Stacking of interferometric data

Radio and mm observations play an important role in determining the star formation properties of high redshift galaxies. However, most galaxies at high redshift are too faint to be detected individually at these wavelengths. A way to study this population of galaxies is to use stacking. By averaging the emission of a large number of galaxies detected in optical or near infrared surveys, we can achieve statistical detection. We investigate methods for stacking data from interferometric surveys. Interferometry poses unique challenges in stacking due to the nature of imaging of this data. We have compared directly stacking the uv data with stacking of the imaged data, the latter being the typically used approach. Using simulated data, we find that uv-stacking may provide around 50% less noise and that image based stacking systematically loses around 10% of the flux

Stacking of large interferometric data sets in the image- and uv-domain -- a comparative study

We present a new algorithm for stacking radio interferometric data in the uv-domain. The performance of uv-stacking is compared to the stacking of fully imaged data using simulated Atacama Large Millimeter/sub-millimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA) deep extragalactic surveys. We find that image- and uv-stacking produce similar results, however, uv-stacking is typically the more robust method. An advantage of the uv-stacking algorithm is the availability of uv-data post stacking, which makes it possible to identify and remove problematic baselines. For deep VLA surveys uv-stacking yields a signal-to-noise ratio that is up to 20 per cent higher than image-stacking. Furthermore, we have investigated stacking of resolved sources with a simulated VLA data set where 1.5" (10-12 kpc at z ~ 1-4) sources are stacked. We find that uv-stacking, where a model is fitted directly to the visibilities, significantly improves the accuracy and robustness of the size estimates. While scientific motivation for this work is studying faint, high-z galaxies, the algorithm analysed here would also be applicable in other fields of astronomy. Stacking of radio interferometric data is also expected to play a big role for future surveys with telescopes such as LOFAR and Square Kilometre Array (SKA).Comment: 15 pages, 12 figures, accepted for publication in MNRA

Stacking of interferometric data at sub-millimeter and radio wavelengths

Understanding the procceses of galaxy evolution require observational constraints on the physical properties of galaxies at different times in the history of the Universe. Large and deep surveys at visible and near-infrared wavelengths have, during the past decade, been used to produce extensive catalogues of high-redshift galaxies, spanning a large range of the history of the Universe. However, to properly understand the properties of these galaxies, and the processes they are going through, we need study them across the full electromagnetic spectrum. Observing the galaxies at mm and radio wavelengths add additional probes of the star formation, and allow us to further constrain their properties. Current radio/mm/submm high-redshift galaxy surveys, however, primarily probe luminous starbursts and AGN. A way to probe the radio andmm emission from less luminous galaxies is stacking. Stacking is a statistical approach to measure the average flux for known objects that are too faint to be detected individually at the target wavelength. This thesis investigates stacking of interferometric data. Typically, stacking at different wavelengths ranges is done using deep imaging surveys observed with a single telescope. However, interferometry is not a direct imaging method, and this presents a number of challenges to stacking. We present a new stacking algorithm that worksdirectly on visibilities, which we refer to as uv-stacking. We compare this algorithm to an image-stacking algorithm, i.e., an algorithm that stacks the sources directly inthe imaged data. The uv-stacking algorithm is found to yield more robust results than the image-stacking algorithm. In the case of JVLA surveys, uv-stacking results in a post-stacking signal-to-noise ratio up to 40% higher compared to image-stacking. Furthermore, it is possible to use the algorithms to estimate an average size of the stacked source population. Stacking marginally extended sources of 1.5arcsec for JVLA, we find that the typical uncertainties of sizes measured with image-stacking are more than twice that of uv-stacking. The stacking techniques are applied to colour-selected, high-redshift galaxies in the 344 GHz continuum survey ALESS (the ALMA survey of sources detected in the LABOCA Extended Chandra deep field south (ECDFS) Submillimetre Survey) and the VLA 1.4 GHz continuum of the ECDFS. Using the uv-stacking algorithm, the average sizes of the galaxies are measured to be around 1′′ , which correspond to a physical size of ∼ 8 kpc at z ∼ 2. Within the uncertainties, the stacked average sizes are consistent with sizes measured at visible and near-infrared wavelengths. While the uv-stacking algorithm is designed primarily around stacking high-redshift galaxies in ALMA and VLA, it can easily be extended to work for other interferometric telescopes and use cases. In particular, the uv-stackning algorithm has been shown to alleviate the effects of high dynamic range

