<p>It has been proposed to supply heat and power to Snøhvit Train II (STII) from onsite heat generation based on natural gas and power import from the power grid. Without carbon capture and storage, greenhouse gas (GHG) emissions from the combustion of natural gas in furnaces make a considerable contribution to the global warming potential (GWP) of this energy system. Depending on the interpretation of marginal power consumption, the power import also contributes to and increases this system’s GWP. A recent SINTEF report claimed that European CO2 emissions are reduced with additional renewable power production in Norway, and it has been suggested to invest in wind power in order to completely offset the GWP of the STII energy system. This paper provides investment analyses for the proposed energy system. A scenario approach was used, with six different scenarios covering two dimensions. The first dimension is the origin of the grid power, with three different interpretations of marginal power representing Cases A, B and C. The other dimension is the STII train size, with two different sizes being analyzed, namely 50 % and 70 % of the Snøhvit Train I design capacity. The proposed energy system was also analyzed with respect to security of supply. Improved reliability and transmission capacity, together with a stable, positive power balance, make a good foundation for security of power supply. The power demand of the two train sizes was estimated to 101 MW and 141 MW, with corresponding heat demand of 94 MW and 131 MW. These estimates were based on a combination of HYSYS simulations and data provided by StatoilHydro (SH), and provided input for both the GWP analysis and the investment analysis. The GWP impact of each scenario determined the share of power import from the grid that would have to be replaced by energy harnessed from wind. The applied capacity factor was 39.6 %, and the rated wind power requirement for the six different scenarios ranged from 101 MW for the A.50 scenario to 257 MW for the C.70 scenario. The break even (BE) energy prices were calculated for each of the six scenarios analyzed. If the power consumption is based solely on power import, with zero StatoilHydro (SH) share of grid reinforcements and no SH development of wind power, the BE power price would be 466 NOK/MWh. The inclusion of wind power development as part of the investment will increase the BE power price by up to 33 NOK/MWh. The additional SH share of grid reinforcement will add 86 NOK/MWh for the 50 % STII or 62 NOK/MWh for the 70 % STII. It was shown that the investment in wind power to offset the GWP of the energy system might also be a reasonable way of hedging against increases in the market price of electricity. It was found that the share of STII power demand that is provided by wind power is one of the parameters that have the least influence on the project’s net present value (NPV). A high share of wind power is an inexpensive investment in improving reputation and predictability of energy price.</p>

<p>This report presents opportunities for use of CO2 as refrigerant in the air conditioning system in public trains. The CO2 system shall provide cooling in the summer and heating in the winter. CO2 is a natural fluid which means that it exists naturally in the biosphere. Today 75% of the air conditioning systems in trains use R134a as refrigerant. The GWP of R134a is 1410 while CO2 used as refrigerant is 0. A replacement from R134a to CO2 gives possibilities of large environmental savings. Three different technical system solutions of the heat pump are presented, each with its own method of provide cooling and heating. Solution I changes between cooling and heating by change the direction of the refrigerant flow through the system. Solution II changes between cooling and heating by change the configuration of the air streams through the heat exchangers. In Solution III the refrigerant flow direction and the configurations of the air streams is always the same. The whole heat pump is placed on a rotatable unit and the change between cooling and heating is done by rotating the whole heat pump 180°. In all the three technical solutions there are separated heat exchangers for fresh and exhaust air. This gives an energy efficient system which recover heat from the exhaust air. Computer simulation shows that a system solution with one evaporation pressure and one stage compression is problematic for low ambient temperatures; the system must stand temperatures to 40 °C. A system solution with two levels on the evaporation pressure and a two stage compression showed to improves the COP from 1,7 to 3,2 when the ambient temperature at 40 °C. A railway coach need cooling when the ambient temperature is above 20 °C and heating below 15 °C. Norway is a country with cold climate. Weather statistic show that a train which drives in Oslo every day from 0600 to 1800 throughout a year will need cooling 3% of the time and heating 83% the time. This heating should be done by a heat pump and not with electrical heating as today. Results of the computer simulation shows that the annual energy consumption of heating the train will be reduced by 78 % if the designed CO2 heat pump is used in stead of electrical heating.</p>

