The centre has been active in many fields for some time. The research maps to these research topics.
|1.||Performance Management||4.||Productivity||7.||Engineering Design|
|2.||Business Process Management||5.||Knowledge Work management||8.||Cost and Engineering Economy Mgt|
|3.||Quality Management||6.||Production Management|
The following is a list of earlier research map to the resesarch topics:
|2012||Inventory Management at the National University Hospital of Iceland||x||GVO|
|2012||Energy return on Investment of Geothermal and Hydro power plants and their respective energy payback time||x||RU|
|2012||Úrgangur til orku. Leiðir til að nýta skólp til eldsneytisframleiðslu||x||RU|
|2013||Improvement Opportunities in Aluminium Production||x||x||GVO|
|2013||Umgjörð ISO 22000 vottunar fyrir starfsemi Mjólkursamsölunnar||x||GVO|
|2013||Experience in transporting energy through subsea power cables: The case of Iceland||x||x||RU|
|2013||Maintenance of the steam turbines at Hellisheiði power plant||x||RU|
|2013||Motion analysis for Arctic char and Atlantic salmon||x||RU|
|2013||Performance Indicators for Maintenance in Geothermal Power Plants||x||RU|
|2013||Raforkunotkun Öskju – Aukin rekstrarhagkvæmni||x||x||x||RU|
|2013||The exploration of a sustainable design method targeting the conceptual and creative design stage||x||RU|
|2014||Breytt áltökuferli í kerskálum Norðuráls á Grundartanga||x||GVO|
|2014||Integrating Sustainability into the Engineering Design process||x||x||RU+GVO|
|2014||Wind energy potential assessment||x||x||RU+GVO|
|2014||Redesign of Cross Frame with Recognized Design Methods||x||RU|
|2014||Simulation Based Grid Energy Storage Optimization to Enhance Renewable Energy Storage in Iceland||x||RU|
|2014||A General Description and Comparison of Horizontal Axis Wind Turbines and Vertical Axis Wind Turbines||x||RU|
|2014||A Mapping of an Agile Software Development Method to the Personal Productivity of the Knowledge Worker.
A Systematic Review of Self-Help Books
|2014||Kostnaðarstjórnun í Silíkondeild Össurar – ABC-greining, kostnaðarskipting og BOM og ROM yfirfarið||x||x||GVO+RU|
|2015||Ferlagreining til umbóta á afgreiðsluferli umsókna um dvalarleyfi hjá Útlendingastofnun||x||x||GVO|
|2015||Mapping aquaculture production systems: A systematic literature review||x||GVO+RU|
|2015||Ferskvatnshumareldi á Íslandi. Efnahagsleg greining||x||x||GVO|
Here is a list of earlier work, more detailed description and their researchers.
Fiskeldi er vaxandi atvinnugrein á Íslandi. Mikilvægustu tegundir í fiskeldi á Íslandi eru lax, bleikja, regnbogasilungur og þorskur. Hlývatnstegundir eins og tilapía og senegal flúra hafa þó verið í tilraunaeldi á Íslandi. Markmið þessarar ritgerðar er að kanna efnahagslegar forsendur fyrir því að fara í frekari rannsóknir á eldi á hlývatnstegundinni ferskvatnshumri í endurnýtingarkerfi á Íslandi. Enn fremur voru lykilþættir verkefnisins greindir. Fræðilegar heimildir og samstarf við íslensk fyrirtæki voru notuð til að finna forsendur sem voru svo nýttar við útreikninga í þessu verkefni. Niðurstöður verkefnisins eru að eldi með endurnýtingarkerfi á ferskvatnshumarstegundinni Astacus astacus er með neikvætt núvirt heildarvirði upp á rúmlega 270 m.kr. m.v. 15,00% ávöxtunarkröfu og
árlega framleiðslu um tæp 22 tonn. Verkefnið er með 6,55% innri vexti þrátt fyrir háa framlegð af hverju framleiddu kílógrammi. Þó er líka hægt að horfa á aðra þætti en einungis arðsemi. Vistvænt eldi og fjölbreytileiki í eldistegundum á Íslandi eru þættir sem mætti hafa í huga umfram arðsemi. Fjölbreytileiki er nauðsynlegur til að koma í veg fyrir algjöra stöðnun í fiskeldi á Íslandi ef áföll verða vegna verðhruns eða sjúkdóma eins og fortíð fiskeldis á Íslandi hefur sannað.
