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| 2. |
- Börjesson, Pål, et al.
(författare)
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The prospects for willow plantations for wastewater treatment in Sweden
- 2006
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Ingår i: Biomass & Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 30:5, s. 428-438
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Tidskriftsartikel (refereegranskat)abstract
- The concept of willow vegetation filters for the treatment of nutrient-rich wastewater has the potential to address two of our most serious environmental problems today -water pollution and climate change- in a cost-efficient way. Despite several benefits, including high treatment efficiency, increased biomass yields, improved energy and resource efficiency, and cost savings, willow vegetation filters have so far only been implemented to a limited degree in Sweden. This is due to various kinds of barriers, which may be the result of current institutional, structural and technical/geographical conditions. This paper discusses the prospects of a more widespread utilisation of willow plantations for wastewater treatment in Sweden, including existing incentives and barriers, based on current knowledge and experience. (c) 2005 Elsevier Ltd. All rights reserved.
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| 4. |
- Ahlbäck, Anders, 1977, et al.
(författare)
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Electricity from Renewable Energy Sources - POPA CTDA : Policy pathways to promote the development and adoption of cleaner technologies
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Executive summary Introduction In the strive towards a sustainable society, environmental technologies will play an increasingly important role. This has been acknowledged by the European Commission, and through the launching of the rather ambitious Environmental Technologies Action Plan (ETAP) the Commission has committed to the wide-spread of clean technologies in all the sectors of society. This programme encourage a numerous of actions designed to “remove barriers for the development and diffusion of environmental technologies”, to “ensure that the EU will take a leading role in developing and applying such technologies”, and to “mobilise all stakeholders in support of these objectives” (EU, 2004a). As a measure within the framework of ETAP, this project is designed to identify policy pathways to the promotion and development of clean technology development (POPA-CTDA) in the sectors of industry, transport, agriculture and energy. This case study deals with renewable energy technologies (RET) (bio-fuelled combined heat and power, wind power and solar power). Currently driven by all three pillars of sustainability in addition to the ‘traditional’ environmental one, RETs are increasingly looked upon as commercially competitive alternative to fossil based energy technologies. Use of renewable energy is growing on the global market - not only in niche applications as e.g. remote installations but on the broader energy/electricity markets as well. The share of renewable energy in the global primary energy supply (TPES) is about 11.3%, which of the vast majority is combustible bio resources (about 10.8%) and about 0.5% being wind, solar and geothermal (IEA, 2005). On the European energy market, RETs accounts for approximately 5% of TPES. This can be compared with the 12% penetration target by 2010 stated by the Commission in 1997. Methodological approach Starting point for the design of an integrated policy strategy supporting the development and adoption of RETs are the barriers and drivers responsible for the corresponding engagement of relevant actors in this field. Both barriers and drivers have been identified in a previous study, Work Package 2 (WP2), by the means of a behavioural approach developed by Montalvo (2001; 2002) on the basis of a survey conducted with actual and potential developers, manufacturers, operators and end-users of RETs from Austria, Germany, Netherlands, UK, Sweden and Hungary. In the survey actors in the energy UGOT POPA-CTDA: Work package 3 5 sector where asked about their opinions concerning development and adoption of RETs. Various aspects of their attitudes where addressed such as economic and environmental risk perception, relevant pressure arising from the social environment, the market and regulatory bodies and of their own technical and managing capabilities. The full analysis of the questionnaire is presented in the WP2 report. In the present study, Work Package 3, plausible policy instruments are identified to address those barriers found in WP2 and to encourage the diffusion of RETs. The insights presented in this report are based on literature study, interviews and the questionnaire study conducted in WP2. Main insights Economy Costs of producing electricity from RETs have been greatly reduced during latest decades but are generally still above the ones of fossil fuels; in particular PV technology that is, roughly, 10 times as expensive as average generation costs.1 The inability to include environmental damage costs of electricity generation (combustion of fossil fuels, nuclear power plants or even renewable technologies), the vast amount of direct or indirect subsidies, tax concessions etc. all distort competition on the energy market. Hence, some level of economic support is required for RETs to compete on the open market. In the case of both wind and solar power, the German feed-in law has proved very successful in lowering investment risk and encouraging new installations. Market On a local level, the job and economic growth opportunities derived from an establishment of local electricity production is becoming increasingly recognised. RETs compared with fossil based technologies are generally more labour intensive and, coupled with increasing recognition of RETs to fulfil national/local sustainability targets, provides an attractive option for politicians and entrepreneurs to promote local business. This is particularly a driver to establish biomass power and, if locally available, biomass resources via crop or forestry industry. 