Results 1 - 10 of 5006
Results 1 - 10 of 5006. Search took: 0.033 seconds
|Sort by: date | relevance|
[en] The past fifty years have witnessed the advent of a new energy source and the beginning of yet another in the series of energy-use transitions that have marked our history since the start of our technological development. Each of these transitions has been accompanied by adaptive challenges. Each unique set of challenges has been met. Today the world faces the need for another transition. This paper outlines some of the associated challenges that lie ahead of us all, as we adapt to this new and exciting environment. The first step in defining the challenges ahead is to make some form of prediction of the future energy supply and demand during the period. Herein, the future up to 2010 is presumed to include two major events – first, a decline in the availability and a rise in price of petroleum, and second a need to reduce greenhouse gases in our atmosphere. Both of these events are taken to be imminent. Added to these expected events is the assumption that the total of wind, solar, and other such energy sources will be able to contribute, but only in a relatively small way, to the provision of needed energy to our ever-expanding human population. (author)
[en] The use of renewable energy sources at global level continues growing at a rapid pace, yet in the frame of a strong decrease of the oil price. Regarding to electric generation, renewable sources represented about 59% of new power installed in 2014, with a market ruled by hydro, wind and photovoltaic solar energies. To the end of 2015, the renewable energy capacity was enough to feed about the 23.7% of the global electric demand, being the main contributions hydro (16.6%), wind (3.7%), bioenergy (2.0%) and photovoltaic (1.2%). In Argentina, even though since 16 years ago there has been various programs to boost their use, the growth of the new renewables, mainly wind and solar, has been very slow. The electricity power mix has a strong dependence on thermal generation based on fossil fuels, whit a relative share over 60% since 2011 to date. At the same time, the share of wind and photovoltaic energies has been very small, representing just the 0.44% of power generation at 2015. Here, an overview at global, regional, and national level of the photovoltaic solar energy development as power generation source is presented. Particularly, the photovoltaic market, the incidence of the photovoltaic technology in the power mix, and aspects concerning to electricity tariff and legal and technical regulations at the local level are analyzed, with special emphasis on distributed generation. (author)
[es]El uso de las fuentes renovables de energía a nivel mundial continúa creciendo a ritmo acelerado, aún en un contexto de fuerte descenso de los precios del petróleo. En lo referente a la generación eléctrica, las fuentes renovables representaron alrededor del 59% de la nueva potencia instalada en 2014, con un mercado dominado por las energías hidroeléctrica, eólica y solar fotovoltaica. A finales del 2015, la capacidad de energía renovable era suficiente para abastecer aproximadamente el 23,7% de la electricidad mundial, siendo sus principales contribuciones la energía hidráulica (16,6%), la eólica (3,7%), la bioenergía (2,0%) y la solar fotovoltaica (1,2%). En la Argentina, si bien hubo diversos programas que incentivaron su uso en los últimos 16 años, el avance de las nuevas energías renovables, principalmente eólica y solar, ha sido sumamente lento. La matriz eléctrica tiene una fuerte dependencia con la generación térmica basada en combustibles fósiles, cuya contribución relativa es superior al 60% desde 2011 a la fecha. Al mismo tiempo, la participación de las energías eólica y fotovoltaica ha sido muy reducida, representando sólo el 0,44% de la generación eléctrica del año 2015. Se presentará un panorama a nivel global, regional y nacional del desarrollo de la energía solar fotovoltaica como fuente de generación eléctrica. En particular, se analizarán el mercado fotovoltaico, la incidencia de la tecnología fotovoltaica en la matriz energética, y aspectos concernientes a la tarifa y al desarrollo de las regulaciones técnicas y legales en el ámbito local, con especial énfasis en la generación distribuida. (author)
[en] The key dilemma is how to increase energy generation while limiting global warming. Take-away messages: the opportunity is carbon; the problem is cost; there are ways to reduce it; government help is needed to make it happen. Nuclear is the largest source of emission-free electricity in the US and Europe by far. A nuclear build-up (at historically feasible rate) can completely decarbonize the world power sector within 30 years. Nuclear electricity can be deployed as quickly as coal and gas at a time of need. Excluding nuclear energy drives up the average cost of electricity in low-carbon scenarios. The business opportunity for nuclear expands dramatically, even at modest decarbonization targets, if its cost decreases. An increased focus on using proven project/construction management practices will increase the probability of success in execution and delivery of new nuclear power plants.