The purpose of this study was to map the production functions of aquaculture production systems, and the methods applied to carry out the functions. Over one hundred articles were systematically analyzed in order to identify the production functions of different systems. The articles were analyzed in terms of the production functions, and the types and intensities of the aquaculture systems covered. The production functions were grouped in these three categories of functions depending on their nature and their role in the map: Input functions, treatment functions and output functions. The map created from this work provides a general overview of the production functions that are applied in aquaculture systems. Furthermore, variations of the map were created to show different applications of the production functions in aquaculture systems of different intensity levels. The analysis of systems of different intensity levels resulted in new definitions of system intensity in terms of the production functions. The map and the variations of the map are tools that can be used by professionals to analyze aquaculture systems in terms of the production functions, and compare them to the maps to look for improvements in the production area. This work gives rise to further studies in this area as it reveals possible gaps in the literature in terms of some of the production functions. Future studies can build on and update the results of this work as new technologies emerge, and more variations of the map can be created in terms of other factors of interest, such as the types of systems or the animals cultured.
Klemenz Hrafn Kristjánsson
Ferlagreining til umbóta á afgreiðsluferli umsókna um dvalarleyfi hjá Útlendingastofnun (in Icelandic)
Á hverju ári afgreiðir Útlendingastofnun um 3.000 umsóknir um dvalarleyfi. Markmið rannsóknar var að rýna ferli við afgreiðslu umsókna, greina núverandi stöðu, hvaða umbætur mætti gera á ferlinu og hvaða áhrifa mætti vænta af þeim umbótum. Framkvæmd var greining á gögnum yfir árstímabil úr upplýsingakerfi Útlendingastofnunar, Erlendi, sem leiddi í ljós að meðalafgreiðslutími var 47 dagar, þar af virðisaukandi tími um 1,5%. Settar voru fram 8 mismunandi umbætur sem saman stuðluðu að styttingu og minni breytileika afgreiðslutíma. Áætlað var að hægt væri að stytta meðalafgreiðslutímann niður í 22 daga um leið og tilfellum sem fara framyfir 90 daga afgreiðslufrestinn sem Útlendingastofnun gefur sér fækkar talsvert. Vænt áhrif þeirrar styttingar er aukin ánægja umsækjanda og starfsmanna, auk þess sem talið var að auka mætti tekjur ríkissjóðs um það sem samsvarar tekjuskatt á 27 ársstörf á hverju ári, þar sem stytting skilar sér í að umsækjendur komast fyrr inn á vinnumarkaðinn.
Áshildur Jóna Böðvarsdóttir
Kostnaðarstjórnun í Silíkondeild Össurar – ABC-greining, kostnaðarskipting og BOM og ROM yfirfarið (in Icelandic)
The object of this thesis was to examine inventory management and apportioning of costs in Össur’s Silicon Department, as well as looking for opportunities for improvement. ABC analysis were made with different parameters: cost, value and margin, and compared to the current ABC analysis for the Silicon Department. New apportioning of costs were made, assigning direct and indirect production costs to products, these were then compared to Össur’s current apportioning of costs. Finally BOM (bill of material) and ROM (route of material) were reviewed for two products.
ABC analysis results showed that Össur’s ABC classification is not in accordance with its definition as well as being incorrect when compared to current state. Results of assigning indirect costs to departments showed that about half of the Silicon Department’s indirect costs belong to other departments; to the amount of hundreds of millions in ISK. Results of a new apportioning of costs showed that although the Silicon Department’s total cost decreased, the cost of about a third of their products increased. Therefore it is clear that the new apportioning of costs had significant impact on cost of goods. Nonetheless, it had little effect on the ABC analysis based on cost. Review of BOM and ROM found that precise definition was not available. All of Össur’s cost information derives from BOM and ROM, which are used as grounds for decision-making. Consequently it is imperative that they are detailed enough not to lead to bad decisions.
