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Europska unija svoj gospodarski rast i razvoj temelji na principima održivog razvoja, a on je nezamisliv bez obnovljivih izvora energije, koje Europa izdašno podupire financiranjem, promidžbom i dijeljenjem dobre prakse. U ovome se radu analiziraju efekti međunarodnog projekta FIRESPOL kroz koji se promicanjem dobre prakse i razmjenom iskustava između različitih zemalja i regija osnažuju ulaganja u obnovljive izvore energije (OIE), a time daje doprinos zapošljavanju i rastu niskougljičnog gospodarstva članica Europske unije., The European Union bases its economic growth and development on the principles of sustainable development – inconceivable without renewable energy sources – which Europe supports generously by financing, promoting and sharing best practice. This paper analyses the effects of the FIRESPOL international project which, by promoting best practice and exchanging experiences between different countries and regions, strengthens investments in renewable energy sources (RES), contributing to the employment and growth of EU’s low-carbon economy.

U 2007. godini dogodile su se mnoge promjene na području zakonske regulative u hrvatskoj energetici. Uz otvaranje tržišta električne energije za sve pravne osobe, 1. srpnja 2007. godine na snagu je stupio i paket od pet podzakonskih akata kojima se regulira poticanje proizvodnje električne energije iz obnovljivih izvora energije. Hrvatska je kao metodu poticaja odabrala zajamčene tarife (engl. feed-in tariffs), koje su najraširenija i trenutačno najuspješnija metoda u Europskoj uniji. U Hrvatskoj se pojavio golem interes kapitala za projekte obnovljivih izvora energije, posebice za projekte vjetroelektrana. Pritom se postavlja pitanje o stvarnoj isplativosti takvih projekata, te je li poticajna otkupna cijena dovoljno visoka kako bi se projekti vjetroelektrana u Hrvatskoj uopće isplatili. U ovom je radu dana analiza jednog generičkog projekta vjetroelektrane, instalirane snage 25 MW (razlozi odabira snage su opisani kasnije) softverom RETScreen International, razvijenim u Kanadi, a korištenom diljem svijeta. Uz uvodni dio, u kojem je opisana trenutačna situacija na području obnovljivih izvora energije u Hrvatskoj, dan je i kratki pregled novouvedenih podzakonskih akata vezanih za poticanje proizvodnje električne energije iz obnovljivih izvora. U radu je detaljno obrazložen unos svih relevantnih tehničkih, ekonomskih i financijskih parametara, te su prikazani rezultati modeliranja vjetroelektrane s faktorima opterećenja (engl. capacity factor) od 18 %, 20 %, 22 %, 25 %, 27 % i 30 % pomoću softvera RETScreen International. Pritom je detaljno prikazana analiza osjetljivosti i rizika za vjetroelektranu s faktorom opterećenja od 25 %, te dan konačni zaključak analize., In 2007 the Croatian energy legislation underwent a series of changes. Along with the opening of the electricity market to all legal entities, on 1 July 2007 a package of five bylaws on the incentives to electricity generation from renewable energy resources entered into force. The incentive method Croatia has opted for are feed-in tariffs, the widest-spread and currently most successful method in the European Union. In Croatia a massive venture capital interest in renewables is recently manifest, especially wind power projects. This raises a question about the real profitability of such projects and whether or not the incentive puchase price is high enough to make the wind power projects viable. The present work analyses a generic wind power plant project, installed power 25 MW (the reasons why this rating has been chosen are given later on), by using RETScreen International Software, developed in Canada and used throughout the world. The introductory part, which describes the current situation in Croatia regarding renewables, is followed by a brief overview of newly introduced bylaws aimed to provide incentives for electricity generation from renewables. The works explains in detail the input of all relevant technical, economic and financial parameters and shows the results of modelling a wind power plant with capacity factors of 18%, 20%, 22%, 25%, 27% and 30% by using RETScreen International Software. A detailed susceptibility and risk analysis is given for a wind power plant with the capacity factor of 25%, followed by a conclusion.

Unutar ovog rada obrađena je tema implementacije “pametnih” uređaja nužnih za automatizaciju distribucijske mreže. Dat je tehnički opis I princip rada “pametnih” uređaja koji se ugrađuju u elektroenergetske objekte u dubinu distribucijske mreže. Automatizacija distribucijske mreže smanjuje vrijeme trajanja kvarova koje uzrokuju prekidi opskrbe električne energije te umanjuje troškove nastale pojavom kvarova. Zbog sve veće implementacije, izgradnje I puštanja u pogon obnovljivih izvora energije(sunčane I vjetro elektrane) potrebno je poboljšavati, odnosno provoditi veći stupanj automatizacije uvođenjem daljinskog upravljanja u distribucijsku mrežu. U radu je opisan način rada “pametnih” uređaja koje se ugrađuju po dubini distribucijske mreže. Daljinski upravljane rastavne naprave osim osnovne funkcije daljinskog upravljanja omogućuju i mjerenje električnih veličina koje su zanimljive za detaljniju analizu pojava koje su praćene nastankom kvarova na distribucijskoj mreži., Within this paper, the topic of implementation of "smart" devices necessary for the automation of the distribution network is discussed. It is a technical description and principle of operation of "smart" devices that are installed in power facilities in the depth of the distribution network. The automation of the distribution network reduces the duration of failures caused by interruptions in the supply of electricity and reduces the costs caused by the occurrence of failures. Due to the increasing implementation, construction and commissioning of renewable energy sources (solar and wind power plants), it is necessary to improve or implement a greater degree of automation by introducing remote control into the distribution network. The paper describes the operation of "smart“ devices that are installed along the depth of the distribution network. In addition to the basic function of remote control, remotely controlled disconnecting devices also enable the measurement of electrical quantities, which are interesting for a more detailed analysis of phenomena that are accompanied by the occurrence of faults in the distribution network.

