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Masteroppgave i vassdragsteknikk : Sammenlikning av små elvekraftverk og kraftverk med magasin / Master Thesis in Hydro PowerLofthus, Sigrid Jacobsen January 2012 (has links)
Det siste tiåret har småkraftutbygginger økt kraftig. Små kraftverk har generelt blitt oppfattet som mindre kontroversielt enn større magasinkraftverk, men lite er gjort for å sammenligne disse to kraftverkstypene når det gjelder nytteverdi og miljøpåvirkning. Målet med denne rapporten var å gjøre en sammenligning av et større magasinkraftverk og flere små elvekraftverk med tanke på produksjon, økonomi, naturinngrep, miljøvirkning og samfunnsnytte. Videre var det ønskelig å gjøre en mer generell vurdering av små kraftverk og et større magasinkraftverk, med utgangspunkt i de analyserte kraftverkene. Studieområdet var Kvannevatn og Sagelva i Rana kommune, der det i dag står tre små elvekraftverk, Kvannevatn kraftverk, Sagelva I og Sagelva II. Minikraft AS, som er eier av disse elvekraftverkene, søkte tidligere om å få bygge et større magasinkraftverk. Sammenligningen tar utgangspunkt i dagens små elvekraftverk og et tenkt tilfelle med kun det planlagte magasinkraftverket. Analysen av magasinkraftverket ble basert på dataprogrammet nMAG2004 som er en simuleringsmodell for drift og kraftproduksjon i vannkraftsystemer. Simuleringene forutsetter informasjon om blant annet magasin, kraftstasjoner, energimarkedet, restriksjonsdata, operasjonsstrategi og hydrologiske data. De hydrologiske dataene for både magasinkraftverket og de små kraftverkene ble basert på en nærliggende målestasjon, Bredek.For å strukturere de ulike konsekvensene ved en planlagt magasinkraftutbygging, ble Samla plan-metoden benyttet. Den kategoriserer konsekvensene inn i primære virkninger, fysiske virkninger, det levende miljø og til slutt brukerinteressene. Metoden ga også et grunnlag for å fastsette en miljøbasert minstevannføring. Ved å bruke Samla plan-metoden ble fisk og den estetiske opplevelsen av elva vurdert til å være de viktigste verdiene i Sagelva for å sette et miljøbasert krav til minstevannføring. Disse verdiene ville mest sannsynlig ikke blitt ivaretatt ved den minstevannføringen som var planlagt basert på tradisjonelle beregninger til å være 0,035 m3/s om vinteren, og 0,135 m3/s om sommeren. Kravet til en miljøbasert minstevannføring ble satt ved hjelp av building block-metoden som baseres på at hvert definerte behov utgjør en building block i vannføringsregimet (Alfredsen, Harby, Linnansaari, & Ugedal, 2011).Resultatene fra denne masteroppgaven viser at magasinkraftverket har mulighet til å slippe en miljøbasert vannføring og fortsatt ivareta en lønnsom produksjon. Den miljøbaserte minstevannføringen for magasinkraftverket ble satt til 0,15 m3/s fra september til og med april, 0,5 m3/s i mai, 1,5 m3/s i juni og juli, og 0,5 m3/s i august. Denne minstevannføringen ville imidlertid ikke vært forenlig med god produksjon for de små elvekraftverkene. Magasinkraftverket kan også produsere kraft gjennom hele året på grunn av reguleringsmuligheten, noe de tre elvekraftverkene ikke har mulighet til. Det ble derfor konkludert med at magasinkraftverket har større samfunnsnytte enn de tre små kraftverkene med tanke på leveringssikkert. Basert på studiet av de tre elvekraftverkene og magasinkraftverket i Sagelva kan det videre konkluderes med at man ikke kan bevare viktige verdier i et vassdrag ved å sette et minstevannføringskrav gjennom et standardisert «skrivebords-studie». Siden hvert eneste vassdrag er unikt, er det rimelig å anta at disse verdiene må kartlegges og vurderes spesielt for hvert vassdrag, og at krav til minstevannføring bør settes spesielt ut i fra hvilke verdier som skal ivaretas.Ut ifra beregninger viste det seg at det opprinnelig planlagte magasinkraftverket ikke var optimalisert, da bare 2-3 meter av en reguleringshøyde på 10 meter ble utnyttet i et normalår. I tillegg ville flomtapet i et normalår være stort. Dette gjorde at sammenligningen av det planlagte magasinkraftverket og de små kraftverkene basert på produksjonen ville bli misvisende, ettersom magasinkraftverket ikke var optimalisert.På grunn av den dårlige utnyttelsen av magasinet som var planlagt opprinnelig, ble det utført en ny beregning av magasinkraftverket. Denne beregningen optimaliserer ikke magasinkraftverket fullstendig, men var ment til å gi en indikasjon på hvilket potensiale det har. Resultatene fra denne beregningen viste at magasinkraftverket har potensialet til å produsere større mengder kraft enn de tre små elvekraftverkene, men at en optimalisering av magasinkraftverket er nødvendig.
