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- Neij, Lena
(författare)
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Dynamics of Energy Systems - Methods of analysing technology change
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Technology change will have a central role in achieving a sustainable energy system. This calls for methods of analysing the dynamics of energy systems in view of technology change and policy instruments for effecting and accelerating technology change. In this thesis, such methods have been developed, applied, and assessed. Two types of methods have been considered, methods of analysing and projecting the dynamics of future technology change and methods of evaluating policy instruments effecting technology change, i.e. market transformation programmes. Two methods are focused on analysing the dynamics of future technology change; vintage models and experience curves. Vintage models, which allow for complex analysis of annual streams of energy and technological investments, are applied to the analysis of the time dynamics of electricity demand for lighting and air-distribution in Sweden. The results of the analyses show that the Swedish electricity demand for these purposes could decrease over time, relative to a reference scenario, if policy instruments are used. Experience curves are used to provide insight into the prospects of diffusion of wind turbines and photo voltaic (PV) modules due to cost reduction. The results show potential for considerable cost reduction for wind-generated electricity, which, in turn, could lead to major diffusion of wind turbines. The results also show that major diffusion of PV modules, and a reduction of PV generated electricity down to the level of conventional base-load electricity, will depend on large investments in bringing the costs down (through RD&D, market incentives and investments in niche markets) or the introduction of new generations of PV modules (e.g. high-efficiency mass-produced thin-film cells). Moreover, a model has been developed for the evaluation of market transformation programmes, i.e. policy instruments that effect technology change and the introduction and commercialisation of energy-efficient technologies. The method of evaluation has been applied to assess methods used to evaluate Swedish market transformation programmes. The evaluation model, and the assessment of the Swedish evaluation methods, illustrates a need for more extensive evaluation methods than those used today.
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| 2. |
- Salay, Jürgen
(författare)
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Energy Use, Efficiency Gains and Emission Abatement in Transitional Industrialised Economies: Poland and the Baltic States
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is a study of how energy use and air pollution in Poland, Estonia, Latvia and Lithuania have been affected by the economic transition after 1989. It consists of six articles, which examine three different aspects of these changes. The first group of articles analyses the structure of energy use in the Baltic states (Article I) and Poland Articles II and III) at the outset of transition. The results show that these countries had a primary energy consumption per GDP which was two to three times higher than in developed market economies because of a more energy intensive structure of the economy and higher specific energy intensities in many sectors of the economy. They also had significantly higher levels of air pollution per primary energy consumption and GDP because of a heavy reliance on fossil fuels, an energy intensive economy and an ineffective control of emissions. The deep fall in energy consumption during the first phase of transition was due to a sharp drop in industrial output and higher fuel prices. In the Baltic states, part of the fall in energy consumption was the result of shortfalls in the supply of oil and gas from Russia. The second group of articles (Articles IV and V) examines changes in electricity production, fuel consumption, generation efficiency and sulphur dioxide (SO2) emissions in the Polish power industry between 1988 and 1997. The results show that SO2 emissions dropped by 45 per cent between 1988 and 1997. The drop in emissions was partly the result of a fall in economic activity and electricity production in the early 1990s. Other reasons were more important. One reason was the restructuring of the power industry, during which hard budget constraints were introduced and the price of coal was raised. Another reason for the fall in emissions was the reorganisation and stricter enforcement of environmental protection. Together, these reforms created strong incentives for power plants to switch to high-quality coal with lower sulphur and ash content. Because of higher coal prices and the introduction of hard budget constraints, power plants improved their generation efficiency, which also contributed to the reduction of emissions. After 1994, the decline in SO2 emissions has continued thanks to the installation of pollution abatment equipment. The final article (Article VI) analyses the conversion of small boilers for heat production from fossil to biomass fuels. It compares the results of six boiler conversion projects in the Baltic states with seven projects in Russia and the Czech Republic. The results show that the conversions in the Baltic states reduced the fuel cost of heat production and achieved cost-effective reductions of SO2 and carbon dioxide (CO2). It also resulted in transfer of technology and know-how, less dependence on imported fuels and the creation of local markets for biofuels.
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| 3. |
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| 4. |
- Börjesson, Pål, et al.
