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- Andersson, Maria, 1965-
(författare)
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Cooperation in local electricity markets : modelling of technical measures
- 1997
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents a system analysis for co-operation in local electricity markets including distributors and customers. The purpose of co-operation is to minimise the system cost of local markets by introducing system measures, such as end-use measures and municipal co-generation plants. Co-operation will strengthen the position of local markets in the national as well as future international electricity markets. With end-use measures local markets will achieve flexibility, additional reserve capacity and ability to avoid sudden large costs for peak loads. Biomass-fired cogeneration plants can become of great importance in an international market. In Sweden there is a simultaneous demand for electricity and district heating, many local markets already include district heating systems and there are major forest areas which can contribute with renewable fuel. The system analysis is partly based on the simulation model (INDSIM) and the linear programming model (MODEST). The simulation model has been further developed (STRATO) to include calculation of system costs. Shadow price analysis has been developed in order to study incentives for system measures. Calculation procedures have been developed that describe cooperation between distributor and customer. Six case studies of a selection of real, existing local markets in Sweden are presented. The studies show the potential economical effects of co-operation measured by system costs and shadow prices. Co-operation has been considered between demand- and supply-side, electricity- and district heating systems and also between different time periods. In a typical local market with 90 000 inhabitants, if end use measures are introduced without cooperation the system cost of the distributor will increase by 14 million SEK for a time period of 25 years. If instead end-use measures are introduced in co-operation, together with a biomass-fired cogeneration plant, the system cost of the local market will be reduced by 444 million SEK. Furthermore, the use of biomass in the local market is increased from 36 to 72 % while the use of oil is decreased from 34 to 1%. Another case study of another local market (50 000 inhabitants) shows that end-use measures will reduce the system cost (excluding investment costs) of an industry by 50 % corresponding to 1.3 million SEK for one year. The end-use measures imply reduced power demand during peak load periods in the local market and increased power demand during non- peak load periods.
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- Andersson, Maria, 1965-, et al.
(författare)
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Cost-effective incentives for cooperation between participants in the electricity market
- 1996
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 54:4, s. 301-313
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Tidskriftsartikel (refereegranskat)abstract
- In the Swedish electricity system there is a great potential for increasing the cost efficiency of electricity use. Today economic incentives, offered for instance by existing electricity tariffs, are too weak to improve the use of the system. On the Swedish electricity market, there are at least three different participants, the power producer, the distributor and the customer. Today these participants act separately owing to low awareness of the costs for electricity over the year and the day. If the participants are aware of the real electricity costs, cost-effective incentives for cooperation will arise. When participants cooperate, the introduction of end-use measures will reduce system costs for those participants that are involved in cooperation. We present a system analysis for cooperation between distributor and customers. We also present results from a project, where behaviours of an existing distributor and existing customers have been analysed. The results show that there exist cost-effective incentives for cooperation when end-use measures are introduced.
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- Andersson, Maria, 1965-, et al.
(författare)
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Cost-effective incentives for end-use measures in a Swedish municipality
- 1996
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Ingår i: Proceedings of the International Symposium [on] Efficiency, Costs, Optimization, Simulation and Environmental Aspects of Energy Systems. - Stockholm : KTH Royal Institute of Technology. - 917170664X ; , s. 557-564
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Konferensbidrag (refereegranskat)abstract
- If actors on the electricity market cooperate when end-use measures are introduced the energy-system, cost will be reduced considerably. The marginal cost for electricity for the energy system of the actors will show cost effective incentives for introducing end-use measures. We present a system analysis for cooperation between distributors and customers. We also present results from a project where an existing distributor and eleven existing customers within a municipal energy system have been analysed. The customers are various industries, a hospital, an ice hockey arena, a harbour, a water-works, a warehouse, and a radio tower. The results show that the customers have in different end-use measures a power reduction capacity of maximum 8642 kW. With electricity costs of 1994 this corresponds to a reduction in the energy system cost of 2,852,000 SEK for one year. The results also show that for the distributor`s load curve of 1994, the full power reduction capacity can not be used since the peak loads of the five winter months are not so large and distinct. In that case the energy system cost can be reduced by 1,909,000 SEK, which is 67% of the maximum cost reduction. The end-use measures that are cost effective in this municipal energy system are load management and electricity generation in reserve power plants. We have also studied the profitability for introducing bivalent heating systems based on oil and electricity for heat loads that originally are based on oil. However, with existing electricity and oil costs there are no incentives for increasing the electricity use during non-peak load periods with bivalent heating systems.
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- Herlitz, Johan, 1949, et al.
(författare)
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Death, mode of death, morbidity, and rehospitalization after coronary artery bypass grafting in relation to occurrence of and time since a previous myocardial infarction.
- 1997
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Ingår i: The Thoracic and cardiovascular surgeon. - : Georg Thieme Verlag KG. - 0171-6425 .- 1439-1902. ; 45:3, s. 109-13
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Tidskriftsartikel (refereegranskat)abstract
- To describe the prognosis during 2 years after coronary artery bypass grafting (CABG) in relation to occurrence of and time since a previous acute myocardial infarction (AMI), data of all patients in western Sweden who underwent CABG without simultaneous valve surgery in the period June 1988-June 1991 were evaluated. In all, 2120 patients were included in the analyses. Of these, 1296 (61%) had a history of AMI and 127 (6%) had suffered an AMI within the last month before CABG. Mortality during the first 30 days after CABG was for patients with no previous AMI, previous AMI > 30 days prior to CABG, and previous AMI < or = 30 days prior to CABG 2.4%, 4.1%, and 5.5%, respectively (p < 0.05). The corresponding figures for the period between 30 days and 2 years after CABG were 3.6%, 4.4%, and 3.4% respectively (NS). In a multivariate analysis among patients with a previous AMI, a recent infarction (< or = 30 days prior to CABG) did not turn out as an independent predictor of death during 2 years of follow-up. A history of AMI was associated with increased mortality during the first 30 days but not thereafter, but recent AMI was not an independent predictor of total 2-year mortality.
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- Herlitz, Johan, 1949, et al.
(författare)
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Determinants of time to discharge following coronary artery by pass grafting.
- 1997
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Ingår i: European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery. - 1010-7940. ; 11:3, s. 533-8
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Tidskriftsartikel (refereegranskat)abstract
- To describe clinical factors prior to and at the time of coronary artery bypass grafting (CABG) associated with the number of days until hospital discharge.
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