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Analysis of Large Scale Adoption of Electrical Vehicles and Wind Integration in Nord-TrøndelagVatne, Åshild January 2012 (has links)
With the ‘Agreement on Climate Policy’ (Klimaforliket) signed by the Norwegian government on January 17th 2008, Norway has set a goal to reduce emission caused by transportation with 2.5 – 4 million tons CO2 equivalents compared with the reference for 2020. To reach this goal, high penetration of electrical vehicles is essential, and new technologies and solutions for the infrastructure must be cleared early in the process. With the aim of triggering a discussion on the topic, this thesis presents a methodology for analysing the impact of large-scale adoption of EVs on the electrical grid. A specific portion of a real network was selected and two charging modalities for the electrical vehicles were investigated. The analysis will focus mainly on chargers located at residences, to then explore how the utility can put forward a system for smart charging strategies ("dumb" vs. "smart" charging). Data from a low voltage network was provided by NTE, located in Steinkjer in Nord-Trøndelag. Three different scenarios were analysed. Scenario 1 was given as the base scenario, were the share of EVs where 0%. This was simulated to get a proper comparison. In scenario 2, a share of 10% EVs was implemented in the grid. The share of EVs in scenario 3 was decided to be 60%. The result obtained in the analysis, verified that the smart charging approach causes less strain on the gird. The low voltage network was not capable to handle a large share of EVs (>60%) without any charging scheduling. The smart charge strategy did not cause any extra strain at the grid during peak hours. In addition, the smart charging can introduce the Vehicle-to-Home solution. The EVs can provide ancillary service and support the network with matching supply/demand and reactive power support. A simplified analysis of V2H and reactive compensation was carried out to demonstrate how the grid could benefit from an implementation of EVs.The second part of the analysis, a series of wind measurement was included into the simulation in order to see if wind power can supply the load of the entire residential area. A design for suitable energy storage was also proposed in order for the system to operate as a stand-alone system. Grid stability and power quality was not included in the analysis. The result from the wind integration shows that in order for the network to operate as a stand-alone system in the worst-case scenario, there is a need of an enormous storage. It is assumed based on the results, that the system is self-supplied most part of the year. This thesis proposes a storage consisting of 7 battery-packs from old vehicles, with the capacity of 50 kWh each. This will result in a 30% reduction of the peak demand from the grid, when wind power is integrated.The case study addressed in the thesis, present a methodology for analysis the impact of a large adoption of EVs on the distribution network. The results obtained from this analysis, is considered transferable to similar networks. In order to achieve smart charging, there is need for further research on scheduling algorithms.
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Determination of the country specific environmental intensities of electricity in Europe: An analysis incorporating different principles for determination of the electricity mix.Berg, Kaja Sofie Fallsen January 2012 (has links)
An analysis incorporating different principles for determination of the electricity mix and the subsequent environmental characteristic.
