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Detta projekt har analyserat sektorkopplingars möjligheter att ta vara på restflöden som genereras vid produktion av vätgas genom elektrolys samt hur dessa flöden kan generera ekonomiska och systemmässiga fördelar. Förutsättningen har varit att all el köps in externt för spotpris. Projektet har redovisat i detalj hur restvärmen, som uppstår i elektrolysen, kan tillgodogöras som fjärrvärme och därigenom öka processens verkningsgrad från cirka 66 till 95 %. EU:s mål om produktion av 10 miljoner ton vätgas per år till 2030 innebär att det bildas 230 TWh restvärme, motsvarande fyra gånger Sveriges totala fjärrvärmeenergi. Det visar potentialen och vikten av att värmeöverskottet nyttjas i framtida investeringar. För varje kilo vätgas som produceras bildas åtta kilo syrgas, som kan användas i för att förbättra förbränningen i en avfallspanna. Alternativt kan syrgasen transporteras till ett närliggande vattenreningsverk, vilket minskar elanvändningen för de pumpar som idag cirkulerar luft i de biologiska reningsstegen. Svenska kraftnät har skapat flera olika marknader för systemtjänster. Vätgasproduktion har goda förutsättningar att delta, särskilt med FCR-D. Analyserna visar att intäkterna från dessa tjänster kan vara större än både restvärmen och syrgasen, förutsatt att restvärmen inte ersätter bränslen som har en högre kostnadsprofil, som exempelvis bio-olja eller pellets. I dessa fall får restvärmen ett betydligt högre värde. Sektorkopplingen mot fjärrvärme skapar ett resurseffektivt energisystem där alla restflöden kan komma till nytta. Vätgaslager kan också bidra till ett mer robust och resilient energisystem, med möjligheter att förse kritiska verksamheter med reservkraft eller för att starta lokala elnät i ö-drift. För bästa lönsamhet, utifrån befintliga data om elpriser och vätgasens värde, bör vätgasen säljas vidare som bränsle till tunga transport eller som råvara till industrier istället för att lagras för senare omvandling tillbaka till el. I en framtid, där b, Produktion av vätgas med sektorkoppling till fjärrvärme HyCoGen Slutrapport 2023-12-18

Liberalized electricity market conditions and concentrating solar power technologies call for increased power plant operational flexibility. Concerning the steam turbine component, one key aspect of its flexibility is the capability for fast starts. In current practice, turbine start-up limitations are set by consideration of thermal stress and low cycle fatigue. However, the pursuit of faster starts raises the question whether other thermal phenomena can become a limiting factor to the start-up process. Differential expansion is one of such thermal properties, especially since the design of axial clearances is not included as part of start-up schedule design and because its measurement during operation is often limited or not a possibility at all.The aim of this work is to understand differential expansion behavior with respect to transient operation and to quantify the effect that such operation would have in the design and operation of axial clearances. This was accomplished through the use of a validated thermo-mechanical model that was used to compare differential expansion behavior for different operating conditions of the machine. These comparisons showed that faster starts do not necessarily imply that wider axial clearances are needed, which means that the thermal flexibility of the studied turbine is not limited by differential expansion. However, for particular locations it was also obtained that axial rubbing can indeed become a limiting factor in direct relation to start-up operation. The resulting approach presented in this work serves to avoid over-conservative limitations in both design and operation concerning axial clearances., QC 20170814

Solar steam turbines are subject to high thermal stresses as a result of temperature gradients during transient operation, which occurs more frequently due to the variability of the solar resource. In order to increase the flexibility of the turbines while preserving lifting requirements, several operational modifications for maintaining turbine temperatures during offline periods are proposed and investigated. The modifications were implemented in a dynamic thermal turbine model and the potential improvements were quantified. The modifications studied included: increasing the gland steam pressure injected to the end-seals, increasing the back pressure and increasing the barring speed. These last two take advantage of the ventilation and friction work. The effects of the modifications were studied both individually as well as in different combinations. The temperatures obtained when applying the combined modifications were compared to regular turbine cool-down (CD) temperatures and showed significant improvements on the startup times of the turbine., QC 20150408

To optimize the start-up schedules of steam turbines operating in concentrating solar power plants, accurate predictions of the temperatures within the turbine are required. In previous work by the authors, thermal models of steam turbines have been developed and validated for parabolic trough solar power plant applications. Building on these results, there is an interest to increase the adaptability of the models with respect to different turbine geometries due to the growing trend of having larger steam turbines in parabolic trough and solar tower power plants. In this work, a modular geometric approach has been developed and compared against both the previous modeling approach and 96h of measured data from an operational parabolic trough power plant. Results show a large degree of agreement with respect to the measured data in spite of the different detail levels. The new model allows for simple and fast prediction of the thermal behavior of different steam turbine sizes and geometries, which is expected to be of significant importance for future concentrating solar power plants., QC 20140922. QC 20160129

