The district heating plant in the village of Vestervig was established in 1964. Today Vestervig District Heating Plant supplies 536 consumers in Vestervig and the neighbouring villages of Krik and Agger with district heating. In 1964 the district heating plant in Vestervig relied solely on oil, but in 1986 a decision was made to use wood chips instead.
- Guided tours: Yes
- Open: By appointment
- Booking: 2 work days prior to visit
- Participants: By appointment
- Admittance fee: None
- Parking: Yes
- Public transportation: Busstop 400 meters from the plant
- Toilet: Yes
- Language: Danish.
the tax on coal was going up and the economically aware Board of Directors at Vestervig District Heating Plant decided on wood chips instead of coal. This decision proved foresighted and today the plant ranks among the top 20 cheapest suppliers of district heating in Denmark. Moreover the plant in Vestervig is intent on delivering CO2 neutral heating based on wood chips from the nearby woods of the region of Thy. The proximity of the raw materials reduces production costs, ultimately making way for lower prices for the customers. Lower costs are also achieved through the high number of users connected to the grid. 95% of possible users in the area are connected to the district heating grid. In recent years renovations of the pipelines have contributed to security of supply and lower loss of heat. Finally a flue gas cleaning system cools the flue gas from the boiler to about 36° Celsius thereby regaining 25% of the heat to be distributed to the consumers.
The ashes from the burned wood chips are recycled in the forest as fertilizer completing the image of an eco-friendly district heating plant.
In 2011 a new 4 MW wood chip boiler with 1 MW flue gas cleaner was installed. Already during its first winter the new boiler proved its worth by producing up to 4.2 MW at times. The DKK 13 million investment in the boiler and a 250 m2 large extension to the buildings at Vestervig District Heating Plant must also be seen in view of the recent increase in the customer base with the nearby villages of Krik and Agger.
Today the plant in Vestervig is a state of the art, eco-friendly and 100% wood chip fired district heating plant with a fully automated feeder system and an annual budget for purchasing wood chips at about DKK 3 million. An emergency power generator guarantees the heat supply in case of power failure on the public power grid.
The original oil fired boiler is still operational but is only used as emergency backup in case the wood chip fired boiler malfunctions. In an emergency situation the oil boiler can produce hot water in just half an hour while the old wood chip fired boiler takes several hours to be operational. The latter is used during planned shutdowns such as service checks.
A Fully Automated Facility
The investment in an new wood chip fired boiler also introduced a new SCADA system. SCADA is an acronym for Supervisory Control and Data Acquisition and describes an electronic system for controlling and supervising an automated facility like a district heating plant. Among other things the conveying of wood chips to the boiler is automated. A grab suspended in the ceiling of the storage room lifts the wood chips and dumps them in the receiving hopper where photocells register the level of wood chips in the hopper controlling the frequency with which wood chips are deposited. From the receiving hopper the wood chips are pushed into the boiler by a powerful hydraulic feeder. Combustion in the boiler is efficient and the wood chips may contain up to 55% water and still be used. The wet wood chips produce a lot of steam and inside the boiler various measures are taken to prevent the steam from condensing leading to corrosion.
The storage room which was built around ten years ago, has two pits with room for wood chips to last 5-6 days. Fuel is produced in the state owned forests in Thy delivering around 17.000 cubic meters of wood chips per year to Vestervig District Heating Plant. At the plant in Vestervig there are no worries as to whether the forests will be able to produce enough wood chips in the future. Dansk Fjernvarmeforening, the trade organization for district heating plants in Denmark, has carried out a survey concluding that the combined forests in Denmark would be able to increase wood chip production with 100%. The privately owned forests are interested in the wood chip market too, which ultimately may lead to lower prices due to competition among the suppliers.
A Flue Gas Cleaner Increases Efficiency
The flue gas exiting the boiler is about 208° Celsius. To extract that surplus heat the flue gas is run through a flue gas cleaner. Before the flue gas reaches the flue gas cleaner it is run through a cyclone cylinder where the gas swirls around forcing the particles to the cyclone wall from where they fall to the bottom, while the cleaned gas exits through the top of the cyclone. From here it is directed into the actual flue gas cleaner where the flue gas is showered with water several times. The water from this process is led to containers with wood shavings, filtering the water before finally letting the cleaned water sift into the sewer.
