<p>U ovom radu je prezentirana metodologija razvoja modela optimizacije<br />podsticaja proizvodnje električne i toplotne energije u<br />kogenerativnim postrojenjima koja koriste drvnu biomasu kao gorivo.<br />Model optimizacije je razvijen koristeći matematičku metodu<br />linearnog programiranja u kome je maksimizirana ukupna ekonomska<br />korist za raspoloživi iznos sredstava za podsticaje. Model<br />optimizacije je primijenjen na kogenerativna postrojenja u drvo-<br />prerađivačkoj industriji u Bosni i Hercegovini i pokazano da se<br />primjenom modela optimizacije, kroz iterativni proces, mogu odrediti<br />optimalne vrijednosti podsticaja za proizvedenu električnu i<br />toplotnu energiju koji rezultuju u maksimalnoj ukupnoj ekonomskoj<br />koristi za društvo u cjelini.</p> / <p>This thesis presents a methodology for the development of a mathematical<br />model for optimization of the level of subsidies for generating electricity and<br />heat in co-generating plants that use woody biomass as fuel. The optimization<br />model is developed using the mathematical method of linear programming to<br />maximize the total economic benefits for a defined amount of available funds<br />for subsidies. This model is applied to co-generating plants in the woodprocessing<br />industry in Bosnia and Herzegovina and shows that the application<br />of this optimization model can, through an iterative process, determine the<br />optimal levels of incentives for electricity and heat that result in the maximum<br />economic benefits for the society as a whole.</p>

Žmonija, žengdama progreso keliu, visą laiką yra priversta spręsti energetines problemas. Iš pradžių vėjas ir vanduo, kietas kuras ir garas. XIX amžiaus pabaigoje, išradus vidaus degimo variklį, vis daugiau reikėjo skysto kuro ir dujų – prasidėjo naftos era, kuri tebesitęsia iki šiol. Jau senokai visame pasaulyje siekiama, kad nors dalis žmonijai reikalingos energijos būtų gaunama panaudojant netradicinius, ekologiškai švarius jos gavybos būdus. Taigi šiame darbe bus pristatoma bendra alternatyvių energijos šaltinių koncepcija, jų istorija. Išskiriami privalumai ir trūkumai bei analizuojama, kodėl alternatyvūs energijos šaltiniai yra patrauklūs, perspektyvūs ir siektini naudoti kiekvienos valstybės energetikos ekonomikoje. Taip pat bus pateikiamos Europos Sąjungos reformos, skatinančios liberalizuoti centralizuotą energijos ūkį ir taip sudaryti tiesiogines galimybes alternatyvios energijos gamintojams bei vartotojams. Atskiru atveju stengiamasi konkrečiai ir tikslingai išanalizuoti ir išnagrinėti Kogeneracijos direktyvą ir jos barjerus, kurie padėtų įgyvendinti šį tikslą. Ne maža darbo dalis yra skirta Europos Sąjungos energetikos rinkos liberalizavimo apžvalgai bei Lietuvos energetikos pokyčiams, kurie skatintų alternatyvios energijos panaudojimą. Taipogi šioje dalyje yra išanalizuota su kokiomis problemomis, pavojais bei iššūkiais susiduria Europos Sąjungos vidinė ir išorinė energetikos politika siekdama energetinio saugumo. / The mankind, in the course of its progress, is forced to solve energy problems all the time. At first, wind and water, solid fuel and vapour. After having invented the internal combustion engine at the end of the 19th century, the demand for liquid fuel and gas started to increase - the era of oil began which lasts up today. The mankind throughout the world has aimed for a long time to extract at leats part of the necessary energy using non-traditional, ecologically clean methods of its extraction. Therefore, this work will present the general concept of alternative energy sources and its history. The advantages and disadvantages are distinguished as well as the question why alternative energy sources are attractive, perspective and should be strived to be applied in energy economy of every state is analysed. Also the reforms of the European Union will be presented that encourage to liberalize the centralized energy economy and thus form the direct possibilities for producers and consumers of alternative energy. In a separate case, we try to analyse accurately and precisely the Cogeneration directive and its barriers that would help to implement this aim. A large part of the work is devoted for the review of the energy market liberalization of the European Union as well as changes in energy in Lithuania that would encourage the usage of alternative energy. This part of the work also analyses the problems, risks and challenges that are encountered by the domestic and foreign... [to full text]

The dissertation investigates typical operation modes of the heat storage tank in the small-scale cogeneration (CHP) plant, analyses formation of thermal stratifi-cation in such storage tank and presents the simulation of the stratification. The main aim of the dissertation is to investigate peculiarities of operation modes of heat storage tank in small-scale CHP plant, develop an algorithm allowing to choose the storage tank volume and present a model allowing determination of thermal stratification in the storage tank at any time of its operation. / Disertacijoje nagrinėjami būdingi šilumos akumuliacinės talpos veikimo režimai, susiformuojantys nedidelės galios kogeneracinėje jėgainėje, tiriamas šiluminės stratifikacijos susidarymas tokioje talpoje ir atliekamas jos modeliavimas. Pagrindinis disertacijos tikslas – ištirti nedidelės galios kogeneracinės jėgainės šilumos akumuliacinės talpos veikimo režimų ypatumus, sudaryti algoritmą, padedantį parinkti tokios talpos tūrį ir pateikti modelį, leidžiantį nustatyti šiluminę stratifikaciją akumuliacinėje talpoje bet kuriuo jos veikimo metu.

