Unpredictable wind energy - the Danish dilemma

Unpredictable wind energy - the Danish dilemma
by Daniel
(richtiger Name und Anschrift sind bekannt)
With limited reserves of only oil and gas and the perceived onset of global warming, Denmark has a great incentive to develop new technologies for exploiting alternative sources of renewable energy and reducing energy demand. One of its many options is the harnessing of wind energy - a route that it has explored in great detail. This report describes some serious problems encountered in the extensive deployment of wind turbines in Denmark, and briefly summarises published accounts of the experiences and opinions of variously implicated Danish and foreign organisations and bodies.

Background
About twenty years ago the Danish wind turbine industry was founded on a tide of "green" idealism. At that time wind turbines were small, and, being financially supported by large public subsidies, they could be afforded by individual citizens and located in close proximity to farm houses and other rural dwellings. Interest in them grew rapidly as more Danes recognised a lucrative way of earning money (often on borrowed finance), and in accordance with egalitarian principles, laws were introduced that limited the numbers of turbines or shares that an individual could own (Krogsgaard, 2001 c). Wind "farms" as such did not exist, and even today most turbines stand alone or in very small groups, although dedicated wind farms do occur.

With growing concerns about global warming, the industry became more competitive, and developments in turbine size and complexity occurred rapidly. By the end of 2000 Denmark had over 6,000 wind turbines of different sizes that delivered about 13 per cent of the country’s total electricity production (Dansk Energi, 2001). Per head of population, this corresponds to about 52 times the current output of wind electricity in the UK. By then, appropriate sites for land-based turbines were almost saturated (Pihl-Andersen, 2000) and large State subsidies were being offered to the owners of older, smaller turbines to dismantle them in favour of larger machines with over three times the installed capacity (From: 2001c). The average size of modern turbines is 850 – 900 kW (a few being much larger), so the cost can now rarely be borne by an individual owner. This has encouraged the formation of a new type of Purchase Co-operative, which includes such manufacturers as Jysk Vindkraft A/S and Dansk Vindkraft A/S, as well as large investors and pension organisations (Andreassen, 2001a). Turbines are now very big business.

Public image
Danish wind energy policy has been presented by the Government and Wind Industry as the epitome of success, and there can be no doubt that the Danish turbine industry is in a lucrative period of very rapid growth. In 1999, for example, the turn-over of turbine manufacturers grew from DKK 7.7 billion to DKK 12.5 billion, and exports of components to foreign manufacturers earned about DKK 1 billion. Production of turbines had increased six-fold in the course of five years, corresponding to an annual growth rate of 44%. The industry was expecting growth of around 10% in the year 2000, with a little more in 2001. Danish wind turbine manufacturers controlled about 50% of world markets in 1999 – or about 65% if foreign joint ventures are included. Employment at Danish turbine factories was up at 3,828, to which can be added about 10,000 jobs with suppliers (Jürgensen, P., 2000).

In May 2001 the picture presented was still one of tremendous optimism. "Wind power gilds Denmark", wrote Lars From (From 2001d) summarising the mood of a conference on energy supply at the Research Centre Risø. He pointed out that ["Today, 12,000 Danes work in the wind industry, and the turn-over lies between DKK 12 and 15 billion. 75-80 percent goes to export. Over 6 years the turnover has grown eight-fold, and everything points to this growth continuing. Half the world’s wind turbines will be produced in Denmark"]. He quoted Flemming Rasmussen, Project Leader of Risø’s Research Programme for Wind Turbines, as saying: ["It is therefore not unrealistic to expect that in 20 year’s time wind turbines will provide 10 percent of the world’s electricity supply. And with Denmark’s dominating role in the market, its wind industry will acquire a significance in line with the importance that the aeroplane and car industries have in other countries"]. By October 2001 Flemming Rasmussen was predicting the production of massive turbines of 6 – 7 MW capacity "in a few years" (Andersen 2001f). It is thus of no surprise that the Danish Government has done everything possible to promote this national money spinner.

An alternative view

Newspaper headlines
Different aspects of the development are suggested by the headlines in many leading Danish newspaper reports: ["Subsidies to turbines out of control"], ["Minister in conflict with the law"], ["Gold for turbine owners"], ["Electricity users led by the nose"], ["Fear of disqualification in the fight against wind turbines"], ["Local politicians benefit from wind projects"], ["Town council majority reported for tinkering with turbines"], ["Power plants: Impossible to check turbine owners"], ["Auken consulting about CO2 deception"], ["Buttered folk to capture customers for district heating"], ["Wind turbine fairytale for billions"], ["Electricity customers cheated of billions"], ["Openly cheating"], ["Turbine swindle"], ["Charge of cheating with turbines"], ["Off-shore turbines cost electricity customers five billion"], ["Electric shock"], ["New billion bill to electricity users"], ["Tax bomb under help for power plants"], ["Denmark’s most superfluous billion investment, thinks Mayor Britta Christensen"] (Krogsgaard, 2001b).