U ovom radu u prvom dijelu su opisani planovi i ciljevi Europske unije za smanjenje štetnih emisija CO2 i sprečavanje klimatskih promjena. Prikazano je trenutno stanje proizvodnje električne energije iz obnovljivih izvora u Europskoj uniji i Hrvatskoj. Posebno je iznesen napredak primjene solarne energije u Europskoj uniji dok je za Hrvatsku prikazan njen solarni potencijal. Napravljen je pregled poticanja obnovljivih izvora energije kojim bi se i građani uključili u energetsku tranziciju. Predstavljeni su modeli otkupa električne energije definirani Zakonom o obnovljivim izvorima energije i visokoučinkovitoj kogeneraciji te modeli naplate koji se trenutno primjenjuju. Nadalje, pojašnjen je princip pretvorbe sunčevog zračenja u električnu energiju u fotonaponskoj ćeliji te je prikazana građa solarnog panela. Razmotrene su sve mogućnosti pohrane energije te je definirano koje od njih su primjenjive na kućanstvo i u kojem obliku. Napravljena je analiza korištenja integrirane fotonaponske elektrane uz primjenu baterijskog spremnika energije za kućanstvo prije i nakon optimizacije za različite tarifne modele. Optimizacijom je ustanovljeno da baterija trenutno nije isplativa za promatrani model. Optimalna snaga fotonaponske elektrane iznosi 3,35 kW. Rezultati analize prikazani su dijagramima u kojima se uočavaju proizvodnja električne energije i profiti nakon realiziranog projekta. Pomoću neto sadašnje vrijednosti i unutarnje stope povrata predstavljeni su ekonomski i financijski tokovi novca, te je na osnovu njih dokazana isplativost projekta. Povećanjem cijene električne energije isplativost se povećava dok se povećanjem investicijskih troškova isplativost smanjuje što je prikazano analizom osjetljivosti. This paper describes the plans and goals of the European Union for reducing harmful CO2 emissions and preventing climate change. The current state of electricity production from renewable sources in the European Union and Croatia is presented. In particular, the progress of the application of solar energy in the European Union was shown, while its solar potential was presented for Croatia. An overview of encouraging renewable energy sources was made, which would also involve citizens in the energy transition. The electricity purchase models defined by the Law on Renewable Energy Sources and High-Efficiency Cogeneration and the billing models are presented. Furthermore, the principle of converting solar radiation into electricity in a photovoltaic cell is explained, and the structure of the solar panel is presented. All energy storage options were considered, and it was determined which of them were applicable to the household and in what form. Optimization found that the battery is not currently profitable to observe in the model. A photovoltaic power plant's optimal power is 3,35 kW. The results of the analysis are shown in diagrams in which electricity production and profits are observed after the project is implemented. With the net current value and internal return rate, economic and financial flows of money were presented, and a project's cost-effectiveness was proven on the basis of them. By increasing the price of electricity, the cost-effectiveness increases as the increase in investment costs decreases, which is shown in the analysis of sensitivity.

U radu je provedena analiza pokrivanja energetskih potreba industrijske zone u kojoj su smješteni data centar, hladnjača, tvornica betonskih proizvoda, tvornica kartonskih proizvoda, pivovara i prehrambeno-prerađivačka tvornica. Zbog povećanja cijene energenata razmotreno je korištenje energije iz obnovljivih izvora energije, i to fotonaponske elektrane i iz bioplinskog postrojenja. Razvijen je optimizacijski model i primijenjen u programskom paketu MATLAB za simulaciju pogona mikromreže kojom se energetske potrebe industrijske zone pokrivaju korištenjem, fotonaponskih modula, bioplinskog postrojenja, dizalica topline, sustava za pohranu električne i toplinske energije i razmjene s elektroenergetskim sustavom. Simulacijom su predložene optimalne strategije vođenja pogona mikromreže po pitanju ekonomičnosti pogona i prema udjelu obnovljivih izvora energije za dva ekstremna slučaja. Jedan je za tjedan u kolovoz kada s razmjerno visokom proizvodnjom električne energije iz fotonaponske elektrane kao i visokim ukupnim energetskim potrebama industrijske zone, a drugi slučaj je za zimski tjedan sa značajno najmanjom proizvodnjom električne energije iz fotonaponske elektrane i najmanjom opskrbom industrijske zone. The work analyses the energy needs of the industrial zone in which data centre, cold store, concrete products factory, cardboard products factory, brewery and food processing factory are located. Due to the increase in energy prices, the use of energy from renewable energy sources was considered, namely the photovoltaic power plant and the biogas plant. An optimization model was developed and applied in the MATLAB software package for simulation of microgrid operation that covers the energy needs of the industrial zone using photovoltaic modules, biogas plant, heat pumps, electricity and heat storage systems and exchanges with the electricity system. The simulation proposed optimal strategies for microgrid operation in terms of operational economy and the share of renewable energy sources for two extreme cases. One is for a week in August when, with relatively high production of electricity from the photovoltaic power plant as well as high total energy needs of the industrial zone, the other is for a winter week with significantly the smallest production of electricity from the photovoltaic power plant and the smallest supply of the industrial zone.

