Hanstholm District Heating Plant And Hanstholm Combined Heat And Power Plant

Hanstholm DHP and Hanstholm CHP exemplify plants that over the years have grown into a large corporation offering heat and power production from many different energy sources. Hanstholm DHP was founded in 1965 and was located in the building at Molevej 13 that had been built during World War II as a mess building for German soldiers stationed in Hanstholm.

 

Hanstholm Varmeværk A.m.b.a.
Molevej 13,
7730 Hanstholm,
Phone: +45 97 96 10 30
www.hanstholmvarmevaerk.dk
Email: varmecentral@mvb.net

Hanstholm Kraftvarmeværk
Industrivangen 41,
7730 Hanstholm,
Phone: +45 97 96 27 41

Hanstholm DHP and Hanstholm CHP plant have many both national and international visitors. Because of the many new initiatives and pilot projects the plants are used to showcase new technologies by partners in industry. The Norwegian company Parat often brings guests to Hanstholm to view the electric boiler in action.

  • Guided tours: Yes
  • Open: By appointment
  • Booking: 2 work days prior to visit
  • Participants: By appointment
  • Admittance fee: None
  • Parking: Yes
  • Toilet: Yes
  • Language: English / German / Danish.

 

was oil fired and from the beginning 51 consumers signed up to receive district heating from the new plant. Today the DHP and the CHP plants supply heating to 810 consumers in Hanstholm and the neighbouring village of Ræhr. 96% of all possible users in the supply area are connected to the district heating grid.

In 1992 the nearby village of Ræhr was included in the supply area of Hanstholm DHP and the laying down of pipelines was initiated. In 1994 the CHP plant at Industrivej 41 in Hanstholm was inaugurated. The plant was owned by the power utility Nordkraft until 2007 when it was purchased by Hanstholm DHP. In 1981 a deal was made between Hanstholm DHP and a local fish meal manufacturer to purchase industrial surplus heating from the production process at the factory. When the need for larger boiler capacity arose in 1988 the plant invested in a new 7 MWh gas fired boiler with flue gas cleaner. The flue gas cleaner contributes to the efficiency of the plant by extracting surplus heat from the flue gas that enters the flue gas cleaner at 300° Celsius and exits with the considerably lower temperature of 20-22° Celsius.

Today the DHP and CHP plant in Hanstholm produce energy from natural gas, biofuel, industrial surplus heat from the fish meal industry and wind power.

The Natural Gas Boilers

hanstholm-fjernvarme_20130221-DSC_4997-Edit At the plant on Molevej heating is produced by two natural gas fired boilers and one biofuel fired boiler. Financial considerations decide which unit is in production and currently the most profitable energy production is from biofuel.

The two Danstoker natural gas fired boilers producing 3.6 MW and 6.3 MW respectively needs to be operated frequently since they function as emergency backup boilers. The smaller of the two dates back to the 1970s and was built for oil but in the 1980s it was converted to natural gas.

Biofuel

In 2007 production facilities at Hanstholm DHP increased by a biofuel fired boiler producing 4.5 MW. The plant currently has two biofuel suppliers delivering a total of 7.5 cubic metres bio oil per week during winter. The fuel is derived from animal fat, a byproduct from the abattoir and meat industries which is not used in food products. The oil is kept in an isolated tank to prevent it from solidifying in cold temperatures.

Flue Gas Cleaner

hanstholm-fjernvarme_20130221-DSC_4987-Edit The biofuel boiler was fitted with a flue gas cleaner in 2009. The facility is located in the backyard at Molevej and comprises two containers where the 300° hot flue gas from the biofuel boiler is lead through. When the fuel is burned in the boiler the humidity in the fuel is transformed to steam with a high energy content. The flue gas cleaner functions as a large scale shower cleaning the flue gas and at the same time transferring the energy in the flue gas to the cleaning water from where the energy is obtained in the circulating district heating water. After being showered twice the temperature of the flue gas has fallen to 48° Celsius thereby improving the efficiency of the boiler with 15%. But that is not enough for Hanstholm DHP where optimal use of the fuel is a constant concern.

Consequently an additional cleaner has been developed extracting even more energy from the flue gas before it exits through the chimney reduced to a temperature of only 20° Celsius.
During this process the flue gas has been effectively cleaned of particles that are gathered and neutralized by for example lye.

Industrial Surplus Heat from the Fishmeal Industry

Since 1981 there has been a partnership between Hanstholm DHP and the fishmeal manufacturer Hanstholm Fiskemelsfabrik A/S involving the use of industrial surplus heat from the production of fishmeal. Energy supply from the fishmeal industry is evidently dependent on the amount of raw material available which in turn depends on factors like the weather and shifting fishing quotas. That is why the industrial surplus heat only makes up for a part of possible energy sources available to Hanstholm DHP. Particularly during the summer months heating in Hanstholm and Ræhr comes from the fishmeal industry. About 10 to 33% of district heating produced at Hanstholm DHP comes from industrial surplus heat.

The surplus heat is a byproduct of fishmeal production. When the district heating water returns chilled from the consumers, it is lead through pipelines at the fishmeal factory where it is used to chill the water from the production. Production water must be cooled to a certain temperature before emitted from the factory. When the district heating water has absorbed the surplus heat at the factory, and once again has obtained a flow temperature of 72° Celsius, it returns to the consumers. During periods of extra heat generation from the factory, when the hot water that is not immediately consumed by the city, it is stored in the accumulation tank.

