demand at its moment of generation ( 36; 64), and only about 4 percent of the region’s domestic power need was covered directly from this source ( 65). In 2004, wind power accounted for about 18.5 percent of all the electricity produced in Denmark, but could directly satisfy only about 6 percent of the country’s electricity consumption. Exports accounted for 70.5 percent of the total national generation of wind power, and were sold at an overall loss ( 75).

Both Norway and Sweden can absorb such surpluses by rapidly adjusting their production of hydro electricity or using power to pump water to elevated reservoirs for the later generation of electricity ( 76; 77). Against this, in windy conditions southern Jutland and northern Germany can experience difficulties with surpluses because of competition between the large amounts of wind electricity synchronously produced on either side of the border ( 56). This situation may worsen as Germany increases its offshore production ( 09).

Until recently, Denmark’s big requirement for regulating power and backup plant was mainly covered by its central coal or gas-burning power stations ( 38; 56), but since September 2005 closer integration with the wider Nordic markets means that these are now also available from the rest of Scandinavia ( 19). At the same time, small domestic CHP plants are starting to enter the market for regulating power ( 20).

4. Carbon emissions

Per head of population, Denmark is amongst the world’s biggest producers of carbon dioxide ( 32). Although the quantitative significance of man-made carbon emissions in the process of climate change remains unsettled, the fear of ‘global warming’ has been freely exploited to promote renewable energy. During 2000, Danish emissions amounted to only 0.0003 percent of the carbon dioxide released into the atmosphere from Earth ( 40), and so would have no detectable impact on climate. Fuel conservation and security of supply are more pressing issues ( 42).

With little or no permanent closure of fossil-fuelled power plant, and the export of most of its wind power, the country’s total emissions have not fallen significantly ( 15). A leading Elsam expert has intimated that with the present system increased deployment of wind turbines will not reduce Danish CO 2 emissions ( 49). This situation reflects the continual need for conventional backup plant to ‘shadow’ the output of wind power and balance generation to demand on the domestic grid ( 38; 56). Increased requirements for spinning reserve mean that some fossil-fuelled generators operate below optimum efficiency and produce greater amounts of CO 2 / kWh ( 76; 77).

Another reason for poor emission savings is that much of Denmark’s exported wind electricity simply displaces ‘green’ hydro electricity produced in Norway and/or Sweden, helping to replenish reservoirs only in dry periods ( 44; 76; 77).

A rarely mentioned factor is the emission cost of processes involved in t he manufacture, installation, maintenance, and subsequent dismantling of massive concrete foundations, turbine components, access roads, pylons, and associated equipment.

5. New approaches

With one eye fixed firmly on the world market for wind turbines and the other focused on security of fuel supplies, the Danish Government aims to decrease the consumption of coal, oil and gas by 15 percent, and increase the proportion of sustainable (largely wind) energy to at least 30 percent by 2025 ( 39). This goal can only be achieved if the country finds ways to integrate a much higher proportion of its wind power into its domestic power system or finds economically attractive options for disposing of large amounts of electricity abroad.

1) Improving turbine economy

To improve the economy and output of individual turbines, the Danish wind turbine industry has proposed that by 2025 at least 50 percent of the country’s electricity demand should be met by about 1,400 turbines, each of up to 150 metres total height. Since onshore turbines can deliver electricity 20 percent cheaper than corresponding offshore plant, it also proposes that the installed capacity should be spread equally between land and sea, the State sharing responsibility for their appropriate location ( 14). Clearly, if implemented, this plan would result in fewer but much larger wind turbines. (Some suggest that future offshore turbines may have a total height of 350 – 400 metres above sea level ( 33)). In any event, such developments would have immense implications for the aesthetic and environmental quality of Denmark’s countryside and coastal regions.