Kako bi se ostvarili ciljevi smanjenja emisija CO2 sukladno Pariškom sporazumu, potrebno je razvijati i ulagati u dekarbonizaciju energetskih sustava uvođenjem tehnologija koje će smanjiti ovisnost o fosilnim gorivima. Ovaj rad je fokusiran na dekarbonizaciju država Srednje Europe, a to su: Hrvatska, Austrija, Švicarska, Njemačka, Češka, Slovačka, Poljska, Mađarska i Slovenija. U radu su detaljno opisani BAU scenariji energetskih sustava svih spomenutih država, ali su prikazani i novi dekarbonizirani scenariji sa naglaskom na dekarbonizaciju elektroenergetskog sustava obnovljivim izvorima energije i nuklearnom energijom te također transportnog sustava pomoću električnih vozila i vozila na gorivne ćelije vodika. Simulacije su napravljene pomoću modela EnergyPLAN te su izlazni podaci novih scenarija uspoređeni sa BAU scenarijima država Srednje Europe., In order to achieve the goals of reducing CO2 emissions in accordance with the Paris Agreement, it is necessary to develop and invest in the decarbonization of energy systems by introducing technology that will reduce dependence on fossil fuels. This paper is focused on the decarbonization of Central European countries, namely: Croatia, Austria, Switzerland, Germany, Czech Republic, Slovakia, Poland, Hungary and Slovenia. This paper describes in detail the BAU scenarios of the energy systems of all the mentioned countries, but also presents new decarbonized scenarios with an emphasis on the decarbonization of the power system with renewable energy sources and nuclear energy, as well as the transport system using electric vehicles and hydrogen fuel cell vehicles. The simulations were made using the EnergyPLAN model, and the output data of the new scenarios were compared with the BAU scenarios of the Central European countries.

Prije desetak godina krenula je inicijativa iz Grada Šibenika o osnivanju sveučilišnih studijskih programa u Šibeniku. U radu su prikazane okolnosti i najvažnije aktivnosti, kao i partneri koji su značajno pridonijeli pokretanju sveučilišnog prijediplomskog studija Energetske učinkovitosti i obnovljivih izvora. Nastava na studiju započela je u listopadu 2015. godine, a provode je nastavnici Fakulteta elektrotehnike i računarstva (FER) i Fakulteta strojarstva i brodogradnje (FSB) Sveučilišta u Zagrebu. Studije je do sada završilo pet generacija prvostupnika inženjera. Dio alumna studija nastavili su školovanje na diplomskim i doktorskim studijima, a dio ih se odmah po završetku studija zaposlio na poslovima „zelene“ energetike, uglavnom u području projektiranja ili vođenja sunčanih elektrana i vjetroelektrana, ali i na brojnim drugim inovativnim poslovima, uključujući i velike europske projekte povezane s obnovljivim izvorima energije. U radu će se razmotriti kako su i koliko postignuti ciljevi ovo šibenskog studija, analizirati njegova uspješnost te izgledi za budućnost.

Glavni proizvod anaerobne digestije je bioplin, koji je obnovljivo gorivo, a sporedni proizvod ovog procesa je digestat, koji se koristi kao gnojivo bogato hranjivim tvarima. Dodatni pozitivni učinci anaerobne digestije su razgradnja organskog otpada te smanjenje neugodnih mirisa i koncentracije patogenih mikroorganizama. Bioplin se uglavnom koristi za proizvodnju električne energije i topline, a u nekim slučajevima se pročišćava da bi se dobio biometan koji se koristi u mreži prirodnog plina, kao gorivo za motore s unutarnjim sagorijevanjem ili kao polazna kemikalija za kemijsku industriju. Zbog svega navedenog, razvoj proizvodnje bioplina ima pozitivne društveno-ekonomske i ekološke učinke. Bioplin proizveden u Hrvatskoj većinom se koristi za proizvodnju električne i toplinske energije u kogeneracijskim postrojenjima. Iako su u Hrvatskoj dostupne različite obnovljive sirovine koje bi se mogle iskoristiti za proizvodnju bioplina, njihov je potencijal do sada bio nedovoljno iskorišten. Kao sirovine za proizvodnju bioplina u nas se pretežno koriste gnojovka i nusproizvodi poljoprivrede, klaonica i prehrambene industrije. Racionalnijim korištenjem zemljišta i razvojem prehrambene industrije mogla bi se povećati količina poljoprivrednih ostataka i nusproizvoda koji nastaju preradom hrane. Usmjeravanjem i poticanjem korištenja ovih nusproizvoda za anaerobnu digestiju može se stimulirati brži razvoj proizvodnje bioplina u Hrvatskoj. Pored mogućeg povećanja vlastite proizvodnje električne energije i goriva, radi se o ekološki povoljnoj tehnologiji koja ima pozitivan društveno-ekonomski učinak., The main product of anaerobic digestion is biogas, which is a renewable fuel, and the by-product of this process is digestate, which is used as a nutrient-rich fertilizer. Additional positive effects of anaerobic digestion are the decomposition of organic waste and the reduction of unpleasant odors and the concentration of pathogenic microorganisms. Biogas is mainly used for the production of electricity and heat, and in some cases it is purified to obtain biomethane which is used in the natural gas network, as a fuel for internal combustion engines or as a starting chemical for the chemical industry. Due to all of the above, the development of biogas production has positive socio-economic and ecological effects. Biogas produced in Croatia is mostly used for the production of electricity and thermal energy at cogeneration plants. Although various renewable raw materials are available in Croatia that could be used for biogas production, their potential has been underutilized until now. Manure and by-products of agriculture, slaughterhouses and the food industry are mainly used as raw materials for the production of biogas in our country. More rational use of land and development of the food industry could increase the amount of agricultural residues and by-products resulting from food processing. Directing and encouraging the use of these by-products for biogas production can stimulate a faster development of biogas production in our Croatia. In addition to the possible increase in own production of electricity and fuel, it is an environmentally friendly technology that has a positive socio-economic effect.

