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Tekno-økonomisk analyse av potensialet for sesonglagring i norsk fjernvarme
Get PDFDenne masteroppgaven har i en tekno-økonomisk analyse undersøkt potensialitet for sesonglagring av termisk energi i det norske fjernarmesystemet. Metoden i oppgaven er todelt, der det først er brukt litteraturstudie for å sette seg inn i Seasonal thermal energy storage (STES) teknologier som er aktuelle, hvilke kostnader disse har, teknisk ytelse og geologiske forutsetninger og modenhet. Deretter er dataene benyttet i lønnsomhetsberegninger og en følsomhetsanalyse for de samme teknologiene ved å modellere et fjernvarmesystem i en lineær programmeringsmodell (LP-modell) i Python.
Litteraturstudiet viser at det finnes mange ulike STES-teknologier. Denne oppgaven fokuserer på lagringsteknologiene som baserer seg på energiformen følbar varme. Teknologiene undersøkt er BTES (Borehole thermal energy storage), ATES (Aquifer thermal energy storage), CTES (Cavern thermal energy storage), FTES (Fractured thermal energy storage), TTES (Tank thermal energy storage) og PTES (Pit thermal energy storage). Med grunnlag i eksiterende anlegg har BTES, ATES og PTES en betydelig lavere investeringskostnad enn TTES og CTES. Litteraturstudiet viser at BTES, ATES og FTES allerede er i bruk i Norge, mens TTES, PTES og CTES er etablert i våre naboland og i Europa. De geologiske forutsetningene i Norge anses som godt egnet for BTES, FTES og CTES, gitt landets krystallinske berggrunn. For ATES er tilgjengeligheten av akviferer en begrensende faktor, mens PTES og TTES krever store arealer over bakken. CTES kan enten etableres i eksisterende gruver/tanker eller kunstig utgraves, der førstnevnte alternativ anses som mer økonomisk. Med unntak av FTES, som til nå kun har et pilotprosjekt, klassifiseres teknologiene som modne i kommersiell fase, med synkende investeringskostnad og økonomisk risiko. Likevel må det her skilles mellom lav temperatur (LT) og høy temperatur (HT) UTES (Undergorund thermal energy system) teknologier, der LT-UTES har høyere modenhet en HT-UTES.
LP-modellen bruker månedlig tidsoppløsning med historiske strømpriser, produksjonskostnader til produksjonsteknologier i et fjernvarmesystem og produksjonsdata fra fjernvarmesystemet Statkraft Varme i Trondheim. Strømprisene brukt er fra årene 2020, 2022 og 2024 for alle fem elspotområdene i Norge, og er henholdsvis lavprisscenario, høyprisscenario og middelspriscenario. Produksjonsteknologiene brukt i modellen er avfallsforbrenning, elektrokjel, biokjel (flis), oljekjel (fyringsolje), gasskjel (LPG), og overskuddsvarme fra avfallsforbrenning som opprinnelig blir bortkjølt. Kapasiteter, produksjonsnivå og etterspørsel av termisk energi er hentet fra dataene til det eksisterende fjernvarmesystemet til Statkraft Varme i Trondheim. Modellen kjøres flere ganger for hver STES-teknologi, der den først beregner produksjonskostnadene til fjernvarmesystemet uten mulighet til lagring i et STES, og så med STES. Differansen beregnes som unngåtte produksjonskostnader, og er inntektene til STES, dersom LP-modellen anser investering i et STES som lønnsomt.
Resultatene fra LP-modellen indikerer at BTES, ATES, PTES og CTES i eksisterende gruver/tanker kan oppnå positive netto nåverdier og lav tilbakebetalingstid under både lave, middels og høye strømprisscenarioer. Disse teknologiene viste seg også å være robuste mot alle justeringer i følsomhetsanalysen, der flere verdier i kostnadsstrukturen og parametere ble justert opp og ned. For TTES og CTES med kunstig utgraving kreves det derimot enten svært høye strømpriser eller betydelige kostnadsreduksjoner for å bli lønnsomme. Modellen valgte nesten utelukkende overskuddsvarme fra avfallsforbrenningen for å lade STES-systemene, noe som viser at der er potensial for å utnytte denne termiske energien, som i dagens fjernvarmesystem går til spille.