2) Reducing surpluses

As early as January 2002, it was suggested that Transmission System Operators must be able to stop heating-related electricity production when it is not required, and use surplus wind-power to replace coal, oil, and gas-fired heating whenever this is appropriate ( 02). Several approaches are now being examined:

i) Switch to market forces

Of Denmark’s 728 decentralised CHP plants (total capacity: 2.17 GW), 43 are of over 10 MW capacity, 56 plants are between 5 and 10 MW, and 629 plants are of less than 5MW. Recently, 123 of the larger plants (1.54 GW of total capacity) have started to supply the electricity market whenever spot-prices are high but to shut down when they are low. Some plants have also entered the market for regulating power to help balance fluctuating wind power. Despite growing interest, however, this market is currently attracting too few operators (and plants which are too small in size) to satisfy Energinet.dk’s need of very large reserves for both upward and downward regulation ( 20; 22).

ii) Wind power for heating water

In energy terms, hot water for district heating is produced most efficiently as a co-product of electricity production at CHP plants. For many years there was an absolute taboo on the use of electricity for heating. A special fund was even set up to subsidise householders to replace electrical radiators with water-based central heating ( 75).

In 2004 a political agreement favoured a U-turn in this policy in order to prioritise the opportunistic use of surplus wind power to heat water at both central and district heating facilities in place of some of the fuel currently burned there ( 64). It is expected that as soon as taxation difficulties have been resolved ( 57), legislation will be introduced to achieve this goal. If successful, this approach could promote a more even and predictable co-production of electricity, with smaller surpluses ( 60; 61; 62) and even a decrease in carbon emissions.

iii) Wind power for hydrogen production

The potential to use surplus wind electricity to produce hydrogen as an energy carrier for fuel cells (and subsequent electricity production) is also being considered ( 06). Storage and transport of this gas appear to be weak links in the process, another difficulty being that of procuring enough cheap electricity to secure the economy of the hydrogen plant. To displace hydrocarbons with hydrogen for transport purposes would require roughly nine times as much electricity as was produced by West Denmark’s turbine carpet during 2003 (see 64).

iv) Integration of CHP and wind power

Big changes in Denmark’s control strategy are clearly needed to provide an electricity system with the high security demands of a modern knowledge-based society. One suggestion is that decentralized plants should actively help in the maintenance of balance and quality, with closer integration of demand and system operation. Possibly thousands of electricity consumers will own and operate micro heat and power producing fuel cells in the future ( 38).

Energinet.dk thinks that local CHP and wind turbines must get away from operating as separate and passive generators in the lower voltage distribution networks, and is in the preliminary stages of testing the division of networks into large numbers of independent, highly automated ‘cells’, each incorporating fully integrated wind turbines and gas-fired CHP plants. The concept is that each cell will operate as an adjustable virtual power plant which can be controlled by the Watch at a regional control centre or Energinet’s national control room. Such cells must be able to automatically uncouple and run in isolation in the event of an impending fall in voltage ( 23; 24).

The regulating features of most of Denmark’s small decentralised CHP plants appear well suited to such an approach because a typical gas motor can be started and reach full load within 10 minutes (in contrast to central power plants which require many hours to accomplish this). One day the cell structure may also involve household CHP equipment, and it may become possible to run the electricity system without central power stations ( 24).

As part of plans to upgrade the basic infra-structure of the current transmission system, it is now proposed to establish inter-connectors between western and eastern Denmark ( 37; 61).

6. Public disquiet

For many Danes, the proliferation of wind turbines has seriously detracted from the former charm, beauty and peace of Danish landscapes and coastlines. It has also had a detrimental impact on home ( 33) and wildlife habitats ( 42).

In earlier years protests came mainly from the immediate neighbours of smaller turbines as well as electricity consumer organisations. Between 1998 and August 2000, over 600 complaints about these machines were received by the Environmental Complaints Board. In rural areas, most criticism related to shadow cast, glinting effects, noise, and aesthetic and local environmental considerations, a few cases alleging infringements of local regulations ( 52). In response to such disquiet some local authorities opposed the deployment of wind turbines on hill-tops, in areas dominated by burial mounds, at the edge of stream valleys, and in the immediate proximity of villages ( 74).