Zadatak ovog rada bio je odrediti optimalne parametre energetske obnove vanjske ovojnice za postojeću obiteljsku kuću smještenu na području Sjevernog Jadrana te određivanje optimalnih pogonskih parametara sustava grijanja, hlađenja, ventilacije i pripreme potrošne tople vode. Glavni cilj je bio smanjenje potrošnje energije za grijanje i hlađenje te postizanje gotovo nulte potrošnje energije. Kako bi se to ostvarilo provedene su mjere energetske obnove vanjske ovojnice koje su uključivale postavljanje izolacije s vanjske strane zidova te zamjenu postojećih prozora i vrata. Također, zamijenjen je postojećih sustav grijanja na kotao s loživim uljem s energetski učinkovitijim termotehničkim sustavom uz primjenu obnovljivih izvora energije. Za provedbu simulacija korišten računalnog programa TRNSYS. U prvom dijelu rada provedena je analiza energetske obnove vanjske ovojnice koja je uključivala izračun godišnje potrošnje energije za grijanje i hlađenje za različite debljine izolacije vanjskih zidova te za različite karakteristike ostakljenja. Optimalno stanje određeno je na temelju minimalnih ukupnih troškova koje čine investicijske troškovi i pogonski troškovi za razmatrani period od 20 godina. Kao optimalno stanje izabrana je izolacija vanjskih zidova mineralnom vunom debljine 5 cm kojom je postignuto stanje koje zadovoljava trenutno važeće propise. U drugom dijelu provedena je analiza predviđenog koncepta tehničkog sustava. Predviđen je novi tehničkog sustav koji sadrži mehaničku ventilaciju s povratom topline, dizalicu topline zrak-zrak, solarne toplinske kolektore i fotonaponske module. Provedene su simulacije proizvedene energije za grijanje i hlađenje i utrošene električne energije te su optimalni parametri određeni na temelju izračunatih specifičnih potrošnji primarne energije i investicijskih i pogonskih troškova. Uz energetsku obnovu kuće i primjenu energetski učinkovitog tehničkog sustava uz primjenu obnovljivih izvora energije postignuta je gotovo nula potrošnja energije. Također, iz rezultata je vidljivo da je prilikom primjene energetski učinkovitih sustava dug period povrata investicije., The aim of this work was to determine the optimal parameters of the energy renovation of the building envelope for an existing family house located in the area of the Northern Adriatic and to determine the optimal operating parameters of the heating, cooling, ventilation and hot water preparation system. The main goal was to reduce energy consumption for heating and cooling and achieve nearly zero energy building. In order to achieve this, energy renovation measures were implemented for the building envelope, which included the installation of insulation on exterior walls and the replacement of existing windows and doors. Also, the existing heating system with a fuel oil boiler was replaced with a more energy-efficient thermo-technical system with the use of renewable energy sources. The computer program TRNSYS was used to carry out the simulations. In the first part of the work, an analysis of the energy renovation of the building envelope was carried out, which included the calculation of the annual energy consumption for heating and cooling for different insulation thicknesses of exterior walls and for different glazing characteristics. The optimal solution is determined on the basis of the minimum total costs consisting of investment costs and operating costs for the considered period of 20 years. The insulation of the external walls with 5 cm thick mineral wool was chosen as the optimal measure which achieved a condition that meets the currently valid regulations. In the second part, the analysis of the chosen concept of the thermo-technical system was carried out. A new technical system is planned, which includes mechanical ventilation with heat recovery, an air-to-air heat pump, solar thermal collectors and photovoltaic panels. Simulations of the produced energy for heating and cooling and the electricity consumption were carried out, and the optimal parameters were determined based on the calculated specific consumption of primary energy and investment and operating costs. With the energy renovation of the house and the implementation of an energy-efficient thermo-technical system with the use of renewable energy sources, nearly zero energy consumption was achieved. Also, it is evident from the results that when applying energy-efficient systems, the investment return period is long.

Svijet sve više prepoznaje važnost obnovljivih izvora energije, što je vidljivo po porastu novoinstaliranih kapaciteta iz godine u godinu. Prethodne 2021. godine instalirano je čak 315 GW novih obnovljivih izvora energije, a tu važnost uočava i Republika Hrvatska, koja po udjelu obnovljivih izvora energije u konačnoj potrošnji električne energije premašuje prosjek Europske unije. Ovim radom nastoji se utvrditi isplativost fotonaponskih sustava za napajanje toplinskih crpki, na način da se postojeće grijanje na plin objekta u Slavonskom Brod zamjenilo toplinskom crpkom (zrak-voda) napajanom fotonaponskim sustavom. Postojeći sustav grijanja predstavlja stvarno stanje potrošnje, preračunato po trenutnim tržišnim cijenama, dok je potrošnja toplinske crpke procijenjena na temelju energije potrošene u prvom slučaju. Radom se zaključilo kako je za povrat investicije potrebno 11 godina po trenutnim tržišnim cijenama, kako energenata tako i samih sustava. Utvrđeno je da je kombinacija fotonaponskih sustava i toplinskih crpki ekonomična i profitabilna investicija. The world is recognizing the importance of renewable energy sources, which is evident from the increase in newly installed capacities from year to year. In the previous year2021, as many as 315 GW of new renewable energy sources were installed, and this importance is also noticed by Republic of Croatia, which exceeds the average of the European Union in terms of the share of renewable energy sources in the final consumption of electricity. This work aims to determine the profitability of photovoltaic systems for powering heat pumps, in such a way that the existing gas heating of an object in the city of Slavonski Brod is replaced by a heat pump (air-water) powered by a photovoltaic system. The existing heating system represents the actual state of consumption, recalculated at current market prices, while the counsumption of the heat pump is estimated bassed on the energy consumed in the first case. The work concluded that it takes 11 years to pay back the investment at current market prices, both for energy sources and for the systems themselves. It was found that the combination of photovoltaic systems and heat pumps is an economical and profitable investment.

