713 research outputs found
Dead Battery? Wind Power, The Spot Market, and Hydro Power Interaction in the Nordic Electricity Market
It is well established within both the economics and power system engineering literature that hydro power can act as a complement to large amounts of intermittent energy. In particular, hydro power can act as a "battery" where large amounts of wind power are installed. This paper attempts to extend that literature by describing the effects of cross-border wind and hydro power interaction in a day-ahead "spot" market. I use simple econometric distributed lag models with data from the Nordic electricity market and a sample of Norwegian hydro power plants with water storage magazines. I suggest that wind power mainly affects prices in the hydro power area by way of shifting the shadow value of water. The empirical results support this view.Wind Power; Hydro Power; Nordic Electricity Market; Empirical
What Happens When it's Windy in Denmark? An Empirical Analysis of Wind Power on Price Variability in the Nordic Electricity Market
High levels of wind power penetration will tend to affect prices in a deregulated electricity market. Much of the analysis in the literature has focused on the effect that wind power has on average electricity prices, this paper attempts to test the effect that wind power production has on the variability of wholesale electricity prices in the spot market. I use a simple distributed lag econometric model and five years worth of hourly and daily data from Denmark, which is one of the few places with a long history of significant wind power penetration. I show that wind power has the effect of reducing intra-day variability but that this result only partially carries over to price variation over weekly time windows. I suggest that the reduction in price variability in turn is due to a steeper supply schedule at peak-load times.Wind Power; Nordic Electricity Market; Empirical; Time Series
The Decision to Scrap a Wind Turbine: Opportunity Cost, Timing and Policy
This paper attempts to empirically identify the key factors involved in the decision to scrap a wind turbine using data from Denmark. The importance of the opportunity cost of operating an older wind turbine is shown to be a prominent factor in the decision to scrap. I show the strong effect that renewable energy policy plays in the decision to scrap a turbine. Through the use of both non-parametric and semi-parametric duration models and an instrumental variables approach I identify a strong effect for scrapping schemes put in place by the Danish government. I also obtain the, initially, counter-intuitive result that more effective wind turbines have a higher hazard of being scrapped.Wind Power; Denmark; Empirical; Duration Models; Scrapping
Rocket noise filtering system using digital filters
A set of digital filters is designed to filter rocket noise to various bandwidths. The filters are designed to have constant group delay and are implemented in software on a general purpose computer. The Parks-McClellan algorithm is used. Preliminary tests are performed to verify the design and implementation. An analog filter which was previously employed is also simulated
Scrapping a Wind Turbine: Policy Changes, Scrapping Incentives and Why Wind Turbines in Good Locations Get Scrapped First
The most common reason for scrapping a wind turbine in Denmark is to make room for a newer turbine. The decision to scrap a wind turbine is then highly dependent on an opportunity cost that comes from the interaction of scarce land resources, technological change and changes in subsidy policy. Using a Cox regression model I show that turbines that are located in areas with better wind resources are at a higher risk of being scrapped. Policies put in place in order to encourage the scrapping of older, poorly placed turbines actually have a larger effect on well-placed turbines
Destabilization of crude oil sludges by chemical and mechanical treatment
The demand for petroleum is still increasing. As a result, various wastes are generated during exploration and production, even though strict rules and regulations are applied to oil and gas industries to optimize waste management programs. The refineries still produce significant amounts of crude oil sludges formed at the bottom of crude oil storage tanks. This waste is identified as hazardous waste. The accumulation of crude oil sludges negatively impacts the storage capacity and the safe operation of the storage tanks.
This study presents the problem connected with crude oil sludges and the alternatives for its treatment. In favor of minimizing the environmental impact caused by oil sludges, the primary strategy for its treatment is to separate the sludge into its main components: oil, water, and solids. The oil in the sludge may be considered a recovery source. The sludge´s complex composition and properties were comprehensively described on how to separate the sludge. A method for destabilizing and separating the sludge into three phases was proposed and tested on two types of sludges (Mongstad sludge and Brenda sludge).
