| 1. |
- Börjesson, Pål, et al.
(författare)
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Regional Production and Utilisation of Biomass in Sweden
- 1996
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Ingår i: Energy. - : Elsevier BV. - 1873-6785 .- 0360-5442. ; 21:9, s. 747-764
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Tidskriftsartikel (refereegranskat)abstract
- Regional production and utilization of biomass in Sweden is analysed, considering the potential of replacing fossil fuels and producing new electricity. Extensive utilization of biomass will decrease biomass-transportation distances. The average distance for biomass transportation to a large-scale conversion plant suitable for electricity or methanol production will be 30–42 km when the conversion plant is located in the centre of the biomass production area. The total energy efficiency of biomass production and transportation will be 95–97% and the emissions of air pollutants will be small. In areas where energy crops from agriculture constitute the main part of the biomass, the transportation distance will be two to three times shorter than in areas where logging residues from forestry dominate. When present Swedish fossil-fuel use for heat and electricity production is replaced, more than 75% of the biomass required can be produced locally within the county. The average transportation distance of the remaining part will be between 130 and 240 km, increasing the cost of this biomass by 15–20%. Increased use of biomass by 430 PJ/yr, the estimated potential for increased utilization of energy crops, logging residues and straw, will lead to an excess of about 200 PJ/yr biomass after fossil fuels for electricity and heat production have been replaced. This biomass could be used for methanol or electricity production. The production of biomass-based methanol will lead to a low demand for transportation, as the methanol produced from local biomass can mainly be used locally to replace petrol and diesel. If the biomass is used for electricity production, however, the need for transportation will increase if the electricity is cogenerated in district heating systems, as such systems are usually located in densely populated areas with a deficit of biomass. About 60% of the biomass used for cogenerated electricity must be transported, on average, 230 km. Changing transportation mode when transporting biomass over large distances, compared with short distances, however, will lead to rather low specific transportation costs and environmental impact, as well as high energy efficiency. Replacing fossil fuels with biomass for heat and electricity production is typically less costly and leads to a greater reduction in CO2 emission than substituting biomass for petrol and diesel used in vehicles. Also, cogeneration of electricity and heat is less costly and more energy efficient than separate electricity and heat production.
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| 2. |
- Christiansson, Lena
(författare)
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Time Dynamics of Electricity Demand in Air-Distribution Systems for Commercial Buildings in Sweden
- 1996
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Ingår i: Energy. - : Elsevier BV. - 1873-6785 .- 0360-5442. ; 21:10, s. 879-888
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Tidskriftsartikel (refereegranskat)abstract
- This paper illustrates the potential for reducing future electricity demand for air distribution in commercial buildings in Sweden. We have developed a general, quantitative, scenario-based framework to describe electricity demand for air distribution and to analyze how governmental and utility-sponsored policy measures affect electricity demand. The results suggest that higher electricity prices will not be very effective in reducing electricity demand, whereas significant electricity savings can be achieved by implementing desirable policy programs.
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| 3. |
- Johansson, Bengt
(författare)
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Will Swedish Biomass be Sufficient for Future Transportation Fuel Demands?
- 1996
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Ingår i: Energy. - : Elsevier BV. - 1873-6785 .- 0360-5442. ; 21:12, s. 1059-1069
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Tidskriftsartikel (refereegranskat)abstract
- There is a potential to increase the annual use of biomass in Sweden by 125 TWh between 1994 and 2015. 125 TWh of biomass would satisfy most of the transportation-fuel demand in Sweden in 2015. Even if the biomass is primarily used for heat and electricity production, a significant fraction will be available for transportation-fuel production, if other non-fossil energy sources are utilized for electricity production and/or substantial energy-efficiency improvements are realized. Improved energy efficiency and the use of renewable energy sources will be required in all sectors to achieve CO2 emission reductions greater than 50%.
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| 4. |
- Gustafsson, Stig-Inge, et al.
(författare)
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Optimal heating-system retrofits in residential buildings
- 1997
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Ingår i: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 22:9, s. 867-874
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Tidskriftsartikel (refereegranskat)abstract
- The optimal heating-system-retrofit strategy for existing buildings differs due to varying prices of energy, building and installation features, climate conditions, etc. We have examined a test building situated in Linköping, Sweden. By using the OPERA model, we were able to arrive at the optimal retrofit strategy, which includes a ground-coupled heat pump using electricity to run the compressor. Unfortunately, the price of electricity differs according to the time of day, month, etc. These variations are not included in the OPERA model. In OPERA, the price should be divided into 12 segments, one for each month of the year since climate data are divided in this manner. Fine tuning of a dual-fuel system (an oil-fired boiler handles the peak load and a heat pump the base thermal load) is optimized using the Mixed Integer Linear Programming (MILP) method. Adding a hot-water accumulator also makes it possible to use low electricity prices for space and domestic hot-water heating. This system competes in the model with traditional heating devices such as district heating. The optimal method of heating the building was found for using the heat pump alone.
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| 5. |
- Westerlund, Lars, et al.
(författare)
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Theoretical investigation of the heat demand for public baths
- 1996
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Ingår i: Energy. - 0360-5442 .- 1873-6785. ; 21:7-8, s. 731-737
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Tidskriftsartikel (refereegranskat)abstract
- Public baths normally use outdoor air to remove moisture from the building. This procedure results in large heating demands. A theoretical hour-based method for estimation of the heating demand has been developed. The method allows for dynamic behaviour with correct time periods for each mass-transfer level. Results of predictions with this method have been compared with yearly estimates of the heating demand based on actual measurements in a public bath. The difference is 3%. A parametric study shows that the air temperature and relative humidity in the building strongly influence the heating demand. Comparisons with other prediction methods based on use of the duration curve or mean annual outdoor temperature show differences less than 5% from results obtained with the hour-based method. The simpler approaches (use of a duration curve or mean value) fail when minimum outdoor airflow must be considered, as will be the case, for instance, when comparing different energy-saving systems or design of components for the climate system.
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| 6. |
- Andersson, Björn A., 1968, et al.
(författare)
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Materials constraints in a global energy scenario based on thin-film solar cells
- 1998
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Ingår i: Energy. - 0360-5442. ; 23, s. 407-411
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Tidskriftsartikel (refereegranskat)abstract
- Harnessing solar energy by using photovoltaic cells has the potential to become a major CO2-free energy source. Materials requirements for the solar cells based on four types of thin-film photovoltaics have been estimated and compared with global reserves, resources and annual refining. The use of solar cells based on Cd, Ga, Ge, In, Ru, Se and Te as a major energy-supply technology has severe resource constraints. Other systems such as a-Si without Ge and crystalline silicon do not involve such constraints. For some of these metals, there is the risk of enhanced, environmentally deleterious concentrations in the ecosphere due to leakage from manufacturing, use or waste handling.
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| 7. |
- Banks, FE
(författare)
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Economics of electricity deregulation and privatization: An introductory survey
- 1996
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Ingår i: ENERGY. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0360-5442. ; 21:4, s. 249-261
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This Paper is intended as an elementary survey of the electricity deregulation-privatization debate as it is being carried out in both the developed and developing world. An attempt is made to clarify certain misunderstandings about introducing more compe
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