Stacking of interferometric data - a submillimetre and radio view on the evolution of distant galaxies

Understanding the processes of galaxy evolution requires observational constraints on the physical properties of galaxies at different times in the history of the universe. Large and deep surveys at visible and near-infrared wavelengths have produced extensive catalogues of high-redshift galaxies, spanning a large range of the history of the universe. Over this time the galaxies undergo significant evolution, increasing not only their stellar content, but also their physical size. In this thesis I will present results from observations of star-forming galaxies at submm and radio wavelengths. Observations at these longer wavelengths probe young stars, showing where new stars are formed in the galaxies. The observations presented in this thesis show that, for star-forming galaxies out to z ≈ 3, the sizes measured at submm and radio wavelengths are significantly smaller than those measured at near-infrared wavelengths. This implies that most stars are formed in the centre of galaxies, indicating that in the absence of other size evolution mechanisms we expect the typical effective radii of galaxies to decrease with time. It highlights the need for other size evolution mechanisms, such as minor mergers or changes in the galaxies due to stellar feedback. A major part of this thesis investigates the technique of stacking for interferometric data. Stacking is a technique to study statistical properties of populations, and is currently essential for the study of high-redshift, star-forming galaxies at submm and radio wavelengths, as many of high-redshift galaxies are too faint to be observed directly. Typically, stacking at different wavelengths ranges is done using deep imaging surveys observed with a single telescope. However, interferometry is not a direct imaging technique, and this presents a number of challenges to stacking. We present a new stacking algorithm that works directly on the visibilities; we refer to it as uv-stacking. We compare this algorithm to an image-stacking algorithm, i.e., an algorithm that stacks the sources directly in the imaged data. The uv-stacking algorithm is found to yield more robust results than the image-stacking algorithm. It is of particular interest for size measurement of stacked galaxies, as it preserves the uv data through stacking, and allows for robust model fitting of the stacked data

Stacking of interferometric data - a submillimetre and radio view on the evolution of distant galaxies

Understanding the processes of galaxy evolution requires observational constraints on the physical properties of galaxies at different times in the history of the universe. Large and deep surveys at visible and near-infrared wavelengths have produced extensive catalogues of high-redshift galaxies, spanning a large range of the history of the universe. Over this time the galaxies undergo significant evolution, increasing not only their stellar content, but also their physical size. In this thesis I will present results from observations of star-forming galaxies at submm and radio wavelengths. Observations at these longer wavelengths probe young stars, showing where new stars are formed in the galaxies. The observations presented in this thesis show that, for star-forming galaxies out to z ≈ 3, the sizes measured at submm and radio wavelengths are significantly smaller than those measured at near-infrared wavelengths. This implies that most stars are formed in the centre of galaxies, indicating that in the absence of other size evolution mechanisms we expect the typical effective radii of galaxies to decrease with time. It highlights the need for other size evolution mechanisms, such as minor mergers or changes in the galaxies due to stellar feedback. A major part of this thesis investigates the technique of stacking for interferometric data. Stacking is a technique to study statistical properties of populations, and is currently essential for the study of high-redshift, star-forming galaxies at submm and radio wavelengths, as many of high-redshift galaxies are too faint to be observed directly. Typically, stacking at different wavelengths ranges is done using deep imaging surveys observed with a single telescope. However, interferometry is not a direct imaging technique, and this presents a number of challenges to stacking. We present a new stacking algorithm that works directly on the visibilities; we refer to it as uv-stacking. We compare this algorithm to an image-stacking algorithm, i.e., an algorithm that stacks the sources directly in the imaged data. The uv-stacking algorithm is found to yield more robust results than the image-stacking algorithm. It is of particular interest for size measurement of stacked galaxies, as it preserves the uv data through stacking, and allows for robust model fitting of the stacked data