Chemical destabilization of crude oil sludges by adding different MudSplit chemicals followed by centrifugation proved to give a positive result. The results showed how variables in sludge composition and properties challenge the treatment process of this waste. Temperature and pH were enhancing factors for Mongstad sludge's destabilization. Heat energy reduced the viscosity of the sludge, and the addition of MudSplit chemicals also reduced the viscosity. Mongstad sludge gave three-phase separation, where in most samples, the upper phase contained >90 % oil and was free of water. The effect of the tested MudSplit chemicals was not comprehensively observed under the different experimental conditions. Brenda sludge showed to be more difficult to destabilize. It was possible to separate the sludge into three distinct phases through chemical and mechanical treatment. The best results for Brenda sludge were recorded using MudSplit6
The effect of oil prices on offshore production : evidence from the Norwegian continental shelf
I use detailed field-level data on Norwegian o↵-shore oil field production
and a semi-parametric additive model to control for the production
profile of fields to estimate the e↵ect of oil prices on production.
I find no significant evidence of a concurrent reaction of field
production to oil prices, though a slight lagged e↵ect is found of the
magnitude of approximately 2 to 4% for a 10 dollar per barrel increase
in the real price of oil. Most of this e↵ect appears to come in
the planning phase of a field’s development
Adults in the room? The auditor and dividends in small firms: Evidence from a natural experiment
We examine the effect of auditing on dividends in small private firms. We
hypothesize that auditing can constrain dividends by way of promoting
accounting conservatism. We use register data on private Norwegian firms and
random variation induced by the introduction of a policy allowing small private
firms to forgo the use of an auditor to estimate the effect of auditing on
dividend payout. Identification is obtained by a regression discontinuity
around the arbitrary thresholds for the policy. Propensity score matching is
used to create a balanced synthetic control. We consistently find that forgoing
auditing led to a significant increase in dividends in small private firms
The information continuum model of evolution
Most biologists agree that evolution is contingent on inherited information shaped by natural selection. This apparent consensus could be taken to indicate agreement on the forces shaping evolution, but vivid discussions reveal divergences on how evolution is perceived. The predominant Modern Synthesis (MS) paradigm holds the position that evolution occurs through random changes acting on genomic inheritance. However, studies from recent decades have revealed that evolutionary inheritance also includes DNA-methylation, RNA, symbionts, and culture, among other factors. This has fueled a demand of a broader evolutionary perspective, for example from the proponents of the Extended Evolutionary Synthesis (EES). Despite fundamental disagreements the different views agree that natural selection happens through dissimilar perpetuation of inheritable information. Yet, neither the MS, nor the ESS dwell extensively on the nature of hereditary information. We do - and conclude that information in and of itself is immaterial. We then argue that the quality upon which natural selection acts henceforth is also immaterial. Based on these notions, we arrive at the information-centric Information Continuum Model (ICM) of evolution. The ICM asserts that hereditary information is embedded in diverse physical forms (DNA, RNA, symbionts etc.) representing a continuum of evolutionary qualities, and that information may migrate between these physical forms. The ICM leaves theoretical exploration of evolution unrestricted by the limitations imposed by the individual physical forms wherein the hereditary information is embedded (e.g. genomes). ICM bestows us with a simple heuristic model that adds explanatory dimensions to be considered in the evolution of biological systems.publishedVersio
Production, mortality, and infectivity of planktonic larval sea lice, Lepeophtheirus salmonis (Krøyer, 1837): current knowledge and implications for epidemiological modelling
Current sea louse models attempt to estimate louse burdens on wild and cultured salmon by predicting the production and distribution of lice larvae and estimating the risk of transmission. While physical characteristics of water bodies and weather can be accurately modelled, many aspects of sea lice biology require further parameterization. The aims of this review are (i) to describe current knowledge regarding the production, mortality, and infectivity of planktonic sea lice larvae and (ii) to identify gaps in knowledge and suggest research approaches to filling them. Several major gaps are identified, and those likely to have the greatest impact on infection levels are (i) egg production, viability and hatching success, (ii) predation in plankton and (iii) copepodid infectivity profiles. A key problem identified in current parameter estimates is that they originate from a number of sources and have been determined using a variety of experimental approaches. This is a barrier to the provision of “best” or consensus estimates for use in modelling. Additional and more consistent data collection and experimentation will help to fill these gaps. Furthermore, coordinated international efforts are required to generate a more complete picture of sea louse infections across all regions experiencing problems with sea lice
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