Postizanje 100% udjela obnovljivih izvora energije u energetskom sustavu zahtjeva dodatne napore u planiranju kako bi se postigao samodostatan i održiv energetski sustav. To se posebno odražava na manje energetske sustave čija je raznolikost sudionika ponude i potražnje za energijom manja, što stvara manjak fleksibilnosti u sustavu i otežava prelazak na obnovljive izvore energije. Potrebno je provesti napredno energetsko planiranje koje će ići u cilju postizanja pametnog energetskog sustava, čime će se omogućiti integracija visokog udjela promjenjive i nestalne proizvodnje energije iz obnovljivih izvora energije. U ovome radu izradio se algoritam na 10-minutnoj bazi unosa podataka po uzoru na satni model EnergyPLAN. Cilj ovog rada je usporedba satnog modela za energetskog planiranje s novim modelom koji se bazira na 10-minutnom unosu podataka. Za izradu proračuna odabran je manji energetski sustav šireg gradskog područja i definirane su se granice sustava. Izradio se model energetskog plana za razvoj pametnog energetskog sustava do 2050. godine. Planom je određena integracija transportnog i toplinskog sektora i njihov prelazak na električnu energiju uvođenjem električnih vozila i dizalica topline. Planirano je povećanje skladišnih kapaciteta energije te povezanost energetskog sustava kroz otvoreno tržište električnom energijom, koje će omogućiti tržišno vrednovanje izvora fleksibilnosti. Povezivanje svih sudionika energetskog sustava osigurat će korištenje informacijsko komunikacijskih tehnologija, što će im omogućiti aktivno i ekonomično sudjelovanje u sustavu i doprinijeti ostvarivanju bolje fleksibilnosti unutar sustava. Novi algoritam nadogradio se razvijanjem modela u programu Calliope u kojem se izradio model za energetski plan do 2050. godine. Rezultati analiza u novom modelu pokazali su da regulacija iznimno brzog punjenja i pražnjenja EV, uvođenjem modela ''vozila na mreži'', pruža veću fleksibilnost energetskom sustavu i potiče integraciju obnovljivih izvora energije. Proračun modela baziran na 10-minutnom vremenskom koraku u programu Calliope rezultirao je smanjenjem prekograničnih kapaciteta i povećanjem izvora fleksibilnosti, te većoj stabilnosti sustava u odnosu na satni model. Samodostatnost sustava ostvarila se integracijom toplinskog i transportnog sektora, uz dodatne skladišne kapacitete i povezanost s tržištem električne energije. Novi model baziran na kratkoročnom vremenskom koraku unosa podataka pruža detaljniju sliku rada elektroenergetskog sustava. Time se stvara više mogućnosti za različite izvore fleksibilnosti, integraciju više sektora, razvoja tržišta i sigurniji prelazak na obnovljive izvore energije. Uvođenje modela ''vozila-na-mrežu'' uz regulaciju iznimno brzog punjenja i pražnjenja električnih vozila na 10-minutnoj bazi rezultira značajno većom mogućnošću integracije obnovljivih izvora energije i pruža veću fleksibilnost elektroenergetskom sustavu. Increase in greenhouse gas emissions is becoming a global concern and many countries are taking effort in dealing with the emission reduction. The first thing to do on that path is the introduction of laws and directives which will lead to goal achievement. The Paris agreement is one of them. Its goal is to limit global warming to well below 2°C, preferably to 1,5°C, compared to pre-industrial levels. It means the reduction of fossil fuel use which causes the emission increase and therefore increase in global temperature. Europe is aiming to reduce the use of fossil fuels by 55% until 2030, as it is prescribed by directives REPowerEU and Fit for 55. The goal can be achieved by replacing the fossil fuels with the renewable energy source (RES) in different sectors. Energy production, transport and thermal sectors are responsible for most of the air pollution. Their transition to electricity and mutual integration could enhance emission reduction. Replacing fossil fuels in energy production with RES could cause instability and uncertainty of energy supply due to intermitted RES, such as wind and solar power. Although, the combination of wind and solar power in electricity production has shown benefits over the stand-alone production systems, it still requires additional efforts in order to achieve stability and security of electricity supply, especially in the systems with a high share of RES in electricity production. Transport and thermal sector have a potential to utilize a high amount of electricity produced by RES if they convert to electricity. In transport sector, it can be done by replacing conventional vehicles with electric (EV) ones. Heat pumps are given as the best solution for thermal sector in order to replace heating and cooling systems based on fossil fuels. Electrical power systems with a high share of RES, even by 100% share, can be achieved but they require additional flexibility in the system in order to enhance stabile and sustainable system. Flexibility needs are derived from intermitted RES electricity production, especially wind and solar power, as well as uncertain electricity demand and unexpected events. On the other hand, there are different sources of flexibility that can be integrated into the system in order to enhance utilization of high share of RES and provide stability to the system. The flexible resource exists in different parts of the power system: in the portfolio of dispatchable power plants; in the ability of the demand side to respond or to be managed; in storage facilities; in interconnections to adjacent power systems to allow trade; and in integration of different sectors. Wind and solar power plants, together with hydropower plants, can be defined as flexible resources as well, since they belong to dispatchable power plants, with the ability to ramp output up and down on demand. Smaller electrical power systems, such as city, region and municipality, have higher needs for flexibility due to their lower number and possibly lower diversity of electric power plants as well as flexible resources. This thesis analyses such a smaller electrical power system of a wider urban area. Dubrovnik wider urban area is selected and energy plan is done until the year 2050. in order to achieve 100% renewable and self-sufficient energy system. Hypothesis and research description The aim of the thesis is the comparison between the hourly energy plan model and a new model based on 10-minute time step. A new model is build according to the EnergyPLAN model tool based on hourly data input and used for energy planning. New model is developed for 10-minute and hourly data input base. It is compared with the EnergyPLAN model tool in order to demonstrate the validity of a new model. New algorithm is upgraded using the Calliope computer program in order to achieve self-sufficient 100% renewable energy system of the selected wider urban area using smart energy system approach. The boundaries of the Dubrovnik wider urban area are defined. They considered urban city and its surrounding which is spatially, demographically, functionally and traffic-wise closely connected to the city. The selected