Large-scale straw supplies to existing coal-fired power stations

It is considered that large-scale supply of straw to power stations and decentral cogeneration plants could open up new economical systems and methods of organization of straw supply in Denmark. This thesis is elucidated and involved constraints are pointed out. The aim is to describe to what extent large-scale straw supply is interesting with regard to monetary savings and available resources. Analyses of models, systems and techniques described in a foregoing project are carried out. It is reckoned that the annual total amount of surplus straw in Denmark is 3.6 million tons. At present, use of straw which is not agricultural is limited to district heating plants with an annual consumption of 2-12 thousand tons. A prerequisite for a significant increase in the use of straw is an annual consumption by power and cogeneration plants of more than 100.000 tons. All aspects of straw management are examined in detail, also in relation to two actual Danish coal-fired plants. The reliability of straw supply is considered. It is concluded that very significant resources of straw are available in Denmark but there remain a number of constraints. Price competitiveness must be considered in relation to other fuels. It is suggested that the use of corn harvests, with whole stems attached (handled as large bales or in the same way as sliced straw alone) as fuel, would result in significant monetary savings in transport and storage especially. An equal status for whole-harvested corn with other forms of biomass fuels, with following changes in taxes and subsidies could possibly reduce constraints on large scale straw fuel supply. (AB) (13 refs.)