Stacking of interferometric data at sub-millimeter and radio wavelengths

Understanding the procceses of galaxy evolution require observational constraints on the physical properties of galaxies at different times in the history of the Universe. Large and deep surveys at visible and near-infrared wavelengths have, during the past decade, been used to produce extensive catalogues of high-redshift galaxies, spanning a large range of the history of the Universe. However, to properly understand the properties of these galaxies, and the processes they are going through, we need study them across the full electromagnetic spectrum. Observing the galaxies at mm and radio wavelengths add additional probes of the star formation, and allow us to further constrain their properties. Current radio/mm/submm high-redshift galaxy surveys, however, primarily probe luminous starbursts and AGN. A way to probe the radio andmm emission from less luminous galaxies is stacking. Stacking is a statistical approach to measure the average flux for known objects that are too faint to be detected individually at the target wavelength. This thesis investigates stacking of interferometric data. Typically, stacking at different wavelengths ranges is done using deep imaging surveys observed with a single telescope. However, interferometry is not a direct imaging method, and this presents a number of challenges to stacking. We present a new stacking algorithm that worksdirectly on visibilities, which we refer to as uv-stacking. We compare this algorithm to an image-stacking algorithm, i.e., an algorithm that stacks the sources directly inthe imaged data. The uv-stacking algorithm is found to yield more robust results than the image-stacking algorithm. In the case of JVLA surveys, uv-stacking results in a post-stacking signal-to-noise ratio up to 40% higher compared to image-stacking. Furthermore, it is possible to use the algorithms to estimate an average size of the stacked source population. Stacking marginally extended sources of 1.5arcsec for JVLA, we find that the typical uncertainties of sizes measured with image-stacking are more than twice that of uv-stacking. The stacking techniques are applied to colour-selected, high-redshift galaxies in the 344 GHz continuum survey ALESS (the ALMA survey of sources detected in the LABOCA Extended Chandra deep field south (ECDFS) Submillimetre Survey) and the VLA 1.4 GHz continuum of the ECDFS. Using the uv-stacking algorithm, the average sizes of the galaxies are measured to be around 1′′ , which correspond to a physical size of ∼ 8 kpc at z ∼ 2. Within the uncertainties, the stacked average sizes are consistent with sizes measured at visible and near-infrared wavelengths. While the uv-stacking algorithm is designed primarily around stacking high-redshift galaxies in ALMA and VLA, it can easily be extended to work for other interferometric telescopes and use cases. In particular, the uv-stackning algorithm has been shown to alleviate the effects of high dynamic range

Staring into the eye of the Medusa

The Medusa is a nearby merger galaxy. The galaxy harbours an ongoing starburst with very efficient conversion of hydrogen to stars. This seems to happen despite the lack of high density gas. In this project I have studied the dynamics and structure of the molecular gas by looking at the rotational CO 2-1 line. I used data recorded with the SMA interferometer. The data from SMA has allowed me to push the resolution to approximately 0"4 and generate the highest resolution molecular gas map of the Medusa yet. At this scale we have been able to observe giant molecular associations(GMAs). We find that the GMAs in general have larger velocity dispersion than what we would expect from their size. I will briefly discuss possible causes for this. In the high resolution data we also find the Eye of the Medusa: a hole in the CO emission that is also associated with radio continuum emission and H0. This seems to be the site of a dramatic star-forming event. The Eye of the Medusa is not located at the dynamical centre of the galaxy, but a few hundred parcecs out. Possibly where the inflowing gas meets the central rotation. The new data has also allowed us a good look at the dynamics of the molecular gas. We found a quickly rotating central body with evidence of inflowing gas moving on non-circular orbits. We propose that what we see might be a molecular ring. This dynamical structure could be helping the starburst by rapidly feeding new gas into the centre

The single-family homes' opportunities to contribute with demand-side flexibility through load control of heat pumps