Mounting disquiet
In addition come complaints from the immediate neighbours of wind turbines, electricity consumer organisations, and knowledgeable and less knowledgeable citizens. There are warnings to solicitors and estate agents about reduced property values close to turbines (LNtV, 2000a) and also mounting protests against specific site developments (Andersen, 2001a). In this country of only 5.3 million people, over 600 complaints to the Environmental Complaints Board about wind turbines were submitted between 1998 and August 2000, of which 60 cases were upheld. In rural areas, most complaints related to impacts mainly associated with aesthetic and environmental considerations, shadow cast, glinting effects and noise, although a few cases were concerned with infringements of local regulations (Pihl-Andersen, 2000). In response to this experience, at the local level such authorities as the Vejle county authorities (Vejle Amt, 2000) have decided that ["A wind turbine will be unfavourably located in the landscape if, for example, it stands on a hill-top, in an area dominated by burial mounds, at the edge of a stream valley, or in the immediate proximity of a village. In an assessment of the location of a turbine in the landscape an evaluation must be made of the interaction between the turbine and landscape elements such as churches, burial mounds, characteristic landscape forms and the distance to groups of buildings"]. Turbines may no longer be erected within 500 metres of dwellings.

The organisation [National Association of Neighbours to Wind Turbines] (Landsforening Naboer til Vindmøller, LNtV; - specifically set up to protect the interests of neighbours of turbines from the excesses of the wind industry) has reported a local authority, a turbine manufacturer and the Ministry to the police for breaking the law. Its chairman Jan Bødker claims that there is an atypical number of local politicians among turbine owners, that some local politicians have fiddled with local plans, and that "we experience nepotism as never before" (Pihl-Andersen, 2000). Most recently, local groups have started to physically obstruct the erection of more land-based turbines in environmentally sensitive areas, such headlines as ["Turbine war"] (Gøttler, 2001), ["Farmers block wind turbines"] (Pihl-Andersen, 2001), and ["Site owners in road blockade"] (Andreassen, 2001b) now beginning to appear in the newspapers.

Other reasons for this disquiet include: the growing burden of turbine subsidies, Government incompetence in controlling and monitoring the allocation of subsidies, alleged disregard of planning laws, and a rising disillusionment with wind turbine technology in general, especially in Jutland and Funen, where over eighty per cent of the land-based turbines are located.

Turbine subsidies and costs
Following a study of Danish conditions, the Organisation for Economic Co-operation and Development (OECD, 2000) stated that subsidies to the wind turbine industry have been and continue to be very large, and come in three main categories: production subsidies, tax subsidies for co-operatively-owned wind turbines, and guaranteed prices for wind-generated electricity. It criticised the Danish government for not publishing any kind of cost-benefit analysis for its wind turbine programme, and gives its own evaluation that "the environmental benefits of using wind turbines instead of gas are far less than the subsidy to wind turbines". It noted that "Denmark is unusual in having a combined Ministry of Environment and Energy", and comments that while co-operation is important there is "a fine line between co-ordination and subordination".

Criticism of subsidies has also been made by many eminent Danes. In a country that in 2001 operated 17 central conventional power stations, about 600 decentralised, combined power and heating stations, and over 6,000 wind turbines it was claimed by Ole T. Krogsgaard (Director; Advisor to the Association of Danish Electricity Heating Consumers) and Niels O. Gram (Head of Energy, Confederation of Danish Industries) that the free market for electricity is an illusion (Krogsgaard, 2001a; Jensen, 2001b), the enforced export of excess Danish electricity even affecting market forces in neighbouring countries on occasion (Jensen, 2001b).

More specifically, Krogsgaard (2001a) claims that Danish electricity consumers annually pay more than DKK 10 billion (including VAT) in excess of what they would if the country only operated its central power stations, said to be amongst the most modern and least polluting in the world. Other estimates put the annual total Danish climate input cost at DKK 15 billion (From, 2001e). About DKK 2.5 billion of subsidies is paid to private owners of turbines (excluding VAT); and a further very large subsidy is paid to combined heat and power (CHP) plants, many of which (e.g. open field plants) are facing serious economical problems. In addition come the extra costs of transmission, the sale of expensively produced electricity abroad at market prices, and the reduction of efficiency at the central generators that results from their growing function as back-up for the small producers. The consumer is also being expected to pay off a loan taken out on a national grid for which it is claimed he has already paid (Krogsgaard, 2001a,b; Kongstad, 2001a). ["More than anything it resembles Ebberød Bank, in that one firstly lets consumers pay large subsidies to build combined heating and power plants and wind turbines and then pay large subsidies to the central power stations to remedy the damage from the first subsidy"] (Krogsgaard, 2001b). Very recently another form of financial support has crept in, with Elsam being offered compensation for not delivering electricity from twelve of its wind farms for 12 hours during a period of predicted over-production at New Year 2002 (Rostgaard, 2002)!