<p>Vane pack demisters in the industry operate with natural gas at pressures up to 100 bara. A new vane pack has been compared with the traditional one used by the industry. The vane packs have been investigated through experiments and Computational Fluid Dynamics, CFD. The fluid flow inside a vane pack consist of turbulence and two fluid phases. The simulations were carried out with a Large Eddy Simulation model and a Scale-Adaptive Simulation model. Phenomena observed in the experiments were confirmed by CFD. A transient Discrete Phase Model,DPM, that should be capable of modeling the generation of a liquid film together with droplets was used. The DPM simulation gave a mist flow pattern that agreed with the one observed in the laboratory. Separation efficiency measurements of the two vane packs using Exxsol D60 as liquid and SF6 as gas were performed at different pressures, ranging from 1 to 8 barg. This corresponds to natural gas density ranging from 8 to 65 barg. Non of the experiments achieved the specification given by the oil and gas industry. The efficiency measurements did show that the pressure had a great influence on the performance. The low pressure measurements were the only experiments which had a efficiency above 97% at a k-value between 0.2 - 0.25 m/s.</p>

<p>A multiregional input-output model representing the world in the year 2000 was constructed based on statistical data, and combined with process specific data on a primary aluminium supply chain, to create a model of the global primary aluminium industry. Using input-output methodology, total emissions of eight substances due to primary aluminium production, their size and origins, were estimated and expressed in terms of global warming potential (GWP) and acidification potential (AP). Simulations from 2000 to 2030 were run based on final demand estimates from external GDP projections and three assumed development scenarios. The baseline, scenario 0, assumed no changes in technologies or relative production and trade patterns - only the model's response to the expected change in final demand was analyzed. By contrast, both scenarios 1 and 2 assumed that the additional aluminium production predicted by the baseline would be produced exclusively in China. Scenario 2 employed the added assumption that the Norwegian aluminium production would experience a steady decline from its 2000 level to zero by 2030. The baseline scenario showed rapidly increasing aluminium output towards 2030, following the expected GDP developments. Emissions followed the same trend, increasing about 3.3 times over the three decades. As for total cradle-to-gate impacts of primary aluminium production, the model showed large variations from one region to another. Emissions per ton of Chinese primary aluminium were high relative to most other regions, hence the total global GWP and AP from primary aluminium production rose more rapidly in scenarios 1 and 2 than in scenario 0. By 2030, the GWP in scenarios 1 and 2 were 11.4% and 12.5 higher than in the baseline, while AP were 50.0 and 51.9 higher.</p>

<p>Spyling (Flushing) av gass med en væske kolonne er viktig i forbindelse med trykk testing av rørledninger. For å vurdere multifase simulatoren OLGA 6.0 sin evne til å predikere spyling av en rørledning har simuleringer i OLGA blitt sammenlignet med små skala forsøk. En test rigg har blitt satt opp med konfigurasjonen av en bølgeformet rørledning. Den viktigste variabelen var høyden på vannet i reservoaret. Forsøkene ble filmet med et video kamera. Slutt tilstanded ble logget ved å måle den vertikale høyden av væske kolonnene i de ulike rør seksjonene. Dette ble sammenlignet med slutt tilstanden i OLGA simuleringene. Et Matlab skripe ble utviklet for å gjøre bilde analyse av filmen. Bilde analysen ble brukt til å sammenligne det transiente forløpet av eksperimentene med simuleringene i OLGA. Slutt tilstanden i forsøkene hvor røret ikke ble spylt var i god overensstemmelse med simuleringene i OLGA. Det transiente forløpet var mye raskere i OLGA. Forholdet mellom tiden det tok væsken å nå utløpet i eksperimentet hvor røret ble spylt og simuleringen i OLGA var 2.5. Dette forholdet avtok med innløpstrykket. Grunnen til denne uoverensstemmelsen er vurdert å komme av at det ikke er noen modell for overflatespenning mellom fluid og vegg i OLGA. For å finne minste løftehøyde for at OLGA skulle predikere spyling av røret, ble en parameterstudie av innløpstrykket utført. Faktoren mellom løftehøyden som var nødvendig for å spyle røret i eksperimentene og OLGA simuleringen var 0.84. Dette var overraskende siden OLGA predikerte et mye raskere transient forløp med større hastighet og bevegelsesmengde. Grunnen til over prediksjonen av den nødvendige løftehøyden antaes å komme av at OLGA til en liten grad tar høyde for strømnings historikk. Effekten av dette er at væskeplugger forsvinner i overgangen mellom et oppover rør og et nedover rør.</p>