Elförbrukningen i Sverige har ökat över tid men utbyggnaden av transmissionskapacitet har varit långsam, vilket har lett att stamnätet mellan norra och södra Sverige är ansträngt. Detta har resulterat i att vissa geografiska områden riskerar att drabbas av kapacitetsbrist under höglastperioder. En tänkbar lösning som uppenbarats till trängseln i elnätet är att nyttja efterfrågeflexibilitet vid tidpunkter då elsystemet är ansträngt. En möjlig resurs som identifierats är laststyrning av värmepumpar vilket syftar till att reducera effektbehovet i elnätet under höglasttimmar. Detta görs genom att minska värmetillförseln till fastigheter med en installerad värmepump genom att utnyttja byggnadens värmetröghet och därigenom moderera effektförbrukningen i elnätet. I nuläget återfinns marknadsplatser som erbjuder handel av flexibilitetstjänster, men möjligheten för en småhusägare att bidra med flexibilitet är kraftigt begränsad. I rapporten undersöks hur stor potentialen är att minska effekttoppar genom smart laststyrning av värmepumpar i ett begränsat nätområde i Stockholms län samt vilka nyttor detta kan medföra för olika aktörer på elmarknaden. Nuvarande hinder och nödvändiga förutsättningar identifieras i syfte att stimulera en utökad flexibilitetsmarkand. Från företaget NIBE erhölls en modell vars syfte var att möjliggöra beräkningar av potential för laststyrning av värmepumpar. För att kunna använda beräkningsmodellen behövdes bland annat ett adekvat dataunderlag av förbrukningsdata, temperaturdata samt indata anpassad för det begränsade elnätområdet. Rapportens arbete tyder på att det är fullt möjligt att reducera effekttoppar i elnätet genom laststyrning av värmepumpar. Arbetet undersökte tre olika typfall i en vintermånad i ett vanligt svenskt villaområde bestående av 440 uttagspunkter varav 407 representerade småhus och av dessa hade 278 en registrerad värmepump. Urvalet av typdagarna baserades på dygnsmedeltemperatur där vi tog den kallaste, varmaste samt median dagen. Resultatet gav minskade effekttoppar mellan 4 – 13 % beroende på vilket scenario som studerades. En generell slutsats från resultaten är att det var svårare att kapa effekttoppar ju kallare utetemperaturen är och om effekttoppen pågår under lång tid. Den utförda extrapoleringen av resultatet till den samlade potentialen av effektreduceringen för Sverige som helhet beräknades till cirka 1,1-3,6 % av den totala medeleffektförbrukningen i Sverige. Nyttor vilka är förenade med laststyrning av värmepumpar handlar generellt om effektivare användning av elnätet och energiresurser och för de olika aktörerna på elmarknaden handlar nyttorna framförallt om olika typer av kostnadsbesparingar. Generella förutsättningar vilka ökar möjligheterna för småhusägare att bidra med efterfrågeflexibilitet är att elkunder behöver timprisavtal för att öka incitamenten till att minska ellerflytta sin elförbrukning. Vad som också krävs för att kunderna ska kunna styra sin last effektivt är timmätning hos varje kund samt installerad styrutrustning. Vår rekommendation kring valet av styrteknik är den styrning som använder en fiktiv utomhustemperatur genom att manipulera temperatursensorn. För att enskilda kunders efterfrågeflexibilitetspotential ska tillgängliggöras behövs dessutom ellagen ändras för att underlätta aggregatorrollen och göra det möjligt för aggregatorer att verka oberoende på elmarknaden. This report examines how great the potential is to reduce power peaks through smart load control of heat pumps in a limited network area in Stockholm County and what benefits this can entail for various players in the electricity market. Current obstacles and necessary conditions are identified in order to stimulate an expanded flexibility market. A model was obtained from the company NIBE whose purpose was to enable calculations of potential for load control of heat pumps. In order to be able to use the calculation model, an adequate database of consumption data, temperature data and input data adapted for the limited electricity network area was needed. The report indicates that it is entirely possible to reduce power peaks in the electricity grid through load control of heat pumps. The work examines three different typical cases in a winter month in an ordinary Swedish residential area consisting of 440 outlet points, of which 407 represented single-family homes and of these, 278 had a registered heat pump. The selection of days were based on the daily average temperature where we took the coldest, warmest and median day. This resulted in reduced power peaks between 4 - 13% depending on the scenario studied. A general conclusion from the results is that it was more difficult to cut power peaks the colder the outdoor temperature was and if the power peak lasted for a long time. The extrapolation of the result to the overall potential of the power reduction for Sweden as a whole was calculated at approximately 1.1-3.6% of the total average power consumption in Sweden. Benefits that are associated with load control of heat pumps are generally more efficient use of the electricity grid and energy resources. The benefits for the various players in the electricity market are primarily about different types of cost savings. General conditions that increase the opportunities for homeowners to contribute with demand flexibility are that electricity customers need hourly price agreements to increase the incentives to reduce or move their electricity consumption. What is also required for customers to be able to control their load efficiently is hourly measurement at each customer and installed control equipment. Our recommendation regarding the choice of control technology is the control that uses a fictitious outdoor temperature by manipulating the temperature sensor. In order to make individual customers' demand flexibility potential available, the Electricity Act also needs to be amended to facilitate the aggregator role and enable aggregators to operate independently of the electricity market

