| 1. |
- Gustafsson, Stig-Inge
(author)
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Carpentry factory and municipal electricity loads
- 1998
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In: Energy Conversion and Management. - : Elsevier. - 0196-8904 .- 1879-2227. ; 39:3-4, s. 343-347
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Journal article (peer-reviewed)abstract
- Load management of electricity loads has received more interest in recent years. At least in Sweden, this is natural because of a rather cheap energy price, while at the same time, the demand charge is high. If a company could save the precise kWh that build the peak demand, then these would have a value of more than 200 times the off-peak kWh. This paper deals with monitored electricity data for two carpentry industries and one municipality, both situated in the south of Sweden. The ideal ! situation would be if the industry could reduce their peak demand and, at the same time, reduce the peak for the utility. Both participants would, in that case, save money, and the payback time for load management equipment would decrease substantially. If, however, a load management system at the carpentry transfers kWh to peak hours for the utility, the industry will save money, while the utility gets higher costs. The result of the study is that the Swedish electricity rates in use today are a very poor means of encouraging worthwhile load management, and often, they even aggravate the situation.
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| 2. |
- Gustafsson, Stig-Inge, 1948-
(author)
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Energy usage and conservation in surfacing lines
- 2000
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In: Energy Conversion and Management. - 0196-8904 .- 1879-2227. ; 41:15, s. 1649-1669
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Journal article (peer-reviewed)abstract
- This paper deals with energy usage and conservation for a surfacing line in a carpentry factory. In this line, wood panels are coated with paint in a highly automated fashion. The products vary in shapes and the way they shall be coated, and therefore, a number of machines are present in the line which is about 100 m long. Sanding machines, roller coaters, dryers etc. are installed, and all machinery uses electricity for their operation. There are, however, other equipments coupled to the line. One example is the wood dust transportation system, and another is the steam system used for heating purposes. By use of a number of electricity meters, monitoring ventilation flow rates etc., it has been possible to analyze how much energy is used in the surfacing line and also to propose measures to reduce this amount.
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| 3. |
- Gustafsson, Stig-Inge, et al.
(author)
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Heat Accumulators in CHP Networks
- 1992
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In: Energy Conversion and Management. - : Elsevier. - 0196-8904 .- 1879-2227. ; 33:12, s. 1051-1061
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Journal article (peer-reviewed)abstract
- In a Combined Heat and Power (CHP) network, it is sometimes optimal to install a device for storing heat from one period of time to another. Several possibilities exist. If the electricity demand is high, while at the same time the district heating load is too small to take care of the heat from the CHP plant, it could be optimal to store heat from peak periods and discharge the storage under off-peak. It might also be optimal to store heat during off-peak and use it under the district heating peak load. The storage is then used for decreasing either the district heating demand or for decreasing the electricity load used for space heating. The paper shows how a mixed integer program is developed for use in the optimization process. As a case study, the CHP system of Malmö, Sweden, is used. Further, a sensitivity analysis is elaborated in order to show how the optimal solution will vary due to changes in certain input data.
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| 4. |
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| 5. |
- Rolfsman, Björn, 1971-
(author)
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Optimal supply and demand investments in municipal energy systems
- 2004
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In: Energy Conversion and Management. - 0196-8904 .- 1879-2227. ; 45:4, s. 595-611
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Journal article (peer-reviewed)abstract
- In many municipalities, there are district heating networks, which are quite commonly supplied by combined heat and power plants (CHP). A district heating network contains buildings of different types. In this paper, one such municipal energy system is analysed. In order to provide space heating and domestic hot water, investments could be made on the supply side in power plants, or on the demand side in the buildings, for example in the form of extra wall insulation. The electricity from the CHP plants is supplied to the municipality but can also be sold to the electricity market, and electricity can, of course, also be bought from the market. The variation in price on the spot market over any given day is significant. The need for district heat in the building stock also varies, for example due to climatic conditions. The energy system in the case study is analysed with a mixed integer linear programming model. The model has 3 h time steps in order to reflect diurnal variations, and an entire year is analysed. A case study is presented for the city of Linköping in Sweden. On the demand side, the options are: extra wall insulation, extra attic insulation and better types of windows. The building stock is divided into nine categories. © 2003 Elsevier Ltd. All rights reserved.