<p>Subsea processing can make production from otherwise unprofitable fields profitable. In subsea processing controlled cooling of the process fluid will often be required. Robust and simple solutions are desirable in subsea processing. Coolers that rely on natural convection from the surrounding seawater are therefore interesting, but control of the process fluid outlet temperature is hard to obtain in such coolers. In this study a calculation model for subsea coolers has been developed. The commercial software MATLAB has been used for developing a program. Heat transfer and frictional pressure drop correlations have been studied and recommendations are made for the model. The model is based on tubes in parallel, and the tubes can be oriented vertically or horizontally. The program allows for open, semi-open and closed arrangements on the waterside, and both natural and forced convection is implemented. The program has been tested through simulations of two test cases and found to be performing as desired.</p>

<p>The performance of a hot wire probe with three wires is investigated for two different flow cases. The wires are made of a platinum/rhodium alloy, and has a diameter of 5 micrometer. The three wires make a probe volume with acrossection of approximately 5 mm. A cosinus fit using the effective angle method gives a deviation of plus/minus 1 degree for a variation of yaw angle equal to plus/minus 20 degrees. First the probe was tested in a fully developed turbulent pipe flow, for Re_D = 10^5. Good results were obtained for |y/R|<0.8, both for mean velocities and turbulent stresses. Closer to the wall the mean flow gradient was to large relative to the probe resolution, giving large errors. The second flow case was a cylinder wake. A traverse of the flow at x/D = 10 was performed at Re_D = 3*10^3. The mean velocities and turbulent stresses was partly found to be in qualitative agreement with results found in litterature. The shear stresses uw and vw were however found to be unphysically large, this is belived to be due to the velocity gradient in the wake. Conditional averaging of the wake results with respect to shedding frequency was also conducted.</p>

<p>The process used by the Norwegian company Hydro for making Vinyl Chloride Monomer (VCM) from natural gas and sodium chloride has been studied. A three dimensional CFD model representing the firebox of the EDC cracker has been developed using the commercial CFD tool Fluent. Heat to the cracker is delivered by means of combustion of a fuel gas consisting of methane and hydrogen. In the developed CFD model used in this work, the combustion reaction itself is omitted, and heat is delivered by hot flue gas. With the combustion reaction left out, the only means of tuning the CFD model is through the flue gas inlet temperature. With the flue gas inlet temperature near the adiabatic flame temperature, the general temperature level of the EDC cracker was reported to be too high. The outer surface temperature of the coil was reported to be 3-400 K higher than what was expected. By increasing the mass flow of flue gas and decreasing the temperature, the net delivered heat to the firebox was maintained at the same level as the first case, but the temperature on the coil was reduced by 100-150 K. Further reductions in the flue gas inlet temperature and modifications in the mass flow of flue gas at the different burner rows, eventually gave temperature distributions along the reaction coil, and flue gas and refractory temperatures, that resemble those in the actual cracker. The one-dimensional reactor model for the cracking reaction represents the actual cracker in a satsifactorily manner. The cracking reaction was simulated using a simple, global reaction mechanism, thus only the main components of the process fluid, EDC, VCM and HCl, can be studied. The model is written in a way suitable for implementation of more detailed chemical reaction mechanisms. The largest deviation in temperature between measured and simulated data are about 5%. At the outlet the temperature of the process fluid is equal to the measured data. The conversion of EDC out of the firebox is assumed to be 50 wt-%, this value is met exactly by the model.</p>