Solar steam turbines are subject to high thermal stresses as a result of temperature gradients during transient operation, which occurs more frequently due to the variability of the solar resource. In order to increase the flexibility of the turbines while preserving lifing requirements, several operational modifications for maintaining turbine temperatures during offline periods are proposed and investigated. The modifications were implemented in a dynamic thermal turbine model and the potential improvements were quantified. The modifications studied included: increasing the gland steam pressure injected to the end-seals, increasing the back pressure and increasing the barring speed. These last two take advantage of the ventilation and friction work. The effects of the modifications were studied both individually as well as in different combinations. The temperatures obtained when applying the combined modifications were compared to regular turbine cool-down temperatures and showed significant improvements on the start-up times of the turbine., QC 20151029. QC 20160214

Steam turbines in solar thermal power plants experience a much greater number of starts than those operating in base-load plants. By maintaining higher internal temperature during idle periods, faster start-up times can be achieved, increasing the flexibility of the plant as well as increasing net electrical production. Prior work by the authors identified a number of methods for achieving this, with strong increases in daily production predicted; only two specific start-up cases were studied however. In order to obtain a more representative evaluation of the performance increase that can be achieved through increased dispatchability of the turbine, the annual improvement needs to be studied. Building on the existing results, a dynamic system model of a parabolic trough power plant has been established and used to determine the distribution of different cool-down times experienced throughout the year, with a view to evaluating the potential annual production increase. A modification of the start-up curves allows an increase in annual electrical production between 6.4% and 2.4% depending upon the operating mode (free operation versus day-time operation). Through application of a combination of heat blankets and an increase in gland steam temperature, further annual production increases between 2.2% and 3.1% are predicted., QC 20120417

Steam turbines in solar thermal power plants experience a much greater number of starts than those operating in baseload plants. In order to preserve the lifetime of the turbine while still allowing fast starts, it is of great interest to find ways to maintain the turbine temperature during idle periods. A dynamic model of a solar steam turbine has been elaborated, simulating both the heat conduction within the body and the heat exchange with the gland steam, main steam and the environment, allowing prediction of the temperatures within the turbine during off-design operation and standby. The model has been validated against 96 h of measured data from the Andasol 1 power plant, giving an average error of 1.2% for key temperature measurements. The validated model was then used to evaluate a number of modifications that can be made to maintain the turbine temperature during idle periods. Heat blankets were shown to be the most effective measure for keeping the turbine casing warm, whereas increasing the gland steam temperature was most effective in maintaining the temperature of the rotor. By applying a combination of these measures the dispatchability of the turbine can be improved significantly: electrical output can be increased by up to 9.5% after a long cooldown and up to 9.8% after a short cooldown., QC 20111213

The paper compares three numerical strategies to predict the aerodynamic rotor excitation sources of "Low Engine Order" (LEO) in a high-pressure turbine stage. Main focus is laid on methods to compute the stator exit flow. The aim is to evaluate computationally cheap approaches to avoid modeling the whole circumference of the stator. A single passage viscous strategy, a single passage inviscid linear blade movement strategy, and a viscous multi-passage sector strategy are compared and evaluated. The assessment of the prediction quality is made by comparison of the computed stator exit flow to experimental data. The main result is that only the global behavior of the stator exit flow is estimated right, both the level and amplitude of Mach number and pressure are computed with poor agreement to experiments. Future evaluations of the resulting rotor excitation pressure are needed to estimate the level of necessary agreement to give acceptable predictions of the low engine order forced response., QC 20111007

This paper demonstrates and evaluates unique flow measurement results obtained in a high pressure test turbine, in order to analyze the effect of Low Engine Order (LEO) excitations. A stator was modified to induce LEO flow variations by either imposing a throat width variation or a blockage of the trailing edge cooling flow from some of the vanes. Laser Two Focus (L2F) and pressure probe measurements were performed at subsonic and transonic flow conditions, without and with the rotor installed and operated. Time resolved velocity data was obtained in front and inside of rotor passages covering the Low Engine Order variation period. The presented results evaluation focuses only on L2F measurements and show that the LEO variation of flow velocity and turbulence intensity is most visible in the gap between stator and rotor and at the first measurement location inside the rotor passage. The overall trend is that stator exit flow Mach numbers are higher behind the passages with smaller pitch and vice versa., QC 20150601