SUCCESS STORY: Straw fired district heating in...
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IEA STRATEGIC STUDY ON RENEWABLE HEAT SUBPROJECT WITHIN IEA BIOENERGY TASK 32 NOVEMBER 2018 PAGE 1/4 Nexø Halmvarmeværk (Nexo straw fired heating plant) was established in 1989-90 to supply district heating to local consumers. After merging with Bornholms Forsyning the district heating distribution grid was expanded to include three neighboring towns to the north of Nexø. To service this larger distribution grid without significant increase in fuel consumption, Nexø Halmvarmeværk invested in a Euro Therm straw-fired biomass plant at the end of 2014. With a boiler output rated at 12.5 MW, the total output of the boiler system is close to 15 MW. The new plant was commissioned during spring 2016 and through boiler design, flue gas condensation and absorption heat pump technology it achieves a market-leading efficiency. The investment and its technology The district heating plant in Nexø had two 5 MW straw- fired boilers in operation and needed to upgrade these boilers in order to service a larger district heating grid. One of the existing boilers was retired, while the other was kept operational as back-up boiler. An 8 MW oil boiler serves as back-up and has been in operation for 100 h during the past 30 years. A new boiler room with auxiliary rooms was added to the existing district heating plant in Nexø. Using the existing storage facilities for straw bales, a completely new boiler system from automatic fuel crane to chimney was installed. Situated on the small island of Bornholm, Nexø Halmvarmeværk had to consider the periodically limited supply of local straw. Therefore, the new boiler system was optimized with flue gas condensation and absorption heat pump technology to fully utilize the energy of the consumed fuel. The investment included both the additional building and the boiler system at a total cost of approx. DKK 35 000 000 (EUR 4 700 000). Factors behind the decision Nexø already had a straw-fired district heating plant and found it feasible to continue with this fuel as the heat demand grew and the existing boilers had reached the end of their lifetime. This solution would enable the company SUCCESS STORY: Straw fired district heating in Nexø INVESTMENT CASE Title: Nexø – 15 MW straw fired district heating plant - a plant with everything Year (commissioned): 2016 Location: Bornholms Forsyning, Nexø Halmvarmeværk, Nexø, Denmark Stakeholders: 1. Tina Wester Dam/ Bornholms Energi & Forsyning – Team leader, Project manager 2. Søren Nielsen / Bornholms Energi & Forsyning – Department Manager (Heating) Authors: Jan Depenau, Euro Therm Allan S. Pedersen, Euro Therm Søren Nielsen, Bornhoms Energi & Forsyning IEA Bioenergy
Transcript of SUCCESS STORY: Straw fired district heating in...
IEA STRATEGIC STUDY ON RENEWABLE HEAT SUBPROJECT WITHIN IEA BIOENERGY TASK 32 NOVEMBER 2018 PAGE 1/4
Nexø Halmvarmeværk (Nexo straw fired heating plant) was established in 1989-90 to supply district heating to local consumers. After merging with Bornholms Forsyning the district heating distribution grid was expanded to include three neighboring towns to the north of Nexø. To service this larger distribution grid without significant increase in fuel consumption, Nexø Halmvarmeværk invested in a Euro Therm straw-fired biomass plant at the end of 2014. With a boiler output rated at 12.5 MW, the total output of the boiler system is close to 15 MW.
The new plant was commissioned during spring 2016 and through boiler design, flue gas condensation and absorption heat pump technology it achieves a market-leading efficiency.
The investment and its technologyThe district heating plant in Nexø had two 5 MW straw-fired boilers in operation and needed to upgrade these boilers in order to service a larger district heating grid. One of the existing boilers was retired, while the other was kept operational as back-up boiler. An 8 MW oil boiler serves as
back-up and has been in operation for 100 h during the past 30 years.
A new boiler room with auxiliary rooms was added to the existing district heating plant in Nexø. Using the existing storage facilities for straw bales, a completely new boiler system from automatic fuel crane to chimney was installed.
Situated on the small island of Bornholm, Nexø Halmvarmeværk had to consider the periodically limited supply of local straw. Therefore, the new boiler system was optimized with flue gas condensation and absorption heat pump technology to fully utilize the energy of the consumed fuel.
The investment included both the additional building and the boiler system at a total cost of approx. DKK 35 000 000 (EUR 4 700 000).
