[en] Full text.In many countries, landfills remain an essential part of any waste management system and often the only economic form of municipal solid waste disposal. Solid waste contains a large percentage of organic materials, which can decompose under anaerobic conditions to produce primarily methane, carbon dioxide and significant quantities of other gases. In Lebanon, as in many developing countries, the solid waste fraction of organic nature with high biodegradability potential reaches 70 percent, which can result in high landfill gas yield. Gas recovery projects for energy use require relatively large landfills that accept adequate quantities of waste with high biodegradable organic fraction. Economy of scale resulted in a trend towards constructing such landfills. Gas recovery at such landfills can reach 90 percent depending on the efficiency of the gas collection system. While gas flaring does not provide economic incentives for landfill operators and can only be imposed through government intervention. In this context, the economic appraisal of any landfill gas exploitation project requires the scrutiny of the overall process of sanitary land filling. This paper describes current solid waste management practices in Lebanon, estimates the corresponding landfill gas generation potential with a description of the factors influencing the generation process, and emphasizes the economics in the context of country specific characteristics of utilizing this gas for possible energy recovery as a landfill site receiving about 2000 tons of refuse per day

[en] Bioenergy is usually considered an environmentally friendly source of energy, mainly because of the international focus on carbon dioxide emission. The article questions this point of view. Less emission of global climate gases comes from bioenergy than from the combustion of natural gas and fuel oil, but much more particulate and acidifying matter. According to a Swedish investigation, bioenergy, waste combustion and fuel oil are worse than natural gas if particles, SOx, NOx and CO2 are weighted equally. Biofuel and fuel oil emit almost twice as much nitrogen oxides as do natural gas and waste combustion. Bioenergy and waste emit on the average 160-210 times as much sulphur as do natural gas and 40-170 times as much particles. To what extent bioenergy is environmentally sound is very technology-dependent. Bioenergy is advantageous with respect to emission of climate gases and by definition does not emit carbon dioxide since this is compensated by photosynthetic absorption. As for hydrocarbons, NOx and SOx, which cause local acidification, bioenergy comes in about halfway between the best and the worst energy sources. The pollution from large bioenergy plants can be effectively reduced, but cleaning systems on small plants are not economical. Small bioenergy plants should not be localised in areas with high particle emission

[en] The objective of the wood pellet seminar, arranged by OPET Finland and North Karelia Polytechnic, was to deliver information on wood pellets, pellet burners and boilers, heating systems and building, as well as on the activities of wood energy advisors. The first day of the seminar consisted of presentations of equipment and products, and of advisory desks for builders. The second day of the seminar consisted of presentations held by wood pellet experts. Pellet markets, the economy and production, the development of the pellet markets and their problems (in Austria), the economy of heating of real estates by different fuel alternatives, the production, delivery and marketing of wood pellets, the utilization of wood pellet in different utilization sites, the use of wood pellets in detached houses, pellet burners and fireplaces, and conversion of communal real estate houses to use wood pellets were discussed in the presentations. The presentations held in the third day discussed the utilization of wood pellets in power plants, the regional promotion of the production and the use of pellets. The seminar consisted also of visits to pellet manufacturing plant and two pellet burning heating plants

[en] Wood pellets became into Austrian markets in 1994. Up to then the Austrian industry had manufactured pellet fireplaces for export, but none was sold into Austria, because there were not pellets available in the Austrian markets. In spite of significant problems in the beginning and unfavourable economic conditions (decrease of oil prices) the pellet markets in Austria have increased since 1996 dynamically. Annual pellet deliveries have increased from 15 000 t/a to present 45 000 t/a. Customers and Austrian industry are interested in pellets and they believe in the future. The pellet manufacturing capacity increases continuously. In 1999 the capacity of 12 companies was 120 000 t. In 2003 the annual pellet consumption is estimated to over 100 000 tons and in 2010 about 200 000 tons. Main portion of the pellet manufactures in Austria is also used in the country by detached houses and small real estate houses. The pellet markets for large real estates are developing after the boiler manufacturers have started to produce pellet-fired equipment. The number of pellet-fired devices in 1997, sold to detached houses was 425, and in 2000 the number was 3500

