The municipality of Höör in Southern Sweden decided to invest in a new heating plant for the town centre. Biomass was the preferred source of fuel as it had already proven to be readily available and economically viable in Sweden. The authorities set up strict emission permits as the plant is located in the city centre close to residential areas and a school. To meet these low emissions requirements the plant has been built based on new technology developed by Petro Ett AB (previously Ekotrans Termik AB) and Ermatherm AB.

Description
Financial resources / Economic Benefits
Results
Energy production
Environmental results
Potential for replication
Contact


Description

The method applied to reduce the emission is to combine particle cleaning with flue gas condensation, which is an expensive part of the installation. Ermatherm AB developed the method and Volvo Aero Supports, with support from the Swedish research programme NUTEK, tested the prototype.

The biomass furnace has a capacity of 2.5 MW. The combination of cleaning and condensing of the flue gas added a further 0.3-0.6 MW, depending on the energy content of the bio fuel.

The biomass plant delivers about 15 GWh annually to the district heating network, which is about 85 % of the heat used by the network. Three 3.3 MW LPG boilers supply the remainder.

The furnace was supplied by Petro Ett AB: The furnace is equipped with a flue gas recycling system, which contributes to accurate control of the temperature and combustion of high energy content fuels. An additional feature of the recycling system is the reduction in emission of nitrogen oxides.

To reduce emission the flue gas is cleaned in a wet electrostatic precipitator before it enters the condenser. Inside the precipitator the flue gas comes into contact with the wet inside of the cylindrical duct and the positive charged dust particles are attracted to the water film on the wall. The flue gas exits the precipitator at the base, where it then travels upwards through a scrubber column.

The project is described in the International Energy Agency's CADDET Technical Brochure No. 156, www.caddet-re.org and in the Swedish magazine 'Energimagasinet', No. 5, 1998, www.energimagsinet.no (in Swedish. The contractor uses the plant as a reference plant for new customers.

Financial resources / Economic Benefits

The total investment was SEK 11,000,000 (€ 1,200,000).

The electrostatic precipitator cost was SEK 1,600,000 (€ 180,000), for which the Swedish National Energy Administration gave a grant of SEK 380,000 (€ 42,000).

The payback period for the plant is approximately 4 years.

Results

Energy production

The plant delivers about 15 GWh a year, of which the biomass plant delivers 13 GWh (85 %).


Environmental results

The installation of the wet electrostatic precipitator increased efficiency and decreased emissions.

If the annual heat output of the biomass plant were to be supplied from LPG boilers, approximately 1,200 tonnes of LPG would need to be used, which would increase the emissions of carbon dioxide by about 3,000 tonnes.

Potential for replication

There are currently a number of similar projects in Sweden and Norway. The potential for projects of this kind is increasing as environmental regulations are getting stricter. The focus on lower emissions within the European Union would contribute bolstering the potential for this technology.

Contact

Main contractor
PETRO ETT AB
Helsingborgsvägen 33, SE-262 72 Ängelholm
Tommy Karlsson
+46 0431 41 00 10
fax: +46 0431 41 00 20
tommy@petroett.se
www.petroet.se

Subcontractor
Ermatherm AB
Eero Erma
Solbacksv. 20, SE-147 41 TUMBA
+46 8 530 689 50
fax: +46 8 530 311 73
eero.erma@ermatherm.se