1 Average spot market price for electricity in the Eu-15 was in 2004 about 30-35 €/MWh, where average generation cost for PV is roughly 500 €/MWh electricity. UGOT POPA-CTDA: Work package 3 6 Technology and infrastructure Several interviewees pointed out performance, power output fluctuations (intermittency), actual power generation costs (factoring in costs of maintenance and service etc.) and lifetime as technological uncertainties and potential barriers to up-take. There is a need for further RD&D (research, development and demonstration) to develop both specific technology characteristic and systemic issues as grid compatibility. The varying power output of renewable generation and its consequences to power distribution is a source for controversy and may pose challenges in grid management. While it was earlier believed that even small fractions of intermittent capacity would cause instability on the power grid, new empirical data from practical examples2 shows that it is foremost a question of grid-management techniques. Institutional and regulative While wind power in general has gained in economic competitiveness, several interviewees mention regulative barriers as, perhaps, the main obstacle to a wide-spread diffusion. Issuing building permits is a complicated and time consuming process, where in Sweden, for example, several authorities at various levels are involved at different stages. A projector has to face the same process twice; first against the planning and building regulation, then the environmental legislation, in order to obtain building permits. Opposing groups may quite easily appeal and, thereby, delaying the process up to several years and risking the economy of a project. Especially small actors with no internal legal resources may face great challenges in the planning phase of a project. The coordination between the involved authorities is regarded as not very well-organised and there most definitely is a large potential to streamline the current processes. Recommendations Policy support on the EU level via communications, directives green/white papers etc. is a significant driver to policy implementation on the national level. It is of most importance to continuing to show this support by stating new targets for RET penetration (post-Kyoto objectives) and ensure compliance with e.g. national Kyoto-bindings. 2 E.g. in western Denmark, over 20% of the total load is covered by wind energy (IEA, 2005). UGOT POPA-CTDA: Work package 3 7 RETs in general • The European Emission Trading Scheme (ETS) has yet to prove its positive affects on RET diffusion. The potential is great however, but is to a large deal dependent on the size of the national allocation plans. If the acceptance and compliance of the scheme is not kept strong enough, the potential might very well get lost in a political barging between member states. • The formation of a single European electricity market have the potential of being the “hardware” necessary for implementing EU-wide supporting schemes. Particularly a common market for Tradable Green Certificates could be realised, where actors all over Europe would trade green electricity, ensuring a wide competition among producers and, thereby, keeping over all costs low. • RETs are in the need of continuing R&D support to increase product performance and lower manufacturing costs. Positive side-effects of R&D and demonstration programmes may be gained from actors forming networks and alliances for knowledge transfers and partnership. This is a necessity to counter powerful coalitions promoting fossil based technologies that for decades have influenced the institutional framework in favour of coal, oil and natural gas. • To minimise risk perception of investment, clear and long-term policy guidelines is needed to support RETs. Almost all interviewees expressed the short-term design of the current supporting schemes as a major barrier to investments. Some level of security is needed to induce investments, and that is foremost achieved by clearly stated rules and stable support. Biomass • Even though biomass is being close to commercially competitive, it is still in the need of economic support. The CHP technology in it self is well proven and developed; future technology developments will probably focus on the gasification of biomass resources, where there is extensive efficiency gains to be made in the production of electricity. UGOT POPA-CTDA: Work package 3 8 Wind Power • For wind power to be able to compete with old (often governmentally financed) installations, some level of economic support is still needed. Germany and Spain have primarily through the use of feed-in systems emerged as world leaders in the use of wind power in their national electricity systems. • Issuing building permit processes are often time consuming and perceived as unreasonably complicated. To counter this, there are needs to both streamline the permit process by coordinating involved governmental bodies and to pre-allocate land for wind power installations. • The intermittency of wind power generation might prove to have deteriorated affects on power quality in regions with relatively high shares of installations. This is mostly a matter of managing the power production/transfer with dedicated routines and technology, but will require R&D efforts to increase the knowledge of how
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- Ahlgren, Erik, 1962, et al.
