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- Ljunggren Söderman, Maria, 1967
(författare)
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Modelling national solid waste management
- 2000
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Ingår i: Waste Management and Research. - 1096-3669 .- 0734-242X. ; 18:6, s. 525-537
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Tidskriftsartikel (refereegranskat)
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- Andersson, Eva Ingeborg Elisabeth, 1956, et al.
(författare)
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Pulp-mill integrated biorefineries: a framework for assessing net CO2 emission consequences
- 2004
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Ingår i: Proceedings, AIChE 2004 Fall Annual Meeting. Nov 7-12, 2004, Austin, Texas, USA. ; , s. p 203-208, s. 203-208
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- There is currently much interest in producing biofuel-based transportation fuels. However, since biofuel is a limited renewable resource, it is important to assess whether such fuels are both produced and used as efficiently as possible. Efficient production can be achieved in the future by integrated biorefinery operations at pulp mill sites, co-producing pulp and biofuel-based energy products. This paper compares production of transportation fuel with other biorefinery options for future pulp mills. The comparison is based on net CO2 emissions, i.e. accounting for off-site consequences associated with changes in the net flows of electricity, biofuel and biofuel-based transportation fuel entering or leaving the mill. The most important conclusion is that system variables (e.g. assumptions regarding the reference fuel and engine efficiency for future transportation systems) are of decisive importance for the net CO2 emissions associated with pulp mill biorefinery operations. This paper illustrates such aspects and underlines the importance of a system perspective in process engineering research.
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- Gustavsson, Leif, et al.
(författare)
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Heating Detached Houses in Urban Areas
- 2003
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Ingår i: Energy. - 0360-5442 .- 1873-6785. ; 28:8, s. 851-875
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Tidskriftsartikel (refereegranskat)abstract
- District heating systems using cogeneration, as well as local fuel-based and electric heating systems for detached houses, are analysed. The analysis includes the whole energy system, from the natural resource to the end user, with respect to primary energy use, emission and cost. The end-use technologies studied are heat pumps, resistance heaters and boilers. It was assumed that the base-load electricity, except for the cogenerated electricity, was produced in stand-alone power plants using wood chips or natural gas, while peak-load electricity and fuel used for transportation were produced from crude oil. The heat pump and district heating systems are found to be most energy efficient, followed by the local fuel-based systems. The wood-fuel-based systems emit about one tenth of the greenhouse gases emitted by the natural-gas-based systems. The sulphur and nitrogen oxide emission, however, is higher for wood-fuel-based systems. Systems based on natural gas are less expensive than the corresponding wood-fuel-based systems. Decarbonization and carbon dioxide sequestration, however, do not reduce the carbon dioxide emission to the low level of the wood-fuel-based systems and, in addition, make the natural-gas-based systems more expensive than the wood-fuel-based systems.
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| 8. |
- Hansson, P.A., et al.
(författare)
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Air emissions from the fuel supply system of a Swedish CHP plant and the effects of stricter emission regulations
- 2003
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Ingår i: Biomass and Bioenergy. - 1873-2909 .- 0961-9534. ; 24:1, s. 59-68
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this work was to quantify the energy use and production of air emissions by supply systems for different biofuels used in a typical Swedish combined heat and power plant. In addition, the effects of the future reductions in the total amounts of exhaust gas emissions, as a result of stricter emission regulations for transport and off-road equipment, were studied. A model was developed and used for the calculations. Input data were collected from a plant situated some 100 km from Stockholm in Sweden. Biofuels used by the plant include chips from limbs and tops, by-products from sawmills and chips from willow energy plantations. The results show that residues from sawmills are very favourable in terms of the studied environmental parameters. Air emissions from limbs and tops is 5-8 times greater than that from sawmills. The use of a terminal for temporary storage means that additional transport and loading operations are necessary which result in a 30% increase in air emissions. The most important effects of the stricter emission regulations are that emissions of nitrous oxides (NOx) caused by the supply system will decrease by up to 70% within 10 years and that the unburned hydrocarbon (HC) emissions will decrease by 30-35%. © 2002 Elsevier Science Ltd. All rights reserved.
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| 9. |
- Karlsson, Åsa, et al.
(författare)
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External Costs and Taxes in Heat Supply System
- 2003
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Ingår i: Energy Policy. - 0301-4215 .- 1873-6777. ; 31:14, s. 1541-1560
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Tidskriftsartikel (refereegranskat)abstract
- A systems approach was used to compare different heating systems from a consumer perspective. The whole energy system was considered from natural resources to the required energy services. District heating, electric heat pumps, electric boilers, natural-gas-, oil- or pellet-fired local boilers were considered when supplying heat to a detached house. The district heat production included wood-chip-fired and natural-gas-fired cogeneration plants. Electricity other than cogenerated electricity was produced in wood-chip- and natural-gas-fired stand-alone power plants. The analysis includes four tax scenarios, as well as the external cost of environmental and health damage arising from energy conversion emission based on the ExternE study of the European Commission. The most cost efficient systems were the natural-gas and oil boiler systems, followed by the heat pump and district heating systems, when the external cost and taxes were excluded. When including the external costs of CO2 emission, the wood-fuel-based systems were much more cost efficient than the fossil-fuel-based systems, also when CO2 capture and storage were applied. The external costs are, however, highly uncertain. Taxes steer towards lowering energy use and lowering CO2 emission if they are levied solely on all the fossil-fuel-related emission and fuel use in the systems. If consumer electricity and heat taxes are used, the taxes have an impact on the total cost, regardless of the fuel used, thereby benefiting fuel-based local heating systems. The heat pump systems were the least affected by taxes, due to their high energy efficiency. The electric boiler systems were the least cost efficient systems, also when the external cost and taxes were included.
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- Tillman, Anne-Marie, 1958, et al.
(författare)
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After 10 years and 300 students. Our LCA teaching experience.
- 2002
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Ingår i: Engineering Education in Sustainable Development. ; , s. 611-616
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Konferensbidrag (refereegranskat)abstract
- Our LCA teaching experience started with organizing the first LCA course in Sweden in 1992 — it was a course on a national level for doctoral students. After that, we continued with one LCA course each year for undergraduate students (3rd or 4th year students). During the first years (1993-1995), the course was given as a summer course for international students. But since 1996, the LCA course is given as an ordinary, elective course for all engineering students at Chalmers, attracting som 30 students every year. Most of them are Chalmers students, but a number of students from Göteborg University, doctoral students and working engineers from around Sweden also find their way to our course. In addition to the LCA course, we also give "the 2 hour lecture" orientation about LCA in the compulsory environmental course for 1st/2nd year students at Chalmers, and we have run around 25 LCA projects as MSc Diploma projects. Based on our broad experience, we will talk about how LCA education can aim at different levels of understanding (from the 'know about" level, via the "reflect critically" level, to the "carry out" level) and what this implies concerning reading material, exercises, the use of LCA software and LCA manuals. We will also talk about student reactions to working in interdisciplinary groups and with open problems.
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