Dec 17 2015
Stockholm: The first delivery of biofuels to Fortums new power plant has arrived in the port
The first vessel supply of biofuels has arrived in the port, Värtahamnen, in central Stockholm, to a special quay dedicated for the plant. This delivery will be the first test for all equipments so they soon will be able to provide Fortum Värme’s new biomass heat and power plants with fuel. In one year the plant will use 3 million tons of wood chips.
The equipment tested include the crane used for unloading the fuel, the specially built pier, delivery belts and the entire reception facility until the huge mountain cave where the biofuel is stored before it is burned in the CHP boiler.
“This is an important milestone for us and an important part of the commissioning of our new biomass power plants, “says Monica Lundgren, logistics manager for the new CHP plant in Värtan.
A ship can hold 10,000 and a train set 4,500 cubic meters of wood chips
Biofuel to the new biomass-fueled heating plant will be provided by ships and trains. A few days ago the first of two special built train sets was delivered. The train set is parked close to the CHP plant waiting to be tested together with the new unloading robot. One train has 30 carriages and can accommodate a total of 4,500 cubic meters.
“The train has special designed containers for us to get as much biofuel as possible per load. It saves both the economy and the environment, “says Monica Lundgren.
The two trains will transport wood chips from about a dozen terminals around Sweden and Norway and will, together with the ship, supply biomass n the form of wood waste and residues from sawmills in the Nordic regionto the power heating plant.
Later in the spring, when the new plant is in operation, emissions are expected to decrease in Stockholm with 126,000 tons carbon dioxide.
The new plant is located on a site very close to the Stockholm city center with different heat and power plants. The new CHP plant will be number 8 and will only be used with biomass. The adjacent base load unit is a pressurised fluid bed boiler using coal with a successive increased share of olive kernels. This unit is the only remaining coal user in the Stockholm area. A third adjacent boiler is fed with a mixture of bioil/oil and is only used for top loads
A fossil free Stockholm
The project to minimise the use with fossil fuels started with adding a small share of olive kernels to the coalfeed to the pressurised fluid bed boiler. The conclusion was it worked well and it was decided to increase the share of kernels from 4 to 17 percent. This was made possible after an investment in new handling equipment and silos in the harbour. The use of olive kernels may in the end even increase to 70 000 t/a or 25 percent.
The new biomass boiler
At most 700 worked on the site building the new dedicated biomass boiler of 330 MW fuel (130 MWe) for a cost of 500 million Euro. In one year 0.75 TWh electricity and 1.5 TWh district heat will be produced. The project include a CHP plant complete with turbine and exhaust gas condensing, an underground mountains storage and 400 meters underground transport tunnels. A new birth able to handle 120 000 m3 Panmax woodchip carriers is also constructed. The boiler is a Circulised Fluidised Bed Boiler (CFB) supplied by Austrian Andritz, the turbine is provided by Skoda Power, generator etc from Siemens and the exhaust gas condensing unit is provided by Radscan.
Chipped wet forest residues with 45 percent moisture, will to 2/3 be supplied by ships and to 1/3 by rail. One train set a day will be unloaded at plant site. Trains will come from Norway as well from the north and south of Sweden. Sea transport by coasters will arrive from locations around the Baltic see. Up to 120 000 m3 wood chips carriers with chips from Africa and America may also be accepted.
The project is spectacular because of its central location, only 2 km from Stockholm city center, in an existing living area and in a district planned for expansion with high status seaside apartments. Therefore there are rigid restriction for noise and dust from ventilation and the final fuel preparation.
Wood chips storage
The wood chips storage room is an earlier oil mountain storage room blasted under the ground. The rebuilt space fits 50 000 m3 wood chips in two 25 000 m3 piles and is supplied from the port by a 200 m long conveyor belt inside a new built tunnel. After the storage another conveyor belt in a tunnel transports the wood chips under a highway to the boiler.
Pellets is at the moment not an option for any of the units, according to Kjell Nilsson, fuel trader at Fortum, even though the CFB plant can accept a wide variation of biofuels including pellets. However the advanced handling and storage system for the CFB plant is designed for wet, not for low moisture fuels.
The new boiler will use 12 000 m3 wood chips a day, except summertime when priority in the Stockholm district heating net is given to waste based heat from other plants.
by Lennart Ljungblom, bioenergy writer