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Design av strømforsyningsanlegg til et elektrisk oppvarmingssystem for undervanns rørledninger / Design of Powersupply for DEHHaugland, Rune January 2012 (has links)
For å forhindre pluggdannelser (hydrater/voks) i transportrør subsea for olje/gass, som kan medføre produksjonsstans har SINTEF/NTNU Elkraftteknikk utviklet et system for elektrisk oppvarming av undervanns rørledninger. Dette systemet forkortes DEH.Oppvarming av røret skjer ved å kjøre en stor strøm gjennom røret, hvor varme utvikles på grunn av rørets resistans. Av sikkerhetsmessige årsaker er røret jordet i begge endene. Dette fører til strømdeling mellom røret og sjøvann, hvilket reduserer effektiviteten til systemet betraktelig. Ineffektiviteten sammen med røroppvarmingens lave effektfaktor gjør at det vil gå en stor strøm i stigerkabelen ned til havbunnen. For å begrense strømmen benyttes det fasekompensering med kondensatorer og et symmetreringsanlegg etter Steinmetz’ krets.For å kunne analysere forsyningssystemet topside, er det valgt å utarbeide en forenklet krets. Kretsen er verifisert av et laboratorieforsøk og datasimuleringer i Matlab og Pscad. Resultatene viser at det aktive tapet i flere av komponentene i kretsen kan neglisjeres, noe som fører til at formlene for Steinmetz’ symmetreringskrets gir god nøyaktighet. Disse formlene sier at verdiene for komponentene i symmetreringkretsen er proposjonal med resistansen den ser. Det er utført analyser av virkningen av lastens effektfaktor som viser at den er bestemmende for den maksimale og minimale resulterende resistansen av lasten og fasekompenseringen, hvilket er den resistansen symmetreringskretsen ser. Analysene viser også at effektfaktoren er dimensjonerende for andre komponenter.
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Life cycle assessment of an offshore electricity grid interconnecting Northern EuropeNes, Rasmus Nikolai January 2012 (has links)
There is a growing demand for increased electricity transfer capacities between the countries surrounding the North Sea. The increased capacities will enable easier integration of intermittent renewable energy sources, decrease the need for balancing power, increase power trade and competition, and increase security of supply across the region. Interregional offshore grid connections are required if large scale deployment of deep sea, far from shore offshore wind energy in the North Sea is to take place. The WINDSPEED research project has resulted in proposals of realistic scenarios for large scale deployment of offshore grid and wind energy in the North Sea. In this study the environmental impacts of an interregional meshed offshore grid as proposed by WINDSPEED have been assessed. Environmental impacts of the offshore wind farms, which may be connected to the grid, have been included in the assessment as well, completing the system boundaries.The methods used to quantify the environmental impacts are process-based life cycle assessment (LCA), input-output assessment (IOA) and tiered hybrid LCA, with main focus on the results of the latter. Four offshore grid scenarios have been assessed, with and without offshore wind farms connected. The offshore grid is primarily composed of 450 kV HVDC technology for long distance transmission, based on the HVDC cables used in the NorNed connection. Wind farms are deployed far from shore (requiring much sea transport and long distance grid connections) and at an average of 43.9 meters depth (requiring large bottom-mounted foundations for the wind turbines). These requirements make the environmental impacts of deep sea, far from shore offshore wind energy substantially higher than for both close to shore offshore wind energy and onshore wind energy.The environmental assessment of the interregional meshed offshore grid found that the largest contribution to environmental impacts is from manufacturing and installation of HVDC cables. Sea transport required for installation of components and operation and maintenance contributes between 5 and 25 percent to most impact categories. The electrical equipment (converters, breakers and switchgear) required by the grid has a quite varying contribution, from almost none to some impact categories to about 35 percent to climate change impact. The environmental assessment of the deep sea, far from shore offshore wind energy, finds that the largest contributors to environmental impacts are the wind turbines. But the other components required – deep sea foundations, offshore grid and sea transport for installation, operation and maintenance – makes the environmental impacts caused by it around twice as high as for onshore wind energy installations. Total climate