Peter Schoubye, (Civil Engineer, Head the Environment Department at the Haldor Topsøe A/S research establishment) calls the system ["completely crazy"], and believes that alone the export of allegedly environmentally friendly electricity costs the Danish customer an annual extra bill of up to DKK 2.0 billion (From, 2001a). He estimates that in 2000 the consumer paid DKK 0.45 per kWh above the market price for each of the 4.4 billion kWh of wind electricity produced, this amounting to an excess bill of at least 2 billion (plus VAT). ["…approximately 40% {of this electricity} was not even used in Denmark but had to be exported as over-production"] (Schoubye, 2001). Niels O. Gram (Consortium of Danish Industries) (Jensen, 2001b), and Eltra (Andersen, 2001e) claim that on occasion Denmark has had to ‘sell’ electricity abroad for nothing, or has even paid to get rid of its surplus.

Other criticisms
A different type of criticism of Danish energy policy has come from the Institute for Energy Technology, University of Aalborg, where Associate Professor Niels Abilgaard (2001) has suggested that although turbines may have saved the burning of some coal in 2000, at one twentieth of the cost the same environmental effect could have been achieved by donating radiator valves to countries east of the Elbe! He has also said that because methane is perhaps 30 times more greenhouse-active than carbon dioxide, leakage of prioritised natural gas could in practice be more destructive than CO2.

Recently, a former Foreign Minister of Denmark, Uffe Ellemann-Jensen, after complaining about the lack of protection of sensitive Danish landscapes, made a similar point, criticising the Government for pressurising the Swedes to close their modern Barsebäck nuclear plant (["the safest nuclear station in the world"]) instead of using the money to dismantle the Ignalina plant in Lithuania (Ellemann-Jensen, 2001).

In response to these criticisms, Kjær (2001) for the Danish Wind Turbine Manufacturers Association, replies that the subsidy paid to owners for electricity from wind turbines is ‘only’ DKK 1.8 billion, and claims that the currently low price of hydro-electricity and the high subsidy for wind electricity will not last for long. A market for "green" energy is on the way (albeit slowly) (Tornbjerg, 2001).

Breakdown of an electricity bill
The major part of the excess charges is imposed by the State as a levy in electricity bills, wind electricity costing DKK 0.60 per KWh for turbines erected before 1St January 2000 and DKK 0.45 - 50 per kWh thereafter. To produce CHP electricity costs slightly less. Consumers regularly pay five to six times the market price for this prioritised "green" electricity. In 2000, a typical electricity bill for NESA customers amounted to 126.82 øre / kWh. This was made up of 23.55 and 14.30 øre / kWh for respectively electricity production and distribution, the remainder comprising electricity and CO2 levies to the State (63.60 øre / kWh) and VAT (25.37 øre / kWh). The Production Cost (23.55 øre / kWh) was made up of a Market price: 11.925 øre / kWh (75% of 15.90 øre / kWh) and a Prioritised Production price: 11.625 øre / kWh (25% of 46.50 øre / kWh). Thus, the average price of production is strongly influenced by the proportion of prioritised electricity (from wind, bio-mass and natural gas), and the State electricity levy and CO2 levy together make up a major part of the electricity bill. VAT is charged even on the levies (Heimann, et al, 2000).

Referring to the high cost of prioritised electricity generated by wind turbines and combined heat and power plants, Ejgil Rasmussen, the chairman of the Transmission System Operator (TSO) company Eltra, recently put it this way: " It should not surprise anyone that when a third of the country’s electricity demand costs 30 – 60 øre per KWh [to produce] when the market price is 10 – 20 øre per KWh the effect will show through on the total price. But this is the result of a democratic political process, and is not a market problem" (Andersen, 2001c).

Government incompetence allegations
The recent report of Government Auditors (Rigsrevisionen, 2000) reprimands the Danish Energy Agency (a section of the Ministry of Environment and Energy) for neglecting its duties to register and monitor individual payments of turbine subsidies adequately (Krogsgaard, 2001a); (LNtV, 2000b). Many illegal erections of turbines are suspected (Krogsgaard, 2001c). At the start of 2000 the Ministry repealed laws and penalties that had been introduced in 1986 to prevent the misuse of subsidies, making retrospective prosecution of suspected law breakers much less likely (Krogsgaard, 2001c). The former Minister of Environment and Energy Svend Auken (2001) claims, however, that the objective of these changes was to promote the replacement of old turbines with new ones. A register of turbine owners was finally set up in October 2000, but this is incomplete and cannot be used to answer the question of whether turbines were legally erected or connected (Krogsgaard, 2001c). In the Folketing Svend Auken is reported as stating that ["it is far more serious to drive above proscribed speed limits than it is for the owner of a wind turbine to have fiddled with the residential demands"] (Krogsgaard, 2001a).

