Energy Production Levels Research Articles

Turbulence Measurement of Vertical Dense Jets in Crossflow

Turbulence measurement of a dense jet perpendicularly issued into a crossflow is investigated experimentally. The flow-velocity components were extensively measured with a high frequency Acoustic Doppler Velocimeter (ADV) system, whereas, a Micro Scale Conductivity Temperature instrument was used to measure the jet salinity. Special attention is given to understand the jet flow-structures in the flow symmetry plane. The flow velocity-fields, the jet trajectory, the turbulence intensities, the turbulent kinetic energy, the turbulent length scales, and the dispersion coefficients have been analyzed. The flow velocity-fields show that the dense jet is characterized by two distinct regions: an ascending region, of jet-like mixing, and a descending region of plume-like mixing. In this study, a new scaling approach of the jet trajectories, based on the jet characteristic length scales, is proposed, leading to an empirical closed-form expression to predict the jet trajectory. The turbulence analysis shows that the jet is accompanied by high levels of flow-turbulence intensities and large kinetic energy production. The results of the turbulent length scales indicate that the ambient flow-field, without jet effect, is an isotropic process. However, in the jet flow-field, a significant spatial-variation of the turbulent length scales was observed, indicating an anisotropic process. The trends of the dispersion coefficients follow those of the turbulent length scales. In comparison with the ambient flow, the jet flow-field shows a decrease of the longitudinal dispersion coefficient and an increase of the vertical one, leading to the increase of the jet width.

Feasibility of WEC installations for domestic and public electrical supplies: A case study off the Calabrian coast

Abstract This paper presents a performance evaluation of Wave Energy Converters (WECs) in terms of electricity production for domestic and public supplies of coastal towns located near hot spot areas. The study was conducted off the coast of Calabria (Southern Italy), a Mediterranean region characterized by a mild wave climate which is quite representative of mean sea states in the Mediterranean basin. The wave energy potential was assessed in deep waters by means of ECMWF wave data validated against RON buoys and UKMO data. Thirteen types of offshore WECs were considered, comparing the performances of full-scale and downscaled devices in terms of yearly and seasonal mean electricity production and operating days. Based on the domestic electricity supplies and those related to the public plants of some selected coastal cities, the number of differently sized devices was calculated in order to satisfy the above needs. To preserve the wave energy production level, the spatial arrangement of wave energy farms was determined in order to minimize possible park effects. The obtained results highlight that the occurrence of offshore WEC farms in a typical Mediterranean zone can lead to a significant number of WECs for domestic and public electricity supplies with a progressive reduction for more energetic sites.

Systematic cross-validation of photovoltaic energy yield models for dynamic environmental conditions

Abstract The continuous growth of photovoltaic installations globally carries hope for a sustainable future but also imposes challenges on all levels of energy production and distribution. Grid operators and designers have to cooperate more closely with monitoring service providers in order to sustain a flexible scheme of energy exchange. The basis of these calculations is accurate energy yield estimation models, which are able to capture all effects of the environment. Especially for locations with highly dynamic irradiance and environmental conditions, this remains a tough challenge. All photovoltaic energy yield models presented in this work aim at accommodating the inherent dynamism of these challenging locations at small time scales. A detailed, physics based electro-thermal energy yield model is validated along with other state-of-the-art models and performs 25% more accurately. Additionally, the results from the dynamic modeling are transferred to a neural network model, increasing the accuracy further up to six times better than any parametric solution.

Optimizing investments in coupled offshore wind -electrolytic hydrogen storage systems in Denmark

Abstract In response to electricity markets with growing levels of wind energy production and varying electricity prices, this research examines incentives for investments in integrated renewable energy power systems. A strategy for using optimization methods for a power system consisting of wind turbines, electrolyzers, and hydrogen fuel cells is explored. This research reveals the investment potential of coupling offshore wind farms with different hydrogen systems. The benefits in terms of a return on investment are demonstrated with data from the Danish electricity markets. This research also investigates the tradeoffs between selling the hydrogen directly to customers or using it as a storage medium to re-generate electricity at a time when it is more valuable. This research finds that the most beneficial configuration is to produce hydrogen at a time that complements the wind farm and sell the hydrogen directly to end users.