Helga Guðrún Óskarsdóttir
A Mapping of an Agile Software Development Method to the Personal Productivity of the Knowledge Worker. A Systematic Review of Self-Help Books
This work explores the problem of how to increase knowledge worker productivity by performing a systematic literature review of personal productivity self-help books. The assumption was that personal productivity self-help books are based on the same underlying concepts and that these concepts can give insight into the personal productivity of the knowledge worker. The intent was to identify these concepts, compare them to the state-of-the-art on knowledge worker productivity and the software development method Scrum. The working hypothesis was that Scrum increases productivity by creating the environment and providing the tools needed by the knowledge worker to perform to his highest potential and produce value for the organization. The research design followed the guidelines for systematic reviews in software engineering by Kitchenham (2004). The research scope was based on a definition of personal productivity. Forty personal productivity self-help guides were chosen in a fair and systematic way from Amazon.com using a software program and rigid selection criteria. These books were read and analyzed by one researcher. Twenty-six concepts of personal productivity were identified and defined from the forty personal productivity self-help books. The concepts were compared to the definition of knowledge workers, personal productivity and ten knowledge worker productivity factors and found to be relevant to the personal productivity of the knowledge worker. The concepts were also mapped to the software development method, Scrum.
Margrét Ósk Óskarsdóttir
A General Description and Comparison of Horizontal Axis Wind Turbines and Vertical Axis Wind Turbines
This master thesis is a general description and comparison of horizontal axis wind turbines and vertical axis wind turbines. Main components of horizontal axis wind turbine are covered. Vertical axis wind turbines are presented along with various sub-types. The design procedure is covered with emphasis on the layout of the wind turbine, both horizontal and vertical. Next, a description of different wind farm layouts is covered along with studies on the subject. Finally, a short description on a decision making process is shown in how to choose the right wind turbine or turbines for certain cases. A simple diagram leads the customer through the decision making process, answering what wind turbine or turbines are best suitable according to the customer’s needs. The diagram is also a foundation for designing a software program, which could link to desirable wind turbines available from an existing database.
The aim of this research is to study and compare different design methods, choose a method for redesign and use a case study to evaluate the outcome. This thesis will help Marel on its journey to implement better design processes.
A literature review of five design methods was conducted and their tools and techniques explained. These methods are Six Sigma, Stage-Gate, Lean (Lean Product Development), Design Structure Matrix and Model Based Design.
This case study is a cross frame from StreamLine weldment, manufactured by Marel. The LPD and Model Based Design were evaluated to be the best-suited methods for this case study. The redesign was carried out by finding, identifying and closing Knowledge Gaps. In Model Based Design method a Finite Element Model and a Cost model were built to verify the results of the redesign.
The findings from this study show that appropriate design method can improve the quality of design work. The redesign is better qualified for cleaning and has less manufacturing cost.
Breytt áltökuferli í kerskálum Norðuráls á Grundartanga (in Icelandic)
The objective of this thesis was to give sensible proposals on how to change the tapping process in Norðurál´s aluminum smelter at Grundartangi with regard to minimizing the staff required. Three different propositions were defined and then created as simulation models in the simulation software Simul8. Banks´, Carsons´, Nelson´s and Nicol´s steps of sound simulation were followed throughout the making of the models. The models show in a reasonably accurate way what happens when something is changed in the process, for example when the number of staff is increased or decreased or new equipment is added. The models can also save executives valuable time in decision making since trying out different solutions can be time consuming when the staff involved is around 2000
Integrating Sustainability into the Engineering Design process using the Global Reporting Initiative Indicators
On a strategic and operational level there is significant evidence of the integration of sustainability into the business environment, however studies have shown that the majority of major organisations do not include the risk and/or opportunities of sustainability in the design and detailed engineering phase of their capital projects.