change impacts were found to be 42.9 g CO2-Eq/kWh; the grid is responsible for 11, foundations 31 and sea transport 9 percent of that. The largest impacts of deep sea, far from shore offshore wind energy as compared to other relevant energy sources are to the impact categories freshwater ecotoxicity, human toxicity and metal depletion. The impacts to these categories are many times larger, up to almost 20 times, compared to other relevant fossil fueled energy sources. The impacts to the other impact categories are substantially lower.The results indicate that the environmental impacts caused by an interregional meshed offshore grid in the North Sea are substantial; it needs to be considered an important part of an environmental assessment of deep sea, far from shore offshore wind energy. On the other hand, the environmental costs are probably not so high that they outweigh the potential benefits of such offshore grid connections. It may in fact lead to net environmental gains because of a decreased demand for fossil balance power. As for large scale deployment of deep sea, far from shore offshore wind energy the environmental benefits as opposed to relevant fossil alternatives are obvious, but, including the significant disadvantages of intermittent energy supply and high monetary costs, overall gain to society is harder to predict.
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Tekniske retningslinjer for tilknytning av plusskunder i lavspenningsnett / Technical guidelines for connection of prosumers in low-voltage networksTranøy, Håkon January 2012 (has links)
TeoriI denne oppgaven er plusskunder sin påvirkning på ulike spenningsparametre i lavspenningsnettet forklart. Parametrene tar utgangspunkt i kravene stilt i ”Forskrift om Leveringskvalitet i kraftsystemet”. Videre er det redegjort for teorien for disse parametrene. For harmoniske spenninger og langvarige spenningsendringer er det i tillegg vist, med eksempler, hvordan beregninger av deres verdi gjøres. SolcelleanleggTeknologien for et nettilknyttet solcelleanlegg blir beskrevet med virkemåte og oppkobling. Et eksempel på et fullstendig solcelleanlegg er vist, der alle komponentene i forslaget deretter forklart. Det er blitt fokusert på vekselretteren og hvordan valget av denne vil være viktig for i hvilken grad en plusskundes solcelleanlegg påvirker spenningsparametere i distribusjonsnettet.SimuleringerDet er blitt gjort lastflytsimuleringer i simuleringsprogrammet SIMPOW for produksjon fra ingen, en eller flere plusskunder i lavspenningsnettet. Det benyttes to ulike eksempelnett; et sterkt og et svakt nett. Det er blitt simulert for ulike lastforhold og plasseringer av plusskunden i distribusjonsnettet. Endringer i spenningsforhold er blitt studert og deretter kommentert. En plusskunde gir størst endring i spenningsverdiene i de ulike tilknytningspunktene til sluttbrukerene i nettet dersom han/hun er plassert ytterst i et svakt nett og har en lav effektfaktor. Krav gitt plusskunderTre viktige dokumenter for plusskunder er nevnt. De er NVEs ”Vedtak av 16. mars 2010”, ”FIKS” og ”ENTSO-E Draft Requirements for Grid Connection Applicable to all Generators”. Forslag til krav som skal stilles en sluttbruker som ønsker å bli plusskunde og en grov oversikt over prosessen en sluttbruker med solcelleanlegg må gjennom for å bli en plusskunde er gitt. Det forklares at bidraget fra et solcelleanlegg til kortslutningsstrømmen kan forventes å være lik merkeverdien. Overstrømsvern kan derfor ikke benyttes, og vekselretteren må frakoble anlegget når den oppdager avbrudd i distribusjonsnettet. Det er forklart hvorfor harmoniske strømmer fra et solcelleanlegg kan være sterkt avhengig av graden av harmoniske spenninger i distribusjonsnettet med plusskunden frakoblet. Bruk av filtre vil forandre effektfaktoren til vekselretteren og vil kunne danne resonansekrets i nettet. Oppgaven viser at plasseringen, valget av vekselretteren og samlet merkeeffekt for solcellepanelene vil gi det aktuelle nettselskapet innsikt til i hvilken grad tilknytningen av solcelleanlegget vil påvirke tekniske forhold i distribusjonsnettet. Størrelsen på merkeytelsen til solcelleanlegget i forhold til kortslutningsytelsen i det aktuelle tilknytningspunktet vil angi om lastflytberegninger skal gjøres.Selv om en ny plusskunde alene ikke skal trenge å føre til betydelige nettanalyser, er det viktig å tenke fremtidsrettet for å være forberedt på konsekvensene et økende antall plusskunder i lavspenningsnettet vil kunne ha. Kravene det aktuelle nettselskapet stiller til plusskundene burde være like for to plusskunder med like parametre. Nettselskapet må også kunne utnytte det store spillerommet ordningen til NVE tillater av tilpassede krav i særskilte saker.