Magistro baigiamajame darbe aptariamas Lietuvos ir Europos Sąjungos šalių energetikos sektorius. Apžvelgiamos direktyvos, strategijos, plėtros planai bei teisės aktai skirti energetikos plėtojimui šalyje. Tiriamuoju objektu pasirenkama Trakų Vokės katilinė, kuri aprūpina šiluma kvartalą degindama gamtines dujas vandens šildymo katiluose. Šiame darbe yra nagrinėjamos penkios alternatyvos: kogeneratorius ir dujiniai katilai, kogeneratorius su akumuliacine talpa ir dujiniais katilais, kogeneratorius su akumuliacine talpa ir biokuro katilais, kogeneratorius su akumuliacine talpa ir šilumos siurbliu, medienos dujofikavimo reaktorius su kogeneratoriumi ir vandens šildymo katilais. Alternatyvos yra nagrinėjamos dviem skirtingais scenarijais, kai kogeneratoriaus pagaminta elektra parduodama pagal VIAP tarifus ir pagal „Nord pool spot“ Lietuva biržos kainas. Tiriamasis darbas atliekamas naudojantis „energyPRO“ modeliavimo programa. Atlikus modeliavimą, sistemų veikimas įvertinamas pirminės energijos suvartojimu, ekologiniu ir ekonominiu požiūriais. Atliekama jautrumo analizė keičiant ekonominius rodiklius bei vertinant šilumos gamybą be kogeneracijos. Pagal gautus rezultatus suformuluojamos išvados. Darbą sudaro 10 skyrių. Apimtis – 79 psl. teksto be priedų, 47 iliustracijų, 10 lentelių, 74 bibliografiniai šaltiniai. / In this master thesis, Lithuanian and European Union’s countries energy sector was discussed. An overview was made on EU directives, Lithuanian strategies, development plans and legalizations. Investigation object was Trakų Vokė boiler house with its district heating system. In the boiler house heat produced by combusting natural gas. During the research five alternatives were analysed: cogeneration and heat only boilers, cogeneration with thermal storage and heat only boilers, cogeneration with thermal storage and biomass heat only boilers, cogeneration with thermal storage and high temperature heat pump, biomass gasification reactor with cogeneration and heat only boilers. Alternatives are analysed based on two scenarios, first on when cogeneration is working by fixed electricity tariffs and second when cogeneration is working by liberalized electricity market conditions. Thesis carried out using “energyPRO” modelling software. All modelled systems are assessed by techno-economic and ecological approach. A sensitivity analysis was made by changing economical values and assessing systems without cogeneration. Based on the results conclusion was formed. Thesis includes 10 chapters. Size of work – 79 pages excluding appendixes, 47 pictures, 10 tables, 74 reference sources.

