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Denmark continues its renewable tradition

Kari Larsen

Denmark is proud of its heritage when it comes to pushing forward the use of alternative energy solutions, and is all set to host the make or break un climate change conference (COP 15) in 2009. renewable energy focus assistant editor Kari Larsen saw some of the Danish projects for herself.

Denmark to host COP15, 2013

Denmark has been a strong supporter of renewables since the early days, seen as the initial trailblazer of the wind power industry and always willing to look at alternative sources of energy. But as the country embraces its role as host of the UN Climate Change Conference (COP15) in 2009 – and bids to host the 22nd World Energy Congress in 2013 –Denmark as a whole, and especially Copenhagen, is more than keen to showcase its renewables industry.

Now at a share of 17%, Denmark has a national renewables target of 30% by 2020. Danish offshore wind capacity remains the highest per capita in Europe and accounts for the majority of the gross electricity consumption produced from renewable sources. In April 2008, E.ON Sweden won the bidding round to build a 200 MW wind farm at Rødsand in Denmark. It is set to come online in 2011. Another 200 MW is planned at Horns Reef II, which is set to come online in 2009.

Renewable energy sources other than offshore wind are slowly having an effect, supported by measures such as a new repowering scheme for onshore wind. Denmark is behind on its EU target with regard to introducing biofuels.


In the waters between Copenhagen and Malmö in Sweden, Vattenfall has installed 48 offshore wind turbines producing 110MW. It is connected to the Swedish grid through a cable dug 1m into the seabed. The Siemens turbines are 150m from the top of the blades, and the hub itself is 68m high. The turbines produce more electricity than needed, with 97% availability when producing. Technically, the farm could be expanded, but currently there is no political will to do so. Vattenfall does have plans for another farm with 5MW turbines at Bremerhaven with E.ON. (See image to the right.)

Today, Denmark offers a fair amount of support for the renewables industry, both in terms of carrots and sticks:

  • A tax on the use of fossil fuels;
  • A tendering procedure is being used for the two new large offshore wind installations mentioned. Operators will receive a spot price and initially a settling price in addition;
  • A spot price, an environmental premium (€13/MWh) and an additional compensation for balancing costs (€3/MWh) for 20 years are available for new onshore wind farms;
  • Fixed feed-in tariffs exist for solid biomass and biogas under certain conditions, and subsidies are available for CHP plants based on natural gas and waste (biomass, being CO2 neutral, is exempt from CO2 duty).
  • Solar heating plants are exempt from both energy and CO2 taxes. The Executive Order Solar heating obligations in new buildings outside the district heating areas which was adopted in 2001 – but has not yet come into force – will require the introduction of solar heating from owners of new buildings (excluding the domestic sector). Solar thermal installations are eligible for subsidies;
  • Tax for landfill useage of €50 per tonne, and waste incineration is taxed at €44 per tonne.

The Danish Minister for Climate and Energy, Connie Hedegaard (Conservatives) says the reason why Denmark is so keen on renewable energy, stems from the energy crisis of the 1970s. And even when Denmark discovered oil and gas in the North Sea, it did not deter Danish determination to go forward with renewables:

“In Sweden they have had hydropower for 300-400 years. We do not have that in Denmark, but we decided to build windmills, which started only 30 years ago. We went from zero at the end of the 1970s, to today when [17%] of our total energy consumption comes from renewables. Wind is delivering 20% of our overall electricity consumption, [in fact] there are days when areas will have 100% of their electricity coming from wind.”

Wind is not the only focus for Denmark, however. Biomass is also being explored by Danish decision makers, and the use of biogas, for example, is increasing. “We just had a new energy agreement [in Parliament]. All parties except one […] agreed on a four year energy plan, saying that we should expand the portion of renewables for whole energy consumption so that in 2011 it will be 20%, and then it will continue to grow by more or less 1% every year until [30% in] 2020. That is a huge expansion of renewables, and it is primarily in wind, biomass and biogas.” Denmark is also known for its feed-in-tariffs (FiTs), and Parliament has just improved the FiTs for wind, biomass and biogas to make investment even more attractive.

In addition to renewable energy sources, Denmark encourages energy efficiency in households and companies through regulation. Denmark has had a CO2 tax for many years, and overall, the tax incentives appear effective: “since 1981 we have had 70% growth in our GDP, but our total energy consumption has been kept almost stable,” Hedegaard adds.

Export figures for 2007 show that exports in the renewables field is growing four times as fast as the average. The wind industry alone employs 20,000 people, and this in the more remote areas of the country where employment could otherwise prove more difficult to find.

The well-documented challenge with wind power is that when the wind is not blowing, no electricity is produced. Storage is one solution, but at present Denmark solves the problem through cooperation with Sweden – which supplies hydro and nuclear power – and Norway which also supplies hydropower. The countries trade their power on the Nordic power exchange, Nord Pool, giving the whole system flexibility. Denmark is also in discussions with Germany to expand cooperation.

