Economical Analysis of Financial Supports for Large-Scale Photovoltaic PV plants in Eastern Europeen Union Countries

Today, photovoltaic (PV) attracts considerable interest among renewable energy sources (RES), because of its potential to significantly contribute to the future of clean energies. However, PV development is strongly related to the support policies introduced by national governments. The modification or fading out of such support schemes can strongly influence the development of the PV market in any given country. Although the PV market in European developing countries is still quite small, it has been growing rapidly in recent years. Until 2006, the installation of small off-grid PV plants prevailed in eastern EU countries. Starting from 2008, large-scale on-grid PV plants have been put into effect. Today on-grid installations constitute more than 95% of the total installed PV plants. The large increase of PV market in the last two years is a consequence of the enormous development of PV sector in the Czech market, stimulated by effective support mechanisms. Other developing member states, such as Slovakia and Bulgaria, have adequate PV support schemes including, in particular, effective Feed-in Tariff (FIT) systems. Other support mechanisms are tradable green certificates (TGCs), capital subsidies, tax credit and net metering. In this paper, after a brief review of national support policies in PV technology in the considered EU developing countries, the authors perform an economic analysis of the main support mechanisms that are implemented in these countries. The comparative analysis is based on the calculation of the cash flow, the Net Present Value (NPV) and the Internal Rate of Return (IRR) indices. The analysis shows that in some situations, support policies can be inconvenient for the owner of the PV system and that, in many cases, the differences between the implementation of the same support policy in different countries, can give rise to significantly different results. The comparative analysis carried out in this work could help: to evaluate the impact of the PV energy measures in eastern EU member states; to gain an insight into green energy companies by identifying potential PV markets and investigating the policy landscape across eastern EU countries

Incremental heuristic approach for meter placement in radial distribution systems

The evolution of modern power distribution systems into smart grids requires the development of dedicated state estimation (SE) algorithms for real-time identification of the overall system state variables. This paper proposes a strategy to evaluate the minimum number and best position of power injection meters in radial distribution systems for SE purposes. Measurement points are identified with the aim of reducing uncertainty in branch power flow estimations. An incremental heuristic meter placement (IHMP) approach is proposed to select the locations and total number of power measurements. The meter placement procedure was implemented for a backward/forward load flow algorithm proposed by the authors, which allows the evaluation of medium-voltage power flows starting from low-voltage load measurements. This allows the reduction of the overall costs of measurement equipment and setup. The IHMP method was tested in the real 25-bus medium-voltage (MV) radial distribution network of the Island of Ustica (Mediterranean Sea). The proposed method is useful both for finding the best measurement configuration in a new distribution network and also for implementing an incremental enhancement of an existing measurement configuration, reaching a good tradeoff between instrumentation costs and measurement uncertainty

Realizzazione e prova di un sistema di controllo ed interfaccia per sistemi combinati accumulo-FER Report 2 - Progettazione esecutiva, realizzazione del prototipo e prova

Il presente Documento riferisce sui contenuti e sui risultati della seconda fase delle attivit\ue0 svolte nell\u2019ambito della ricerca dal titolo: \u201cProgettazione, realizzazione e test di un sistema di controllo ed interfaccia per sistemi combinati accumulo-FER\u201d, oggetto di un Accordo di Collaborazione tra ENEA e DIEETCAM (Universit\ue0 degli Studi di Palermo) nel quadro delle attivit\ue0 relative al Piano Annuale di Realizzazione 2011 dell\u2019Accordo di Programma MSE-ENEA sulla Ricerca di Sistema Elettrico. Nel corso della seconda fase delle attivit\ue0, a partire dal lavoro di definizione delle specifiche tecniche di tutti i componenti, e dell\u2019insieme delle funzionalit\ue0 del dispositivo in progetto, si \ue8 proceduto alla progettazione esecutiva del dispositivo, nonch\ue9 alla realizzazione di un prototipo. E\u2019 stata infine condotta una campagna di test e prove al fine di: applicare e validare in ambiente simulato l\u2019algoritmo di gestione del sistema combinato per profili di variabilit\ue0 della domanda tipici di alcune utenze di media taglia del settore terziario; verificare sperimentalmente (attraverso specifici test condotti in laboratorio) il regolare funzionamento dei singoli componenti di potenza del sistema, sotto diverse condizioni operative di funzionamento (in modalit\ue0 stand-alone e grid-connected); verificare sperimentalmente (attraverso specifici test condotti in laboratorio) l\u2019operativit\ue0 delle funzioni di protezione e comunicazione (verso la rete) implementate. Le attivit\ue0 sono state condotte in sinergia con il personale tecnico di ENEA e con la collaborazione dell\u2019azienda Layer Electronics s.r.l. di Erice (TP)