Landsforening Naboer til Vindmøller [i.e. The National Association of Neighbours to Wind Turbines] was set up specifically to protect the interests of people affected by these machines. Amongst other activities, it has given warnings to solicitors and estate agents concerning the scrutiny of planning applications and the reduction of property values close to turbines ( 46).

Local groups of citizens have taken direct action by obstructing the erection of turbines in environmentally sensitive areas. Such headlines as [“Turbine war”] ( 34), [“Farmers block wind turbines”] ( 53), and [“Site owners in road blockade”] ( 11) have appeared in national newspapers.

Little is known about the quantitative impact of wind turbines on birds and bats in Denmark’s largely agricultural countryside. A provisional assessment suggests that during daylight hours offshore turbines, such as those at Horns Rev, may not be a serious danger to bird life, less than one bird being killed annually per turbine ( 07). In contrast, within eight month’s of the opening of a windfarm on the island of Smøla in neighbouring Norway, nine Sea Eagles have been killed by these machines. Six of the birds were fully-developed adults whose loss will have dramatic consequences for a species with low fecundity and a potentially long life span. Last year radio-emitters were attached to six young eagles on Smøla, but already three of these birds have been killed ( 54). These Norwegian observations mirror those made for raptors and many other species of birds and bats in other countries. Clearly, inappropriately located wind turbines can have a devastating impact on wildlife.

With better understanding of the technical and environmental limitations of wind technology, public opposition has grown. Protests from citizens and lobby organisations have thwarted the erection of bigger wind turbines many places in the country, and this is one reason why turbine deployment has come to a virtual halt ( 51; 69; 71). One scientist even fears that public opposition may put Denmark’s wind technology at risk, with the Industry moving abroad ( 01). The Environment Minister is therefore prepared to put pressure on local authorities to grant planning permission for the new generation of massive turbines: “[We cannot continue to be the world leader for wind turbines if we do not make room for the turbines in our own country. Municipalities have a huge responsibility for the successful local development of wind turbines. And with my compliments I will tell them that if they cannot sort it out, we can prepare a directive about it]” ( 51). Clearly, the promotion of wind technology in Denmark is as much to do with commercial and political interests ( 39) as with conservation of fossil fuels.

7. Conclusions

a) At present, Denmark has the world’s highest concentration of wind turbines per head of population. Its 5,267 turbines (3.126 GW installed capacity) produce the mathematical equivalent of almost a fifth of the country’s annual demand for electricity, yet at the moment of its generation, only about one-third of this wind electricity (equivalent to the output of about 1 GW of installed wind capacity) can be used within national borders. In 2005, only about 6 percent of the country’s annual demand for electricity was supplied directly from this source, and this needed the continual backup of conventional fossil-fuelled generators.

b) Most of Denmark’s annual production of wind electricity has presently to be exported (at considerable economic cost) in order to secure the operational integrity of its conventional power transmission systems. This surplus is transferred to the grid systems of Norway, Sweden and Germany via international connectors (5.19 GW capacity) big enough to take the total output of the country’s wind carpet. Relative to average electricity demand, this capacity is about 25 times that of the UK, and without it Denmark would face serious difficulties maintaining the integrity of its grids and disposing of its large surges of wind power.

With its much lower capacity of international connectors and fewer ‘storage’ facilities, the UK cannot achieve comparable proportions of wind power penetration. Its electricity demand is about ten times that of Denmark, so without a massive re-build of infra-structure and inter-connectors, serious transmission problems may be expected to surface once the installed capacity of wind turbines reaches about 10 GW. This estimate is virtually identical to the maximum of 10 GW wind power capacity proposed for the UK in a more comprehensive study published in 2005 ( 67).

c) To resolve its present transmission problems and avoid the expensive generation of surpluses, Denmark is examining the opportunistic use of excess wind power for the resistance heating of water at district heating plants. It is also considering the manufacture of hydrogen as a fuel carrier. Both approaches appear feasible, albeit at considerable extra cost.