Looking forward, Denmark is planning to make further investment in renewables. By 2010, public funding of R&D within energy efficiency and environmental technologies will be doubled from 2006 levels. A commission of experts has been set up to come up with a plan to make Denmark 100% fossil fuel-free. It is due to report its findings in 2010.

Alternative energy in Denmark – DONG's Multifuel CHP plant “has 95% efficiency”

DONG Energy's Avedøreværket combined heat and power (CHP) plant in Copenhagen, is one of the world's most efficient, and reportedly has a 95% efficiency rate. The plants two units are capable of supplying 200,000 households with heat, and 1.3 million households with power – approximately 30% of the power consumption in Zealand.

Avedøreværket fuel distribution
  • Coal: 64.6%;
  • Biomass: 12.8%;
  • Natural gas: 10.3%;
  • Fuel oil: 7.8%;
  • Waste: 4.5%.

This 810 MW plant uses a range of energy sources, from fossil fuels to waste. Coal makes up its staple fuel source, but the multifuel boiler in the plant's newer 575 MW Unit 2 uses natural gas, fuel oil and wood pellets. In addition, there is a straw firing boiler, and a gas turbine which is used to get high efficiency when more power is needed (see image on the right).

Power production is determined by supply and demand on the Nord Pool, and the prices on fuel and power. Gas, for example, is used when prices are low and there is a demand for power.

“Normally we start on fuel oil or natural gas, and when we have a good fire we change over to wood pellets. When the wood fire is good, you start your additional fire with gas or oil,” explains Bent O. Petri, senior director at Avedøreværket.


The straw is supplied from farmers on Zealand by trucks. DONG energy has contracts with about 500 farmers, who agree to store the straw until needed. Normally, the straw burner runs on full load all year burning around 172,000 tonnes of straw. However, last autumn was very wet in Denmark and farmers could not collect all the straw in the fields, so DONG is now effectively out of straw until the next harvest in August.

This has lead to an increase in the use of wood pellets, which amounted to 400,000 tonnes this year, compared with the normal 250,000 tonnes.

DONG would not use straw, however, if it was not subsidised by the Danish government: “We get about 10-15 øre/kWh [in subsidies] and the price on the market when we sell [power is] 0-50 øre/kWh,” adds Petri.

District heating

District heating is the key to Avedøreværket's high efficiency, using the heat from power production to provide warmth to households in Copenhagen. The plant has two district heating accumulators where it can store heat in the form of hot water when demand is low. The capacity is equal to 8 hours full load.
Copenhagen has an extensive DH system based on hot water, but in the centre of Copenhagen, the system is based on steam. Although old, there are no plans to change the steam system to a newer, more efficient one, as this would involve digging up whole streets.

Alternative energy in Denmark – Amagerforbrændingen Waste to Energy

Another CHP plant in Copenhagen is the municipality-owned waste to energy facility Amagerforbrændingen, which in 2007 treated 420,000 tonnes of waste from 8 recycling sta tions in Copenhagen – enough to produce 202 MWh electricity and 2.98 TJ heat.

The waste incineration itself works quite simply; put 200kg-300kg of waste into the incinerator, wet a cloth with petroleum and throw it in – Amagerforbrændingen does not use any additional fuel for its burners. Each incinerator burns 15 tonnes of waste per hour, and all kinds of non-recyclable waste is used, with a 50-50 split between household and industrial waste.

Amagerforbrændingen does not have any competition, as there is a monopoly on waste handling in Denmark. However, because it is municipally owned, Amagerforbrændingen cannot make a profit – it has to break even every year.

At the moment, the plant is hoping to build a new facility and tear down the old one, as the current capacity is too small. However, due to political disagreement, the plans are on hold. The authorities want to minimise waste, whilst there is an increasing need to deal with waste in Copenhagen. Even though waste incineration is carbon neutral, Amagerforbrændingen's managing director Ulla Röttger, hopes the new plant will have carbon capture facilities.

Alternative energy in Denmark – Risø National Laboratory for Sustainable Energy

Risø National Laboratory for Sustainable Energy is part of the Technical University of Denmark (DTU), and conducts research into a wide range of energy technologies, from wind and fuel cells to second generation biofuels and power system administration.

One aim of Risø is to turn research into actual projects and products for the marketplace. The centre is working closely with the Government and industry to achieve this goal, recognising that projects must be economically viable to be taken up by industry.

Polymer solar cells laboratories

Researchers at Risø are working on polymer solar cells, and according to head of programme, Peter Sommer-Larsen, the objective is to develop polymer solar cells for niche products driving small electronic equipment like mobile phones, and to transfer the technology to industry, something that is already in progress.

Within R&D, the focus is on efficiency, stability and production methods. The hope is to reach an efficiency of around 10% – at the moment the rate is only 2%. Another problem is lifespan, as the cells get bleached by the sun. However, they are cheap and easy to produce, as the polymer solar cells can effectively be “printed” on materials, making them much easier to mass produce. At present, the printed solar cells last around a year, but they in turn only have 1% efficiency. It appears if you increase efficiency, lifespan and production suffer, and vice versa. However, an efficiency of only 2-3% is enough to run small electronic gadgets, and another advantage is that they can be printed directly onto textiles.

