| 1. |
- Andersson, Viktor, 1983, et al.
(författare)
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Integrated Algae Cultivation for Municipal Wastewater Treatment and Biofuels Production in Industrial Clusters
- 2012
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Ingår i: World Renewable Energy Forum, WREF 2012. - 9781622760923 ; 1, s. 684-691
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Konferensbidrag (refereegranskat)abstract
- This paper presents a case study on biofuels production from microalgae cultivated in municipal wastewater in Gothenburg, Sweden. A) Combined biodiesel and biogas production and B) only biogas production, are compared in terms of product outputs, impact on global CO2 emissions reduction and economic performance. Land-use efficiency of biofuels from microalgae was compared with other biofuel production routes. The biofuel production process is assumed to be integrated with a wastewater treatment plant and an industrial cluster, providing the opportunity to reduce the CO2 emissions of the process compared to stand-alone operation.The results show that case A is advantageous in terms of all the studied factors. A higher area efficiency of algae biofuels production routes compared to other biofuel production routes was shown. Nutrient availability in municipal wastewater is shown to be the limiting factor regarding product output. The competitive advantage of co-location with a wastewater treatment plant is clearly shown.
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| 2. |
- Broberg, Sarah, 1983-, et al.
(författare)
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Integrated Algae Cultivation for Biofuels Production in Industrial Clusters
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Declining fossil resources and the issue of climate change caused by anthropogenic emissions of greenhouse gases make global action towards a more sustainable society inevitable. The EU decided in 2007 that 20 % of the union´s energy use should origin from renewable resources by the year 2020. One way of achieving this goal is to increase the utilisation of biofuels. Today 2nd generation biofuels are being developed. They are seen as a more sustainable solution than 1st generation biofuels since they have a higher area efficiency (more fuel produced per area) and the biomass can be cultivated at land which is not suitable for food crops. One of these 2nd generation biofuels are fuels derived from microalgae. In this study a thorough literature survey has been conducted in order to assess the State-of-the-Art in algae biofuels production. The literature review showed the importance of a supplementary function in conjunction with algae cultivation and therefore algae cultivation for municipal wastewater treatment and capturing CO2 emissions from industry was included in the study. It was assumed that all the wastewater of the city of Gothenburg, Sweden, was treated by algae cultivation. A computer model of the whole production process has been developed, covering; algae cultivation in conjunction with wastewater treatment, algae harvesting and biofuels production. Two different cases are modelled; a first case including combined biodiesel and biogas production, and a second case investigating only biogas production. Both cases have been evaluated in terms of product outputs, CO2 emissions savings and compared to each other in an economic sense. Utilising the nutrients in the wastewater of Gothenburg it is possible to cultivate 29 ktalgae/year. In the biogas case it is possible to produce 205 GWhbiogas/year. The biogas/biodiesel case showed a production potential of 63 GWhbiodiesel/year and 182 GWhbiogas/year. There is a deficit of carbon in the wastewater, hence CO2 is injected as flue gases from industrial sources. The biodiesel/biogas case showed an industrial CO2 sequestration capacity of 24 ktCO2/year while in the biogas case 22.6 ktCO2/year, could be captured. Estimating the total CO2 emissions savings showed 46 ktCO2/year in the biodiesel/biogas case and 38 ktCO2/year for the biogas case. The importance of including wastewater treatment in the process was confirmed, as it contributes with 13.7 ktCO2/year to the total CO2 emissions savings. Economic comparison of the two cases showed that biodiesel in conjunction with biogas production is advantageous compared to only biogas production. This is mainly due to the higher overall fuel yield and the high willingness to pay for biodiesel. The total incomes from biodiesel/biogas sales were calculated to 221 million SEK/year and 193 million SEK/year for biogas. It was found that the higher incomes from biodiesel/biogas sales repay the increased investment for the biodiesel process in approximately 3 years.
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| 3. |
- Andersson, Viktor, 1983, et al.
(författare)
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Algae-based biofuel production as part of an industrial cluster
- 2014
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 71, s. 113-124
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a study on the production of biofuels from algae cultivated in municipal wastewater in Gothenburg, Sweden. A possible biorefinery concept is studied based on two cases; Case A) combined biodiesel and biogas production, and Case B) only biogas production. The cases are compared in terms of product outputs and impact on global CO2 emissions mitigation. The area efficiency of the algae-based biofuels is also compared with other biofuel production routes. The study investigates the collaboration between an algae cultivation, biofuel production processes, a wastewater treatment plant and an industrial cluster for the purpose of utilizing material flows and industrial excess heat between the actors. This collaboration provides the opportunity to reduce the CO2 emissions from the process compared to a stand-alone operation. The results show that Case A is advantageous to Case B with respect to all studied factors. It is found that the algae-based biofuel production routes investigated in this study has higher area efficiency than other biofuel production routes. The amount of algae-based biofuel possible to produce corresponds to 31 MWfuel for Case A and 26 MWfuel in Case B.
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| 4. |
- Andersson, Viktor, 1983, et al.
(författare)
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Dubbel energivinst med alger som biobränsle
- 2013
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Ingår i: Energimagasinet.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Idag kan produktionen av biobränsle påverka livsmedelsförsörjningen negativt. Istället för att biobränsleproduktion ska konkurrera med produktion av livsmedel kan en hittills outnyttjad resurs - kommunalt avloppsvatten - användas för produktion av alger som i sin tur kan användas till biogas och biodiesel. Ny forskning visar på denna potential.