A more holistic long-term project aims to re-structure the whole transmission system, and fully integrate wind power with gas-fired local CHP plants in highly automated ‘cells’. It is predicted that these cells will operate as independent, adjustable, virtual power plants controlled by regional and national control centres. Major weaknesses of this approach are its high cost and operational complexity, and the long-term commitment of Denmark to potentially insecure supplies of natural gas (methane is itself an important greenhouse gas).

Only time will reveal the economic and technical feasibility of these approaches and, more especially, their potential to conserve fossil fuels or reduce carbon emissions in the holistic context. The Administrative Director of DONG Energy (Denmark’s biggest player in the wind turbine market) has commented : “[In the foreseeable future, wind power cannot solve the energy problem because it is too unstable and perhaps too expensive]” ( 68). Vattenfall’s Head of Information suggests that it is unrealistic to imagine that wind power can overtake other forms of energy within the next ten years ( 70). In any event, the irregular supply of wind power will continue to challenge the efficient operation of gas-fired backup plant.

d) In the highly politicised, commercial environment of wind technology (in which politicians are seeking to make Denmark a ‘Shop Window’ for their product ( 31; 39)), many Danes fear that the aesthetic quality of their countryside and wilder regions will continue to deteriorate as cherished landscapes, seascapes, and wildlife habitats become dominated by ever-taller wind turbines, with their associated access roads, pylons and cables. At the local level, opposition has already grown to a level at which national politicians are having to put pressure on Municipalities to find sites for bigger turbines.

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References

01) Aalborg University, 2006: “Kun få nye vindmøller i Danmark.” “[Only a few new wind turbines in Denmark].” Press coverage of an article published in Nyhedsavisen on 18 th October 2006. http://vbn.aau.dk/research/kun_faa_nye_vindmoeller_i_danmark(5096042)/

02) Andersen, P. 2002: “Eltra behøver nye metoder til at genskabe et solide elsystem.” “[Eltra needs new methods to re-establish a solid electricity system].” Eltra Magasinet, 1, January.

03) Andersen, P., 2003: “Der-ud-af uden speeder, rat, kobling og bremser.” “[Out there without accelerator, steering wheel, clutch or brakes].” Eltra magasinet, 1, January.

04) Andersen, P., 2004a: “Forskere endevender søsyge transformere.” “[Researchers scrutinise seasick transformers].” Eltra magasinet, 2, February.

05) Andersen, P., 2004b: “Staten overtager Eltra og Elkraft fra årsskiftet.” “[The State takes over Eltra and Elkraft from New Year].” Eltra magasinet, 4, April.

06) Andersen, P., 2004c: “Eltra støtter og får viden fra norsk vind/brint-projekt.” “[Eltra supports and gets information from Norwegian wind/hydrogen project].” Eltra magasinet, 8, October.

07) Andersen, P, 2004d: “Fuglene flyver uden om havmølleparker.” “[Birds fly around offshore wind stations].” Eltra Magasinet, 6, June-July.

08) Andersen, P., 2005a: “Da stormen tog til stod møllerne af.” “[When the storm increased the turbines switched off].” Eltra magasinet, 1, February.

09) Andersen, P., 2005b: “Tysk netstudie: Muligt at nå 20 procent vind om 10 – 15 år.” “[German grid study: Possible to achieve 20 percent wind in 10 – 15 years].” Eltra magasinet, 2, March.

10) Andersen, P., 2005c: “Mølleparker: Skyggevirkning mærkes fem kilometer borte.” “[Turbine parks: Shadow effect is felt five kilometres away].” Eltra magasinet, 4. June-July.

11) Andreassen, J., 2001: “Lodsejere i vejblokade.” “[Site owners in road blockade].” Berlinske Tidende, 20 th June.

