Bioenergy, is held in southern Sweden every two years. OPENING TOURS Clearly we can learn a lot here as we wind up our own potentially larger biomass industry, and that’s why Canadian Biomass made the trip. So too did many other Cana- dians, as our forest nation made up the largest foreign delegation at Elmia World Bioenergy 2008. The formal event started Mon- day night with a reception at the famous Elmia conference facility in Jönköping, an hour south of Stockholm, but it really kicked off sensibly enough with full-day tours from Stockholm’s Arlanda airport to the conference site. We joined a bus that happened to have another 30 or so Canadians, and visited facilities that ranged from combined heat and power plants (CHP) to integrated pellet mills and biomass plantations. With fi ve stops spread over a few hundred kilometres, we pulled into Jönköping a little tired, a little late for the reception, a tad under- dressed, but with a whole new perspective on what’s possible when industry, landowners, local communities, and various levels of government set their mind to it. The fi rst stop was a shining example. The city of Enköping and its 20,000 inhabitants rely on a single combined heat-power (CHP) plant for 85% of their heat- ing needs. Ena Energi AB is a 100% community-owned company that runs the plant and its three boil- ers, which have been converted to run on biomass rather than oil or propane. And they must be proud of it – The plant is right in town, not hidden from anyone’s view. Biomass is a mix of materials, from sawdust (20%) and bark (30%) to pre-hogged forest har- vest residues (40%) and material from nearby salix (willow) planta- tions (10%). Some 6,400 truck- loads bring 35 m3 each to the plant annually, and each is sam- pled for MC. Suppliers are paid by the MWh after MC sampling, providing an incentive to bring well-dried material. The reference rate we were given was 21 Euro ($35) per MWh at the gate. This material is dumped into an infeed pit, where screw conveyors serve to both transport and mix the bio- mass en route to a large peaked storage building. The biomass is scraped onto a belt conveyor for transport to the boiler, with an MC level that ranges from 20 to 70%. Aside from 220 GWh of heat per year, it provides 100 MWh of power to the grid, although currently the problem is the im- balance between heat and power needs in summer. To boost year round capacity, the plant is adding a cooling system, as well as a new low-temperature biomass drying system from Exergy Engineering and Consulting that will dry the biomass from its current mix of 47% MC to 30% MC. Both sys- tems will be running this fall. Our proud hosts were more than willing to tell us costs per MW for different types of deliv- ered biomass, fi nal cost of heat and power to its community cli- ents, delivered to over 1,500 cus- tomers (1,180 single homes) via 84 km of pipes. Yet since all such costs are market and distance spe- cifi c (they hauled in from 100 to 200 km or less), they meant little to the raft of Canadian municipal and forestry delegates on tour with us. One issue we can all under- stand is the benefi t of fast-growing energy wood close to the power plant. In this case, Ena Energi AB is part of a local fast-growing salix plantation program that kills sev- eral birds with one stone. First, it provides an outlet for both 1,500 tonnes of ash the plant makes every year, and an equal amount of sludge from the local sewage treatment plant. It is combined as fertilizer for the salix, greatly reducing the nitrogen and phos- phorous load in the local lake, and eventually the Baltic. This fer- BooForssjoʼs automated the pellet bagging process in 2001 with this system from Italian supplier Ital Meccanica. It also delivers bulk pellets to homeowners using a heating oil style truck. tilizer in turn takes care of another potential issue in the bioenergy cycle – soil nutrient depletion. Finally, by creating a local salix plantation, the plant has a steady supply of raw material within sight, and one that can be harvested every two to five years. The growth rate of the site we saw, measured in MWh of course, is 20 MWh/ha/yr. It’s a pretty con- vincing bioenergy cycle, so some 1,200 ha of salix has been planted to date, with 10% of it required to get rid of the ash and sewage mix each year. The various partners in- volved since 2001 have each been charged with measuring key indicators, such as heavy metal absorption (ash), nitrogen reduc- tion, and growth rate. So far all in- dicators point to a rousing success story. Yet like many such stories in Scandinavia’s bioenergy sector, it involves a number of partners co-operating for individual ben- efi t and the common good. In this case, that’s the town’s wastewater treatment authority, the power plant, the local conservation board, town council, and local farmers. PELLET POWER A business model a little closer to home was BooForssjo, a saw- mill and our third stop. In 1995 it added a pellet plant to its facil- ity, an integrated approach where heat from the mill is used to dry both lumber and the pellet raw material. A 15 MW hot gas oven fi red with bark and green wood chips makes both hot water (kiln steam) and hot gas (sawdust for pellets, lumber drying). Hot gas and fl ue gas from the boiler are mixed to create a safe temperature for drying sawdust in a multiple pass rotary dryer. The plant uses Andritz-Sprout Matador pellet mills, and given the fire/explo- sion risk in handling the dry wood powder, uses one of Firefly AB’s custom-made pellet spark suppression systems. The mod- estly scaled plant is run on mul- tiple shifts to still produce 53,000 tonnes of pellets per year. Somewhat different than Ca- nadian mills is the packaging CanadianBIOMASS 27
Canadian Biomass August 08: Page 27
