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Majstrovic G.,Energy Institute Hrvoje Pozar | Polen W.,United States Energy Association
Energy and Environment | Year: 2015

The Southeast Europe Cooperation Initiative Transmission System Planning Project (SECI TSP) is a unique development assistance collaboration supported by the transmission system operators of Southeast Europe (SEE), the United States Agency for International Development (USAID) and the United States Energy Association (USEA). Members of the SECI TSP include 10 transmission system operators from Albania, Bosnia-Herzegovina, Bulgaria, Croatia, Kosovo, Macedonia, Montenegro, Serbia, Romania and Turkey. Slovenia, Greece and Italy participate in the SECI TSP as observers.This paper provides a brief introduction to the SECI TSP and reviews results of a SECI TSP study of the capacity of the high voltage electricity transmission network in SEE to integrate wind power. The analysis results from wind power plant (WPP) data collected and verified by 12 TSOs (including Slovenia and Greece) through a series of detailed questionnaires (324 inputs collected) and intensive regional cooperation supported by USAID and USEA since 2000. Besides that, large set of input data on hourly WPP generation profiles for each SECI country for the 2020 planning horizon was employed from the Pan-European Market Database (87,600 output data). Historical data on WPP generation was used as a reference when such data was available, as well as the data available from the national wind integration studies.The study identifies limiting factors for large scale WPP integration in SEE, contains an analysis of expected WPP output variation, forecasts reserve capacities in the region, identifies network bottleneck resulting from large scale wind integration, and calculates the impact of WPP on regional network losses.The study results indicate that owing to the sub-regional characteristics of wind patterns, the countries of SEE could reduce by approximately 50% the amount of reserve capacity needed to balance intermittent wind production if such capacity is provided on a regional basis as opposed to the traditional country-by-country approach. This would open up more than 2,000MW of capacity to be available to the regional electricity market as opposed to holding them in reserve on an individual, country-by country basis. Also, more than 30 regional network bottlenecks were identified as a result of large scale WPP integration through different load flow scenarios.

Medic I.,University of Split | Bajs D.,Energy Institute Hrvoje Pozar | Sutlovic E.,University of Split
International Review of Electrical Engineering | Year: 2010

An analytical method for calculating the low-frequency fault currents and related voltages, at any point along neutral conductors (i.e., metallic screens and adjacent earthing wires) of multi-cable power lines, is presented in this paper. The earthing system under consideration consists of two substation earthings, which are interconnected by insulated metallic screens/sheaths of modern XLPE cables and also by bare earthing wires laid in parallel in the same cable trench. The analytical expressions, derived by solving a set of differential equations, are based on the assumption of uniformly distributed self and mutual conductances to ground ("leakances") of earthing wires. The proposed mathematical model also takes into account mutual inductive couplings between all conductors (phases, cable screens/sheaths and bare earthing wires). In addition, the values of related substation grounding impedances at the power line terminals are not neglected and are now taken into account as known input values. Particularly, in the case of a double-circuit cable line with two earthing conductors in trench, a set of generalized equations for currents and voltages along the related neutral conductors are derived in detail. As an illustrative example, the derived mathematical expressions are applied to three-phase double-circuit power cable line, consisting of six single-core power cables and two earthing conductors laid alongside. © 2010 Praise Worthy Prize S.r.l. - All rights reserved.

Kulisic B.,Energy Institute Hrvoje Pozar | Par V.,University of Zagreb | Metzler R.,MVV DECON GmbH
Biomass and Bioenergy | Year: 2015

Energy planning relies on potential assessments where the role of each energy source in the energy balance will correspond to the attributed potential.Biogas is a gaseous renewable energy fuel derived from biomass. It origins from numerous substrates and provides all useful energy forms which makes biogas potential assessment challenging. Biogas production and utilization has also side-effects from which a country could both benefit, and, if not properly addressed, suffer.Practice proves that a demand based approach to agricultural biogas potential assessment is not providing the value(s) to which either energy or rural development policy planning can work with. The problem stems from three main challenges: (a) biogas rarely occurs in monodigestion, (b) co-digestion has to compete with other non-food sectors for co-substrates, (c) biogas production needs constant inputs.Paper provides methodology to assess the technical and economical on-farm biogas potential of a geographic region. Technical potential assessment links resource based, statistical data with spatial data of single farms to detect farms with plausible biogas production. Return on investment is used to trim the technical to economic potential. Results provide sufficient data for developing on-farm biogas production and its conversion to useful energy forms in energy planning.The methodology is applied to Croatia as a case study. The results indicate discrepancy between the existing biogas supporting measures and features of the Croatian livestock sector. In addition, the results suggest that biogas potential is underestimated which is potentially loss in public money dedicated for development of renewable energy sector. © 2015 Elsevier Ltd.

Krajacic G.,University of Zagreb | Loncar D.,University of Zagreb | Duic N.,University of Zagreb | Zeljko M.,Energy Institute Hrvoje Pozar | And 3 more authors.
Applied Energy | Year: 2013

This paper analyses potential supporting schemes for pumped hydro storage (PHS) facilities in Croatia, which would guarantee recovery of the investment cost, with feed-in tariffs - for instance - which would guarantee payment for discharging wind-originated power as a reward for boosting the integration of renewable energy sources (RESs). The payment level acts as a floor basis for the PHS operator during the decision-making process to contract fixed payments for wind support or to act market-free on other market segments, through price arbitrage and reserve provision. The market share required for the efficient operation of a PHS facility and the levels of feed-in tariff (FIT) are set mathematically. Main findings put the level of FIT for an applied project in Croatia in the range 42-265. €/MW. h for an average load factor of 20%, depending on particular local conditions, such as the level of wind power curtailment in the system, the power price for charging the storage and the number of pumps and penstocks, which could lower the capital cost. It is claimed that not all services that PHS provides to the electricity system are adequately rewarded by the electricity market, and thus there is a serious uncertainty as to how investment costs in energy storage would be recovered. Other elements, outside the market, are likely to influence the operation of PHS, such as the regulated level of a desirable rate of curtailment of RES power excess, the adequate level of energy security and the reserve margins which PHS could help to ensure. © 2012 Elsevier Ltd.

Agency: Cordis | Branch: FP7 | Program: CSA-SA | Phase: REGIONS-2007-2-02 | Award Amount: 223.01K | Year: 2008

Central Eastern Europes rural areas have been facing great challenges due to their geographical handicaps and economic structural problems, although they possess an unexploited natural treasure: the thermal water. The overall concept of the CLUSTHERM project is: enabling the regional actors to bring the geothermal R&D achievements to the ground of local services and products. Access to research provision and the clustering between the economic and public actors could allow the dynamic, knowledge based development of these rural economies. A more concentrated research on geothermal resources can lead to the development of high added value products and services. The CLUSTHERM project aims to set up a new research driven cluster in Central Europe on thermal water utilization that will develop the capacity and research potential of Central Eastern Europes rural economies rich in thermal water to access and benefit from research on the exploitation. The direct objectives are: - analyse the RTD development and the needs of geothermal energy utilisation - promote synergies and catalyse links between regional, research and business actors (vertical clustering) - foster the transnational and cross-border co-operations between the regional actors (horizontal clustering) - develop and enhance transnational mutual learning through information exchange possibilities of regional stakeholders in creating research driven clusters and to disseminate good policy practices and benchmarking activities - develop joint action plan and research strategy among the participating regions to increase the regional economic competitiveness through concentrated use of natural resources

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