Factors behind the decisionNexø already had a straw-fired district heating plant and found it feasible to continue with this fuel as the heat demand grew and the existing boilers had reached the end of their lifetime. This solution would enable the company
SUCCESS STORY:
Straw fired district heating in Nexø
INVESTMENT CASETitle: Nexø – 15 MW straw fired district heating plant - a plant with everythingYear (commissioned):2016Location:Bornholms Forsyning, Nexø Halmvarmeværk, Nexø, Denmark
Stakeholders:1. Tina Wester Dam/ Bornholms Energi & Forsyning – Team leader, Project manager2. Søren Nielsen / Bornholms Energi & Forsyning – Department Manager (Heating)
Authors:Jan Depenau, Euro ThermAllan S. Pedersen, Euro ThermSøren Nielsen, Bornhoms Energi & Forsyning
IEA Bioenergy
IEA STRATEGIC STUDY ON RENEWABLE HEAT SUBPROJECT WITHIN IEA BIOENERGY TASK 32 NOVEMBER 2018 PAGE 2/4
to keep the existing fuel logistics, storage and handling equipment that were already in place.
The choice of straw for heat purposes makes sense in Denmark as biomass used for heating is exempted from the energy tax that applies to fossil fuels. Further, straw combustion technology has been developed through many years in Denmark to reach a maturity level that omits any doubt about the operational stability.
Lessons learnedClose co-operation between supplier and the owner/operator of the plant is an important key to reach a properly
operating heating plant, especially when the operator is really experienced.
Success factorsThe energy tax exemption regarding solid biomass for heating purposes is instrumental for making the decision to invest.
The system where a municipal loan guarantee covers the risks, enables easy financing.
Straw combustion technology has been developed through many years in Denmark.
Fuel type: Wheat strawFeedstock origin: Domestic agriculture, “dry” by-products / residuals: straw husk, peals, corn stoves Conversion system: Boiler combustion, e.g. stand-alone boiler plant including co-firing and combined heat and powerCo-fire: Heat generator (i e boiler) is 100 percent biomass-fired.Heating system heat sources: Biomass is the only heat source in system
Comments: The boiler plant includes an absorption heat pump powered by the super-heated water from the biomass boiler. Existing fossil fuel boiler is only maintained as reserve boiler.
IEA STRATEGIC STUDY ON RENEWABLE HEAT SUBPROJECT WITHIN IEA BIOENERGY TASK 32 NOVEMBER 2018 PAGE 3/4
Take urgent action to combat climate change and its impacts
Protect, restore and promote sustainable use of terrestrial ecosystems,
sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss
Contribution of the investment: The investment supports and sustains the transition from fossil fuels to sustainable, locally grown, renewable fuels in the supply of heat.
End poverty in all its forms everywhere
End hunger, achieve food security and improved nutrition and promote
sustainable agriculture
Ensure healthy lives and promote well-being for all at all ages
Ensure access to affordable, reliable, sustainable and modern
energy for all
Promote sustained, inclusive and sustainable economic growth, full and
productive employment and decent work for all
Build resilient infrastructure, promote inclusive and sustainable
industrialization and foster innovation
Make cities and human settlements inclusive, safe, resilient and
sustainable
Ensure sustainable consumption and production patterns
Relation to Sustainable Development Goals: Replicability potential: High local replicability High regional replicability High national replicability High international replicabilityComment:The technology from Euro Therm has proved itself and district heating systems with similar conditions are found throughout Denmark and internationally.
Scale-up potential: Medium local potential Medium regional potential Medium national potential Medium international potentialComment:Similar technology can be applied to smaller as well as larger boiler systems.Connection to policy case:
IEA STRATEGIC STUDY ON RENEWABLE HEAT SUBPROJECT WITHIN IEA BIOENERGY TASK 32 NOVEMBER 2018 PAGE 4/4
Web sites:www.ri.sewww.energimyndigheten.se/en/www.iea.org/tcp/www.ieabioenergy.com
Contact:Jan Depenau, Euro ThermE-mail: [email protected] LinkedIn
Allan S. Pedersen, Euro ThermE-mail: [email protected]
Søren Nielsen, Bornhoms Energi & ForsyningE-mail: [email protected]
IEA Bioenergy
IEA Bioenergy