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Investigation on an Open Cycle Water Chiller based on Desiccant DehumidificationPettersen, Sindre January 2012 (has links)
In this thesis, a novel open cycle desiccant dehumidification system is experimentally studied. The system is installed and operated at Shanghai Jiao Tong University (SJTU) as part of the Green Energy Laboratory (GEL) initiative. The system uses two-stage desiccant dehumidification as well as regenerative evaporative cooling for chilled water production. The purpose of the thesis is to evaluate the system performance during different ambient and operational conditions. The investigated system has great potential regarding the environmental aspect of HVAC system solutions. The system is more energy efficient compared to conventional air conditioning systems and uses solar thermal power provided by evacuated tube solar air collectors as the main source of energy. Therefore, this type of system can contribute in reducing the use of non-renewable energy sources.A lot of experiments have been performed from June to July 2012 during varying ambient conditions. As a first step, the necessary regeneration temperature level is established. The results show that this temperature should be in the range of 70-75˚C or higher to be able to achieve desired dehumidification effect. Then, experiments regarding the overall system performance during different ambient temperature and humidity conditions are performed and analyzed. The results show that the system excels good performance during periods of high ambient humidity and is capable of achieving average COPth and COPel around 0.8 and 5.7 respectively. The total dehumidification efficiency is approximately 58% and is proven to vary with respect to the regeneration temperature, where increasing regeneration temperature results in higher amount of moisture removed from the processed air. The solar collectors providing heat to the regeneration air has an efficiency of 47-60% depending on the available level of solar radiation intensity. During periods of low intensity it is proven that the heating system needs assistance from an auxiliary device to be able to generate a sufficient temperature level. The evaporative cooler producing chilled water is capable of providing water at a temperature below 21˚C during periods of high ambient temperature, and temperatures below 16˚C if the ambient temperature decreases. The achieved dehumidification and cooling capacity of the desiccant system makes it possible to provide qualified supply air with temperature in the range of 20-26˚C and absolute humidity below 12 g/kg. Also, an experiment with the purpose of investigating the newly installed second desiccant wheel is carried out. The system is operated with only the second wheel running and the results show that the dehumidification performance is very good when the second wheel provides the first stage dehumidification. Lastly, experiments investigating the impact of the pre-cooling heat exchanger is performed and analyzed.
