In 2003 the European Commission introduced the Directive 2003/54/EC and Regulation 1228/2003/EC which increased the focus on the liberalization of the European electricity market. The international electricity trade has increased and created new challenges related to cross-border transmission and compensation mechanisms. The focus of the report has been to discuss the development of the electricity market in Europe, and the status of international exchange. The report also discusses the concept of cross-border trade and transit, and investigates a proposed ITC model and whether correct investment incentives are given. Price data from the main power exchanges in Europe indicate that the market is experiencing increasingly integration and efficiency. There has also been a trend towards market based congestion management methods. Regional markets have successfully developed in Spain and Portugal (the Iberian market) and between France, Belgium and The Netherlands (the Trilateral Market Coupling, TLC). Further plans for regional coupling are also underway (see chapter 5. The most common definition of transit is the one adopted by ETSO (Association of European Transmission System Operators), where transit is defined as the minimum between exports and imports. This definition could create opportunities for market participants to manipulate transit income (discussed in chapter 5.3). The Inter-TSO compensation (ITC) model used in this report is based on the With-and-Without transit algorithm. The model only focuses on costs and load flow, and do not include market incentives or evaluation of benefits. The model bases the compensation calculation on the transit term, which can lead to misguided identification of network responsibility. Two scenarios were compared with a base case scenario in order to identify possible investment incentives. The first scenario included a situation where one of the cross-border lines in the network was constrained. Results from this simulation indicate that the transmission system operators involved would experience increased ITC payment, and therefore not receive investment incentives. The TSOs involved would benefit from the bottleneck in form of increased revenue (assuming Cost-Of-Service regulation). In the second scenario an extra cross-border line was implemented, and the situation was compared to the base case. The results from this simulation show that the TSOs involved would receive a positive effect in form of reduced ITC cost. The ITC mechanism would in this case be in line with the European Commission’s Regulation 1228/2003/EC, and give the involved TSOs correct investment incentives. The lack of correlated results in these two cases indicates that the ITC mechanism (in this case modeled by the WWT algorithm) cannot be regarded as relevant from an investment incentive perspective (more information found in chapter 7.3).

Experimental studies as well as simulations have been performed on the Back-to-Back starting schemes low frequency-, partial frequency-, and soft -start-up. A Back-to-Back configuration of two synchronous machines has been established in the laboratory, upon which parameter estimation and start-up experiments have been performed. Extensive parameter estimation was conducted in order to replicate the laboratory machines in the simulation model as accurately as possible. This was done in order to verify the validity of the simulation model. Studies into the effects of inductance interconnecting the machines were made in the laboratory and in the simulation model. Effects of resistance and inertia were studied in the simulation model. It is concluded that the simulation model appears to be as reliable as is its input parameters. Discrepancies were found in line voltages, due to faulty implementation of field current replication. Full scale simulations using Motorformer parameters were performed in the simulation model, featuring low frequency- and soft -staring. The effects of an interconnecting cable were studied. It is concluded that low frequency starting appears to be most reliable and least violent starting method. However, it might be limited by the availability of a turbine. This is not the case for soft starting, which has a lower starting capability and is more violent to the motor damper- and field windings. Low frequency startig is the recommended starting method of the ones studied. Dynamic short circuit simulations were done on a fixed speed LNG-facility. The fixed speed alternative appears to be more stable when responding to a short circuit. This is because the motors contribute to upholding the voltage during a fault by delivering reactive power to the short circuit, and because the motors do not loose all torque as is the case for LCI drives when the voltage dip exceeds 20$%$. Further work is needed in up-scaling the experiments. A sophisticated simulation model should be established and its validity tested on the up-scaled experiments. Preliminary custom design of machines should be initiated depending on what starting scheme is chosen. Custom machine parameters should then be used in full scale simulation using the more sophisticated model.