Water Treatment with Reverse Osmosis

In order to cut production costs Hanstholm DHP installed a new water treatment system in 2006. All district heating systems are prone to bacterial growth that covers surfaces with a thin thermally insulative film. Also the waste products from the bacteria may cause corrosion.
hanstholm-fjernvarme_20130221-DSC_5008-Edit As a result the district heating plant spends resources on cleaning and repairing the pipes. Several measures can be taken to reduce bacterial growth in district heating systems. One solution is to starve the bacteria of food supply by avoiding materials like plastic and rubber in the pipes. Another solution is to add lye and chemicals like phosphate and sulfate to the water. Some chemicals increase the pH level in the water while others tie oxygen or increase conductivity.

At Hanstholm DHP a third option was chosen: Reverse osmosis which is a membrane-technology filtration method that removes many types of molecules from the water, like for example calcium. The water is submitted to three treatments before submitted into the district heating system:
Firstly the water is lead through a decalcification plant with little golf ball shaped balls that the calcium sticks to. Secondly the water is lead through a reverse osmosis plant removing nutrients by applying pressure on the water when it is on one side of a selective membrane.

Finally the water is deoxygenated in a pressure boiler and added a non toxic colorant to effectively spot leaking. Through this process the water becomes less harmful to the district heating system saving the plant expensive repairs.

Hanstholm Combined Heat and Power Plant

In the early 1990s the Danish Energy Regulatory Authority imposed on the district heating plant in Hanstholm an obligation to establish combined heat and power. In 1994 the CHP plant at Industrivej was established in partnership with the power utility Nordkraft. Hanstholm DHP was in charge of the daily operations at the plant and in 2007 the plant was purchased by Hanstholm DHP. Four natural gas fired engines are producing a total of 7 MW heat and 5.5 MW electricity.

Wind Power at the CHP Plant

In 2011 a 10 MW electric boiler was installed at Hanstholm CHP plant producing hot water from wind power generated by wind turbines at nearby Hjertebjerg. The electric boiler is part of the frequency controlled power grid where boiler output is constantly adjusted to current needs. This means that when energy produced by the electric boiler is cheaper than energy produced by the natural gas fired engines, hot water for the consumers in Hanstholm and Ræhr is generated by the electric boiler. hanstholm-fjernvarme_20130221-DSC_5027-Edit

The electric boiler is a prototype developed in partnership with the Norwegian company Parat, who have been in the industrial steam and heating equipment business for over 100 years. The boiler consists of an outer and an inner chamber. The inner chamber holds three electrodes that generate heat by ohmic resistance, which is the property of electric conductors causing a loss of energy when an electric current passes through the conductors. When the wind turbines at Hjertebjerg generate power, water in the inner chamber is pushed upwards until the electrodes are submerged and heat up the water. The heated water from the electric boiler is then either directed to the consumers or to the 25 meters high accumulation tank containing a maximum of 5000 m3. The conductivity of the water is important and is frequently checked, just as the water quality. Like at the plant at Molevej the water at the CHP plant undergoes treatments with reverse osmosis.

Ræhr District Heating

The village of Ræhr has no district heating plant and since 1992 the village has been included in the supply area of Hanstholm DHP. Ræhr District Heating is an autonomous company and it owns the transmission line from the city limits in Hanstholm as well as the rest of the pipelines in Ræhr and Nytorp.

Meter Reading and Service Check

In 2012 Hanstholm DHP invested in a new system for remote controlled reading of meters. Readings are carried out two to three times a week with particular attention to return temperature, i.e. how well the consumer’s installation uses the heat from the district heating water. If the return temperature rises above the required 40° Celsius a technician from the plant will visit the consumer to locate the source of the problem and pass the information on to a plumber.

The installations are fitted with heat exchangers on domestic water and on the central heating water. This means that the district heating water does not flow directly into the radiators in peoples’ homes, but is used to heat up water from the water works in a heat exchanger. The flow temperature of the district heating water is 75° Celsius and the pressure is 4.8 bar.

Prices

Each year district heating plants in Denmark submit their price lists to the Danish Energy Regulatory Authority. According to the price list of August 2013, district heating from Hanstholm District Heating costs DKK 500 per MWh VAT included. This means an annual cost of DKK 11.750 for heating in a standard flat of 75 m2 consuming 15 MWh per year, and an annual cost of DKK 13.300 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

Production Data

  • Established in 1965
  • 3.6 MW natural gas fired boiler, Danstoker
  • 6.3 MW natural gas fired boiler, Danstoker
  • 4.5 MW bio fuel fired boiler with flue gas cleaner
  • In 2006 new water treatment system
  • In 2012 remote controlled meter reading equipment.

Hanstholm CHP

  • Established in 1994
  • Four natural gas fired engines, 7 MW heat, 5.2 MW electricity
  • One 10 MW electric boiler, Parat
  • 5000 m3 accumulation tank.

Production data for the financial year 2011 – 2012

  • Bio oil boiler: 12.367 MWh (38.5%)
  • Industrial surplus heat : 6.083 MWh (19.0%)
  • Natural gas boilers: 5.499 MWh (17.2%)
  • Combined heat and power: 4.558 MWh (14.2%)
  • Electric boiler including availability compensation: 3.551 MWh (11.1%).