12) Bendtsen, B., 2003: Parliamentary answer to Question S 4640, 2 nd September 2003. http://www.ft.dk/Samling/20021/spor_sv/S4640.htm.

13) Bendtsen, B. & Hedegaard, C., 2004: “Vindmøller i vælten.” “[Wind turbines in fashion].” Jyllands-Posten, 21 st September.

14) Bjerre, A., 2006: “Energipolitik. Tre anbefalinger til Folketinget.” “ [Energy policy. Three recommendations to Parliament].” Naturlig Energi, October.

15) Bruun, H., 2005: “Progress toward the Kyoto targets”. Danmarks Miljøundersøgelser. [National Environmental Research Institute, Denmark]. 15 th April.

16) Bülow, T., 2002: “Mange møller skrottes i utide.” “[Many wind turbines are scrapped prematurely].” Eltra magasinet, 10, December.

17) Bülow, T., 2003: “Den mest vindfattige februar nogensinde.” “[The most wind-deficient February ever].” Eltra magasinet, 4, April.

18) Bülow, T., 2004: “Guleroden væk – derfor småt med ny vindkraft.” “[No carrot – therefore little new wind power].” Eltra magasinet, 2, February.

19) Bülow, T., 2005: “Snart regulerkraft fra hele Norden.” “[Regulating power from all Scandinavia soon].” Eltra magasinet, 4, June-July.

20) Bülow, T., 2006a: “Regulerkraften halter bagefter.” “[Regulating power falls behind].” Energinet.dk’s Nyhedsmagasinet OmEnergi, 1, 2006.

21) Bülow, T., 2006b. “Skrotningsbeviser bag alle nye møller.” “[Scrapping certificates behind all new turbines].” Energinet.dk’s Nyhedsmagasinet OmEnergi, 2, 2006.

22) Bülow, T., 2006c: “De små værker tjener godt på regulerkraft.” “[Small plants earn well on regulating power].” Energinet.dk’s Nyhedsmagasinet OmEnergi, 5, 2006.

23) Bülow, T., 2006d: “Elsystemmets fremtid bygger på celler.” “[Electricity system’s future builds on cells].” Energinet.dk’s Nyhedsmagasinet OmEnergi, 4, 2006.

24) Bülow, T., 2006e: “Vestdansk elsystem mest under pres.” “[West Danish electricity system most under pressure].” Energinet.dk’s Nyhedsmagasinet OmEnergi, 4, 2006.

25) Bülow, T., 2007: Personal communication.

26) Dyrekilde, J., 2002: “Denmark to scrap supplements for wind power by 2004.” Reuters, 11, February.

27) Editor, 2004: “Dansk vindmøller på havet – enten opført eller på vej.” “[Offshore Danish wind turbines – either erected or on the way].” Eltra magasinet, 2, February.

28) Eltra, 2004: Annual Report 2003. (In English).

29) Eltra, 2005: Annual Report 2004. (In English)

30) Energinet.dk, 2005: “Nye problemer for møllerne på Horns Rev.” “[New problems for the turbines at Horns Rev].” Energinet.dk’s Nyhedsmagasinet OmEnergi, 1, 05.

31) Energinet.dk, 2007.: “Dansk vindkraft har tabt pusten.” “[Danish wind power is getting out of breath].” Energinet.dk’s Nyhedsmagasinet OmEnergi, 1, 07.

32) Energinet.dk, 2007: “Danmark er et stort kulsvin.” “[Denmark is a big coal pig].” Energinet.dk’s Nyhedsmagasinet OmEnergi, 1, 07.

33) Energinet.dk, 2007: “Giganterne kommer.” “[The giants are coming].” Energinet.dk’s Nyhedsmagasinet OmEnergi, 1, 07.

34) Gøttler, K., 2001: “Mølle-Krig.” “[Turbine war].” Ekstra Bladet, 21 st June.