area covers the area from Slano in the northwest to Pločice in the southeast. The aim is to develop the energy plan model of 100% renewable energy system of the selected area until 2050 with 100% share of RES electricity production and transition of thermal and transport sector to electricity. All of the personal conventional vehicles are considered to be replaced by the electric ones and all of the fossil fuels used in thermal sector will be replace with seawater heat pumps (SWHP) until 2050. Year 2014 is selected as a base scenario. The first step was to collect the data on electricity demand, electricity production, thermal demand and transport, as well as the potential on renewable electricity production capacities, storage capacities and capacities of interconnection lines to the adjacent energy systems of the selected area based on 2014. Collected data are arranged in hourly and 10-minute time step. Collected data on electricity demand, outside temperature, solar radiation and wind speed are selected to analyse linear correlation and regression in-between the data based on a short-term scale of 10 minutes. The analyses are done in STATISTICA program tool for the data selected for 2012, 2013 and 2014 for four selected scenarios. First group of data considered the analyses of the relationship in between three consecutive years for each of the selected data based on a 10-minute time scale. Other three groups of data took into account analyses of the relationship in between the data for all selected years based on a mean monthly values and 10-minute time step. These analyses present a novelty according to previous literature and give an insight in a relationship between the selected data based on a short-term scale, which are used for further calculations in a new model. Energy plan model of the Dubrovnik wider urban area was done until 2050 for all system participants located within the boundaries of the selected area. Electricity demand data are provided by Elektrojug d.o.o. for substation Komolac and projections are done until 2050. Electricity production consists of the production from hydropower plant (HPP) Dubrovnik and the projected production capacities of wind (WPP) and solar power plants (SPP). Data on transport sector are collected for 2014 and projections are done until 2050 with the assumption that all of the personal conventional vehicles will be replaced with electric ones. Characteristics of the EV batteries (BES) are defined and EV electricity demand until 2050 is gained based on the traffic data. Data on thermal demand are collected and projected until 2050, with the assumption that all of the fossil fuel based heating and cooling system will be replaced with SWHP systems. Energy storage facilities are also considered in the system in order to provide additional flexibility. These are additional thermal energy storages (TES) for heating and cooling purposes, battery second use (B2U) and hydrogen energy storage with electrolyser and fuel cell. B2U model is used for BEV when they end their life in EV and lose 20% of their initial capacity. Hydrogen is used to store electricity by converting it to hydrogen gas using electrolyser, storing hydrogen in a tank and converting it again to electricity using fuel cell. The ability of SWHP system to utilize high share of RES in electricity production is analysed for one part of the selected area, the old city of Dubrovnik. District heating and cooling SWHP system is analysed for three scenarios and three cases. First scenario took into account SWHP as a stand-alone system and the other two scenarios took into a consideration battery energy storage (BES) and TES. First scenario is done on the hourly and 10-minute data calculation base, while the other two are done on the hourly basis. First two cases considered WPP and SPP as stand-alone systems while the third case considered combination of wind and solar resources in electricity production. BES and TES are compared according to their required capacity, volume and costs. Transport sector is in more detail analysed developing a new model. New model is built on hourly and 10-minute data base input according to EnergyPLAN model tool. Analyses done using new model took into account electricity production from RES, electricity demand and EV electricity demand of the selected area and projections until 2050. Two scenarios are observed, for 2030 and 2050, doing calculation on hourly and 10-minute time step. Comparison is done according to two different time step calculations and regulation of EV charging and discharging in the system. Unregulated system considered unregulated EV charging which is based on consumer needs and habits due to their driving needs. Regulated system took into account the implementation of ‘vehicle-to-grid’ (V2G) model and a regulation of EV charging and discharging according to the production from RES. V2G vehicles are charged when there is excess in electricity production and discharged in the time of a lack of electricity production in the system in order to reduce import and export capacities. All of the EV are considered as one integrated battery. It is assumed that all of V2G vehicles are available for charging and discharging in every time step, if they are not driving or charging in order to meet the user's driving needs. V2G are charged and discharged if there is enough battery capacity available in each time step. Hourly time step calculations took into account EV standard charging and discharging that requires 5 hours to recharge the BEV up to 100% SOC. 10-minute time step calculations took into account EV extremely fast charging and discharging that requires 10 minutes to recharge the BEV up to 100% SOC. Four cases are done for two scenarios and comparison is done according to unregulated and regulated system on hourly and 10-minute time base. Case 1 took into account production from WPP and SPP, electricity demand and EV electricity demand with the assumption that all of the EV are available for charging and discharging in each time step. In case 2, defined system in case 1 is upgraded with HPP Dubrovnik. Case 3 analysed minimal BEV connection capacity required in order to meet the results gained in case 1. Case 4 analysed cost and saving of EV consumers after the implementation of V2G model and the replacement of present two-tariff model (P2T) in electricity prices with variable two-tariff model (V2T). Results of a new model are compared to the results gained in EnergyPLAN according to the scenario 1 and case 1. New model is upgraded in Calliope energy plan model tool in hourly and 10-minute time base in order to achieve self-sufficient and 100% renewable smart energy system of a wider urban area until 2050. The upgrade contained the integration and electrification of transport and thermal sector through implementation of EV and SWHP systems, additional ES and the integration through the open electricity market. Transport sector included 100% share of personal EV with regulated model V2G. V2G model is developed in Calliope and the results are