<p>This master thesis describes a quadratic programming model used to calculate the spot prices in an efficient multi-area power market. The model has been adapted to Northern Europe, with focus on Denmark West and the integration of large quantities of wind power. In the model, demand and supply of electricity are equated, at an hourly time resolution, to find the spot price in each area. Historical load values are used to represent demand which is assumed to be completely inelastic. Supply is modeled according to the type of generation: Thermal generators are represented by piecewise linear, upward sloping, marginal cost curves. Historical wind generation data is used to model the fluctuating wind power output, and wind power is considered to have zero marginal cost. Hydro power is modeled by one aggregate reservoir for Norway and one for Sweden; the marginal cost of hydro power is set as a function of the difference between the reservoir level and the historical median reservoir level. Additionally, decentral combined heat and power plants in Denmark are considered to operate irrespective of the market. Six separate price areas constitute the model: Denmark West, Denmark East, Norway, Sweden/Finland, Germany, and Central Europe. The areas are modeled as having no internal bottlenecks and are connected by tie-lines constrained by active power limits. This report quantifies the impact the installed wind power capacity has on the power price in Denmark West by scaling up the wind power output in the model. Because wind power has a marginal cost close to zero, it will force prices down. The effect will be most prominent during high wind speed hours in a power system with substantial amounts of wind power. Results show that the impact is modest; average power prices fall by only 10% if the installed wind power capacity is doubled, and thermal generation will set the power price in all hours until wind energy exceeds 50% of domestic demand in Denmark. Since prices fall the most during hours with high wind power output, income to wind turbine owners will decline quickly as the installed capacity becomes large. The effect is most pronounced at wind energy shares above 40%, thereafter the income -- per MWh sold -- falls rapidly. In absence of government subventions, this effect will limit the economically viable level of installed wind power capacity. Expansion of the cross-border transmission capacity and higher thermal generation costs can both help offset the income reduction to wind turbine owners from higher wind power penetration. Alone, a 30% increase in thermal generation costs can allow 50% of wind energy and still retain todays income to wind turbine owners. Use of the Norwegian hydro reservoirs to balance out fluctuations in wind power output is found to stabilize and reduce the price. This benefits both consumers and wind turbine owners in Denmark. Expansion of transmission capacity to Norway will further stabilize the price; a new 1000MW cable lets the Danish market easily accomodate 50% wind energy. With lower and more volatile prices as a result of high wind power penetration, a load can profit by being flexible. Water electrolysis is one such load; it uses electricity to produce hydrogen, and production can quickly be ramped up and down in accordance with the power price. Presently, steam methane reforming is the least expensive method of producing hydrogen, but with higher wind power penetration, electrolysis might become competitive. Using a previously developed model to assess the cost of electrolysis, in combination with the power market model developed here, this report finds that wind energy must exceed 85% of domestic demand in Denmark, combined with higher natural gas prices, for electrolysis to break even with steam methane reforming.</p>

<p>Nordel is the organisation for the Nordel synchronous system, held by the Nordic Transmission System Operators. In their work to harmonise the Nordic electricity markets they have agreed upon harmonising the Nordic balance management. This will imply three large changes, firstly the settlement of the production balance will be done by a 2-price settlement, (instead of the 1-price settlement in Norway), and secondly there will be a new intraday market for settling the balances after 12- 36 hours and before operating time. Finally the Balance Responsible Parties will have to take their share of the costs for operating the reserves. Paying a penalty through paying more in the regulating market than in the spot market is meant as an incentive for the market to maintain their power balance. This will help the system operator reduce their need to contract and use reserve power and consequently reducing total costs. These new regulations will reduce the net income from producers of wind and other power plants that cannot control their production, like run of river hydro power plants. The market for electricity is currently divided into three consecutive markets. Nord Pool fixes the price the day ahead of operation, followed by the intra-day market Elbas (not in Norway), where power is traded up to one hour before operation, and lastly, the balancing market which helps maintain the balance in the operational hour and settles the costs afterwards. The costs of balancing wind power production in the balancing market (1- price and 2-price) are analysed. Wind series from three Norwegian wind parks have been nominated to the spot market and the deviation settled in the balancing market, by the 1-price settlement as reference and the 2-price settlement. The nominations have been done to three different years; 2004, 2005 and 2006 in Norway, and park A is nominated to 2006 in Sweden and Denmark. It is assumed that the wind power production and the spot and regulating prices are independent of each-other. The resulting change in income with deviation compared to making no prediction error for a 100 MW wind farm is presented. The highest loss compared to making no prediction error is when making a common bid for park A and B (11 677 000 in 2006), followed by the common bid for park A+B with wind series from the second year(8 555 000 in 2006) and park A (7 733 000 in 2006) in Denmark. One of the best ways to integrate large amounts of wind energy is to improve the forecasting methods. In that way the production planning will go easier, and deviations and corresponding costs are reduced. The savings achieved by introducing a prediction tool equals 3 523 000, 4 122 000, 4 921 000 compared to the base case of the corresponding MAEs equal to 39%,30% and 18%. The smoothing effect emerges when nominating geographically spread parks in a group(Holtinnen, 2005). Three parks, that are separated by several 100 km, are nominated by a single BRP. The resulting costs compared to separate nominations are reduced by 31,5 %. This result requires that the wind farms is in the same price area, which they in this case does not. The result is interesting nevertheless as Nordel continuously seek to to invest in transmission capacity in order to create an efficient Nordic market for electricity. The Elbas market is mainly a market to reduce risks. If a deviation should occur it is likely that the best way for balancing it, will be in the regulating market. This is due to the principle of the merit order, which implies that the cheapest regulating power offered is used first. By comparing the data there were quite a few hours were the middle Elbas price was higher than the regulating price. In this sense it might have been wise to wait, although the lower regulating price may also have been a result of more energy being settled in the Elbas market, reducing the volume needed to be settled in the regulating market, and accordingly reducing the price.</p>