35) Halkema, J.A., 2006: “Wind energy: Facts and fiction. A half truth is a whole lie.” http://www.countryguardian.net.

36) Harrington, M., 2006: “Study takes air out of wind power’s sails.” Newsday, 30 th October.

37) Havgaard, H., 2006. “Kabel over Storebælt financier sig selv.” “[Cable over the Great Belt will finance itself].” Energinet.dk. Nyhedsmagasinet OmEnergi, 1, 2006.

38) Jacobsen, S.H., 2006: “Professor vil have elsystemet til at tænke selv.” “[Professor wants the electricity system to think for itself].” Energinet.dk’s Nyhedsmagasinet OmEnergi, 5, 2006.

39) Jacobsen, S.H., 2007: “Energiministeren: Med flere vindmøller følger politisk ansvar for elsystemet.” “[Energy Minister: With more wind turbines comes more political responsibility for the electricity system].” Energinet.dk’s Nyhedsmagasinet OmEnergi, 1, 07.

40) Jyllands-Posten, 2001: “0.0003 pct.” “[0.0003 percent].” Editorial. 1 st September.

41) Jyllands-Posten, 2004a: “Energiforliget.” “[Energy agreement].” Editorial, 30th March.

42) Jyllands-Posten, 2004b: “Ud med møllerne.” “[Out with the turbines].” Editorial, 22 nd September.

43) Jürgensen, P., 2000: “Tekniske fejl tynger vindmølleindustrien.” “[Technical problems weigh down the wind turbine industry].” Maskinmesteren, December, 12.

44) Kongstad, J., 2001: “Grøn el sælges med tab.” “[Green electricity is being sold at a loss].” Jyllands-Posten, 26 th April.

45) Krogsgaard, O.T., 2001: “Energipolitik som vinden blæser.” “[Energy policy as the wind blows].” Politiken, 14 th January.

46) LNtV, 2000: http://www.naboertilvindmoller.dk/

47) Møller, T., 2005: “Erstatningskrav på 17 mill. Kr. for transformer-havarier.” “[Compensation claim of DKK 17 million for transformer damages].” Naturlig Energi, March.

48) Nielsen, S., 2004: “The Danish Wind Power Experience”, The Utilities Journal, OXERA. May Edition, 22-23.

49) Nissen, F., 2004: “ Hvordan kan vindkraft styrke danske energiselskaber på det europæiske marked?” “[How can wind power strengthen Danish energy companies in the European market]?” Elsam presentation at a conference “Vind eller forsvind”, held at the Dansk Design Center, Copenhagen, on 27 th May 2004. http://www.windpower.org/media(254,1030)/ELSAMFlemmingNissen.ppt

50) Oswald, J., Raine, M., Ashraf-Ball, H. &Murphy, E., 2006. “UK wind farm performance 2005, based on Ofgem ROC data.” Oswald Consultancy Ltd, 1 st November. (An assessment conducted for the Renewable Energy Foundation, London).

51) Pedersen, T., 2006: “Danskerne kæmper mod vindmøller.” “[Danes fight wind turbines].”

Nyhed fra Børsens Nyhedstjeneste, 17 th October.

http://borsen.dk/dagens-nyheder/tv2finans/?ids%5B%5D=96936

52) Pihl-Andersen, A., 2000: “Vindmølle-klager er mere end fordoblet.” “[Wind turbines – complaints more than double].” Jyllands-Posten, 14 th August.

53) Pihl-Andersen, A. 2001“Landmænd blokerer for vindmøller.” “[Farmers block wind turbines].” : Jyllands-Posten, 20 th June.

54) Ree, M., 2006: “Smøla vindpark er i ferd med å bli en katastrofe for havørna!.” “[Smøla windfarm is starting to become a catastrophe for Sea Eagles].” 9 th May. http://www.birdlife.no/naturforvaltning/nyheter/?id=43.

55) Renewable Energy Access, 2004: “Troubled wind farm undergoes dismantling.” 13th July. http://www.solaraccess.com/news/story?storyid=7116&amp:p=1.