[en] The author reviews in his presentation the development of Turku Energia, the organization of the company, the key figures of the company in 2000, as well as the purchase of energy in 2000. He also presents the purchase of basic heat load, the energy production plants of the company, the sales of heat in 2000, the emissions of the plants, and the fuel consumption of the plants in 2000. The operating experiences of the plants are also presented. The experiences gained in Turku Energia on mixed combustion of coal and wood pellets show that the mixing ratios, used at the plants, have no effect on the burning properties of the boiler, and the use of wood pellets with coal reduce the SO₂ and NO_x emissions slightly. Simultaneously the CO₂ share of the wood pellets is removed from the emissions calculations. Several positive effects were observed, including the disappearance of the coal smell of the bunker, positive publicity of the utilization of wood pellets, and the subsidies for utilization of indigenous fuels in power generation. The problems seen include the tendency of wood pellets to arc the silos, especially when the pellets include high quantities of dust, and the loading of the trucks and the pneumatic unloading of the trucks break the pellets. Additionally the wood pellets bounce on the conveyor so they drop easily from the conveyor, the screw conveyors designed for conveying grain are too weak and they get stuck easily, and static electricity is easily generated in the plastic pipe used as the discharge pipe for wood pellet (sparkling tendency). This disadvantage has been overcome by using metal net and grounding

[en] This short article introduces the Swiss standard that has been adapted from the German standard for heating pellets made of untreated wood. The various requirements placed on the materials used in the manufacture of the pellets and their influence on the pollution emissions produced by boilers and ovens using the pellets as a heating fuel are listed. Further points in the standard referring to declarations to be made by the manufacturer, size and specific weight of the pellets and instructions for the storage and burning of the pellets are discussed

[en] Import of biomass to be used in electric power plants is expensive. To reduce the costs of transport, wood from trees can be converted into charcoal on-site

[en] Based on bibliographical references, in a theoretical model based on a fermentation process, the relationship between the speed of oxygen transfer and the biochemistry demand is implemented, in order to discover the different conditions of aeration and of agitation speed, under those which the microbial growth is not affected by deficiency in the oxygen supply. This correlation was adapted to the cultivation of B. Thuringiensis, and of this form, maximum biomass concentration to the one, which is possible to supply oxygen efficiently with a group of defined operation conditions, could be estimated

[en] Short Rotational Coppice is an energy crop that can be grown on surplus agricultural land for energy production. It can be used in wood burning gasifiers for production of electricity and this process is well documented. The logistics of collecting wood chips from the production site and delivering to a central sustained power station are complex and the costs not inconsiderable. The need for a method of assessing the economics of short rotational coppicing for gasification and on site electricity production are recognised. For this reason a flexible spreadsheet was developed to calculate the costs and profitability of the crop. The spreadsheet was designed to be adjustable to suit particular circumstances of any given project. The results of this calculation can be used as an indicator to whether the project is viable or not. The program requires input data such as agricultural expenditure, including preparation and harvesting costs. Capital costs for the gasifier, filtration units and generator connection charges are included. A maintenance program is also required to ensure continuous smooth running, although unexpected failure may occur with extra costs and power loss not accounted for. Using the spreadsheet it will be possible to compare different parameters such as land area used, generator efficiency, fuel calorific value and preparation costs. (author)

[en] Favorable soil and climate conditions for production of biomass crops in Florida, and a market for their use, provide the essentials for developing a biomass energy system in the State. Recent surveys showed that there is low opportunity cost land available and several high yield herbaceous and woody crops have potential as biomass crops. Comparison of biomass crop yields, farmgate costs, and costs of final products in Florida and other states show that Florida can be considered as one of the best areas for development of biomass energy systems in the United States. This paper presents facts and figures on biomass production and conversion in Florida and addresses issues of concern to the economics of biomass energy in the State. (author)