Interaction between plasma synthetic jet and subsonic turbulent boundary layer

This paper experimentally investigates the interaction between a plasma synthetic jet (PSJ) and a subsonic turbulent boundary layer (TBL) using a hotwire anemometer and phase-locked particle imaging velocimetry. The PSJ is interacting with a fully developed turbulent boundary layer developing on the flat wall of a square wind tunnel section of 1.7 m length. The Reynolds number based on the freestream velocity (U∞ = 20 m/s) and the boundary layer thickness (δ99 = 34.5 mm) at the location of interaction is 44 400. A large-volume (1696 mm3) three-electrode plasma synthetic jet actuator (PSJA) with a round exit orifice (D = 2 mm) is adopted to produce high-speed (92 m/s) and short-duration (Tjet = 1 ms) pulsed jets. The exit velocity variation of the adopted PSJA in a crossflow is shown to remain almost identical to that in quiescent conditions. However, the flow structures emanating from the interaction between the PSJ and the TBL are significantly different from what were observed in quiescent conditions. In the midspan xy plane (z = 0 mm), the erupted jet body initially follows a wall-normal trajectory accompanied by the formation of a distinctive front vortex ring. After three convective time scales the jet bends to the crossflow, thus limiting the peak penetration depth to approximately 0.58δ99. Comparison of the normalized jet trajectories indicates that the penetration ability of the PSJ is less than steady jets with the same momentum flow velocity. Prior to the jet diminishing, a recirculation region is observed in the leeward side of the jet body, experiencing first an expansion and then a contraction in the area. In the cross-stream yz plane, the signature structure of jets in a crossflow, the counter-rotating vortex pair (CVP), transports high-momentum flow from the outer layer to the near-wall region, leading to a fuller velocity profile and a drop in the boundary layer shape factor (1.3 to 1.2). In contrast to steady jets, the CVP produced by the PSJ exhibits a prominent spatiotemporal behaviour. The residence time of the CVP is estimated as the jet duration time, while the maximum extent of the affected flow in the three coordinate directions (x, y, and z) is approximately 32D, 8.5D, and 10D, respectively. An extremely high level of turbulent kinetic energy production is shown in the jet shear-layer, front vortex ring, and CVP, of which the contribution of the streamwise Reynolds normal stress is dominant. Finally, a conceptual model of the interaction between the PSJ and the TBL is proposed.

The Causality Link Between Electricity Consumption and Economic Growth in Turkey: Evidence from ARDL Bounds Testing Procedure

(ProQuest: ... denotes formulae omitted.)1.IntroductionThe level of energy production and consumption is widely accepted as an important indicator to stimulate the level of socio-economic development process (Ghosh, 2002: 125). The International Energy Agency (IEA) (2016) also reports that energy is the primary factor of the production and economic growth in the developing countries, and Turkey's energy demand is the fastest growing one among the member countries. Several analytical studies mostly dealt with the different types of energy sources (renewable - hydro, solar, geothermal, nonrenewable -gas, oil and coal) and economic growth relations in the literature emphasized the interaction between energy and growth to better understand the causality link between them. However, a limited number of some studies mainly focused on the association between electricity consumption (EC) and economic growth (Y) in a causality manner (cause and effect) in developed and developing countries. According to World Development Indicators (WDI) (2016), Turkey as a developing country with a population of 79.3 million people equivalent to the 1.1% of the whole World population is listed as the 18th biggest economy in the world by GDP. Due to relatively high growth rate of the urbanizing population and economic activities, the energy demand of Turkey is increasing rapidly year by year. Turkey's annual percentage growth rate of GDP is 4.5% (5.4) from 1960 to 2014 (2010 to 2014). Over the same period, the growth rate of net EC is 8.7% yearly on average. In the last five years, average growth rate of net EC is 5.8%.The Turkish Ministry of Energy and Natural Resources (MENR) (2014) reports that electricity demand has steadily increased and gross EC is estimated to increase by about 6% per year for next 5 years. Turkey's gross EC in 2000, 2005, 2010, 2014 was 128, 160, 210, 257 billion kWh. Furthermore, it is only since the last 15 years, the gross EC has increased nearly 100%. The Turkish Ministry of Foreign Affairs (2016) reports that Turkey became the second country after the China, in terms of electricity demand increase in the World since in 2005. Turkey currently produces only 26% of total EC by domestic resources, the most of the energy demand is provided by imports. As of 2014 in Turkey, the share of natural gas, coal and hydro in total electricity production are 121, 76 and 41 billion kWh. At present, around 48% of total electricity production relies directly on imported natural gas (TEIAS, 2014: 13). Due to continuously increasing EC and demand, Turkey is considered as one of the dynamic energy dependency economies. The total net EC of Turkey can be divided into five sectors in 2014 -housing, service-commerce, government, public street lighting and industry. The consumption from the housing represents 22.3% (46 billion kWh) of overall consumption, the service-commerce sector 19.2% (40 billion kWh), the government sector 3.9 (8.1 billion kWh), 1.9% (4 billion kWh) street lighting and 47.2% (98 billion kWh) industry sector. Electricity is the largest (almost 50%) energy source for industry. In order to increase domestic electricity supply, to generate a more reliable and competing energy market, Turkey issued the Electricity Market Law numbered as 4628 in 2001 and the Electricity Market Law numbered 6446 (EML) in 2013 (TETAS, 2014: 9). Due to privatization and encouraging private investors, Turkey steadily increased the share of the private investors in electricity production and privatized thermoelectric and hydroelectric plants. After the Electricity Market Laws and new regulations in liberalization programs, the share of electricity produced by the private sector increased from 57% in 2003 to 72% in 2014.The study is organized as follows: the first part presents some crucial points regarding the causality link between Y and EC in the Turkish economy. The second part overviews the period of data, methods and findings of the relevant empirical studies undertaken in both Turkey and various countries. …