Solar Energy: Incentives to Promote PV in EU27

The growth in the use of renewable energies in the EU has been remarkable. Among these energies is PV. The average annual growth rate for the EU-27 countries in installed PV capacity in the period 2005-2012 was 41.2%. While the installed capacity of PV has reached almost 82 % of National Renewable Energy Action Plan (NREAP) targets for the EU-27 countries for 2020, it is still far from being used at its full potential. Over recent years, several measures have been adopted in the EU to enhance and promote PV. This paper undertakes a complete review of the state of PV power in Europe and the measures taken to date to promote it in EU-27. 25 countries have adopted measures to promote PV. The most widespread measure to promote PV use is Feed- in Tariffs. Tariffs are normally adjusted, in a decreasing manner, annually. Nevertheless, currently, seven countries have decided to accelerate this decrease rate in view of cost reduction of the installations and of higher efficiencies. The second instrument used to promote PV in the EU-27 countries is the concession of subsidies. Nevertheless, subsidies have the disadvantage of being closely linked to budgetary resources and therefore to budgetary constraints. In most EU countries, subsidies for renewable energy for PV are being lowered. Twelve EU-27 countries adopted tax measures. Low-interest loans and green certificate systems were only sparingly used

Wind Turbine Mechanical Characteristics and Grid Parameters Influence on the Transient Voltage Stability of a Fixed Speed Wind Turbine

This paper describes the effect of wind turbine mechanical characteristic of construction and grid parameters on the transient voltage stability of a fixed speed wind turbine (FSWT) connected to a simple grid. The model of FSWT has been developed in Matlab/Simulink. Using this model, a three-phase fault is applied close to the wind turbine (WT) and cleared by disconnecting the faulted line. The effects of mechanical construction of WT and of grid parameters on the voltage stability of this simple case are evaluated and discussed. The considered parameters are the inertia coefficient of the WT, the short-circuit power at the connection bus, the hub-generator resonant frequency, the wind speed and the reactive power compensation. For each parameter, the terminal voltage and the generator rotor speed for different fault-clearing time are drawn. At last, the terminal voltage and the generator rotor speed obtained for a fifth-order model of the induction generator are compared with those obtained for a third order model. The differences between the two models are discussed. The obtained results will help to understand the transient stability phenomena in wind farms

Effects of Electrical Parameters of Induction Generator on the Transient Voltage Stability of a Fixed Speed Wind Turbine

This paper describes the effect of electrical parameters of the induction generator on the transient voltage stability of a fixed speed wind turbine connected to a simple grid; the dynamic behavior of a wind turbine connected to the grid is examined. The model of the fixed speed wind turbine has been developed in the simulation tool Matlab/Simulink. It\u2019s composed by the induction generator, the shaft system, the aerodynamic model of the wind turbine rotor and the pitch control system. Using this model, a threephases fault is applied close to the wind turbine and cleared by disconnecting the faulted line. The effect of different electrical parameters of the induction generator on the voltage stability of this simple case is evaluated and discussed. The considered parameters are the stator and rotor resistances, the leakage stator and rotor inductances, and the mutual inductance. For each parameter, the terminal voltage and the generator rotor speed for different fault-clearing time are drawn. The obtained results will help to understand the transient stability phenomena in wind farms

Transient stability simulation of a fixed speed wind turbine by Matlab/Simulink

This paper describes the dynamic behavior of a typical fixed speed wind turbine connected to the grid; the model is developed in the simulation tool Matlab/Simulink and created as a modular structure. The pitch control system is used for stabilization of the wind turbine at grid faults. In this way, voltage stability of the system with grid-connected wind turbines can be improved by using blade-angle control for a temporary reduction of the wind turbine power during a short-circuit fault in the grid. This paper shows a new variable control for maintaining of voltage stability, when a three-phase fault is applied close to the wind turbine and cleared by disconnecting the affected line. In this way, a better re-establishing of the voltage after the fault is obtained

Financial Measures for Supporting Wind Power Systems in Europe: A Comparison between Green Tags and Feed\u2019in Tariffs

Distributed Generation demonstrates to be able to significantly influence the electric power system, bringing considerable benefits to the quality of service and improving the energetic efficiency of the distribution network. In particular, in the last few years, Distributed Generation from renewable energy sources is considerably increased thanks to the many support policies promoted worldwide with the aim of facing the environmental issue and the problem of the permanent rise of prices of the fossil energy. In this contest, after a brief review on the financing strategies carried out in Europe in the last decade for promoting the recourse to renewable energy, the paper presents a comparison among the main support strategies for Wind Farms (Feed-in tariffs and Green Tags), taking into account the situation in some European Countries