The single-family homes' opportunities to contribute with demand-side flexibility through load control of heat pumps

Elförbrukningen i Sverige har ökat över tid men utbyggnaden av transmissionskapacitet har varit långsam, vilket har lett att stamnätet mellan norra och södra Sverige är ansträngt. Detta har resulterat i att vissa geografiska områden riskerar att drabbas av kapacitetsbrist under höglastperioder. En tänkbar lösning som uppenbarats till trängseln i elnätet är att nyttja efterfrågeflexibilitet vid tidpunkter då elsystemet är ansträngt. En möjlig resurs som identifierats är laststyrning av värmepumpar vilket syftar till att reducera effektbehovet i elnätet under höglasttimmar. Detta görs genom att minska värmetillförseln till fastigheter med en installerad värmepump genom att utnyttja byggnadens värmetröghet och därigenom moderera effektförbrukningen i elnätet. I nuläget återfinns marknadsplatser som erbjuder handel av flexibilitetstjänster, men möjligheten för en småhusägare att bidra med flexibilitet är kraftigt begränsad. I rapporten undersöks hur stor potentialen är att minska effekttoppar genom smart laststyrning av värmepumpar i ett begränsat nätområde i Stockholms län samt vilka nyttor detta kan medföra för olika aktörer på elmarknaden. Nuvarande hinder och nödvändiga förutsättningar identifieras i syfte att stimulera en utökad flexibilitetsmarkand. Från företaget NIBE erhölls en modell vars syfte var att möjliggöra beräkningar av potential för laststyrning av värmepumpar. För att kunna använda beräkningsmodellen behövdes bland annat ett adekvat dataunderlag av förbrukningsdata, temperaturdata samt indata anpassad för det begränsade elnätområdet. Rapportens arbete tyder på att det är fullt möjligt att reducera effekttoppar i elnätet genom laststyrning av värmepumpar. Arbetet undersökte tre olika typfall i en vintermånad i ett vanligt svenskt villaområde bestående av 440 uttagspunkter varav 407 representerade småhus och av dessa hade 278 en registrerad värmepump. Urvalet av typdagarna baserades på dygnsmedeltemperatur där vi tog den kallaste, varmaste samt median dagen. Resultatet gav minskade effekttoppar mellan 4 – 13 % beroende på vilket scenario som studerades. En generell slutsats från resultaten är att det var svårare att kapa effekttoppar ju kallare utetemperaturen är och om effekttoppen pågår under lång tid. Den utförda extrapoleringen av resultatet till den samlade potentialen av effektreduceringen för Sverige som helhet beräknades till cirka 1,1-3,6 % av den totala medeleffektförbrukningen i Sverige. Nyttor vilka är förenade med laststyrning av värmepumpar handlar generellt om effektivare användning av elnätet och energiresurser och för de olika aktörerna på elmarknaden handlar nyttorna framförallt om olika typer av kostnadsbesparingar. Generella förutsättningar vilka ökar möjligheterna för småhusägare att bidra med efterfrågeflexibilitet är att elkunder behöver timprisavtal för att öka incitamenten till att minska ellerflytta sin elförbrukning. Vad som också krävs för att kunderna ska kunna styra sin last effektivt är timmätning hos varje kund samt installerad styrutrustning. Vår rekommendation kring valet av styrteknik är den styrning som använder en fiktiv utomhustemperatur genom att manipulera temperatursensorn. För att enskilda kunders efterfrågeflexibilitetspotential ska tillgängliggöras behövs dessutom ellagen ändras för att underlätta aggregatorrollen och göra det möjligt för aggregatorer att verka oberoende på elmarknaden. This report examines how great the potential is to reduce power peaks through smart load control of heat pumps in a limited network area in Stockholm County and what benefits this can entail for various players in the electricity market. Current obstacles and necessary conditions are identified in order to stimulate an expanded flexibility market. A model was obtained from the company NIBE whose purpose was to enable calculations of potential for load control of heat pumps. In order to be able to use the calculation model, an adequate database of consumption data, temperature data and input data adapted for the limited electricity network area was needed. The report indicates that it is entirely possible to reduce power peaks in the electricity grid through load control of heat pumps. The work examines three different typical cases in a winter month in an ordinary Swedish residential area consisting of 440 outlet points, of which 407 represented single-family homes and of these, 278 had a registered heat pump. The selection of days were based on the daily average temperature where we took the coldest, warmest and median day. This resulted in reduced power peaks between 4 - 13% depending on the scenario studied. A general conclusion from the results is that it was more difficult to cut power peaks the colder the outdoor temperature was and if the power peak lasted for a long time. The extrapolation of the result to the overall potential of the power reduction for Sweden as a whole was calculated at approximately 1.1-3.6% of the total average power consumption in Sweden. Benefits that are associated with load control of heat pumps are generally more efficient use of the electricity grid and energy resources. The benefits for the various players in the electricity market are primarily about different types of cost savings. General conditions that increase the opportunities for homeowners to contribute with demand flexibility are that electricity customers need hourly price agreements to increase the incentives to reduce or move their electricity consumption. What is also required for customers to be able to control their load efficiently is hourly measurement at each customer and installed control equipment. Our recommendation regarding the choice of control technology is the control that uses a fictitious outdoor temperature by manipulating the temperature sensor. In order to make individual customers' demand flexibility potential available, the Electricity Act also needs to be amended to facilitate the aggregator role and enable aggregators to operate independently of the electricity market