Wave Energy Assessment along Sicilian Coastline, Based on DEIM Point Absorber

The use of renewable energy sources is one of the most relevant goals to be achieved in order to match the climate protection targets. As a case study, the paper shows the current electrical energy production by sources in the Sicilian context. Among the renewable energy sources, the paper investigates the wave energy potential along the Sicilian coasts, because of the favorable climate around the island. A point absorber is present in order to exploit this source. Two scenarios are presented, with two different levels of energy production.

Energy production and economic growth in Saudi Arabia: Dynamic causality

ABSTRACTEnergy helps stimulate economic growth and development. Energy production on a large scale indicates the level of economic prosperity of a nation. Studies maintain that countries with higher level of GDP per capita tend to have a higher energy production level per capita. Mixed evidences exist in literature on the direction of causality between energy in general and economic growth with varying policy recommendations. In the current study, the nexus between per capita energy production and economic growth is examined for Saudi Arabia. Utilizing the standard Granger causality in the context of an unrestricted Vector Autoregression model, a unidirectional causality from economic growth to energy production is found in Saudi Arabia. The result suggests an urgent need to vigorously pursue sustainable and efficient energy conservation policy in Saudi Arabia. The study concludes that Saudi Arabia requires a holistic approach to energy conservation with emphasis on renewable energy sources.

Hawkmoths use nectar sugar to reduce oxidative damage from flight.

Nectar-feeding animals have among the highest recorded metabolic rates. High aerobic performance is linked to oxidative damage in muscles. Antioxidants in nectar are scarce to nonexistent. We propose that nectarivores use nectar sugar to mitigate the oxidative damage caused by the muscular demands of flight. We found that sugar-fed moths had lower oxidative damage to their flight muscle membranes than unfed moths. Using respirometry coupled with δ13C analyses, we showed that moths generate antioxidant potential by shunting nectar glucose to the pentose phosphate pathway (PPP), resulting in a reduction in oxidative damage to the flight muscles. We suggest that nectar feeding, the use of PPP, and intense exercise are causally linked and have allowed the evolution of powerful fliers that feed on nectar.

Sharing R&D investments in breakthrough technologies to control climate change

This paper examines international cooperation on technological development as an alternative to international cooperation on greenhouse gas (GHG) emission reductions. In order to analyse the scope of cooperation, a three-stage technology agreement formation game is solved. First, countries decide whether or not to sign up to the agreement. In the second stage, the signatories (playing together) and the non-signatories (playing individually) select their investment in R&D. In this stage, it is assumed that the signatories not only coordinate their levels of R&D investment but also pool their R&D efforts to fully internalize the spillovers of their investment. Finally, in the third stage, each country decides non-cooperatively upon its level of energy production. For linear environmental damages and quadratic investment costs, the grand coalition is stable if marginal damages are large enough to justify the development of a breakthrough technology that eliminates emissions completely, and if technology spillovers are not very important.