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| 6. |
- Sundberg, Gunnel, et al.
(author)
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Investments in combined heat and power plants : Influence of fuel price on cost minimised operation
- 2002
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In: Energy Conversion and Management. - 0196-8904 .- 1879-2227. ; 43:5, s. 639-650
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Journal article (peer-reviewed)abstract
- Liberalisation of the electricity market and governmental politics influence heat and power supply in Sweden, like in many other countries. In this paper, the impact of subsidies and fuel and electricity costs on a representative Swedish district heating system is analysed. The energy system model MODEST (model for optimisation of dynamic energy systems with time dependent components and boundary conditions) was used to optimise investments and operation for heat and power production plants. At higher electricity prices, combined heat and power introduction may be profitable in the studied system. With current fuel prices, a natural gas fired combined cycle would primarily be favourable. A lower woodchips price and a governmental grant would make cogeneration with a biomass fired steam cycle more beneficial. © 2002 Elsevier Science Ltd. All rights reserved.
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| 7. |
- Ahlgren, Benjamin, et al.
(author)
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A simplified model for linear correlation between annual yield and DNI for parabolic trough collectors
- 2018
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In: Energy Conversion and Management. - : Elsevier. - 0196-8904 .- 1879-2227. ; 174, s. 295-308
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Journal article (peer-reviewed)abstract
- This paper proposes a simple method for estimating annual thermal performance of parabolic trough collectors (PTCs) based on a linear relation with annual DNI for a certain latitude. A case study with simulations for a novel concentrating solar collector in 316 locations for three operating temperature scenarios worldwide was carried out and showed promising results for the latitudes and continents investigated. For a certain latitude and mean operating temperature, the annual yield of a PTC was found to be linearly proportional to yearly DNI. The proposed method will serve as a simplified alternative to the steady-state and quasi-dynamic methods already used. Estimating performance based on yearly DNI can be used by design engineers to do quick preliminary planning of solar plants. Customers can also use this method to evaluate existing solar collector installations. A TRNSYS/TRNSED tool that uses a steady-state model has been developed to carry out the simulations and it has been validated against a PTC array at Technical University of Denmark (DTU). The results show that the simplified method can give reliable estimates of long-term performance of parabolic trough collectors.
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| 8. |
- Ahlström, Johan, 1990, et al.
(author)
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Economic potential for substitution of fossil fuels with liquefied biomethane in Swedish iron and steel industry – Synergy and competition with other sectors
- 2020
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In: Energy Conversion and Management. - : Elsevier Ltd. - 0196-8904 .- 1879-2227. ; 209
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Journal article (peer-reviewed)abstract
- In Sweden, the iron and steel industry (ISI) is a major source of greenhouse gas (GHG) emissions. Most of the emissions result from the use of fossil reducing agents. Nevertheless, the use of fossil fuels for other purposes must also be eliminated in order to reach the Swedish emissions reduction targets. In this study, we investigate the possibility to replace fossil gaseous and liquid fuels used for heating in the ISI, with liquefied biomethane (LBG) produced through gasification of forest residues. We hypothesize that such utilization of fuels in the Swedish ISI is insufficient to independently drive the development of large-scale LBG production, and that other sectors demanding LBG, e.g., for transportation, can be expected to influence the economic potential for the ISI to switch to LBG. The paper investigates how demand for LBG from other sectors can contribute to, or prevent, a phase-out of fossil fuels used for heating purposes in the ISI under different future energy market scenarios, with additional analysis of the impact of a CO2 emissions charge. A geographically explicit cost-minimizing biofuel production localization model is combined with heat integration and energy market scenario analysis. The results show that from a set of possible future energy market scenarios, none yielded more than a 9% replacement of fossil fuels used for heating purposes in the ISI, and only when there was also a demand for LBG from other sectors. The scenarios corresponding to a more ambitious GHG mitigation policy did not achieve higher adoption of LBG, due to corresponding higher biomass prices. A CO2 charge exceeding 200 EUR/tonCO2 would be required to achieve a full phase-out of fossil fuels used for heating purposes in the ISI. We conclude that with the current policy situation, substitution of fossil fuels by LBG will not be economically feasible for the Swedish ISI.