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| 5. |
- Backlund, Sandra, 1986-, et al.
(författare)
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Energy efficiency potentials and energy management practices in Swedish firms
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In order to improve energy efficiency and reach the EU:s 20-20-20 primary energy saving target, focus has mainly been on diffusion of technology. Previous studies have illustrated large untapped energy saving potentials from implementing energy management practices in firms. Energy management practices have large effects on energy utilization and also a short pay-back time. According to these studies, energy management practices also effect investment decisions and the outcome of investments in energy efficient technologies. This paper investigates to what extent energy management practices influence firms estimation of energy efficiency potentials. Further it investigates two Swedish policy programs that promote industrial energy management practices: The Programme For improving Energy efficiency in energy-intensive industry (PFE) and the energy audit program and whether these have increased energy management practices in Swedish firms. A multiple case study has been conducted in order to investigate energy practices in firms in different industrial sectors. Employment of energy management varies between firms. The firms estimate equal energy efficiency potentials from implementation of energy efficient technology as for energy management practices. In total the firms estimate energy efficiency potentials of 12 %. The study shows that firms that have participated in the programs work more actively with energy management. This can be illustrated by the fact that 75 % of the firms that have not participated in any of the programs lack a person responsible for energy management and 50 % also lack a long term energy strategy. For firms that have participated in the programs the corresponding figures are 30 % and 33 %. The results indicate an untapped potential of energy efficiency measures that could be reached through increased energy management in Swedish industries.
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| 6. |
- Broberg Viklund, Sarah, 1983-
(författare)
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System studies of the use of industrial excess heat
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Energy, materials, and by-products, can be exchanged between companies, having positive effects in the form of improved resource efficiency, environmental benefits, and economic gains. One such energy stream that can be exchanged is excess heat, that is, heat generated as a by-product during, for example, industrial production. Excess heat will continue to play an important role in efforts to reduce greenhouse gas (GHG) emissions and improve energy efficiency. Using excess heat is therefore currently emphasized in EU policy as a way to reach EU climate targets.This thesis examines the opportunities of manufacturing industries to use industrial excess heat, and how doing so can positively affect industry, society, and the climate. Since different parts of the energy system are entangled, there is an inherent complexity in studying these systems and introducing excess heat in one part of the energy system may influence other parts of the system. This analysis has accordingly been conducted by combining studies from various perspectives, by applying both quantitative and qualitative methods and covering a broad range of aspects, such as technical possibilities as well as climate, policy, economics, and resource aspects.The results identify several opportunities and benefits accruing from excess heat use. Although excess heat is currently partly used as a thermal resource in district heating in Sweden, this thesis demonstrates that significant untapped excess heat is still available. The mapping conducted in the appended studies identifies excess heat in different energy carriers, mainly low-temperature water. Analysis of excess heat use in different recovery options demonstrated greater output when using excess heat in district heating than electricity production. Optimizing the trade-offs in excess heat used in a district heating network, heat-driven cooling, and electricity production under different energy market conditions while minimizing the system cost, however, indicated that the attractiveness of excess heat in district heating depends on the type of heat production in the system. Viewing excess heat as a low-cost energy source also makes it economically interesting, and creates opportunities to invest in excess heat-recovery solutions. Excess heat is often viewed as CO2 neutral since unused excess heat may be regarded as wasted energy. The GHG mitigation potential of using excess heat, however, was found to be ambiguous. The appended studies demonstrate that using excess heat for electricity production or for applications that reduce the use of electricity reduces GHG emissions. The effects of using excess heat in district heating, on the other hand, depend on the energy market development, for example, the marginal electricity production and marginal use of biomass, and on the type of district heating system replaced. The interviews performed reveal that energy policy does influence excess heat use, being demonstrated both to promote and discourage excess heat use. Beyond national energy policies, internal goals and core values were identified as important for improved energy efficiency and increased excess heat use.
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| 7. |
- Broberg Viklund, Sarah, 1983-, et al.
(författare)
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Technologies for utilization of industrial excess heat : Potentials for energy recovery and CO2 emission reduction
- 2014
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 77, s. 369-379
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Tidskriftsartikel (refereegranskat)abstract
- Industrial excess heat is a large untapped resource, for which there is potential for external use, which would create benefits for industry and society. Use of excess heat can provide a way to reduce the use of primary energy and to contribute to global CO2 mitigation. The aim of this paper is to present different measures for the recovery and utilization of industrial excess heat and to investigate how the development of the future energy market can affect which heat utilization measure would contribute the most to global CO2 emissions mitigation. Excess heat recovery is put into a context by applying some of the excess heat recovery measures to the untapped excess heat potential in Gavleborg County in Sweden. Two different cases for excess heat recovery are studied: heat delivery to a district heating system and heat-driven electricity generation. To investigate the impact of excess heat recovery on global CO2 emissions, six consistent future energy market scenarios were used. Approximately 0.8 TWh/year of industrial excess heat in Gavleborg County is not used today. The results show that with the proposed recovery measures approximately 91 GWh/year of district heating, or 25 GWh/year of electricity, could be supplied from this heat. Electricity generation would result in reduced global CO2 emissions in all of the analyzed scenarios, while heat delivery to a DH system based on combined heat and power production from biomass would result in increased global CO2 emissions when the CO2 emission charge is low.
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