Implications of the new government for subsidy policy
With the recent election of a government led by the right-of-centre Venstre party, the scene seems set for a radical change in Danish policy concerning the payment of subsidies for wind electricity. It appears that the Ministry of Environment and Energy is to be split up, so that energy matters come under the Ministry of Economics. In this context, the wind turbine industry is greatly disturbed by the statement of the in-coming Minister of Finance, Thor Pedersen, that Denmark’s new government will remove the billions of subsidy for wind electricity (Rasmussen, 2001). Thor Pedersen wants wind electricity to be self-sufficient when in 2003 the government is free to negotiate a new energy reform. ["The whole idea of the liberalised electricity market in the EU is that companies and consumers receive their electricity at the cheapest possible price. But they do not get this when they are forced to buy a large part of their energy from wind turbines at five or six times the market price for electricity"], said Thor Pedersen to the daily newspaper Børsen. He maintains that the wind industry has itself stated that it can survive without subsidies because the turbines have become so effective that they can compete with traditional power stations.

Christian Kjær, economist for the European wind energy organisation EWEA, fears the consequences of Pedersen’s statement. ["Seen from an international perspective it is a catastrophe that the country which for 20 years has been the leader in sustainable energy, not least in the wind turbine area, suddenly throws out everything and says "We won’t do it any more". …. "Abroad, where they take a close look at Danish environment policy, it will have the consequence that they re-consider the development of wind energy when the Danes suddenly pull out" (Jensen, 2001a). The chairman of the Wind Turbine Industry, Karl Gustav Nielsen, (Director of Vestas) also worries about the statement, and warns that one must be careful not to undermine the export success of the Danish wind turbine industry by making it appear that the industry is directly subsidised by the State. He maintains that if one had to pay real power station prices inclusive of pollution levy, wind turbine energy would not need to receive favourable prices (Rasmussen, 2001).

Denmark’s economics minister has very recently cancelled the plans of the previous government to build three 150 MW off-shore wind energy plants because: "We are very concerned about the costs for society and for Denmark’s competitiveness if we continue to expand the use of green energy" (Environment Daily, 2002). For the Danish Wind Industry Association, Director Søren Krohn has replied that clocking up machine years was essential to attracting investors to a new technology like off-shore wind turbines, and accused the minister of "throwing overboard a very important market". A source in the economy ministry rejected this: "I’m not sure that’s a real argument… Why go off-shore when there is so much room on-shore at cheaper price in many other countries?"

Technical transmission problems
As the leading pioneer of wind turbine technology it is hardly surprising that Denmark has encountered many technical problems on the way. In practice, the production of electricity by a turbine is intermittent and unpredictable, and over a very short time can vary from zero to full load, depending upon whether the wind speed is about 5 or 11 metres per second. With wind speeds below about 5 metres per second no electricity is produced (Eltra magasinet, 2001). With speeds above about 20 – 24 metres per second turbines can become dangerous, the blades must be "feathered", and production is stopped.

The balancing act
Denmark’s two main Transmission Service Operators (TSOs), Eltra and Elkraft, are responsible for maintaining a reliable and stable electricity supply, the effective marketing of electricity, the development of sustainable energy sources, and collaboration with neighbouring countries. Consequently, integration of the electrical output of wind turbines with that provided by other power sources is of crucial importance for maintaining balance throughout the electricity supply network and for drawing up optimal sales agreements on the electricity exchange.

In practice, the balancing of Danish electricity supply to demand is relatively easy in periods of high atmospheric pressure or when the total amount of wind electricity produced is so small that it comes within the normal supply range experienced by the TSOs. However, with no facility for storing large amounts of excess electricity and the legal obligation to accept all prioritised electrical energy, transmission problems in western Denmark increase rapidly in periods of low pressure, especially with an ever-increasing proportion of wind electricity in the overall supply. It is claimed that within one to two hours wind speeds can vary so much that the change in electricity produced by wind turbines west of the Great Belt corresponds to the effect of rapidly putting two power stations on or off stream, so the risk of power failure is evident (Jensen, 2001b).

Over-production (euphemistically referred to as "over-run") is more likely to occur in winter and at night; and in winter, it can be aggravated by the output of the many small CHP plants that produce a lot of electricity along with the heat (From, 2001a,b). The situation is further complicated by the fact that central generators are economically penalised for producing extra electricity from fossil fuels, making the balancing act even more difficult. However, until very recently, whenever over-production occurred the excess could always be exported to neighbouring countries.

According to Henrik Hornum of the Association of Danish Power Companies, [Dansk Energi]) on average for the year 2000, wind turbines intermittently generated about 13 per cent of the country’s total annual production of electricity; the central power stations, the combined heat and power plants, and the hydro-electricity plants providing about 62, 25 and 0.1 per cent, respectively (Dansk Energi, 2001). In spite of having a tremendous reserve-capacity for generating electricity (Krogsgaard, 2001b), however, for the first time since 1993, in 2000 Denmark became a net importer of electricity (Dansk Energi, 2001). Even so, according to Claus Andersen (Danish Energy Agency) during the year about 3 per cent of the total production of electricity had to be disposed of abroad at dumping prices (Wittrup, 2001a; From, 2001a, b).