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Analysis on Methods and the Influence of Different System Data When Calculating Primary Energy Factors for Heat from District Heating SystemsKallhovd, Magnhild January 2011 (has links)
A steady growing global demand for energy and rising greenhouse gas emissions has resulted in several initiatives from the European Union with the purpose of increasing energy efficiency. A part of this strategy is the introduction of energy performance certificates for buildings, containing a numerical primary energy indicator. Another instrument is to encourage an increased use of cogeneration. As a member of the European Economic Area agreement, these events also affect Norway. The main aim of the project was to investigate how various relevant parameters influence the primary energy factor of district heating when a combined heat and power (CHP) plant is the heat producing unit. The study was to be based on Norwegian conditions. To select relevant technologies, a mapping of existing and planned CHP facilities connected to district heating (DH) networks in Norway was carried out. The findings were that at present, there are nine steam cycle CHP plants connected to DH networks that are based on waste incineration, one steam cycle that is based on demolition wood and one reciprocating engine that is running on biogas. The installed electric capacity ranged from 0,3 MW to 22,8 MW and the annual district heating production from 1,5 GWh to 196 GWh. Based on this, it was decided to study steam cycle CHP plants further. Three different sizes were chosen: 2 MWel, 10 MWel and 25 MWel.In addition, the situation in Europe was looked into. Here, steam cycle and combined cycle were found to be the two most dominant CHP technologies. To have a different technology to compare with, a combined cycle with 22,7MWel capacity was also included in the study.By running plant simulations, the effects of part load operation, various district heating supply and return temperatures and different fuel types were quantified. STEAM Pro was utilised to design the steam cycle models, while GT Pro was used to design the combined cycle models. STEAM Pro was also used to perform design simulations for different temperature levels in the DH network and to study the effect of different types of fuels. To be able to investigate the part load performance of the plants based on a given district heating demand, the models from STEAM Pro and GT Pro was imported into Thermoflex and modified.Reducing the DH supply temperature from 120 to 80 °C and the return temperature from 80 to 35 °C in the 10 MW steam cycle plant increased the power efficiency by 25% and the power to heat ratio by 33%, but the total efficiency was only slightly increased. Variation of fuel, on the other hand, influenced the power efficiency and the total efficiency almost equally, and the power to heat ratio was hence left relatively unaltered. The results from the simulations at the defined full load conditions showed that power efficiency was more than twice as high for the combined cycle than for the steam cycle plants, and the power to heat ratio was almost four times higher for the CC plant. The total efficiency was approximately 10 % lower for the combined cycle than for the steam cycles.Performance also varied between the different sizes of steam cycles, and both boiler type and turbine size influenced power efficiencies and power to heat ratios. In contrast, the total efficiencies were close to equal. Part load had a great influence on power efficiency and power to heat ratio for all technology types. Especially at very low load levels, the power efficiency was considerably reduced. The combined cycle experienced a total fall in power efficiency of 40%, while the reduction varied from 60% to only 29% for the steam cycle plants. The part load total efficiency was only slightly reduced for all plants. Based on the part load simulations, annual efficiencies and power to heat ratios were calculated for different annual load distributions. The annual power to heat ratio and power efficiency was clearly influenced by changes in the annual load distribution pattern, while the effect was less notable for the annual total efficiencies. To calculate the primary energy factors, the total efficiency and power to heat ratio results from the CHP plant simulations were implemented in an excel tool developed by [16]. Some other modifications were also performed.The district heating primary energy factors (PEFDH) for the defined base case varied from 0,85 for the Combined Cycle* alternative to 1,4 for the 2 MW steam cycle plant. The base case was defined to have medium energy density(8 MWh/m). This was later found to not represent the actual Norwegian conditions, where the average energy density is closer to 4 MWh/m. When this energy density was used, the PEFDH for the 10 MW steam cycle plant increased 9,4%, from 1,38 to 1,51. This value is still considerably lower than the primary energy factor for the average electricity production in the Nordic countries, which is 2,16.It was found that the combined heat and power plant parameters had a significant influence on the primary energy factors. The power to heat ratio was particularly important when the power bonus method was utilised. One main conclusion is therefore that it is important that the performance indicators that are used for the CHP plant are realistic, and takes into account technology type, part load performance and what load duration curve the plant is subject to. In most of the cases studied, the fuel handling process and the use of additives contributed most to the primary energy losses related to the PEFDH, while the sum of primary energy losses was dominated by the losses occurring in the CHP plant and the fuel handling. Nevertheless, what process and parameters that could potentially improve the PEFDH most depended on technology and choice of allocation method. In all cases studied, pump work related to circulating the DH water and energy consumption related to ash transport, construction and dismantling of the CHP plant and DH pipes were negligible or close to negligible. Heat loss became a considerably more dominant primary energy loss contributor when a low energy density was assumed. In the end, the calculation of primary energy factors involves many choices that influence the results. It is therefore important that the calculation method becomes more standardised. As it is today, some processes are optional, for instance the use of additives. In this study, the use of additives had a non-negligible influence on the results. Furthermore, the CHP simulation results underlined the importance of taking type of CHP technology and operational conditions into account when calculating primary energy factors for this kind of systems.According to NS-EN 15316-4-5, the power bonus method is the allocation method that should be utilised when calculating primary energy factors for district heating. This makes the district heating primary energy factors extremely dependent on power to heat ratio and the choice of PEF for avoided electricity. If the amount of avoided electricity production in fact is smaller than the full amount of CHP production or if the PEF of the avoided electricity is lower than what is assumed, this might lead to a severe underestimation of the PEFDH. The ultimate goal with the use of primary energy is to encourage more efficient energy use. It is therefore important that the issues mentioned in the two paragraphs above are further studied and discussed as a part of exploring how a standard method should be designed to face this challenge.
