HEAT & POWER
Dall selected for Denmark’s first green waste CHP plant
In Denmark, Dall Energy has
been selected by local heat-
ing utility Sorø Fjernvarme
A/S to supply a turnkey
combined heat and power
(CHP) plant to the town of
Sorø. The 12 MWth and 1
MWe plant will primarily be
fired on local woody green
waste and will replace a fos-
sil gas fired facility as part
of the goal to have 100 per-
cent of the district heating
from renewable sources.
–
IT WILL BE THE FIRST
district en-
ergy 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.
– We see from our recycling facilities that we can recover most of the fuel needed for the new heating plant. The green
waste is local, CO
2
neutral and renewable, said Tommy Fer, Project Manager at Sorø Fjernvarme.
Recycling, materials,
nutrient– and energy
recovery
Sorø Fjernvarme is local district
heating utility acquired by Affald-
Plus in January 2018 from Sorø
municipality. AffaldPlus is a joint
municipal waste management com-
pany owned by six municipalities
(Faxe, Sorø, Næstved, Vording-
borg, Slagelse and Ringsted) in
south and west Zealand. A major
operator in Denmark, AffaldPlus
runs 20 recycling sites throughout
the six municipalities servicing
around 300 000 citizens and
30 000 businesses.
Approximately 170 000 tonnes
per annum of household and indus-
trial waste is handled by AffaldPlus
of which about 80 percent of the
volume is recovered into more than
40 different types of recycled and
secondary materials from cardboard
and paper to chemicals and recycla-
ble PVC. The company also operates
two waste-to-energy facilities, lo-
cated in Næstved and Slagelse, for
energy recovery of materials that
cannot be recycled while less than 6
percent ends up in landfill.
Ten green waste
receiving centres
The Danish government's resource
strategy stipulates that 25 percent
of all garden and park waste should
be converted into biomass fuels to
replace fossil fuels. This led Affald-
Plus to look for alternatives to com-
posting several years ago. Recycling
and recovery efforts at AffaldPlus
thus 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 ur-
ban green areas.
Digestible organic material
from ten green waste receiving
centres is supplied to local biogas
plants whereas woody residues
such as tree-care debris, hedge-
and bush trimmings is currently
processed into biomass fuel at
Næstved and Faxe. The fuel, cur-
rently being supplied to third-par-
ties, will be used for the new CHP
plant. Residual green waste mate-
rial that cannot be used as a sub-
strate or biomass fuel is used to
make raw compost for use as a soil
improver for agriculture.
– We’ve seen from our other en-
ergy plant installations that one can
use such fuel as woody green waste.
However, this is the first project
contract that we have signed explic-
itly with the assurance that it will be
possible to fire the plant with 100
percent woody green waste, said
Jens Dall Bentzen.
The furnace design started in
Q4 2019, and the plant is sched-
uled to be handed over for com-
mercial operation during the
summer of 2021.
at our recycling centres which has
remained relatively stable over the
years, said Tommy Fer.
To be operated as a baseload
plant, it will have a thermal capac-
ity of 12 MW heat and approxi-
mately 1 MW electricity. The plant
efficiency will be up to 110 percent
(LCV based) depending on the fuel
quality.
Turnkey delivery for Dall
The scope of Dall Energy delivery
comprises of a biomass gasification
furnace and a hot oil boiler, includ-
ing all associated auxiliary equip-
ment such fans, piping, a fuel feed-
ing system, ash handling system,
electrical and control systems. Dall
Energy is responsible for turnkey
delivery of the equipment, includ-
ing design, procurement, installa-
tion and commissioning.
Base load heat and
power plant
The plant will be designed for op-
eration on 100 percent green waste
but can also utilise regular wood-
chips, 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. This is based on
the volume of green waste received
Significant savings for
heat customers
Once commissioned, the plant is
also expected to provide energy
cost savings to district heat cus-
tomers along with the environ-
mental and climate benefits. Ac-
cording to AffaldPlus, an average
130 m2 Danish household can ex-
pect reduced annual heating costs
of up to DKK 3 748 or almost 25
percent by the end of 2022 com-
pared to current levels in the Sorø
Fjernvarme network.
Text: Alan Sherrard
Photos: AffaldPlus
BI109/6509/AS
18 B i o e n e r g y I n t e r n a t i o n a l
No 109, 1-2020