by Linda Bertelsen
the 12 MWth / 1 MWe cogeneration Sorø Bioenergy Plant from the article by Dall Energy on page 3. You see only pure steam rising from the chimney. Photographer: Steen Knarberg

Operational for over a year since its inauguration, Sorø Bioenergy converts garden-parc waste from the municipalities into heat and electricity. The 12 MWth biomass plant is a perfect example of using local biomass resources correctly.

By Ann Bouisset, Cand. Oecon/MBA, General Sales Manager, Dall Energy

AffaldPlus, the plant owner, collects the garden-parc waste in 13 waste-receiving depots located throughout the six municipalities and prepares the garden-parc waste in their biomass platform in Næstved, Denmark. Here the garden parc waste passes through a simple two-stage process: it is shredded and screened into three fractions, fines for composting, fuel ready for biomass gasification, and oversized, which is put back into the shredder again. Annually 53,000 tons of garden waste is aggregated. Of this, 11,000 tons are used in the gasification process to create heat, and 32,500 tons are composted.

Unique patented gasification technology makes it possible.

The Dall Energy gasification furnace allows the Sorø Bioenergy plant to use very inhomogeneous biomass, with qualities that vary substantially over the year. The flexibility of mixing a wide range of fuels and with humidity levels from 20-60% makes it possible to use biomass that could previously not be used.

The gasification furnace can use a mix of difficult fuels such as garden-parc biomass.

The gasification furnace can use a mix of difficult fuels such as garden-parc biomass. Photographer: Steen Knarberg

The technology also allows for a great load-flexibility, from 100% right down to 10%, without compromising on emissions such as dust, NOx, and CO. This flexibility is crucial, especially for plants operating without accumulation tanks like the Dall Energy plant in Rouen, France with Dalkia, or where there is solar heating in the district heating mix like in the Silkeborg, Denmark or Salon de Provence, France projects.

The gasification process allows for very low emissions without bags or electro-filters.

The Dall energy furnace combines updraft gasification with gas combustion in the same chamber, which results in full performance and environmental benefits without the historical problems related to external combustion. Primary air injection is about half of what is used in traditional grate incineration, which results in very low NOx emissions. The gas velocity in the bottom part is very low, so dust emissions out of the oven are between 30-60 mg per Nm3. Also, most of the particles are subsequently removed by a quench bringing the dust levels down to 10 -20 Nm3, thus complying with EU standards without using expensive bags or electro filters.

The top of the Dall Energy gasification furnace in Sorø

The top of the Dall Energy gasification furnace in Sorø. Photographer: Steen Knarberg

The advantages of Dall Energy gasification technology are recognized not only in Denmark but also in France.

The advantages of the technology receive great recognition. Dall Energy recently signed a contract for a 20 MW biomass gasification plant with Silkeborg in Denmark and several contracts in France with large energy companies and industrial customers.

10,000 tons CO2 reduction per year

The Sorø Bioenergy plant converts approximately 30,000 tons garden-parc waste to climate friendly heat and electricity. By utilising garden-parc waste instead of gas 10,000 tons of CO2 is saved per year. This saving is equivalent to each of their customers driving 1.3 times around the earth in a car.

For further information please contact: Ann Bouisset, apb@dallenergy.com

“Circular biomass energy – with citizens heated by their garden-parc waste” was published in Hot Cool, edition no. 3/2023
Circular Biomass Energy in Sorø Dall Energy
Download and print the article here

Meet the author

Ann Bouisset
Cand. Oecon/MBA, General Sales Manager, Dall Energy