Sharing R&D Investments in Breakthrough Technologies to Control Climate Change

This paper examines international cooperation on technological development as an alternative to international cooperation on GHG emission reductions. In order to analyze the scope of cooperation, a three-stage technology agreement formation game is solved. First, countries decide whether or not to sign up to the agreement. Then, in the second stage, the signatories (playing together) and the non-signatories (playing individually) select their investment in R&D. In this stage, it is assumed that the signatories not only coordinate their levels of R&D investment but also pool their R&D efforts to fully internalize the spillovers of their investment in innovation. Finally, in the third stage, each country decides non-cooperatively upon its level of energy production. Emissions depend on the decisions made regarding investment and production. If a country decides to develop a breakthrough technology in the second stage, its emissions will be zero in the third stage. For linear environmental damages and quadratic investment costs, the grand coalition is stable if marginal damages are large enough to justify the development of a breakthrough technology that eliminates emissions completely, and if technology spillovers are not very important.

An Analysis of the Current Directions in the Development of Green Energy

An analysis has been conducted on the current directions in the development of traditional and non-traditional sources of energy that do not have a negative environmental impact. The progress regarding the current level of energy production by means of the Sun and wind has been shown. The prospects of using wind energy to solve the energy resource accumulation problem are outlined. One of the directions of the development of non-traditional energy is hydrogen energy, which solves the issue of utilization of hydrogen as a future energy resource and one of the possible ways of energy resource accumulation. As the hydrogen production technology develops in the direction of cost lowering, also the level of utilizing hydrogen energy will increase since the reserves of hydrogen contained in natural water resources are practically unlimited. An important feature of green energy is the need to integrate the capacities into united complexes not only on a country-by-country scale but also on the scale of large supranational regions.

Influence of smart grid and renewable energy sources on energy efficiency: foreign experience

The article analyzes foreign influences on energy efficiency of such factors as raising the level of energy production from renewable sources and introducing smart technologies in power networks. Econometric analysis of experience in increasing energy efficiency of the United States, China, India, and Germany in comparison with Russia has been performed using a number of hypotheses to construct models. The necessity of transition to a new energy structure based on active introduction of energy efficient equipment, advanced energy and information and communication technologies, renewable energy sources, complex systems and services of intellectual energy built on an open network architecture is substantiated.

Energy Cultures in the European Union

Energy Cultures in the European Union

Gene expression and drought response in an invasive thistle

Though rapid phenotypic evolution has been observed in many invasive plant species, less is known about the associated genetic mechanisms. Some hypotheses invoke the evolution of trade-offs in resource allocation to explain phenotypic differences between the native and invaded ranges of a species. Alternately, invasive species may benefit from a generalist strategy and perform well in many environments. Identification of the molecular changes associated with successful invasions can offer clues regarding the mechanistic basis of such hypotheses, even in non-model organisms. To complement studies of phenotypic variation, we investigate gene expression during drought response that might underlie variation in drought tolerance between native and introduced populations of diffuse knapweed (Centaurea diffusa), and possibly contribute to invasion success. Using species-specific microarrays and tissue sampled under drought and control conditions at three time points, we identified genes whose expression either varied constitutively or responded to drought stress differently between ranges. Further, we functionally investigate these genes. Based on these data, invasive populations have constitutively higher levels of expression relating to energy production and lower levels of signal transduction expression relative to native populations. Under drought conditions, invasive populations may maintain energy production and react less strongly to drought than native populations, which may allow them to maintain fitness across moderate environmental variation. This supports the expectation of invasive populations consisting of generalist genotypes capable of fitness homeostasis, which may have facilitated the successful invasion of many environments in North America.