Peter Schoubye (2001) estimates that in 2000 about 1.5 - 2 GWh of wind electricity were exported in this way, this being equivalent to 34 to 45 percent of the total production of wind electricity. Ejgil W. Rasmussen (Chairman of Eltra) has stated that in western Denmark alone the potential power available from wind turbines and CHP plants amounts to 1,865 and 1,400 MW, respectively, but that during winter months ["there is regularly produced 1,000 – 2,000 MW more than is needed"] (Kongstad, 2001b). The over-production of electricity is expected to rise five-fold by 2003 (Andersen, 2001d). One can only imagine what will happen if Denmark’s neighbours embrace the same unpredictable wind energy policy, and need to export their over-production of electricity at the same time!

Eltra’s over-run problem
Both Eltra (the TSO for Jutland and Funen) and the government’s own Danish Energy Agency agree that in the absence of large electricity storage facilities or disposal options the unpredictable nature of wind energy is the principal cause of the over-run phenomenon, the output from CHP plants being more readily predicted.

The problem lies with the fact that to efficiently integrate wind electricity TSOs must receive forecasts of wind conditions that are accurate from hour to hour. Accurate forecasts are available over 36 hours in periods of high pressure, but when a depression passes over the country the uncertainty of predictions becomes very great (Anderson, 2001b). According to E.W. Rasmussen (Chairman of Eltra), large inaccuracies occur in almost one third of wind prognoses from the Danish Meteorological Institute (Kongstad, 2001b), Carl Hilger (Eltra’s Head of Management) suggesting that forecasts from this Institute are encumbered with a 30 – 40 percent margin of error (Andersen, 2001b).

Jørn Mikkelsen (Head of Marketing Design, Eltra) was amongst the first to draw attention to the fact that the large amounts of wind electricity produced in western Denmark are seriously unbalancing the Danish electricity supply system, making it ever more vulnerable and presenting Eltra with a substantial technical distribution challenge (Wittrup, 2001a). The company experienced a very uncertain and critical situation as early as Christmas 2000, when demand and production became completely unsynchronised. Because of the Christmas break, the company was unable to export the excess and was on the verge of having to close down a central generator.

Acute management problems were also experienced by Eltra on New Year’s Day 2002, when Elsam was asked to shut down twelve of its wind farms for a 12-hour period because of fears of over-capacity on the grid (Rostgaard, 2002). This problem arose because windy conditions occurred at a time when the demand for electricity was low (industrial shut-down in holiday period), but cold conditions ensured a high demand for heat from the combined heat and power plants, and the export option was not available. Carl Hilger (Eltra’s Head of Management) recently reported that western Denmark has now become entirely dependent on the support of neighbouring countries when unexpected excesses or deficiencies of electricity occur (Andersen, 2001b). The matter was raised by the Parliamentary Energy Policy Committee in the Folketing, where the former Minister for Energy and Environment (Svend Auken) acknowledged the basic facts, and announced the establishment of a working group to report back in October 2001 with possible solutions (Parliamentary Report, 2001).

Importance of wind forecasts
Carl Hilger (Eltra’s Head of Management) states that ["If we could improve the quality of wind prognoses by even one percent we would make savings of DKK 2 millions"]. The implications of uncertain wind predictions are thus enormous, and are becoming steadily more serious as the number of on-line turbines increases (Andersen, 2001b). To emphasise this point, the front cover of the May edition of Eltra Magasinet (2001) splashed the headline: ["We bring you a weather forecast. For the next 24 hours the forecast is for gentle to fresh breeze, rising to strong breeze. Translated to Eltra language: ‘We will receive between 0 and 2,000 MW wind energy tomorrow’ "].

Possible long-term solutions
The use of electricity for direct heating is controversial, though favoured by some politicians and Eltra’s chairman (Kongstad, 2001b). Several other approaches to the problem of over-production are therefore now being examined. Firstly, Eltra is promoting research at Risø National Laboratory and the Informatics and Mathematical Modelling department of the Technical University of Denmark to improve the accuracy of forecasting wind speeds. Secondly, in collaboration with Innogy Technology Ventures Limited, Eltra is currently exploring the long term feasibility of using fuel cells for the short-term storage of large amounts of electricity (Bülow, 2001). Finally, as mentioned, at the initiative of the Danish Energy Agency, an analytical group comprising representatives of Eltra, Elkraft System, Elfor, Danish District Heating Association, Organisation for Sustainable Energy, and Denmark’s Wind Turbine Association has recently been examining how best to use the excess of wind electricity.