1. Initial problem formulation 2. Iterative approach building for one reservoir 3. Testing for two cascaded reservoirs 4. Testing for four cascaded reservoirs 5. Further work

This report is the results of the work on a master thesis concerning intelligent monitoring of hydro power stations. In the report two different types of computer software is investigated to find out whether they are suitable to make out a monitoring system capable of giving the user information about faults and unwanted operating conditions at an early stage. It is also investigated whether the software has proven the capability to detect faults and unwanted operating conditions. The different advantages and disadvantages of the two software products are commented and the two software products are compared. This report shows that the two software products are quite different. The software from Volve is software meant to construct an expert system capable of recognising faults from previous cases of faults. The software from SKF is software that gives intelligent machine diagnostics from analysis of vibration measurements in addition to measuring and trending of other variables. It also gives the user tools for analysing the root cause of faults influencing the bearing system of different industry machinery. This means that the software from SKF demands some involvement from the user to produce the best and most precise results. The expert system developed from the Volve software on the other hand is meant to present only results and advice to the user. The results from tests and simulations of the expert system developed by the Volve software are very limited. It is not possible to conclude which of the two software products is better before more tests of the Volve system is performed. In addition to the investigation of these two monitoring software products two different types of sensors are investigated. The sensors that are investigated are smoke sensors and sensors for detection of ultrasonic sound. Both types are commonly used in monitoring of industry processes similar to those in hydro power stations. These two sensors are capable of giving additional information to the monitoring system making it possible to detect faults that it is difficult to detect today. This is because the two sensor types perform measurements that the normal measuring equipment of today is incapable of. This will increase the information flow to the monitoring systems of hydro power stations making it possible to perform better and more precise monitoring.

Lowering the cost of wave energy conversion is an essential task for it to succeed as a future energy resource. In this work a converter, assumed cheaper than the regular back to back converter setting, have been investigated for a electric direct drive point absorber. Both experimental work and simulations are used in the analysis. In the experimental work, a permanent magnet generator with a 6-pulse diode rectifier, a DC-link and a DC/DC converter equivalent, was used. Steady state, dynamic and transient measurements were preformed and a simulation model was compared to the measurements. Good results were obtained and deviations were in general small, mostly +-3% for voltage and current measurements and +-8% for torque measurements. Based on transient measurements and simulations a general linearization of the system was made in order to obtain useful information about the system. A step up converter was used in the simulation and it demonstrated stable passive loading control. By using the information obtained by the linearization, the performance of the simulation model was improved by decreasing the DC-link capacitance. The modified simulation model had significant less torque ripple than the initial. The linearization model also can been used to identify time delay represented by the power take off unit in a wave energy converter. This will be done for a commercial size wave energy converter summer 2009.

This Master thesis analyzes the optimal use of the hydro resources in Albania. Albania is a country totally dependent on hydro power. More than 90% of the electricity today comes from hydro power, mainly from the Drin river system. There are three hydro power plants located in the Drin river system: Fierze (500 MW), Koman (600 MW) and Vau Dejes (250 MW). Only one third of Albania’s hydro power potential is today exploited, and Albania is a net importer of energy. The main objective with this study is to analyze the utilization of the hydro resources in Albania and look at potential improvements in the short term (next years) and the long term (after Albania joins the regional market). Two scenarios were worked out. The first scenario focuses on the present market situation in Albania. Investigations are done through simulations with the EOPS model. The results were analyzed and compared with historical data to discover potential upgrades of the utilization of water in Fierze, Koman and Vau Dejes. In the simulations the production in Drin river system is increased with 1.3 TWh in an average year. Fierze power plant has the highest potential with 25% more production in the simulation than what is shown through historical data. Under the process towards a liberalized market, the optimizing problem regarding the production planning will change. Today the main task is cost minimization given an expected demand. In a free market it will be profit maximizing given a price expectation. A second scenario dealing with the potential market situation in Albania in 2020 was worked out. In addition to the new market situation four new power plants were included in the EOPS model. With new plants in the Drin and a functioning market it is possible to achieve 1 TWh more production during an average year compared with the simulation for the present market situation in Albania. If the implementation of the market, new power plants and transmission lines are accomplished, the supply situation in Albania will improve substantially through more secure power delivery. However a participation in a regional market forces the production company to plan each day like the participants in the Nordic market, both in the long and short the term, to be able to exploit the technical and financial opportunities and develop their country.

Gas turbines in offshore power systems contribute to about 23% of Norway’s total emissions of CO2. One method for reducing these emissions could be the addition of wind turbines to the offshore utility grids. Power from shore is another alternative, but has been proven costly due to long cables and expensive HVDC converter stations. In this thesis work, the behaviours of different wind turbine technologies during transient fluctuations in an offshore utility grid have been studied. For this purpose, a dynamic model for an offshore oil platform was developed. Models of squirrel cage and doubly fed induction generator based turbines were developed as well. None of the modelled generators experienced problems with the disturbances caused by the electromechanical transient fluctuations. Based on the behaviour of the DFIG’s grid side converter, it is believed that the result would be the same for a wind turbine with full frequency conversion. Variable speed wind turbines are expected to remain controllable throughout electromechanical transient fluctuations such as for the simulated case. However, the controllers, converters and equipment have to be designed while bearing these fluctuations in mind. The controllability of the variable speed wind turbines could be used to contribute to voltage control by production and consumption of reactive power. A controller scheme with the purpose of stabilising the voltage at the gas turbine generators’ terminal was developed, but had low impacts on the power system behaviour. A stator flux feed forward term for the speed controller was developed. The term stabilised the power output of the doubly fed induction generator. However, the impact on the power system’s frequency response was minimal, and there is probably no material value of such an addition to the control loop.