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| 9. |
- Andersson, Jim, et al.
(author)
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Co-gasification of black liquor and pyrolysis oil : Evaluation of blend ratios and methanol production capacities
- 2016
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In: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 110, s. 240-248
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Journal article (peer-reviewed)abstract
- The main aim of this study is to investigate integrated methanol production via co-gasification of black liquor (BL) and pyrolysis oil (PO), at Swedish pulp mills. The objectives are to evaluate techno-economically different blends ratios for different pulp mill capacities. Furthermore, the future methanol production potential in Sweden and overall system consequences of large-scale implementation of PO/BL co-gasification are also assessed.It is concluded that gasification of pure BL and PO/BL blends up to 50% results in significantly lower production costs than what can be achieved by gasification of unblended PO. Co-gasification with 20–50% oil addition would be the most advantageous solution based on IRR for integrated biofuel plants in small pulp mills (200 kADt/y), whilst pure black liquor gasification (BLG) will be the most advantageous alternative for larger pulp mills. For pulp mill sizes between 300 and 600 kADt/y, it is also concluded that a feasible methanol production can be achieved at a methanol market price below 100 €/MW h, for production capacities ranging between 0.9 and 1.6 TW h/y for pure BLG, and between 1.2 and 6.5 TW h/y for PO/BL co-gasification. This study also shows that by introducing PO/BL co-gasification, fewer pulp mills would need to be converted to biofuel plants than with pure BLG, to meet a certain biofuel demand for a region. Due to the technical as well as organizational complexity of the integration this may prove beneficial, and could also potentially lower the total investment requirement to meet the total biofuel demand in the system. The main conclusion is that PO/BL co-gasification is a technically and economically attractive production route for production biomethanol.
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| 10. |
- Arfan, Muhammad, et al.
(author)
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Life cycle assessment and life cycle costing of hydrogen production from biowaste and biomass in Sweden
- 2023
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In: Energy Conversion and Management. - : Elsevier. - 0196-8904 .- 1879-2227. ; 291
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Journal article (peer-reviewed)abstract
- In this study, an environmental and economic assessment of hydrogen production from biowaste and biomass is performed from a life cycle perspective, with a high degree of primary life cycle inventory data on materials, energy, and investment flows. Using SimaPro LCA software and CML-IA, 2001 impact assessment method, ten environmental impact categories are analyzed for environmental analysis. Economic analysis includes capital and operational expenditures and monetization cost of life cycle environmental impacts. The hydrogen production from biowaste has a high climate impact, photochemical oxidant, and freshwater eutrophication than biomass while it performs far better in ozone depletion, terrestrial ecotoxicity, abiotic depletion-fossil, abiotic depletion, human toxicity, and freshwater ecotoxicity. The sensitivity analysis of LCA results indicates that feedstock to biogas/pyrolysis-oil yields ratio and the type of energy source for the reforming process can significantly influence the results, particularly climate change, abiotic depletion, and human toxicity. The life cycle cost (LCC) of 1 kg hydrogen production has been accounted as 0.45–2.76 € with biowaste and 0.54–3.31 € with biomass over the plant's lifetime of 20 years. From the environmental impacts of climate change, photochemical oxidant, and freshwater eutrophication hydrogen production from biomass is a better option than biowaste while from other included impact categories and LCC perspectives it’s biowaste. This research contributes to bioresources to hydrogen literature with some new findings that can be generalized in Europe and even globally as it is in line with and endorse existing theoretical and simulation software-based studies.
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