Darbe apžvelgtos užsienio valstybių centralizuoto šilumos tiekimo (CŠT) sistemų darbo režimai ir pagrindiniai parametrai. Išskirtinai atsižvelgta į CŠT sitemas, kuriose yra kogeneracinės jėgainės su šilumos akumuliavimo talpomis. Darbe pateikiami pavyzdžiai, kokios gali būti ir kaip pritaikomos šilumos akumuliavimo talpos. Tokių sistemų pagrindiniai privalumai yra tai, jog naudojantis ŠAT sistema galima subalansuoti CŠT sistemose esančių įrenginių darbo režimus, taip pat esant kogeneracinėms jėgainėms galima pereinant nuo šilumos vartojimo grafiko jų darbą adaptuoti prie elektros vartojimo grafiko. Darbe analizuojamas Mažeikių miesto šilumos tiekimo sistemos darbas esant kogeneracinėms jėgainėms su šilumos akumuliacijos talpomis. Modeliuoti galimi įrenginių darbo režimai dviem prioritetais: pastoviosios galios ir maksimaliosios pikinės elektros energijos gamybos. Gauta, kad efektyvus šilumos akumuliacijos kiekis turėtų būti 200 MWh tai – atitiktų 4 tūkst. m3 talpą dirbant Mažeikių ŠT darbo parametrais. Nustatyta, kad valandinis ŠAT sistemos prijungimo vamzdžių pralaidumas turi būti 17 MW. Ekonominėje dalyje vertinamas ŠAT sistemos pelningumas. ŠAT sistemos pelningumas dirbant pastovios galios režimu yra neigiamas, taigi projektas būtų ekonomiškai nenaudingas, tačiau ŠAT sistemą naudojant pikinės elektros gamybai pelningumas svyruotų nuo -0,5 mln. Lt iki 0,9 mln. Lt, priklausomai nuo to, kaip susiformuos pikinės elektros rinka. / The thesis surveys working regimes and main parameters of centrally supplied heat (CSH) systems of foreign states. The exclusive attention is paid to CHS systems, having combined heat and power plans with heat accumulation tanks. Examples are provided in the thesis of the types of heat accumulation tanks and their application. The main advantages of such systems are that working regimes of devices in the CHS systems may be balanced with the help of HAT system, as well as that their work may be adapted from heat usage schedule to electricity usage schedule, if combined heat and power plants are used. The thesis analyzes the work of Mažeikiai town heat supply system, having combined heat and power plants with heat accumulation tanks. Possible working regimes of devices in two priorities have been modelled: fixed power and maximum peak electric power production. It has been received that the efficient quantity of heat accumulation should be 200 MWh; this would conform to 4 thousand m3 tank under Mažeikiai HS working parameters. It has been determined that the hourly capacity of pipeline of HAT system connection must be 17 MW. Economical part evaluates profitability of HAT system. HAT system’s profitability, using the fixed power for maintenance is negative; the project would be economically unprofitable; however using HAT system for production of peak electric power, profitability would fluctuate from -0.5 million LTL to 0.9 million LTL, depending on formation of peak... [to full text]

<p>Predložen je i testiran model za energetsko vrednovanje kogenerativnih postrojenja pri čemu se proračun koeficijenta gubitka električne snage obavlja pomoću postupka koji je posebno naveden i predložen.<br />Sam model može i treba da predstavlja snažan alat prilikom kreiranja energetske politike, u delu koji se odnosi na kogeneraciju, s obzirom na to da pruža mogućnost jasnog energetskog vrednovanja postrojenja u smislu efikasnosti i uštede primarne energije kao i definisanja koji deo i koliko kogeneracija treba da bude stimulisana, odnosno potencijalno zastupljena u okviru nekog energetskog sistema.<br />Predloženi model je testiran na složenom kogenerativnom postrojenju snage 150 MW.</p> / <p>A model for energy evaluation of a cogeneration plant is proposed<br />and tested with the calculation of electric power loss done by means<br />of a procedure which is particularly specified and proposed.<br />The model itself can and should be used as a powerful tool for the<br />creation of energy policies in the part regarding cogeneration since it<br />gives opportunities for a clear energy evaluation of a plant in terms of<br />efficiency and primary energy saving, as well as for defining which<br />part and to what extent cogeneration should be stimulated, that is,<br />potentially represented within a specified energy system.<br />The proposed model has been tested on a cogeneration plant with<br />the capacity of 150 MW.</p>

Human’s energy demand is growing and there is a necessity to solve questions of sustainable energetics, such as security of energy supply, energy efficiency and environment protection. Possible way of the solution of these problems is new and more efficient technologies and new energy sources. Fuel cells are one of the developing and environmentally clean technologies. This master’s report is dealing with cogeneration technologies and only fuel cells are analyzed thoroughly. Most usable type of fuel cells for decentralized power and heat generation is identified and its operating principles and properties are analyzed. Advantages and disadvantages of solid oxide fuel cells are given. Power of the fuel cell is chosen in the particular case, when energy demand of building complex of the hospital is analyzed. The fuel cell is integrated into the energy supply system with other equipment. There are made several alternatives to estimate the operation of the system technologically and economically. The simple pay back period and the net present value are used to estimate economical benefit of the system, when prices of energetic sources and fuel cells are varied. Finally, academic knowledge and calculation results are summarized and conclusions of the final report are given.

After closure of Ignalina nuclear power plant its capacity is going to be replaced by large-scale Lithuania’s power plants burning imported fossil fuel. This can lead to high energy system dependency from foreign countries, supplying mostly gas, and to the increase of environmental pollution. Meanwhile, some of small Lithuanian district heating companies suffer from high heat prices and consumers debts. Heat prices for consumers in small districts are by approximately 30 % higher, than for consumers in large cities. Needed electricity capacity could be partially replaced and district heating prices could be reduced by introducing small-scale cogeneration. This report is dealing with cogeneration technologies, their advantages and drawbacks. The possibilities and obstacles for implementation of these technologies in Lithuania are examined. The benefits from introduction of these technologies versus condensing power plants are analyzed. These issues have been assessed by simulating combined heat and power production in selected district heating company. There is evaluated the impact of electricity prices on the economy of different scenarios and heat prices. Finally, the conclusions about the feasibility of cogeneration implementation and the sufficiency of support schemes are made.