Modern bioenergy options have not been typical choices when the supply of heat, power and liquid fuels are contemplated. However, as bioenergy evolves from being a peripheral alternative to becoming a mainstream player in the energy sector, conditions for designing strategies for the segment change significantly. The framework within which bioenergy shall compete becomes more and more apparent.

Not least, there is the difficult question of where in the supply chain the avail­able biomass resources are optimally utilized. Key actors in this competition are positioned and organized, and this includes biomass producers, the various links of the energy industry, and the combustion sector, as well as the agencies and institutions involved in energy research.

fact box 3.!. Integrated system for bioenergy, water treatment arid regional development — the experience of Enkoping

Enkoping is a small town located in the middle of Sweden, about 7(1 km from Stockholm. In 1972, the municipality founded Enkopings Varmeverk to produce and distribute heat to the local community. Today, 20000 people live in the urban area of Enkoping. Thirty-six employees work with the operation and maintenance of the 76-km-long district heating network that provides the majority of residential, commercial and industrial buildings of the town with heating services. Some 220 GWh of heat are distributed to more than 1400 customers every year, of which some 1100 are single-family houses.

Originally, the three boilers at Enkopings Varmeverk operated on oil and propane gas but, nowdays, the heat production relies mostly on biofuels. One of the boilers has been converted for burning wood powder and has an output of 20 MW, It produces around 15-18 per cent of the requirement for district heating and runs from the middle of May to the middle of September. It also runs during the w inter at low temperatures. In the colder part of the year, from the middle of September to the middle of May, the ЬіоГиеІ — fired CHP plant, Ena Kraft, meets the demand for healing. The CHP plant produces around 80-85 per cent of the yearly consumption of district heating in Enkoping. The plant uses bark, sawdust, residues from logging operations and satis.

Local farmers are planting the saiix that is heating homes and industries in Enkoping. As part of an innovative project, the municipal council has financed the saiix planta­tions. and a leasehold agreement has been established with each individual landowner. Residual ash from the power plant, approximately 1500 tons per year, is mixed with sludge-water and distributed to local saiix plantations. The water used for irrigation passes the conventional purifying process prior to being pumped into ponds. After filtration, the water is distributed throughout the 80-hcctare saiix plantation. In this way. approximately 60 tons of nitrogen/hcetare are dispersed every year.

This bio-cyclical solution that utilizes nutrients from sewage treatment and ashes from energy generation to grow energy crops has been the result of a cooperation coordi­nated by the County Council and involving local authorities, the power plant and the farmers in Enkoping. Nitrogen and phosphorous effluence, that would otherwise pollute the Lake Miilarcn and the Baltic Sea. is being used to fertilize energy planta­tions, reducing the harvest time by 25 per cent. It is understood that the conditions for emissions of heavy metals comply with the prevailing limits and regulations. Saiix is being used to help purify wastewater emanating from private septic tanks and the municipal sewage plant.