Much of the discussion on sustainability in capital project management and engineering has centred on the feasibility or pre-project phases; however decisions taken during the design phase have a significant influence on the final outcome of the project, and tools or working methods must be provided to engineers and project managers to facilitate decisions during this phase of a project.
In this thesis a new working method for decision making during the engineering design phase will be developed based on the internationally recognized Global Reporting Index sustainability indicators and Project Management Body of Knowledge (PMBOK) process. The goal of the work is to determine which indicators of sustainability are most relevant to the design phase of an engineering project and then to integrate those indicators into the PMBOK project management process.
A test case is used to determine the suitability and usefulness of the proposed method, and the conclusion is that the method proposed can be used by engineers to analyse their design and inform decision makers with a focus on sustainability of the project.
Birgir Freyr Ragnarson
Wind energy has just recently been considered as a serious alternative for energy harnessing in Iceland. This thesis is dedicated to researching the potential cost of wind energy production in Búrfell (Iceland). A LCOE approach was applied when estimating the potential cost, the wind energy potential at the site was assessed using a new wind speed simulation approach based on historical wind data. Key results were that the LCOE for wind energy at Búrfel was estimated 0.0756-0.0857 USD/kWh (assuming 10% WACC), which classies Búrfell among the lowest LCOE sites for wind energy in Europe. As a conclusion the decision stands whether the estimated LCOE is low enough for wind energy harnessing to be protable in Iceland. This conclusion is considered to be an introduction to a further research.
Michael E. Sugar
Renewable energy resources are contributing evermore to the generation mix worldwide, however, expanding grids in size and complexity have given rise to unforeseen complications such as frequency oscillations, voltage sags and spikes, and power outages. In 2013, nearly 100% of electricity generation in Iceland was from hydropower and geothermal sources; there is also high potential for wind and tidal energy, both options are being explored and would benefit from additional technologies to manage fluctuations and store energy surplus. Landsnet hf. is the sole transmission system operator (TSO) responsible for energy balance in Iceland. On the consumer side, load variations represent difficulties for utilities to meet ever-changing demand. Research indicates high-capacity electricity energy storage (EES) has the potential to be economically beneficial as well as carbon neutral, all while improving power and voltage quality, peak- shaving, reducing the number of grid failures and smoothing out natural fluctuations in renewable energy (RE) sources. Two complex resource deployment scenarios are modeled using GridCommandTM Distribution: (1) large-scale EES at the transmission level, and (2) small-scale community energy storage at the residential level. These scenarios are demonstrated to behave harmoniously in the Icelandic power system. Results reveal 10 MWh capacity battery EES at a density of 60% in the transmission model provides optimal performance conditions. The residential model requires a lower EES density of 30% using 45 kWh capacity batteries. Optimal conditions are defined by EES performance metrics, and signify improvements in power quality, energy balance, and peak-shaving when electricity demand is at its highest. EES technologies are presented and tested at different locations across the Icelandic grid to predict which solutions are best for the future development of the electricity system. The role of EES integration into Iceland’s electricity grid has been explored with primary focus on improving energy efficiency, grid optimization, transmission and distribution control, and maintaining infrastructure.
Improvement Opportunities in Aluminium, Production Optimization of Cell Batching and Improvements in Production Planning
The topic of this thesis is an analysis of Alcoa’s Fjarðaál, from tapping to casting, emphasizing on effects of production planning. An optimization model for cell batching was developed and its results compared to the current algorithm used. The model was also used to estimate impact of improved production planning in the cast house. The model developed is a binary integer model, a so called Set Partitioning Problem. It was solved by use of the Gurobi solver.
Currently Alcoa Fjarðaál is using an optimization algorithm developed by Alcoa and is a part of their ERP system and one of this thesis’ objective is to estimate the quality of its solutions. A comparison of tapping plans from the two models showed that the current model delivers much better results than a naive algorithm that batches 3 adjective cells together but does not deliver an optimal solution.