[en] In order to increase Renewable Energy (RE) in the power generation, the present technology of Nuclear Power Plants (NPPs) should be utilized. This paper introduces a ‘Thermal Hub’ concept which consists of the two hybrid systems with Concentrated Solar Power (CSP) for the heating steam in the reheater and Ocean Thermal Energy Conversion (OTEC) for waste heat recovery of discharged water from the NPP. These renewables were chosen based on the NPP’s thermodynamic characteristics. Both thermal hybrid systems will contribute to reduce the cost for the electricity of renewables. A useful chart is introduced for visualization of the relationship between nuclear and renewable energies in the various hybrid systems. (author)
[en] An effective computational method is developed for electronic-structure calculations in few-electron atoms and ions on the basis of the Dirac-Coulomb-Breit Hamiltonian. The recursive formulation of the perturbation theory provides an efficient access to the higher-order contributions of the interelectronic interaction. Application of the presented approach to the binding energies of lithiumlike and boronlike systems is demonstrated. The results obtained are in agreement with the large-scale configuration interaction Dirac-Fock-Sturm method and other all-order calculations.
[en] Numerical modeling of heat exchange during water flow in a porous medium In this work we present numerical modeling of water flow in a porous medium, heat conduction in water and medium and their mutual heat exchange. It is a numerical approximation of the solution of a system of three differential equations, the first of which, the flow of water in a porous medium, is strongly nonlinear and degenerate, but independent of the rest. The second, heat conduction in water, is strongly dependent on the previous one and is related to the third equation of heat conduction in the environment. In short, we describe the individual methods used to derive equations and the calculation algorithm. The work is a continuation of last year's work Transport of heat and water in a porous environment. The extension includes a specification of the dispersion coefficient and proof of the existence of a solution. An important benefit of this work is the design of a model to determine the heat transfer coefficient between water and porous media, because it is technically impossible to measure at a given point separately the temperature of the environment and water in the pores. (authors)
[en] Pakistan has framed policies to further the development of intermittent renewable resources (IRR) in the country. Consequently, IRR share is steadily growing in the electric power supply system (EPSS). This research work assesses the impacts of IRR on the EPSS in long term future, more specifically on the operation cycle of dispatchable power plants and system economics. The EPSS is analysed considering different shares of IRR in the system. The analysis shows that the EPSS of Pakistan can accommodate up to 50–60 GW IRR at a future demand level of 149 GW, which corresponds to about an 11% share of IRR in the total electricity generation. Beyond that, the country can face both operational and economic challenges in handling the power supply system. (author)
[en] Cooperative become one of discussion material in amendment of Law Number 10 Year 1997 (Nuclear Energy Act), that is concerning capability of Cooperative in cooperation with implementing agency (BATAN) on nuclear utilization activity. The role of cooperatives in the development of nuclear technology applications and their abilities are discussed here, which in turn can be considered in the change of the nuclear power law. As found in the United States, the cooperative is a party that can cooperate in rural power utilization and can certainly be strengthened with capital support from the Government, or a cooperative can become one of the shareholders of the activity. Cooperatives are one of the economic forces that encourage the growth of the national economy, and the welfare of society. Cooperatives are expected to occupy a place and an important position in the national economic order of Indonesia so that its role in Amendment to the Law of nuclear power should still get attention. (author)
[en] If used correctly, digitization can accelerate the energy revolution and make it more efficient and cost-effective. In the 2018 issue, the scientists show how information and communication technologies can support the transformation process in order to implement the goals of ecology, economy and social sustainability on an equal footing.
[de]Richtig eingesetzt kann Digitalisierung die Energiewende beschleunigen und sie effizienter und kostengünstiger gestalten. Im Themenheft 2018 zeigen die Wissenschaftlerinnen und Wissenschaftler wie die Informations- und Kommunikationstechnologien den Transformationsprozess unterstützen können, um die Zielrichtungen Ökologie, Ökonomie und soziale Nachhaltigkeit gleichgewichtig umzusetzen.