compare to the results of a new model gained according to the scenario 2 and case 1. Thermal sector included the implementation of SWHP systems with the additional TES for heating and cooling purposes. Other additional storage facilities are also considered within the upgrade, such as B2U and hydrogen energy storage with electrolyser and fuel cell. Input data of each of the selected technologies, with their main characteristics, are defined within the model together with their operation, maintenance and installation costs. Data on technology costs are taken from the Danish Energy Agency. Energy system is considered to be connected to the adjacent system through interconnection lines, which will enable electricity trade according to the variable electricity prices at the open market. Market electricity prices are defined according to CROPEX electricity prices from 2018. Calliope model operation is focused on RES integration and minimization of costs. Of all of the provided and defined technologies of the developed model, optimization analyses done in Calliope will result in optimal solution with minimum cost for the developed system. The aim of Calliope model is to achieve 100% renewable, self-sufficient and stable energy system. Research results and contributions Results of the linear correlation and regression analyses, for the first group of data, showed that the 10-minute values of solar radiation, air temperature and electricity demand can be pronounced with linear regression line. The relationship between the data for three consecutive years is shown to be significant with correlation coefficient of around 0,8. This means that the data distributions have similar pattern in between years even on 10-minute resolution. Results for the wind speed data showed that the data cannot be pronounced with linear regression line in between years and their relationship is not significant. It confirms the fact that the wind speed, as a renewable resource, is very hard to predict, with a variable pattern on 10-minute resolution in between years. Results of the analyses of the third and fourth group of data, based on 10-minute resolution, in between the selected data for all three years, showed that the relationship between the data cannot be pronounced with linear regression line since it was not significant. This means that none of the data can be used to predict other type of the selected data on 10-minute resolution. 10-minute resolution analyses can provide more details and insight in a real state of the system. These analyses present an upgrade according to the previous literature and give an insight in possible weather cast on 10-minute resolutions. The analyses of the SWHP district heating and cooling system, in the old city of Dubrovnik, showed the ability of the system to utilize high share of RES electricity production. Results of the scenario 1 showed that the combination of WPP and SPP in electricity production, in case C, provides more opportunities for RES utilization than stand-alone WPP or SPP. RES production, in case C, was able to cover up to 67% of electricity demand of the stand-alone SWHP system. Adding TES and BES to the SWHP system in other two scenarios and their comparison resulted in 60 – 78% of ES cost and volume reduction in case C with combined RES production. It is shown that BES requires 13 times higher cost, but 40 times lower volume in each case in comparison to TES. New algorithm for energy planning is developed, based on hourly and 10-minute data input, according to EnergyPLAN model. Comparison of the results, gained by a new model and EnergyPLAN, showed that models provide similar results on hourly and 10-minute data base, which approved validity of a new model. Transport sector of the selected area is analysed in a new model for four different cases. Results of a case 1 showed no significant difference between hourly (standard charging and discharging) and 10-minute (extreme fast charging and discharging) based model after the implementation of regulated V2G model. Implementation and regulation of V2G model led to about 60 – 70% decrease in export, while import was still high. Case 1 presented the limiting case when all of V2G, available for charging and discharging at the given moment, are able to be connected to the grid. Adding HPP Dubrovnik to the electricity production, in case 2, led to decrease of import by 97%, while export increased by 15 times. Case 3 analysed the minimum BEV capacity required in order to gain the same results as the one gained by a limiting case, case 1. Comparison of hourly and 10-minute model in case 3 showed that regulated V2G model of extreme fast charging and discharging, requires only 3% V2G vehicles to be connected to the grid in each time step, while standard charging and discharging resulted in 80% of V2G connection. When compared on hourly basis, regulated V2G model of extreme fast charging and discharging can provide 7 times more flexibility to the system, than the standard one. Due to that, regulated V2G model of extremely fast charging and discharging could enhance the integration of high share of RES production in the system. Results of the case 4 showed that, the replacement od P2T model in electricity prices with V2T model and the implementation of regulated V2G model of extreme fast charging and discharging, could provide saving for EV owners. Highest savings are provided by 10-minute model, about 200 EUR/year per EV. The results of the analyses, done using a new model, showed that the regulated V2G model of extreme fast charging and discharging could provide higher flexibility to the electrical power system. 10-minute based model provided more details on a real state of the system and enabled better integration of high share of intermitted RES production. The implementation of V2T model could enhance participants of the system to take active action and earn savings if they are stimulated with electricity prices. Upgrade of the new model in Calliope showed that the 100% renewable self-sufficient system of a wider urban area can be achieved through the integration and electrification of transport and thermal sectors, connection through the open electricity market based on variable electricity prices and additional storage facilities. Calliope model was developed on hourly and 10-minute data base. The result showed that 10-minute model can provide more details for electricity market development and more favourable market valuation of flexible sources, since it provides opportunity for the integration of more different sources of flexibility. It enables safer integration of high share of RES, which was manifested in the reduction of cross-border transmission capacities and contributed to the system stability. The total reduction of cross-border transmission capacities was about 60% compared to the hourly model. 10-minute model provided safer system operation by equalizing import and export capacities, which contributed to the reduction of the difference between import and export by 7 times compared to the hourly model.

