Logistik för stråbränsle

Abstract: Today energy prices are rising. As a result biomass fuel is getting more and more interesting. Wood chips is very popular, but also straw from grain production is on the table. Lunds Energi AB project a combined power and heating plant in Örtofta out of Lund. Wood chips is meant to be the main energy source, complemented by straw. In this thesis the transportation of straw for fuel is studied. The aim is to find out the cost, what it consists of, how it can vary, and to find out the most efficient way to transport straw for fuel. Straw can be handled in many different ways. Bales, chopped loose material, and as briquettes. There are many different sizes of bales, but for energy purposes the biggest is most often used; square bales, appr. 1,2x1,3x2,5 meters. Chopped straw is cheap, and relatively easy to handle, but the transportation is expensive since the loose material is relatively bulky. Briquettes are expensive to produce, but transportation is cheap. The bale alternative is somewhere in between, and absolutely most often used. To find out the cost, and to be able to compare different methods, calculations have been made. The used values (i.e. diesel price, labour cost, driving speed and straw density) have been varied, to see changes in the total transportation cost. Furthermore, the costs at different distances have been calculated. Every calculation has been made with two alternatives, for lorry and tractor. The transportation cost consists of machinery, labour and fuel costs, where the latter is the smallest. Lorry is cheaper than tractor, especially when the distance is getting longer. But within 20 kilometres, the tractor might compete. In most cases big square bales seem to be interesting. The harder the bales are, the cheaper the management gets. Vehicles with low load platform (0,9 m) can carry bigger load, which also reduces costs. A combination, where both bale density and transport volume are maximized, gives transportation costs almost as low as the costs for briquettes. • The best way to reduce the transportation costs is to maximize load capacity, through large and well used load volume, and high material density. • Fuel price has relatively small effect on the total transportation costs. • With well planned storage places and transports, extra costs can be avoided. • Lorry transports are cheaper than tractor transport, but at short distances the tractor alternative can be of interest. • I believe that for Lunds Energi AB, the best thing to do is looking for flexibility, in order to let different methods and techniques together build the optimal system.