Att överbygga kunskapsgapet för nya markandsaktörer i det svenska elkraftsystemet

The need for ancillary services is on the rise due to the increasing share of weather-dependent power sources in the electric power system. This master thesis focuses on the Swedish FCR-D Up market. It is a national balancing market for transmission system operator’s procurement of the ancillary service called FCR-D Up, that is the up-regulating frequency containment reserve in case of system disturbances. The FCR-D Up market is undergoing significant changes to adapt to the changing electric power system, which may affect the current market dominance of hydropower suppliers due to the emergence of new suppliers and regulatory changes by the Swedish transmission system operator. This master thesis establishes a conceptual qualitative market development system model for price formation on the FCR-D Up market. The research question addressed is: "What FCR-D Up market developments and regulatory market changes on the supply and demand side respectively are expected in Sweden in the upcoming years, 2024-2026, and how will they affect the market prices?" The research was based on the theoretical concepts of system modeling and price formation, using Soft Systems Methodology. Data was collected from various sources and analysed using CATWOE analysis, Casual Loop Diagram, as well as supply and demand curve model theory. It was concluded that price-influencing market development and regulatory changes are focused on the supply side of the market. These include the market entry of new suppliers, transition to marginal pricing, new technical requirements for market participation and increasing value stacking opportunities for FCR-D Up suppliers on Nord Pool’s electricity markets and the other balancing markets. Behovet av stödtjänster ökar på grund av den ökande andelen väderberoende kraftkällor i elkraftsystemet. Denna masteruppsats fokuserar på den svenska FCR-D Upp-marknaden. Det är en nationell balansmarknad för transmissionsnätsoperatörens upphandling av den stödtjänst som kallas FCR-D Upp, som är den uppreglerande frekvenskontrollreserven vid störningar i systemet. FCR-D Uppmarknaden genomgår betydande förändringar för att anpassas till det föränderliga elkraftsystemet, vilket kan påverka den nuvarande marknadsdominansen av vattenkraftsleverantörer på grund av tillkomst av nya leverantörer och regulativa marknadsförändringar av transmissionsnätsoperatören. Denna masteruppsats etablerar en konceptuell kvalitativ systemmodell för marknadsutveckling avseende prisbildning på FCR-D Upp-marknaden. Forskningsfrågan är: "Vilken utveckling av FCR-D Upp-marknaden och vilka regulatoriska marknadsförändringar på utbuds- respektive efterfrågesidan förväntas i Sverige under de kommande åren, 2024-2026, och hur kommer de att påverka marknadspriset?". Arbetet baserades på teoretiska koncept kring systemmodellering och prisbildning, med fokus på Soft Systems Methodology. Data samlades in från olika källor och analyserades med hjälp av CATWOE-analys, Casual Loop Diagram samt modellteori för utbuds- och efterfrågekurvor. Slutsatsen var att prisinfluerande marknadsutvecklingar och regulatoriska marknadsförändringar är inriktade på marknadens utbudssida. Det handlar bland annat om nya leverantörers inträde på marknaden, övergången till marginalprissättning, nya tekniska krav för marknadsdeltagande och ökande möjligheter till värdestapling för FCR-D Upp leverantörerpå Nord Pools elmarknader och de andra balansmarknaderna