Impact of errors in material requirement planning in cast house on the tapping plan suggested by the model was estimated by generating tapping plans based on the actual usage and assumptions used by Alcoa´s employees. It showed that errors in material requirement planning have a significant impact on the tapping plan generated.
Potential gain of improving allocation of metal to casting lines in the furnace area of the cast house was estimated. It revealed that improved planning of the tapping process can have a significant impact.
Áslaug Dagbjört Benonýsdóttir
Umhverfisstjórnunarkerfi (in Icelandic)
The main task of the study was threefold and involves the fallowing theses:
a) What are the reasons that encourage companies to implement environmental management system?
b) What obstacles might companies face during the implement stage.
c) What do companies benefit from implementing and using environmental management system?
Theoretical value of the study is based mainly on the methodology to examine studies that have been conducted on similar subjects. Author collected data from the conclusions of foreign studies and compared that with the results of interviews the author conducted with three Icelandic companies as well as email correspondence with another company. Sum total being four companies.
In order to approach the subject matter and answer the theses the author lined up with author used case research in operations management. The design and implementation of interviews was based on semi-structured interviews. The conclusion is, based on the study that the author made with the Icelandic companies, that reasons for the decision of implementing environmental management system is due to internal factors. That goes against findings of previous studies. When looking at the obstacles facing the implemental stage of the environmental management system, the author found the main obstacle to be within the operations (of the companies) in both cases. That is to say when looking at previous findings as well as authors own study. Viewing the benefits of using the environmental management systems within the companies, author found the influence to be within the operations, and that consists with the findings of previous studies.
Gunnar Freyr Þórisson
The aim of the research project was to evaluate MS Iceland Dairies position to implement the ISO 22000 standard. The focus of the project was twofold:
- Which parts of the current quality system of MS Iceland Dairies have to be amended to comply with the requirement of ISO 22000?
- What potential risks could MS Iceland Dairies face by implementing the ISO 22000?
During project evaluation, it became apparent that a third additional research question needed to be addressed, namely regarding the attitude of the company towards food safety systems in general.
To respond to the aforementioned research questions the content of the ISO 22000 and the Quality Hand Book of MS Iceland Dairies were used for reference. The documentation was complemented by interviewing the quality and environmental officer of the company and by studying various academic articles in the field.
The main finding of the research project is that the present quality system of MS Iceland Dairies does address many of the requirements of the ISO 22000, but not in a well-organized manner. The company needs to adapt its present quality system to the requirements of the ISO Standard. Adaptation to the standard should be carried out on the basis of each chapter of the Standard and this is explained in some details in the summary of the report. The report identifies measures that the company should undertake to facilitate the implementation and the adaptation to the ISO Standard. Risk to the operation of the company associated with the introduction of ISO 22000 is in good harmony with risks identified in the implementation of ISO Standards in general.
Eymundur Sveinn Leifsson
The main objective of this study is to investigate whether any of three selected MRP methods could reduce inventory and inventory related costs at NUHI’s central storeroom. NUHI recently adopted the JIT/Kanban so an evaluation of their new system was made by comparing NUHI expenses with the consumer price index (CPI). However, the focus of this research was on NUHI’s central storeroom, which services the JIT/Kanban system but itself uses a s,S inventory policy. Three Material Requirement Planning (MRP) lot-sizing techniques, The Economic Order Quantity (EOQ), The Silver-Meal heuristic (SM) and The Least Unit Cost heuristic (LUC) were compared to the central storerooms current system of choice. NUHI provided daily demand data for 60 items which were chosen with an ABC analysis. The data was analyzed and used as an input for an inventory simulator created to compare the four inventory control methods. Under simulation there the current s,S policy performed significantly best by returning the least total cost. The simulation also shows that the amount of money tied up in inventory can be reduced significantly by improving visibility and adjusting the service level. The research concludes that NUHI must define the goals and parameters of its supply chain in order to properly evaluate its supply chain system. Furthermore, a way to improve visibility and reduce inventory at the central storeroom is suggested. Also, all methods are discussed theoretically and a literature review presented with theoretical and case studies relevant to this research.