Europa har et stadig økende energiforbruk, og har samtidig mål om å redusere bruken av fossile brensel. De termiske kraftverkene er trege å regulere, og et økende innslag av vindkraft forsterker en allerede vanskelig effektsituasjon. Vannkraft egner seg godt til effektregulering på grunn av rask og billig lastendring. Norge kan bidra som effektregulator for Europa. Ved å øke effektinstallasjonen i eksisterende vannkraftverk ved og ved å bygge pumpekraftverk. Fallet mellom Tyrvelstjerna og Strandevatnet i Hol er godt egnet for et pumpekraftverk. Strandevatnet er allerede regulert som en del av Hol-reguleringen og Tyrvelstjerna ligger slik til at de kan demmes sammen til et magasin på 9Mm3 med en 230m lang og 30m høy dam. Høydeforskjellen er ca 500m og avstanden mellom magasinene er ca 2km. Svingesjakt er ikke nødvendig på grunn av den korte vannveien. Stålforing av trykksjakt blir heller ikke nødvendig hvis stasjonen plasseres langt nok inne i fjellet. Det går vei langs Strandevatnet og 2 420kV-linjer går mellom Strandevatnet og Tyrvelstjerna. Utbyggingskostnadene for Tyrvla pumpekraftverk er regnet ut ved hjelp av NVE’s kostnadsgrunnlag for vannkraftanlegg(Slapgård,05). Kostnadene for utbygginger fra 10 til 1000MW er undersøkt. De totale årlige kostnadene for kraftverket består av årlig avskriving av investeringskostnaden og de årlige driftskostnadene. Den totale virkningsgraden i pumpedrift er ca 89 %. I turbindrift er virkningsgraden ca 90 %. Det betyr at en taper ca 20 % av energien ved å først pumpe vann opp og så produsere vannet ned igjen. Dermed må strømprisen under pumpedrift være minst 20 % høyere når det produseres enn når det pumpes for å få positivt driftsoverskudd. Simulering av drift med spotpriser fra Sør-Norge i 2006 og 2007 gir ikke nok inntekter til at investeringen er lønnsom. Spotprisenes døgnvariasjoner er ca 1 øre/kWh i disse årene. Spotprisene på den nederlandske APX-børsen hadde i 2007 en døgnvariasjon på ca 12 øre/kWh. Med disse prisene ville Tyrvla pumpekraft blitt svært økonomisk. Kraftverket blir lønnsomt allerede med en døgnvariasjon på ca 5øre/kWh. Hovedgrunnen til at kraftverket ikke er lønnsomt nå er begrenset nettkapasitet. Hvis nettkapasiteten mellom Norge og Europa blir stor nok vill vi få prisvariasjoner som ligner mer på de europeiske i Norge. Men nettkapasiteten også internt i Norge må styrkes for at prisvariasjonene skal bli store nok til lønnsomhet for Tyrvla pumpekraftverk. Etter at kraftforbindelsen mellom Nederland og Norge ble åpnet har Statnett varslet at Sørlandet kan bli eget prisområde på grunn av begrenset nettkapasitet. Dermed vil prisvariasjonene fra denne kabelen bli dempet mot Hallingdal inntil kapasiteten i det norske nettet er øket.