Cilj ovog rada je definirati pojam nula energetske zgrade, opisati trenutno stanje najbolje dostupnih tehnologija za postizanje nZEB standarda i simulacijom u programskom paketu HOMER Grid postići nZEB standard optimizacijom i tehnološko-ekonomskom analizom fotonaponskog sustava i baterijskog sklopa spojenih na mrežu za obiteljsku kuću na lokaciji Tenja. Rezultati simulacije su pokazali kako je sustav za pohranu električne energije u početku bio uključen, ali je kasnije uklonjen kako bi se ostvarile veće uštede i optimizirao udio obnovljive energije. Udio energije iz obnovljivih izvora se povećao na 62,7%, dok se nivelirani trošak (LCoE) smanjio sa 0,883 kn/kWh na 0,199 kn/kWh. U današnje vrijeme gotovo je nemoguće postići nZEB standard obiteljske kuće bez vlastite proizvodnje. Osim što fotonaponski sustavi smanjuju trošak električne energije, u korelaciji sa drugim sustavima grijanja kao na primjer sa toplinskom crpkom mogu uvelike smanjiti mjesečne troškove za grijanje. The aim of this study is to define the concept of zero energy building, describe current state and best avaliable technologies for achieving the nZEB standard and, conduct a techno-economic performance and optimisation analysis of grid-connected photovoltaic system and battery packs for residential house situated in Tenja. The simulation software HOMER Grid was used to analyse and optimise the renewable energy required by the institution. The simulation results showed that the energy storage system was initially included, but it was later removed to achive greater savings and optimeze the share of renewable energy. The renewable energy faction incresed to 62,7%, while local cots of energy (LCoE) decresed from HRK 0,883/kWh to HRK 0,199/kWh. Nowadays, it is almost impossible to achive the nZEB standard of residential house without on-site electricity production. In addition to the fact that photovoltaic system reduce the cost of electricity, in combination with other heating systems, such as heat pump, they can greatly reduce monthly heating bills.

U ovom radu razmatraju se različite izvedbe toplinskih crpki, po čemu se razlikuju, te koje su im prednosti i mane. U prvome dijelu smo započeli sa definicijom toplinskih crpki, te njihovoj povijesti. Zatim smo odredili toplinski množitelj, te godišnji toplinski množitelj. Nakon toga smo odredili prednosti i mane, tipove, izvore i načine rada toplinskih crpki. Detaljno smo analizirali izvore toplinske energije i tipove toplinskih crpki koje se koriste njima. Definirali smo radne točke, temperaturne režime i vanjske faktore bitne kod rada toplinskih crpki. Za kraj smo krenuli sa analizom energetskih performanci, počevši od definiranja energetskih performansi za ovaj rad, te simuliranjem grijanja objekta različitim toplinskim crpkama u dva načina rada, u GeoT*Sol programu. Title: Comparison of heat pump energy performances In this thesis we look at different heat pump solutions, what makes them different from one another and what are their pros and cons. In the first part we started with the definition of heat pumps, aswell as their history. After that, we defined the Coefficient of performance and Seasonal performance factor. Next, we took a look at the pros and cons, types, sources and work modes of heat pumps. We have analysed the energy sources and types of heat pumps that use them, in detail. We have defined the work points, temperature regimes and outer factors that are important for heat pump operation. For the end we have started by energy performance analysis, starting with defining energy performance for this thesis, aswell as simulating the heating of an object via various heat pump types, in two operation modes, in GeoT*Sol aplication. Key words: Coefficient of performance, Efficiency, Energy performance, Heat pumps, Renewable energy sources

The energy sector is characterized by a growing share of variable renewable energy sources, primarily solar and wind power plants, and the spread of electrification in the heating, transport and industry sectors. Such trends require an increase in flexibility in the power system, which can be achieved by developing smart grids and new business models. The dissertation explores the potential of local energy markets to mitigate unfavourable consumption/production patterns and contribute to maintaining voltages and currents within limits. Furthermore, if local energy trading can increase the competitiveness of local flexibility providers and improve social welfare, meaning it could serve as a mean to enhance the integration of renewable energy sources in electrical distribution networks through price incentives for supply/demand balancing. The original scientific contribution was achieved as follows: 1. Short-term model for near real-time local electricity market over a distribution network; 2. Method for determining the effects of local energy trading on voltage profiles and power flows over electrical distribution networks; and 3. Method for assessing the impacts of the local electricity market on market participants. Energetski sektor karakterizira rastući udio varijabilnih obnovljivih izvora energije, prvenstveno sunčanih i vjetrenih elektrana, te širenje elektrifikacije u sektorima grijanja, prometa i industrije. Ovakvi trendovi zahtijevaju povećanje fleksibilnosti u elektroenergetskom sustavu što se može postići razvojem naprednih mreža i novih poslovnih modela. Disertacija istražuje potencijal lokalnih energetskih tržišta za ublažavanje nepovoljnih obrazaca potrošnje i proizvodnje te doprinos održavanju napona i struja unutar granica u distribucijskim mrežama. Nadalje, modelira se i analizira mogućnost lokalnog trgovanja za povećanje konkurentnosti lokalnih pružatelja usluga fleksibilnosti i poboljšanje društvenog blagostanja, odnosno njihov potencijal za poboljšanje integracije obnovljivih izvora energije u elektroenergetske distribucijske mreže putem cjenovnih poticaja za uravnoteženje ponude i potražnje. Izvorni znanstveni doprinos postignut je na sljedeći način: 1. Kratkoročni model za lokalno tržište električne energije u gotovo stvarnom vremenu na razini distribucijske mreže; 2. Metoda za određivanje utjecaja lokalnog trgovanja električnom energijom na profile napona i tokove snaga u lokalnoj distribucijskoj mreži; i 3. Metoda za procjenu učinka lokalnih tržišta električnom energijom na tržišne sudionike.