This thesis presents the results of a study, which aimed to understand and evaluate the locomotion of Atlantic salmon and Arctic char under three different swimming conditions, slow, medium and fast. A Fourier-series based numerical model that describes the swimming mode for each condition is presented and the control variables for a swimming fish are evaluated.
The numerical model is based on a video analysis of a swimming fish. A video recording system was used to record the movement of two fish species under different swimming conditions in a respirometer tunnel. The movements of eleven points on the fishes were tracked from the video recordings and logged. The movements of each point were then analyzed in Matlab and a model constructed to describe the motion. Fourier series was used to determine the fish motion and mathematically important variables such as frequency, amplitude, acceleration, phase difference and the most important factor, flexibility. The change in swimming behavior of fish has not been fully understood, neither how it changes with increased swimming velocity. The change in flexibility or stiffness is addressed for sub-Carangi form type of fish and results graphically illustrated.
In a geothermal power plant the working fluid used to produce electricity is often wet steam from geothermal wells, which is composed of corrosive chemicals. In this situation, more frequent maintenance of the equipment is required. By constructing an overview for the maintenance in geothermal power plants and how it can be done with minimum power outages and cost, the geothermal energy can be made more competitive in comparison with other energy resources. The focus of this thesis is to examine the maintenance needed for the steam turbines in the geothermal power plant at Hellisheiði. The local ability of the staff there to repair or construct turbine parts on-site is explored. It is also explored how the maintenance and condition monitoring is carried out today and what can be improved in order to reduce cost. Failure Mode and Effect Analysis (FMEA) is used to analyze the data, which were collected but that can help organizing maintenance and condition monitoring of Hellisheiði power plant in the future. Furthermore, the thesis presents an overview of currently employed maintenance methods at Hellisheiði power plant, the ability of domestic workshops to maintain and repair the steam turbines there and the power plant’s need for repairs. The results show that the need for maintenance of the geothermal steam turbines at Hellisheiði power plant is high and that on-site maintenance and repairs can decrease operation cost.
Svandís Hlín Karlsdóttir
This Master´s thesis analyses the experience from subsea power cable projects in Europe to bring new aspects and gain more information and insights to this project. The main focus is on technology, reliability and environmental impact. This study of the European experience is transferred to Iceland and is evaluated as to which technology is suitable for Icelandic conditions, what to avoid and what to keep in mind, and also to evaluate the reliability of possible subsea power cables from Iceland to mainland Europe, or to Great Britain.
Karl Martin Kjærheim
The purpose of this thesis is driven by the notion of giving designers a tool to be creative with sustainable design practices. After conducting a thorough literature review it was evident that the conceptual design phase holds the most influence on decisions defining the final product, and that no tool currently exists targeting this phase, a sustainable design model was created and the content of a conceptual design tool targeting sustainable intervention proposed. Environmental problems related to the apparel industry, design processes and creativity were explored, in order to provide suitable answers to the inherent problems. A questionnaire was utilized to understand the designer’s perception (visual analogue scale), needs and wanted features (open text) within a future tool targeting their conceptual design process. Further, a sustainable design model was created to be able to fully understand where in the conceptual design process sustainable strategies would be best implemented. Results from the questionnaire showed that most of the designers were positive towards the inclusion of further sustainable practices, but felt the need for more incentives and recognition, more educated help and further guidance from management. The results from the sustainable design model indicated when and where designers should include sustainable practices within their conceptual process, and therefore acted as a blueprint towards the future implementation and success. The results from both the questionnaire and the sustainable design model aided the birth of a proposed solution to the inherent problems that exist within developing a computer-based platform in which collaboration, creativity and sustainable practices may thrive.