САНОЦЕНТРИЧНА СТРАТЕГІЯ ОХОРОНИ ЗДОРОВ'Я: ПРЯМИЙ ШЛЯХ ДО ЗДОРОВ'Я НАСЕЛЕННЯ

We discuss the fundamental position of the essence of life and health as a manifestation of the transformation of solar energy into other forms of energy (thermal, mechanical, electrical, etc.). It is alleged that the efficiency of intracellular energy production as an expression of mitochondrial function (the final stage of the transformation of solar energy) is a measure of the body's resistance to internal and external negative influences. There is a level of energy production above which neither endogenous risk factors, nor the disease are registered. It was given quantitative characteristic named «safe level of health». It is postulated (in addition to the «sickness industry» - the Ministry of Health institutions) the need to form the «health industry», based on the preservation and improvement of energy potential biosystems.

Real Options-Based Framework for Hydropower Plant Adaptation to Climate Change

AbstractThe economic feasibility of hydropower depends on the level of energy production, which in turn depends on weather conditions. Changes in runoff volumes directly influence energy production. Therefore, decision makers should take into account different climate change scenarios when making investment decisions for existing hydropower plants. The authors propose a real options-based framework to assess economic benefit of adapting hydropower plants to climate change. The framework enables evaluation of climate change impacts to hydropower. A case study of South Korea shows that investment on adaptation projects creates additional benefit in the regions with increasing precipitation under future climate scenarios. The findings suggest that adaptation projects prevent energy spilling and improve the productivity of hydropower.

JET, the largest tokamak on the eve of DT operation

The Joint European Torus (JET) is the world’s largest operating tokamak and the only such machine capable of operating with the fuel mixture (deuterium-tritium) foreseen for a fusion reactor. Since it came into operation in 1983, JET has explored fusion plasmas “in conditions and dimensions approaching those of a fusion reactor” [1]. JET has demonstrated world-record levels of fusion power and energy production, in conditions where the ratio of the fusion power generated to the input power to the plasma, Q, approaches unity.

A comprehensive economic analysis method for selecting the PV array structure in grid–connected photovoltaic systems

In grid–connected photovoltaic (GCPV) systems, applying a solar tracker results in a higher energy production level. However, this does not necessarily mean a greater profit due to the excess of generation selling, since the capital and maintenance costs increase as well. In this paper, a comprehensive economic analysis method for selecting the PV array structure type has been proposed. To this end, a precise method to compute the yearly generated electrical energy (solar converted energy) has been presented by applying the global radiation relation between different structures, i.e. fixed, single axis (vertical and horizontal) and dual axis trackers. Also, the simple and yet accurate efficiency model and power relation are used for solar inverter and panel, respectively. The analysis is accomplished by determining the economic parameters, including net present value (NPV), internal rate of return (IRR), and payback period time (PBT) for all PV structures with the same electrical energy generation or profit. Due to the results simplicity and robustness in different economic conditions, the same energy production scenario is chosen in this paper. In accordance with this assumption, PV panel, inverter and tracker sizes and net present costs (NPC) are determined. Since the net present benefit (NPB) for all structures is equal, the lowest NPC is considered the most economic choice. The performance of the suggested algorithm is evaluated through a commercial dual axis GCPV system simulation. Moreover, in order to determine the best suited economic parameters, a sensitivity analysis has also been carried out in the process.

Dopamine Coupling to Mitochondrial Signaling: Implications for Transplantation.

The persistence of major medical disorders afflicting millions of humans worldwide involves a functional pathophysiological coupling of systemic pro-inflammatory processes and tissue hypoxia. Mechanistically, reciprocal triggering of multiple ischemic/hypoxic and pro-inflammatory events, if not corrected, will promote pathophysiological amplification leading to a deleterious cascade of bio-senescent cellular and molecular signaling pathways that converge to markedly impair mitochondrial energy production. Given the level of energy production and utilization that can vary in and between cells and regionally in the same type of cells found in the body, e.g., dopamine neurons, the metabolic energy regulator, the mitochondrion, assumes a high position in the potential to maintain normal health and develop abnormal activities, resulting in chronic pathologies. The intra-mitochondrial availability of molecular oxygen as the ultimate electron acceptor drives the evolutionarily fashioned chemiosmotic production of ATP as a high-efficiency biological proton pump process. The mechanistic evolutionary bases of diabetes have demonstrated the profound alteration of normative mitochondrial function, notably deregulated respiratory processes. This same phenomenon provides evidence of mitochondrial linkages to neurological disorders, such as Parkinson's disease. To date, and despite considerable research efforts, the practical realization of advanced mitochondrial targeted therapies has not been forthcoming.