Amongst the longer-term options considered consideration (Wittrup, 2001b) were:

to use the electricity exchange as a kind of seasonal store in which over-produced winter electricity is bought back during the summer,
to increase the use of heat pumps, geothermal sources, and electrical heating,
to use more electricity in the transport sector – for example in trains and electrical cars,
to shut down power stations or wind turbines when there is over-production,
to establish heat stores in district heating systems, such that the production of power and heat can be reduced when there is over-production,
to promote energy conservation
to establish power cables across the Great Belt, and
to establish large electricity storage systems.
The committee delivered its conclusions to the government in October 2001, and new legislation must follow. Meanwhile, to secure balance in the Jutland – Funen system this winter, and to minimise the burdening of neighbouring systems with un-planned imports of electricity, Eltra has devised an emergency plan for use in the event that the wind turbines again produce "critical over-run". This plan involves the closure of central heat and power plants, Elsam’s wind farm (c. 170 MW – un-prioritised), Elsam’s decentralised heat and power plants (c. 20 MW – un-prioritised) and about 70 decentralised heat and power plants (c. 830 MW prioritised production) (Andersen, 2001e). Parts of the plan had recently to be implemented.
The need for stability and quality
Local plants account for more than half of western Denmark’s production capacity, and are connected to the grid at low voltage levels. Of the total installed capacity of 6,534 MW, 600 MW are connected at 60 kV, and 2,921 MW at 20 kV or less. "More and more frequently operational situations arise that make it necessary to develop new regulation, control and monitoring methods in order to maintain a reliable supply and system" (Andersen, 2001d). Referring to the Danish situation, Laughton & Spare (2001) have recently emphasised the importance of stability and quality in the electricity supply, and raise the question as to whether direct connection to the electricity system is the most appropriate way forward for the UK in the long term if a significant proportion of the generating capacity is provided by renewable generation plant.

Off-shore wind power
Solutions to the problem of unpredictable production clearly need to be found and implemented in Denmark as rapidly as possible, not least because of the planned development of off-shore facilities. The installed capacity of onshore turbines is currently about 1,900 MW, but opportunities for further expansion on land are limited. Instead, over the next three decades, using much bigger machines (Andersen, 2001f), the previous government aimed to erect 4,000 MW of turbines at sea, where the negative environmental impacts are less and energy production is said to be more predictable and between 50 – 100 percent more efficient (Eltra 2001). It was predicted that in 2005 bio-mass and wind energy would account for a total of about 32 percent of Denmark’s electricity production, and that export peaks would reach as high as 3,000 MW during a windy January night (Wittrup 2001b). The recent change in government policy (Environment Daily, 2002) will probably change these estimates, but the problem of over-production will undoubtedly grow unless practical solutions to the problem are found.

Significance of wind electricity for carbon emissions
A common argument used to promote wind farm development is that an expansion of wind electricity will help to prevent global warming, the assumption being made that the latter is at least partly caused by the atmospheric accumulation of greenhouse gases, particularly the carbon dioxide produced by man. This may or may not be so, but in the affirmative the important question to ask is "to what degree?".

Compared to other countries, Denmark is a useful model for examining this question, although currently its wind farm developers can only hope to reduce carbon emissions in association with the production of electricity for the grid. The Danish Wind Industry assumes that wind electricity directly replaces electricity generated by coal-fired generators, and will therefore save the emission of about 850 g carbon dioxide per kWh of wind energy. Since the overall production of carbon dioxide in Denmark was about 52.7 million tonnes in 2000 (From, 2001e), one can estimate a theoretical overall saving in carbon dioxide emissions of about 7.2 percent.

However, this is probably a serious over-estimate because:

It does not fully account for the consumption of fossil fuels in the manufacture, installation and dismantling of wind turbines.
It does not allow for the nature of the fuel or power source actually displaced. Combined heat and power plants produced about 25 percent of the total production of electricity from natural gas and bio-mass, etc. (Dansk Energi, 2001), and possibly 34 to 45 percent of the total production of wind electricity in 2000 was sent abroad (Schoubye, 2001) where it partly displaced hydro- and nuclear electricity generated in Norway, Sweden and / or Germany.
Finally, it takes no regard of the fact that because of the unpredictable nature of wind, the running of back-up generators on fossil fuels (usually coal) is necessary, and this process becomes less efficient when operating in "spinning reserve" mode. Emissions from conventional power stations are minimised by reducing demand fluctuations and maximising the base load, this allowing the cleanest systems to predominate. However, unpredictable wind electricity imposes extra demand fluctuations on power stations, decreases base load, and thus raises emissions because the mix of power plant must change to provide more spinning reserve. Neither nuclear power nor gas (CHP) is technically suitable as spinning reserve to provide electricity at immediate notice, so the use of wind turbines tends to restrict the choice of back-up fuel to coal.
It is often argued that the introduction of wind electricity could remove the need for nuclear electricity. However, unless overall electricity demand is reduced, the replacement of nuclear with wind electricity would actually increase carbon emissions, because of the need for fossil-fuelled back-up for wind-based generators to maintain a steady supply of electricity. Denmark has to import its nuclear electricity.
For all these reasons, as pointed out by the OECD (2000), "views differ on the value of the environmental benefits that have been obtained". Certainly the true savings in carbon dioxide from wind electricity production are much less than the figure of 7.2 percent, and could be closer to the projected 2.7 percent contribution of wind energy to Denmark’s overall energy demand for 2000 (Dansk Energi, 2001. The point was recently raised by the Chairman of Eltra, E.J. Rasmussen, who asked of Danish politicians ["Is it environmentally friendly to produce electricity with wind turbines if there is no-one who can use it? And is it environmentally friendly to burn natural gas in decentralised heat and power plants while dumping the over-production from Danish wind electricity in Norway, where it possibly leads to water being diverted away from the water turbines?"] (Kongstad, 2001b).