(författare)
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Produktionsrelaterade systemstudier
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I denna rapport, Produktionsrelaterade systemstudier – flexibla el- och värmesystem, har kortfattat ett antal områden som kan tänkas få betydelse för utvecklingen av de svenska el- och värmeförsörjningssystemen analyserats. Målet har varit att ge en bakgrundsbeskrivning av ett antal tekniska och teknisk-ekonomiska områden som kommer att påverkas av och/eller påverka framtida el- och värmeförsörjning. Författarna har utgått från de övergripande frågorna, såsom försörjningstrygghet i en avreglerad marknad och energisektorns miljöpåverkan speciellt med avseende på klimatpåverkan. Systemgränsen runt el- och värmesektorn har avsiktligt dragits mycket brett så att också bebyggelse- och industrisektorerna är inkluderade, eftersom dessa är de klart dominerande sektorerna både med avseende på elanvändning och med total energianvändning. Avsikten med detta har varit att peka på den stora betydelse som ändrade energiefterfrågemönster inom bebyggelsesektorn och än annan syn på industrisektorn, inte bara som energianvändare utan också delvis som energileverantör, kan få för det framtida el- och värmeförsörjningssystemet. Studien behandlar produktionsrelaterade elsystemfrågor, men med ett perspektiv av interaktion mellan tillgång och efterfrågan. Ett stort antal tillförseltekniker och –system har kort berörts. Vissa av dessa dominerar systemet idag, andra kan tänkas få en inte oväsentlig betydelse i framtida system. Genomgående trycks på behovet av en integrerad analys där hänsyn tas till samspel mellan tillförsel och användning, mellan teknik och ekonomi, mellan kort och lång sikt, mellan el och värme och även transporter, för att uppnå en högre verkningsgrad och därmed minskad miljöbelastning. Verkningsgraden har betraktats utgående från ett systemperspektiv snarare än från ett anläggnings-perspektiv. Slutsatsen av analysen är att det fortfarande finns ett antal markanta kunskapsluckor, och att dessa framför allt finns på systemnivå i samspelet, eller det möjliga samspelet, mellan ovan nämnda områden; tillförsel och användning; el, värme och transporter; samt betydelsen för försörjningssystemet av förväntade ändringar med tiden av såväl el- och värmeefterfrågan, som av tillgängliga tekniska lösningar.
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| 6. |
- Ahlman, Stefan, 1973
(författare)
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Modelling of Substance Flows in Urban Drainage Systems
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Stormwater is recognised as a large contributor of toxic substances to receiving waters. Different measures to manage stormwater quality have been proposed, including structural and non-structural best management practices (BMPs). Computer models have become useful tools for the analysis, evaluation and design of these BMPs. The main objective of this study was to develop a modelling framework that enables an analysis of the pollutant sources in urban drainage systems. In the modelling framework the sources of pollutants from different activities in the urban area were separated according to their origin, e.g. material corrosion, brake wear and tyre wear.The model was named SEWSYS® and was developed in MATLAB/Simulink. SEWSYS simulates substance flows in urban drainage systems. At present the model contains 20 different substances, including nutrients, heavy metals and organic pollutants. The model can simulate both stormwater and domestic wastewater flows, in either combined or separate sewer systems. In the stormwater quality module, the pollutants from sources such as atmospheric deposition, traffic and construction materials are generated and accumulated on impervious surfaces during dry weather until they are washed away during rainfall. Validation studies of the SEWSYS model were carried out using measurements of stormwater flow and quality. Calibration and validation were performed using a split-sample technique, i.e. with independent data sets for calibration and validation. The hydrological part of the model performed well in the validation but the quality part produced less reliable results.Uncertainty analysis of the stormwater module in SEWSYS was carried out for the model outputs runoff volume, pollutant concentrations (EMCs and SMC), and pollutant load of heavy metals for an uncalibrated and calibrated model. Uncertainty assessment methods included Monte Carlo simulations, multi-linear regression and a Markov-Chain Monte Carlo method for parameter calibration. The results of the uncertainty analysis showed that predictions made with an uncalibrated model were associated with a considerable amount of uncertainty. It was also shown that by means of calibration this uncertainty could be reduced to an acceptable level.The application of the SEWSYS model in different types of scenario studies has been an important part of the model development. The results from the application studies demonstrate that the model is a useful tool for simulating and evaluating pollutant source control measures.