Menneskene tilbringer mesteparten av livet innendørs, og inneklimaet har innvirkning på vår helse, trivsel og prestasjonsevne. Tilfredsstillende ventilasjon og klimatisering av bygninger er derfor av stor betydning. Ved hjelp av avanserte tekniske installasjoner kan et godt inneklima oppnås. Ulempen er imidlertid at slike løsninger er svært energikrevende og gjør at bygningssektoren står for en stor del av den totale energibruken. I et samfunn som retter stadig større fokus mot energisparing og effektiv energibruk, er det derfor viktig å undersøke hvorvidt tekniske installasjoner for klimatisering av rom kan gjøres mer energiøkonomiske, uten at det går utover deres funksjon. Behovsstyrt ventilasjon gir en mulighet til å redusere energien som brukes til drift av ventilasjonsanlegg. Ved å tilpasse mengder tilført luft til forurensningskonsentrasjonen i et rom, kan det unngås å ventilere for mye når forurensningsbelastningen er liten, og på denne måten reduser energibehovet til behandling og transport av ventilasjonsluften. For å få fullt utbytte av et slikt system er det svært viktig å velge ut passende styringsstrategi og plassere sensoren som skal styre anlegget slik at den gir et representativt bilde av inneklimaet i rommet. Gjennom dette arbeidet blir forurensningsspredningen i et klasserom med omrøringsventilasjon og bakkantsinnblåsning undersøkt ved hjelp av laboratorieforsøk, for å finne en passende plass for montering av en CO2 sensor. Målet var å finne en et sted hvor forurensningskonsentrasjonen varierte i samme takt som forurensningskonsentrasjonen i oppholdssonen. Resultatene viste at en god løsning for den gitte forsøksoppstillingen vil være å montere sensoren på et sted som ikke ligger i veien for brukere, men nærme oppholdssonen og forurensningskildene. Et mer konkret forslag til plasseringen krever ytterligere undersøkelser og målinger. Det er viktig å nevne at konklusjonene som her er blitt trukket mest sannsynlig ikke gjelder for rom med andre typer ventilasjon. Ved valg av plassering må det tas hensyn til at forurensningsspredningen vil påvirkes av kildestyrke, kildens plassering, varme og kalde flater, bevegelser, samt luftstrømninger generert av ventilasjonen. Derfor er det behov for å gjennomføre flere forsøk med ulike typer ventilasjonssystemer.

Det har de siste årene vært en betydelig vekst i kraftforbuket i Midt-Norge. Det forventes videre vekst i årene som kommer. Siden det ikke har vært en tilsvarende vekst i kraftproduksjonen i regionen, forventes det at Midt-Norge vil ha et betydelig kraftunderskudd. Statnett har beregnet dette undrskuddet i 2010 til 9 TWh for et normalår. I et tørrår vil dette underskuddet kunne bli betydelig større. Beregninger gjort ved hjelp av Samkjøringsmodellen og Statnetts modell for 2010 bekrefter dette. Midt-Norge vil ha et kraftunderskudd på 9,6 TWh i et gjennomsnittår og vil i tørrår måtte rasjonere deler av forbruket for å skape balanse. Det vil være nødvendig med maksimal import mesteparten av tiden. Det tyder ikke på at det vil være effektmangel i Midt-Norge. Prisene vil være stabile over døgnet. Det vil derimot være en klar pristopp senvinters. Midt-Norge er for tiden inndelt i et eget prisområde hos kraftbørsen Nord Pool. Normalt inngår Midt-Norge i samme prisområde som Nord-Norge. Regionen er skilt som et virkelmiddel for å oppnå kraftbalanse. Beregniger viser at Midt-Norge vil ha merkbart høyere priser som eget prisområde enn hva som er tilfelle når regionen inngår i samme prisområde som Nord-Norge. For Nord-Norge blir situasjonen motsatt, og Nord-Norge har mye å tjene på å være eget prisområde. Forbruket til kraftkrevende industri modelleres normalt ved hjelp av utkoblbare kontrakter. Når kraftprisen kommer over utkoblingsprisen kobles forbruket ut. Erfaringer fra høyprisperioder tyder på at det er en treghet i tilpasningen til industrien. Forbruket vil reduseres gradvis om prisene holder seg høye lenge. SINTEF tester for tiden ut en ny måte å modellere fleksibiliteten på. Ved å modellere kun en viss prosentandel av forbruket som prisavhengig fra uke til uke, vil Samkjøringsmodellen kunne ta høyde for tregheten. Simuleringer med ulik treghet i forbruket viser at redusert fleksibilitet medførere høyere priser og økt rasjonering. Om fleksibiliteten økes ytterligere vil det medføre at magasindisponeringen legges om. Modellen legger opp til en høyere magasinfylling, noe som medfører mer flom. Resultatene i Midt-Norge blir annerledes enn resten av Norge. Dette kan ses i sammenheng med at situasjonen i Midt-Norge er anstrengt fra før. Den nye modelleringen er i utviklingsfasen og erfaringer viser at ytterligere uttesting er ønskelig for å oppnå stabile resultater.