56) Sandøe, N., 2003a: “Flere vindmøller skaber kaos.” “[More wind turbines cause chaos].” Jyllands-Posten, 4 th June.

57) Sandøe, N., 2003b: “Varmt vand af vindenergi.” “[Hot water from wind energy].” Jyllands-Posten, 5 th June.

58) Sandøe, N., 2004a: “Energiforlig sætter fart i møllerne.” “[Energy agreement speeds up the wind turbines].” Jyllands-Posten, 30 th March.

59) Sandøe, N., 2004b: “Planøkonomi erstattes af tilskud.” “[Planned economy replaced by supplement].” Jyllands-Posten, 30 th March.

60) Sandøe, N., 2004c: “Billig vindkraft til danske boliger.” “[Cheap wind power for Danish residences].” Jyllands-Posten, 28 th May.

61) Sandøe, N., 2005a: “Vindmøller kan varme boliger op.” “[Wind turbines can heat homes].” Jyllands-Posten, 17 th June.

62) Sandøe, N., 2005b: “Vindmøller skal opvarme boliger.” “[Wind turbines must heat homes].” Jyllands-Posten, 7 th October.

63) Sharman, H., 2003: “The practicalities of developing renewable energy in the UK – in the light of Danish experience.” Submission to the House of Lords Energy Committee.

64) Sharman, H., 2004: “Electrolysis for Energy Storage & Grid Balancing in West Denmark.” Work Group Report prepared for Energistyrelsen [Danish Energy Authority], August.

65) Sharman, H., 2005a: “Danes blow away wealth in wind power exports.” Financial Times, 24 May.

66) Sharman, H., 2005b: “Why wind power works for Denmark.” Proceedings of ICE. Civil Engineering, 158, 66-72.

67) Sharman, H., 2005d: “Why UK wind power should not exceed 10 GW.” Proceedings of ICE. Civil Engineering, 158, 161-169.

68) Stenvei, M., 2007: “DONG-chef: Vindenergi er for ustabil.” “[DONG Boss: Wind energy is too unstable].” Jyllands-Posten, 19 th January.

69) The Copenhagen Post, 2006: “Wind turbines: not in my backyard.” Internetavisen Jyllands-Posten, 18 th October.

70) The Copenhagen Post, 2007: “Energy giants say wind power is hot air.” 19 th January. < http://www.wind-watch.org/news/2007/01/19/energy-giants-say-wind-power-is-hot-air/>

71) Thomson, A., 2006. “Danes go cold on wind farms.” The Scotsman, 1 st November. < http://thescotsman.scotsman.com/international.cfm?id=1613772006>

72) Tornbjerg, J., 2001: “Energi: Lange udsigter for grøn strøm til billig penge.” “[Energy: Long time before cheap green electricity].” Politiken, 2nd February.

73) Troen, I. & Petersen, E.L., 1989: European Wind Atlas. Published for the European Communities by Risø National Laboratory, Roskilde, Denmark. ISBN 87-550-1482-8.

74) Vejle Amt, 2000: Vindmølleplan. “Områder til opstilling af store vindmøller. Tillæg nr. 7 til Regionplan 1997 – 2000 for Vejle Amt.” “[Wind turbine plan. Areas for the erection of large wind turbines].” Supplement No. 7 to the Regional Plan 1997 – 2009 for Vejle County], p.17.

75) Vestergaard, F., 2005: “Bistand til Tyskland.” “[Aid for Germany].” Weekend Avisen, 4 th November.

76) White, D.J., 2004a: “Danish wind: Too good to be true?” The Utilities Journal, OXERA. July Edition, 37-39.

77) White, D.J., 2004b: “Reduction in carbon dioxide emissions: estimating the potential contribution from wind-power.” Report commissioned and published by the Renewable Energy Foundation. December.

© Dr V.C. Mason and Country Guardian