Conclusions
Following a study visit to Denmark, Asle Selfors (Wind Power Consultant for the official Norwegian Water Resources and Energy Administration (NVE)) reported in the company’s in-house magazine that the Danish initiative suffered from ["inadequate controls"] and ["massive and unrestrained funding"] which in turn have led to ["serious environmental effects, insufficient production, high production costs, high grid costs, and wind farms where there is too little wind"]. The main advantage of the Danish investment in wind power would appear to be that it has ["laid the foundations of an industry for the production of wind turbines"] (Norbye, 1998).

Many agree with this assessment and would add that the current deployment of wind turbines in Denmark has, on occasion, badly disrupted its electricity transmission system, and produced relatively small reductions in carbon emissions. Clearly, the current practice of exporting the critical over-run of wind electricity to neighbouring countries can only continue as long as these countries do not themselves operate many wind farms! Until systems are available for storing the over-run it will be necessary to use the wind electricity for direct heating, or find industrial uses for the intermittent supply, - such as the heating of water at CHP plants, hydrogen production etc.. As intimated by OECD (2000) and Niels Abildgaard (2001), for the same investment much greater savings in carbon emissions could have been achieved by rationalising and constraining energy consumption at home and assisting less developed countries to modernise their electricity and heating systems with new technology.

References:
The original texts of Danish articles are available on request.

1. Abilgaard, N., 2001: Jyllands Posten, 8th February. "Nej til vind og gas". ["No to wind and gas"].

2. Andreassen, J., 2001a: Berlinske Tidende, 11th April. "Staten betaler for vindmølleskrotning". ["The State pays for scrapping turbines"].

3. Andreassen, J., 2001b: Berlinske Tidende, 20th June. "Lodsejere i vejblokade". ["Site owners in road blockade"]

4. Andersen, P., 2001a: Eltra magasinet, February. "Sen, men massiv protest mod havmøller ved Grenaa havn". ["Late, but massive protest against sea-turbines near Grenaa harbour"].

5. Andersen, P., 2001b: Eltra magasinet, April. "The Good – the Bad – the Ugly". ["The Good – the Bad – the Ugly"].

6. Andersen, P, 2001c: Eltra magasinet, May. "Eltras formand:- Vindkraften har skabt akut behov for nytænkning". ["Eltra’s Chairman: Wind power has produced an acute need for new thinking"].

7. Andersen, P., 2001d: Eltra magasinet, June/July. "Det vestdanske elsystem er på godt og ondt vendt på hovedet". ["For better or for worse the electricity system for western Denmark has been turned on its head"].

8. Andersen, P., 2001e: Eltra magasinet, November 2001. "Eltra forbereder nødplan for vinterens eloverløb" ["Eltra prepares an emergency plan for this winter’s over-run of electricity"].

9. Andersen, P., 2001f: Eltra magasinet, November 2001. "Om 15 år har vi møller på mere end 20 MW". ["In 15 years we will have turbines of more than 20 MW"].

10. Auken, S., 2001: Jyllands-Posten, 27th August. "Det evige omkvæd". ["The eternal chorus"].

11. Bülow, T., 2001: Eltra magasinet, June/July. "Eltra forbereder lagring af vindkraft på tanke". ["Eltra prepares for the storage of wind electricity in tanks"].

12. Dansk Energi, 2001: Henrik Hornum, personal communication. "Contribution of wind turbines and other sources to Danish electricity production in 1999 and 2000".

13. Ellemann-Jensen, U., 2001: Berlinske Tidende, 11th August. "Vindmøller og vindbøjtler". ["Wind turbines and windbags"].

14. Eltra, 2001: http://www.eltra.dk/show.asp?id=12905. "From wind turbines to wind power stations".

15. Eltra magasinet, 2001. May. "Vi får mellem 0 og 2.000 MW vindkraft i morgen". ["We will receive between 0 and 2,000 MW wind energy tomorrow"].