(författare)
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Biomass Transportation
- 1996
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Ingår i: Renewable Energy. - : Elsevier BV. - 0960-1481. ; 9:1-4, s. 1033-1036, s. 1033-1036
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Tidskriftsartikel (refereegranskat)abstract
- Extensive utilisation of logging residues, straw, and energy crops will lead to short transportation distances and thus low transportation costs. The average distance of transportation of biomass to a large-scale conversion plant, suitable for electricity or methanol production using 300 000 dry tonne biomass yearly, will be about 30 km in Sweden, if the conversion plant is located at the centre of the biomass production area. The estimated Swedish biomass potential of 430 PJ/yr is based on production conditions around 2015, assuming that 30% of the available arable land is used for energy crop production. With present production conditions, resulting in a biomass potential of 220 PJ/yr, the transportation distance is about 42 km. The cost of transporting biomass 30-42 km will be equivalent to 20-25% of the total biomass cost. The total energy efficiency of biomass production and transportation will be 95-97%, where the energy losses from transportation are about 20%. Biomass transportation will contribute less than 10% to the total NOx, CO, and HC emissions from biomass production, transportation, and conversion.
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| 5. |
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| 6. |
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| 7. |
- Börjesson, Pål, et al.
(författare)
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Future Production and Utilisation of Biomass in Sweden: Potentials and CO2 Mitigation
- 1997
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Ingår i: Biomass & Bioenergy. - 1873-2909 .- 0961-9534. ; 13:6, s. 399-412
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Tidskriftsartikel (refereegranskat)abstract
- Swedish biomass production potential could be increased significantly if new production methods, such as optimised fertilisation, were to be used. Optimised fertilisation on 25% of Swedish forest land and the use of stem wood could almost double the biomass potential from forestry compared with no fertilisation, as both logging residues and large quantities of excess stem wood not needed for industrial purposes could be used for energy purposes. Together with energy crops and straw from agriculture, the total Swedish biomass potential would be about 230 TWh/yr or half the current Swedish energy supply if the demand for stem wood for building and industrial purposes were the same as today. The new production methods are assumed not to cause any significant negative impact on the local environment. The cost of utilising stem wood produced with optimised fertilisation for energy purposes has not been analysed and needs further investigation. Besides replacing fossil fuels and, thus, reducing current Swedish CO2 emissions by about 65%, this amount of biomass is enough to produce electricity equivalent to 20% of current power production. Biomass-based electricity is produced preferably through co-generation using district heating systems in densely populated regions, and pulp industries in forest regions. Alcohols for transportation and stand-alone power production are preferably produced in less densely populated regions with excess biomass. A high intensity in biomass production would reduce biomass transportation demands. There are uncertainties regarding the future demand for stem wood for building and industrial purposes, the amount of arable land available for energy crop production and future yields. These factors will influence Swedish biomass potential and earlier estimates of the potential vary from 15 to 125 TWh/yr.
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| 8. |
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| 9. |
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| 10. |
- Börjesson, Pål
(författare)
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Biomass in a Sustainable Energy System
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The increased use of biomass for energy is as a key strategy in reducing carbon dioxide (CO2) emission, which represents the largest anthropogenic contribution to the greenhouse effect. In this thesis, aspects of an increase in the utilisation of biomass in the Swedish energy system are treated. Modern bioenergy systems should be based on high energy and land-use efficiency since biomass resources and productive land are limited. The energy input, including transportation, per unit biomass produced is about 4-5% for logging residues, straw and short-rotation forest (Salix). Salix has the highest net energy yield per hectare among the various energy crops cultivated in Sweden (Article I). The CO2 emissions from the production and transportation of logging residues, straw and Salix, are equivalent to 2-3% of those from a complete fuel-cycle for coal (Article II). Substituting biomass for fossil fuels in electricity and heat production is, in general, less costly and leads to a greater CO2 reduction per unit biomass than substituting biomass-derived transportation fuels for petrol or diesel. Transportation fuels produced from cellulosic biomass provide larger and less expensive CO2-emission reductions than transportation fuels from annual crops (Article III). Biomass has the potential to become the dominating energy source in Sweden. The current use of about 80 TWh/yr could increase to about 200 TWh/yr, taking into account estimated production conditions around 2015. Swedish CO2 emissions could be reduced by about 50% from the present level if fossil fuels are replaced and the energy demand is unchanged (Articles III and IV). There is a good balance between potential regional production and utilisation of biomass in Sweden. Future biomass transportation distances need not be longer than, on average, about 40 km. About 22 TWh electricity could be produced annually from biomass in large district heating systems by cogeneration (Article IV). Cultivation of Salix and energy grass could be utilised to reduce the negative environmental impact of current agricultural practices, such as the emission of greenhouse gases, nutrient leaching, decreased soil fertility and erosion, and for the treatment of municipal waste water and sludge, leading to increased recirculation of nutrients (Article V). About 20 TWh biomass could theoretically be produced per year at an average cost of less than 50% of current production cost, if the economic value of these local environmental benefits is included (Article VI).
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