Search results for "NEWA"

Stability analysis of load frequency control for power systems with interval time-varying delays

2023

This study investigates the stability problem of load frequency control (LFC) for power systems with interval time-varying delays. The two categories of time delays, the lower bound being zero and non-zero, are considered. The systems can be described as time delay systems of load disturbances. First, an augmented Lyapunov–Krasovskii functional (LKF) is constructed. Some delay-dependent nonintegral terms and single integral terms are additionally introduced to make full use of the information on the system state variables and the time-varying delays. Second, to overcome the problem of nonlinear inequalities caused by the augmented LKF, the nonlinear inequalities are converted into linear ma…

Renewable electricity producing technologies and metal depletion: A sensitivity analysis using the EROI

2015

International audience; More and more attention is being paid to renewable technologies because they are seen as a great opportunity to disengage our society from its dependence on fossil fuels. Such flow-based energy resources that rely on solarenergy are supposed to lead us toward a sustainable energy future. However, because of their high capitalintensity, renewable technologies require large amounts of matter, including both common and rare metals.These metals require energy for their production, and more specifically for their extraction. The energy costassociated with metal extraction is linked to mineral ore grade, meaning that as depletion progresses, energycost increases. In additi…

Family firm prerequisites for international business operations: a production and marketing capabilities approach

2014

The purpose of this study is to compare SME family firms’ and non-family firms’ organisational prerequisites for international business operations. The main focus lies in the production and marketing capabilities needed for conducting international business. A quantitative study was conducted in Finland. A random sampling was done by utilising the database of the Confederation of Finnish Industries (EK). A sample of 2,000 firms was gathered from the target population, EK database, which consisted of 16,000 firms. The answer rate for the study was 28%. All together, 555 firms answered the mail survey. Three hundred thirty three respondents were coming from family firms and 222 replies repres…

Renewable energy and security for Ukraine: challenge or smart way?

2016

The dark side of the sun: How solar power production affects the market value of solar and gas sources

2015

Abstract Using daily data for the Italian wholesale day-ahead power market over the period 2008–2013, we assess the impact of solar production on the market value of solar and gas sources, defined using the concepts of value factor and unit revenues. We find that, on average, solar generation negatively affects the solar source market value, causing a departure from the grid parity condition and mining their competitiveness once public incentives are removed. This negative relation is not constant over time and becomes stronger for increasing solar penetration in the energy mix. Interestingly, the opposite is found when looking at gas. While the relation between solar production and the gas…

- STRATEGIC PIGOUVIAN TAXATION, STOCK EXTERNALITIES AND POLLUTING NON-RENEWABLE RESOURCES

2001

This paper extends Wirl and Dockner¿s (1995) model designed to analyze the long-term bilateral interdependence between a resource exporting cartel and a coalition of resource importing country governments. Firstly, depletion effects are introduced into the analysis of the intertemporal properties of a pigouvian tax. Secondly, the feedback Stackelberg equilibria are computed. The results show that the dynamics of the tax depends critically on the level of the marginal environmental damage. Moreover, they also show that the tax defined by the Markov-perfect Nash equilibrium is a neutral pigouvian tax in the sense that it only corrects the market inefficiency caused by the stock externality. H…

The Influence of Oil Price on Renewable Energy Stock Prices: An Analysis for Entrepreneurs

2020

Abstract This study investigates the relationship between oil price fluctuations and renewable energy stock returns using daily data on Brent crude oil prices and global renewable energy stock market indices between 29 November 2010 and 18 February 2020. The investigation is based on the existing evidence on positive correlations between stock prices and oil prices, but it also considers the shift from non-renewable to renewable sources of energy. A two-stage GARCH(1,1) model and a Granger causality test were applied. Our results show that volatility clustering is present in the renewable energy companies‘ stock prices, but, oil price volatility does not seem to induce any significant effec…

Computational Screening of Doped Graphene Electrodes for Alkaline CO2 Reduction

2020

The electrocatalytic CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) is considered as one of the most promising approaches to synthesizing carbonaceous fuels and chemicals without utilizing fossil resources. However, current technologies are still in the early phase focusing primarily on identifying optimal electrode materials and reaction conditions. Doped graphene-based materials are among the best CO<sub>2</sub>RR electrocatalysts and in the present work we have performed a computational screening study to identify suitable graphene catalysts for CO<sub>2</sub>RR to CO under alkaline conditions. Several types of modified-graphene frame…

Replacement of Vehicle Fleet with EVs Using PV Energy

2016

The diffusion of Electric Vehicles (EVs), the reduction of environmental pollution and the production of energy from renewable sources (RES), in particular photovoltaic system, wind farm, hydroelectric plants, bioenergy and geothermal plants are the principal aspects discussed in the world. For this reason, the goal of this work is to study for 2014 year in all Italy's Regions; the energy production obtained to photovoltaic systems (PV) and the possibility to use with different percentage this energy for recharge the electric vehicles. In particular, they have been considered different scenarios in function to the km travelled per year from the population. This paper examines the integratio…

Enhanced flexible algorithm for the optimization of slot filling factors in electrical machines †

2020

The continuous development in the field of industrial automation and electric mobility has led to the need for more efficient electrical machines with a high power density. The improvement of electrical machines’ slot filling factors is one of the measures to satisfy these requirements. In recent years, this topic has aroused greater interest in the industrial sector, since the evolution of the winding technological manufacturing processes allows an economically sustainable realization of ordered winding arrangements, rather than random ones. Moreover, the manufacture of electrical machines’ windings must be preceded by an accurate design phase in which it is possible to evaluate the maximu…