16. Environmental Daily, 2002. 28th January. Denmark puts the brakes on green power.

17. From, L., 2001a: Jyllands-Posten, 30th January. "Tab på salg af strøm". ["Loss on the sale of electricity"].

18. From, L., 2001b: Jyllands-Posten, 31st January. "Elbiler på overskudsstrøm". ["Electric cars on excess electricity"].

19. From, L, 2001c: Jyllands-Posten, 7th February. "Milliard til skrotning af vindmøller". ["Billions for scrapping wind turbines"].

20. From, L., 2001d: Jyllands-Posten, 1st May. "Vindkraft forgylder Danmark". ["Wind power gilds Denmark"].

21. From, L., 2001e: Jyllands-Posten, 29th August. "Energi: Klimaindsats koster 15 mia.". ["Energy. Climate input costs 15 Billion"].

22. Gøttler, K., 2001: Ekstra Bladet, 21st June. "Mølle-Krig". ["Turbine war"].

23. Heimann, K., May, K., Morsing, T., Schumacher, E., Ølgaard, P.L., & Østergaard, K., 2000: Jyllands-Posten, 17th March. "Fup eller fakta". ["Fact or Fiction"].

24. Jensen, L.W., 2001a: Berlinske Tidende, 24th November. "Grønt el-tilskud giver prestige". ["Subsidies for green electricity give prestige"].

25. Jensen, S.L., 2001b: http://www.di.dk/miljoeogenergi/artikel.asp?page=doc&objno=122610. "Danmarks elreform skaber risiko for strømsvigt". ["Denmark’s electricity reform is creating a risk of power failure"].

26. Jürgensen, P., 2000: Maskinmesteren, 12, December, p.17. "Har seksdoblet produktion på kun fem år". ["Six-fold increase in production in only five years"].

27. Kjær, C., 2001: Politiken, 26th January. "Matematisk makværk". ["Mathematical mess"].

28. Kongstad, 2001a: Jyllands-Posten, 28th February. "Ny milliardregning til el-forbrugerne". ["New billion bill for electricity users"].

29. Kongstad, 2001b: Jyllands-Posten, 26th April. "Grøn el sælges med tab". ["Green electricity is being sold at a loss"].

30. Krogsgaard, O.T., 2001a: Politiken, 14th January. "Energipolitik som vinden blæser". ["Energy policy as the wind blows"].

31. Krogsgaard, O.T., 2001b: Jyllands-Posten, 30th March. "Lovgivning, troværdighed og energipolitik". ["Legislation, Credibility and Energy Politics"].

32. Krogsgaard, O.T., 2001c: Jyllands-Posten, 24th May. "Lovlydighed som vinden blæser". ["Respect for the law as the wind blows"].

33. Laughton, M. & Spare, P., 2001: Energy World, Institute of Energy, 1st November, "Limits to renewables – how electricity grid issues may constrain the growth of distributed generation".

34. LNtV, 2000a: Personal communication. Summary of article.

35. LNtV, 2000b: http://www.naboertilvindmoller.dk , 6th December. ["State Accountants have officially reprimanded the Danish Energy Agency for lack of control with windmill subsidies"].

36. Norbye, V.H., 1998: Vann og Energi, 2-98 (Norwegian Water Resources and Energy Administration, (NVE)). "Dyrekjøpte vindkrafterfaringer i Danmark". ["Expensively bought wind power experiences in Denmark"].

37. OECD, 2000: OECD Economic Surveys – Denmark, July. IV. "Encouraging environmentally sustainable growth."

38. Parliamentary Report, 2001: Report J. No. ENS 601-0222. "Miljø- og energiministerens besvarelse af spørgsmål nr. 241 af Folketingets Energipolitiske Udvalg". [Energy Minister’s answer to Question No. 241 raised by the Parliamentary Energy Policy Committee] (Alm. del – bilag 461).

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

40. Pihl-Andersen, A. 2001: Jyllands-Posten, 20th June. "Landmænd blokerer for vindmøller". ["Farmers block wind turbines"]

41. Rasmussen, J.E., 2001: Jyllands-Posten, 24th November. "Vindmølleindustri frygter V-indgreb". ["Wind industry fears V-measures"].

42. Rigsrevisionen, 2000: Rigsrevisionen – RB B502/00 – November 2000. "Beretning til ststsrevisionerne om ststens driftstilskud til vindmøller". ["Report to State Auditors concerning state aid to wind turbines"].

43. Rostgaard, A., 2002: Jyllands-Posten, 5th January. "Vindmøller stoppet nytårsdag". [Wind turbines stopped on New Year’s Day].

44. Schoubye, P. 2001: Haldor Topsøe a/s. Personal communication. Untitled.

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

46. 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.

47. Wittrup, S., 2001a: Ingeniøren, 23rd February. "Grøn strøm er for svær at styre". ["Green current is too difficult to control"].

48. Wittrup, S., 2001b: Ingeniøren, 23rd February. "Opgør med el-dogmer på vej". ["Showdown with electricity dogmas on the way"].