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Smart energy city critical infrastructuresLara, Topol January 2014 (has links)
Smart energy cities have a potential to lead the transition from fossil age into the age of renewables. After a theoretical background is presented, of why the transition is necessary and what steps need to be taken in that direction, this paper brings insight into the paradigm of smart cities. The focus is set on the smart building as its fundamental building block. Fifteen cases of turning Norwegian and Croatian households into smart ones have been analyzed. Those are various combinations of consumption, generation and storage options. Expenses and revenues in case of implementing such smart households are presented by conducted cost and benefit analysis, as well as profitability of such projects.This assignment is realized as a part of the collaborative project "Sustainable Energy and Environment in Western Balkans" that aims to develop and establish five new internationally recognized MSc study programs for the field of "Sustainable Energy and Environment", one at each of the five collaborating universities in three different WB countries. The project is funded through the Norwegian Programme in Higher Education, Research and Development in the Western Balkans, Programme 3: Energy Sector (HERD Energy) for the period 2011 - 2014.
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Net electricity load profiles of Zero Emission buildings : A Cost Optimization Investment Model for Investigating Zero Balances, Operational Strategies and Grid RestrictionsÅnestad, Astrid January 2014 (has links)
On the way to meet the internationally sanctioned climate targets, zero emission buildings / zero energy buildings (ZEB) will be an important step. Research is ongoing on what a reasonable definition of ZEB will contain. In Norway, it is decided that the building code should be nearly zero energy buildings from the year 2020. In this master’s thesis, an optimization model for finding cost-optimal investment and operational strategies for ZEB is developed. The building modelled, is a passive school with a hydronic heat distribution system. Possible investments include photovoltaic solar cells (PV), solar collectors, heat pumps, biomass boilers, electric boiler, heat storage and connection to the district heating grid. The model is designed as a dynamic mixed integer programming model, and implemented in Mosel Xpress. The model minimizes the total discounted costs of operations and investments over the lifetime of the building. Different restrictions of zero CO2 emissions, zero primary energy consumption and level of grid burden can be applied. The analysis shows that if a zero CO2 restriction with Norwegian CO2 factors are applied, the least expensive way to reach ZEB is by investing in PV in combination with pellet biomass boiler as base load and district heating to cover peak demand. To reach the zero balance for the school with Norwegian CO2 factors, the highest hourly value for export of electricity per hour exceeds the maximum hourly value of imports by about 120%. If European factors for CO2 is applied, it will be more reasonable to reach ZEB than with Norwegian factors. If asymmetric primary energy factors are used instead of symmetric factors, investment in PV becomes higher, and the peak export values increases. The model is developed as a deterministic model, and does not take into account uncertainties in input data. To compensate for this, various sensitivity analyses are conducted. Future work includes testing the model with load profiles for other types of buildings.
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