Dall Energy selected for Denmark's first green waste CHP plant


Spring 2020

In Denmark, Dall Energy has been selected by local heating utility Sorø Fjernvarme A/S to supply a turnkey combined heat and power (CHP) plant to the town of Sorø.

Full sustainability is reached based on a circular economy concept, avoiding dependency on fresh water, arable land and inorganic fertilizers. The Life Cycle Assessment (LCA) performed on the demonstration plant showed an energy return on investment (EROI) of 4, changing the paradigm of effluent treatment from energy consumer to net energy exporter.

The 12 MWth and 1 MWe plant will primarily be fired on local woody green waste and will replace a fossil gas fired facility as part of the goal to have 100 percent of the district heating from renewable sources.

"It will be the first district energy plant in Denmark that will use local woody green waste from gardens and parks as the main fuel", said Jens Dall Bentzen, CEO of Danish biomass gasification and combustion technology providers Dall Energy.

Recycling, materials, nutrient– and energy recovery
Sorø Fjernvarme is local district heating owned by Affald Plus. AffaldPlus is a joint municipal waste management company owned by six municipalities (Faxe, Sorø, Næstved, Vordingborg, Slagelse and Ringsted) in south and west Zealand.

Recycling and recovery of resources is a key priority for AffaldPlus which also includes green waste such as hedge- and roadside trimmings, grass cuttings, bush and tree “lop and top” and pruning from private gardens, public parks and other urban green areas.

This fuel is currently being supplied to third-parties, but will in the future be used for the new CHP plant in Sorø.

Turnkey delivery for Dall Energy
The scope of Dall Energy delivery comprises of a biomass gasification furnace and a hot oil boiler, including all associated auxiliary equipment such fans, piping, a fuel feeding system, ash handling system, electrical and control systems. Dall Energy is responsible for turnkey delivery of the equipment, including design, procurement, installation and commissioning.

"We've seen from our other energy plant installations that they can use such fuel as woody green waste."

"However, this is the first project contract that we have signed explicitly with the assurance that it will be possible to fire the plant with 100 percent woody green waste", said Jens Dall Bentzen.

The contract was awarded to Dall Energy in Q4 2019, and the plant is scheduled to be handed over for commercial operation during the summer of 2021.

Significant savings for heat customers
The plant will be designed for operation on 100 percent green waste but can also utilise regular woodchips, providing extensive fuel flexibility.

"We estimate that on an annual basis, about 80 percent of the fuel will be green woody waste with the balance made up of forest biomass and woodchips", said Tommy Fer.

The plant efficiency will be up to 110 percent (LCV based) depending on the fuel quality. Once commissioned, the plant is also expected to provide energy cost savings to district heat customers along with the environmental and climate benefits. According to AffaldPlus, an average household can expect reduced annual heating costs of almost 25 percent.