Ut ifra en helhetlig vurdering, har UTES-teknologiene BTES, ATES og CTES (i eksisterende gruver / tanker) og PTES, det største potensialet som STES-teknologi i det norske fjernarmesystemet. FTES blir en spennende teknologi å følge med på, ettersom den kan redusere antall borehull og investeringskostnader sammenlignet med BTES-teknologien.This master’s thesis conducts a techno-economic analysis to assess the potential of seasonal thermal energy storage (STES) in the Norwegian district heating system. The methodology is divided into two parts: First, a literature review was conducted to identify relevant STES technologies, their associated costs, technical performance, geological conditions, and maturity levels. Subsequently, the collected data was applied in profitability calculations and a sensitivity analysis for the same technologies by modeling a district heating system using a linear programming model (LP model) in Python.
The literature review reveals that several STES technologies are available. This study focuses on storage technologies based on sensible heat. The technologies examined include Borehole Thermal Energy Storage (BTES), Aquifer Thermal Energy Storage (ATES), Cavern Thermal Energy Storage (CTES), Fractured Thermal Energy Storage (FTES), Tank Thermal Energy Storage (TTES), and Pit Thermal Energy Storage (PTES). Based on existing installations, BTES, ATES, and PTES have significantly lower investment costs than TTES and CTES. The literature review shows that BTES, ATES, and FTES are already in use in Norway, whereas TTES, PTES, and CTES have been established in neighboring countries and in Europe. The geological conditions in Norway are considered well-suited for BTES, FTES, and CTES, given the country’s crystalline bedrock. For ATES, the availability of aquifers is a limiting factor, while PTES and TTES require large surface areas. CTES can either be established in existing caverns/tanks or excavated artificially, with the former considered more cost-effective. Except for FTES, which currently only has a pilot project, the technologies maturity is classified as commercially, with declining investment costs and economic risk. Nonetheless, a distinction must be made between low-temperature (LT) and high-temperature (HT) UTES (Underground Thermal Energy Storage) technologies, where LT-UTES is more mature than HT-UTES.
The LP model operates with a monthly time resolution using historical electricity prices, production costs for production technologies in a district heating system, and production data from the existing district heating system Statkraft Varme in Trondheim. The electricity prices used are from 2020, 2022, and 2024 for all five price zones in Norway, representing low, high, and medium price scenarios. The production technologies modeled include waste incineration, electric boilers, bio boilers (wood chips), oil boilers (fuel oil), gas boilers (LPG), and excess heat from waste incineration that would otherwise be lost. Capacities, production levels, and thermal energy demand were based on data from Statkraft Varme in Trondheim. The model was run several times for each STES technology, first calculating the production costs for the district heating system without being able to store heat in a STES, and then with. The difference was calculated as avoided production costs, representing the revenues for STES if the LP model considers the STES investment profitable.
The LP model results indicate that BTES, ATES, PTES, and CTES in existing caves/tanks can achieve positive net present values (NPV) and short payback periods under both low, medium, and high electricity price scenarios. These technologies also demonstrated robustness against all adjustments in the sensitivity analysis, in which several cost structure values and parameters were adjusted up and down. For TTES and CTES with artificial excavation, extremely high electricity prices or substantial cost reductions are required for profitability. The model primarily selected excess heat from waste incineration to charge the STES systems, indicating potential for utilizing thermal energy that is currently lost in the district heating system.
From a comprehensive assessment, the UTES technologies BTES, ATES, and CTES (in existing mines/tanks) and PTES, are considered to have the greatest potential as STES technologies in the Norwegian district heating system. FTES is a promising technology to follow, as it could reduce the number of boreholes and investment costs compared to BTES
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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