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| 8. |
- Andersson, Klas, 1977, et al.
(författare)
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Process evaluation of an 865 MWe lignite fired O2/CO2 power plant
- 2006
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904. ; 47:18-19, s. 3487-3498
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Tidskriftsartikel (refereegranskat)abstract
- In order to reduce emissions of carbon dioxide from large point sources, new technologies can be used in capture plants for combustion of fossil fuel for subsequent capture and storage of CO2. One such technology is the O2/CO2 combustion process (also termed oxy-fuel combustion) that combines a conventional combustion process with a cryogenic air separation process so that the fuel is burned in oxygen and recycled flue gas, yielding a high concentration of CO2 in the flue gas, which reduces the cost for its capture. In this work, the O2/CO2 process is applied using commercial data from an 865 MWe lignite fired reference power plant and large air separation units (ASU). A detailed design of the flue gas treatment pass, integrated in the overall process layout, is proposed. The essential components and energy streams of the two processes have been investigated in order to evaluate the possibilities for process integration and to determine the net efficiency of the capture plant. The electricity generation cost and the associated avoidance cost for the capture plant have been determined and compared to the reference plant with investment costs obtained directly from industry. Although an existing reference power plant forms the basis of the work, the study is directed towards a new state of the art lignite fired O2/CO2 power plant. The boiler power of the O2/CO2 plant has been increased to keep the net output of the capture and the reference plant similar. With the integration possibilities identified, the net efficiency becomes 33.5%, which should be compared to 42.6% in the reference plant. With a lignite price of 5.2 $/MWh and an interest rate of 10%, the electricity generation cost increases from 42.1 to 64.3 $/MWh, which corresponds to a CO2 avoidance cost of 26 $/ton CO2.
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| 9. |
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| 10. |
- Assefa, Getachew
(författare)
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Systems analysis of technology chains for energy recovery from waste
- 2006
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Ingår i: WMSCI 2006. - ORLANDO : INT INST INFORMATICS & SYSTEMICS. - 9789806560727 ; , s. 183-188
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Konferensbidrag (refereegranskat)abstract
- This contribution is based on the result of a project entitled "Systems Analysis: Energy Recovery from waste, catalytic combustion in comparison with fuel cells and incineration" is financed by The Swedish National Energy Administration. The aim of the project was to assess the energy turnover as well as the potential environmental impacts of biomass/waste-to-energy technologies. Four technology scenarios are be studied: (1) Gasification followed by low temperature fuel cells (i.e. Proton Exchange Membrane (PEM) fuel cells) (2) Gasification followed by high temperature fuel cells (i.e. Solid Oxide fuel cells (SOFC)) (3) Gasification followed by catalytic combustion (CC) and (4) Incineration with energy recovery. Looking at the result of the four technology chains in terms of the impact categories considered with impact per GWh electricity produced as a unit of comparison and from the perspective of the rank each scenario has in all the four impact categories, SOFC appears to be the winner technology followed by PEM and CC as second and third best respectively with incinerations as the least of all. On other hand, looking at the three important emissions (CO,. NOx and SOx) from the total systems (include both the core system and the external system), SOFC is the best technology equally followed PEM and CC as the second best. A comparison of the same emissions from the core systems places CC on equal level with SOFC as the best technologies with PEM as the second best.
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