Tómas Björn Guðmundsson
This project aims to observe the electricty consumption in Askja, the building for biology and geoscience, at Háskóli Íslands in order to decrease the usage and cost of electrcity. The project is divided into three sections where each part aims to decrease consumption and stabilize it, without affecting the day to day activity in the building. The first part analyzes and maps out the electricity consumption in order to suggest improvements. In the second part a forecast is made for the electricity consumption of the building and a warning system developed to prevent energy peaks before they happen. The third part aims to give real-time graphical feedback on energy consumption in order to raise energy awareness among the students and staff in the building. The conclusion is that with simple actions electricity consumption can be reduced and thus money saved. With more complex actions even more money can be saved.
Reliability is important when operating a geothermal power plant. Maintenance is mainly carried out according to preventive maintenance in order to ensure delivery reliability and durability of expensive assets in the production. Preventive maintenance on the other hand is expensive, and maintenance of geothermal power plants is one of the most costly factors in the operation. In order to reach the available opportunities for optimization in the field, measurements have to be made. Performance indicators can be used to track maintenance performance and manage maintenance activities. They provide managers with the right tools for detecting underperformance in the planning or execution process of maintenance activities. When implemented thoroughly, maintenance performances indicators should as well allow for a means of improving on the shown figures. This Master’s thesis was carried out in cooperation with all the operators of geothermal power plants in Iceland and an assessment was made of the current maintenance performance measurement system. Finally an ideal maintenance performance measurement system is presented and a comparison made between the organizations’ current procedures and the ideal model.
Þórður Ingi Guðmundsson
By law, sewage in Iceland must be utilized if there is a feasible way to do that but it is not done at the moment. Sewage from the greater Reykjavík area flows through two treatment plants and from there to the ocean. In this study, ways to utilize sewage sludge will be investigated and cost and benefits of sewage sludge usage calculated. Number of ways are possible to use sludge but this study focuses on two of them, namely methane production through anaerobic digestion and hydrogen production through gasification. This study will compile data on usable materials in sewage in greater Reykjavík area and how much can be produced from them. From those analysis a model is constructed that predicts sewage flow from an urban area with central heating from weather data. From sewage sludge in greater Reykjavík area it is possible to produce 1.200.000 Nm3 of methane and 3.000.000 Nm3 if grease trap removal sludge and organic waste from greater Reykjavík area is added. Investment cost is approximately 0,8 – 2 billion ISK and repayment is in 12 – 40 years given 6% interest. It is theoretically possible to produce 730 tonnes of hydrogen of sludge through gasification. Sewage water is analyzed through regression analysis into hot water for central heating and regular use, that is showers, washing etc. and cold water and rain water. This is a preliminary study and therefore some uncertainties are present in the calculations.
Reynir Smári Atlason
Energy return on Investment of Geothermal and Hydro power plants and their respective energy payback time
The purpose of this study was to compare the energy efficiency between hydro and geothermal power plants. The plants analysed were Nesjavellir (geothermal), and Fljótsdalsstöð (hydroelectric) power plants. The Energy Return on Investment (EROI), which is the ratio between output and input energy, was calculated for both plants. A recently proposed methodology was used, so the boundaries are consistent to other similar studies and can therefore be compared. Real data was gathered from stakeholders regarding construction, maintenance and operation of the plants. Therefore close to accurate results can be expected from these calculations. Results show that Nesjavellir geothermal plant returned approximately 33 units for every 1 unit that was used for construction, maintenance and operation at the plant over 40 years. Fljótsdalsstöð hydro station however, returned approximately 112 units for the same criteria. Own consumption was shown to be the largest consuming factor at both sites when looking at the whole lifetime of the plants. A scenario was calculated where hot water production was excluded at Nesjavellir, where the EROI dropped to approximately 9:1. These results are very close to the results published in 1975 and 1979 when the EROI for electricity production from a geothermal power plant was last calculated. This scenario underlines the efficiency improvement hot water production has. Energy payback time was calculated, where geothermal was quicker to reach an EROI of 1, but Hydro quicker to pay back the total energy consumed over its lifetime. The EROI is considerably higher for hydroelectric plants compared to geothermal. EROI is particularly low for electric production alone at geothermal power plants and has arguably not improved over 30 years.