“The photovoltaic effect takes place in a polymer layer consisting of a conjugated polymer (typically a polythiophene) and Fullerene (Carbon 60 or C60). They form what is known as a bulk hetero junction. On absorption of light, an electron is transferred from the conjugated polymer to the C60. The electron is transported through the C60 to the negative electrode. A positive hole is left in the conjugated polymer and it is transferred through the polymer to the positive electrode,” explains Sommer-Larsen.

Fuel Cells

The Fuel Cells and Solid State Chemistry Department headed by Søren Linderoth, is doing research into optimising fuel cells and making them more commercially viable.

World Energy Showroom planned in Copenhagen

The Managing Director at Amagerforbrændingen, Ulla Röttger, is also involved in a project called the World Energy Showroom. The plan is to use the vast array of renewable energy and energy efficient utility plants in Copenhagen as a living exhibition of Denmark's achievements.

“In 2009 there is a climate summit in Copenhagen [COP15], and we have found that in Denmark we have a lot of research results on renewable energy, which is not realised – there are barriers to commercialising ideas. One of the barriers is that it is very difficult to make demonstration plants,” says Röttger.

“The vision is to make a centre where you can come and see solutions that are very good in big cities. The UN says that in 2035, 75% of the world's population will be living in cities, so we have a lot of challenges on how to deal with waste, as well as what to do about energy supply and transportation.”

She believes Copenhagen is ideal for a showroom because the city already has a large concentration of environmentally friendly solutions.

“There are two reasons why fuel cells are not on the market yet: cost has to go down, and durability has to go up,” says Linderoth. Risø recently entered into a consortium with the Danish catalyst and technology company Haldor Topsøe. Out of the Topsøe-Risø consortium has sprung a new company called Topsøe Full Cells, which will focus on the manufacturing of solid oxide fuel cell technology (SOFC), when it becomes operational this autumn. It is built to produce up to 200,000 cells per year.

Linderoth's team is also working on optimising the fuel cells looking at both input and electrical output. One discovery that has been made is that magnetism can be used to cool down the cells, rather than using a compressor.

Wind energy department

At the Wind Energy Department, researchers are working on a laser-based system to measure wind input and wind structure around wind turbines, as well as the effect on blades and the overall wind turbine structure.

One aim is to close the gap from initial composite testing to full blade test as much as possible to save both time and money in the development of new wind turbine blades.

The SysLab, or systems laboratory, at Risø looks at how to integrate renewables such as wind into energy systems. They use Risø as a big lab, as Risø has wind power, PV, biomass, fuel cells, and a hybrid car used to store energy. The aim is to measure and gather data on a distributed system with different types of power input.

Biosystems department

Erik Steen Jensen, Head of Programme, says Risø is working on 2nd generation biofuels. A major aim is to have sustainable production of biofuel without impacting food resources. His team is therefore looking at the use of lignocellulose, or straw, which is seen as a by-product of agriculture. The problem with using straw, however, is that the cellulose is well protected, and the straw therefore needs pre-treatment before biofuel can be extracted.

True to the ethos of Risø, the department is working with industry to transfer the technology to the market. On this project, Risø is collaborating with DONG Energy, which is to build a demonstration plant north of Risø, which can treat four tonnes of straw an hour. It is also working with two leading enzyme producers: called Novozymes and Danisco owned Genencor.

At the moment, the price for one litre of ethanol from straw is US$1.5, but Steen Jensen believes this will go down as technologies improve and the production costs go down. Currently, his team is able to produce 250 litre of ethanol from one tonne of straw, but the potential is 400-500 litres.

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Bioenergy  •  Energy efficiency  •  Energy infrastructure  •  Energy storage including Fuel cells  •  Green building  •  Photovoltaics (PV)  •  Policy, investment and markets  •  Solar electricity  •  Wind power  •  World Future Energy Summit



Gregor Giebel said

19 November 2009
As a researcher at Risø DTU, I have to add that there is more to the Wind Energy Division than the mentioned projects. We are some 140 people in this division alone, plus a few handful in the Materials and Energy Systems divisions, and cover essentially the whole chain from wind power meteorology over turbines and blades to the integration of wind power in the grid and in the market. Please find the link here:

Gregor Giebel said

19 November 2009
As a researcher at Risø DTU, I have to add that there is more to the Wind Energy Division than the mentioned projects. We are some 140 people in this division alone, plus a few handful in the Materials and Energy Systems divisions, and cover essentially the whole chain from wind power meteorology over turbines and blades to the integration of wind power in the grid and in the market. Please find the link here:

Ram Prasad Viswanath said

17 June 2009
Fiscal Incentives by Government agencies is necessary for reducing the dependance on fossils. Nature is a source of enarmous potential for these renewables and human ingenuinity is required to harness them.

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