But the flue gas cleaner not only cleans the flue gas. The system also uses the heat from the flue gas to heat up the cooled return water that runs back to the plant from the consumers. This process increases the output of the district heating system, which is evident from the fact that the steam emitted from the chimney is only 36° as opposed to the 208° that went into the flue gas cleaner. During winter the flue gas cleaner produces 1 MWh.
The quality of the water in a district heating system is crucial to the operations of the plant. For example the water cannot contain calcium since it will lead to calcification in the pipes. To compensate the water at Vestervig District Heating Plant is lead through a decalcification system consisting of little balls of resin that tie the calcium. The water from the public water works contains oxygen which increases the risk of corrosion in the pipes and therefore the plant adds chemicals that lower the oxygen content. Finally lye is added to the water to obtain a pH value of 9.7. To prevent corrosion in the district heating system, the pH value should be between 9.6 and 10.
Extending the Grid to Krik and Agger
In 2010 Vestervig District Heating Plant extended the supply area to neighboring villages Krik and Agger. Local initiative in the two villages and a combined wish to get cheaper heating made way for the project. Many households in Krik and Agger were facing a replacement of their oil burners and it seemed a good time to consider alternative solutions. At the same time Thisted Municipality launched the Energetic Citizens of Thy initiative aimed at furthering renewable energy business development in the villages and rural areas of Thy. Also the aim is to cement a base for energy solutions reducing CO2 emissions.
During the winter of 2009 / 2010 a sufficient number of households in Krik and Agger agreed on getting district heating from Vestervig and in May 2010 the first sod was turned in the laying down of 10 km of pipeline between the plant in Vestervig and consumers in Krik and Agger. Work was carried out by local entrepreneurs and the investment of 10 million DKK will be payed by the new consumers through their heating bills. The pipeline to Krik and Agger consists of highly insulated twin pipes with a minimum loss of heat which adds to the efficiency of the plant. In Agger and Krik the district heating units are equipped with remote controlled meters while in Vestervig the technicians at the plant manually read the meters in the consumers’ households once a year.
Read more about Energetic Citizens of Thy at
Energy from the Sun
At the district heating plant in Vestervig a continuous effort is made to lower heating prices. The latest initiative is the projecting of a 7000 m2 large solar thermal power plant on a field adjacent to the district heating plant. The solar panels will be harnessing solar energy for thermal energy. Energy production from the panels will be sufficient to cover almost 25% of energy consumption in the plant’s distribution area. By installing heat pumps the plant expects to enter the regulated electricity market.
The facility is designed by the Danish company ARCON Solar that produces HT solar panels specifically designed to accommodate the distinct needs and specifications of large-scale units. Solar panels are known from other district heating plants in Denmark, among others Gram Fjernvarme where 10.073 m2 of solar panels with a maximum effect of 7000 kW are producing about 4.857 MWh per year covering 17% of the district heating consumption in Gram.The new solar thermal power plant project is ready for implementation the moment the project is authorized by the authorities.
Each year district heating plants in Denmark submit their price lists to the Danish Energy Regulatory Authority. According to the price list of December 2012, district heating from Vestervig Fjernvarmeværk costs DKK 300 per MWh VAT included. This means an annual cost of DKK 9.406 for heating in a standard flat of 75 m2 consuming 15 MWh per year, and an annual cost of DKK 11.711 for heating in a standard single-family house consuming 18.1 MWh per year.
The above mentioned prices are standard prices and in order to calculate the actual price for heating it is necessary to consider the actual heat consumption of a given family and the fixed costs of for example subscription. For more Danish district heating prices see www.energitilsynet.dk
- Established in 1964
- In 1986 a change from oil to wood chips is made
- In 2010 the supply area is extended to include Krik and Agger
- In 2011 a new emergency power generator is installed
- One 4 MW wood chip fired boiler, Danstoker, with 1 MW flue gas cleaner, Weiss, installed in a new building in 2011
- One 2.5 MW wood chip fired boiler with 0.7 MW flue gas cleaner, Hollesen, backup
- Two oil fired boilers for emergency backup.