European Network Of Transmission System Operators Research Articles

Assessing the Carbon Intensity of e-fuels Production in European Countries: A Temporal Analysis

The transport sector heavily relies on the use of fossil fuels, which are causing major environmental concerns. Solutions relying on the direct or indirect use of electricity through e-fuel production are emerging to power the transport sector. To ensure environmental benefits are achieved over this transition, an accurate estimation of the impact of the use of electricity is needed. This requires a high temporal resolution to capture the high variability of electricity. This paper presents a previously unseen temporal analysis of the carbon intensity of e-fuels using grid electricity in countries that are members of the European Network of Transmission System Operators (ENTSO-E). It also provides an estimation of the potential load factor for producing low-carbon e-fuels according to the European Union legislative framework. This was achieved by building on top of the existing EcoDynElec tool to develop EcoDynElec_xr, a python tool enabling—with an hourly time resolution—the calculation, visualisation, and analysis of the historical time-series of electricity mixing from the ENTSO-E. The results highlight that, in 2023, very few European countries were reaching low carbon intensity for electricity that enables the use of grid electricity for the production of green electrolytic hydrogen. The methodological assumptions consider the consumption of the electricity mix instead of the production mix, and the considered time step is of paramount importance and drastically impacts the potential load factor of green hydrogen production. The developed tools are released under an open-source license to ensure transparency, result reproducibility, and reuse regarding newer data for other territories or for other purposes.

Wind Power Generation Scheduling Accuracy in Europe: An Overview of ENTSO-E Countries

Despite the rapid spread of the use of wind energy to generate electricity, harnessing this energy source remains a great challenge due to its stochastic nature. One way of dealing with this is to prepare accurate wind power forecasts. This paper explored the accuracy of day-ahead and intraday scheduling of energy generation of the onshore and offshore wind farms of the member countries of the European Network of Transmission System Operators (ENTSO-E) in the period from 2013 to 2021. The precision of the scheduling activities showed a varying picture: the onshore wind farms of Germany, Spain, France, and Sweden produced more precise forecasts than others, with annual downward and upward regulatory needs between 0.8% and 14.4%, and from 0.8% to 6.5%, of the yearly energy generation, respectively. In certain countries, however, the forecasts were less accurate, with discrepancies exceeding 41% for downward and 132% for upward regulation. As for offshore wind farms, the annual downward and upward regulatory needs ranged between 0.9% and 61.7%, and from 1.3% to 44.1%, respectively, with Germany and Denmark producing the most accurate schedules. The innovative novelty and practical contributions of this study are that it determines and presents information related to the accuracy of the day-ahead and intraday wind power generation forecasting of the ENTSO-E countries, which is of practical relevance to the transmission system operators (TSOs), the main actors in the energy market and the decision-makers, too. This information may also help investors who invest in onshore and offshore wind farms with the economic aspects, and it may also greatly contribute to the market-related development of the management systems of energy storage solutions related to these technologies.

Energy security aspects related to the National Power Grid

National Power Grid is an important element within the National Power System, having in its composition critical infrastructures of national importance without which the national economy could not operate, and its non-operation, totally or partially (black/brown-out), generates energy insecurity, negative factor with devastating and catastrophic effects on industrial, economic and national security. Due to the fact that National Power Grid is of national strategic importance, it has to be assessed and monitored permanently in terms of security risks, in order to identify vulnerabilities, and this need for assessment also comes from the European perspective because Romania is interconnected to ENTSO-E (European Network of Transmission System Operators) which interconnects various power overhead lines from North to South, from West to East, or even with Africa and Asia. In order to secure the National Power Grid, the authors have set out in this paper to identify possible internal or external vulnerabilities and what impact they have on the National Power Grid and National Power System. By knowing the vulnerabilities, one can automatically identify the dangers and threats to which it is subjected and engaged, being able to develop national/European measures or strategies for the protection and security of the critical infrastructures related to. For this reason, it is considered that the identification of vulnerabilities must become a pressing issue of national, and European energy security and be a useful tool for authorities to develop a energy strategy (short – long term) for the proper functioning of the National Power Grid and the national economy, because all sectors of the economy depend on electricity. The identified vulnerabilities are eliminated by National Energy Strategy 2021 – 2036 (short, medium,and long term) proposed by the authors, with the aim of increasing energy and national security.

OPF-based under frequency load shedding predicting the dynamic frequency trajectory

The paper describes a centralized Under Frequency Load Shedding (UFLS) method, where load shedding decisions are based on the solution of an optimization problem. The proposed approach anticipates the evolution of the grid frequency trajectory by means of a system dynamic model. Moreover, the method is augmented by the equations derived from the Optimal Power Flow (OPF) problem allowing to constrain asymptotic values of node voltages and line currents. The proposed OPF-based method differs from traditional UFLS methods as it enables the user to compute the minimum amount of load to be shed and, at the same time, provides a feasible grid trajectory. The trajectory of the system frequency due to the contingency, and the subsequent load shedding, is predicted over the entire time horizon by means of a second-order dynamic model. The feasibility and applicability of the proposed method are assessed by means of numerical simulations carried out using a real-time simulator, where the time-domain full-replica model of the IEEE 39-bus system has been implemented. Two contingency scenarios are investigated and the performance of the proposed method is compared against the UFLS strategy recommended by the European Network of Transmission System Operators (ENTSO-E). The metrics used for such a comparison are the amount of energy not served, the frequency variation and the violation of the grid safety constraints.

Impacts of Wind Energy Integration to the Utility Grid and Grid Codes: A Review

Background: This paper reviews the requirements imposed by Transmission System Operators (TSOs) in their grid codes to address intolerable implications of integrating large Wind Power Plants (WPPs) to the grid. Besides the common objectives, terminologies used by different TSOs were distinct. Therefore, developing a harmonized grid code is imperative. Introduction: On the recommendation of the European Commission, European Network of Transmission System Operators for Electricity (ENTSO-E) has made concerted efforts in the direction of developing a harmonized grid code, and published its document in March 2013. Method: Several TSOs have updated their grid codes in accordance with the increasing wind energy penetration. We have made an effort to present a comparison between different integration requirements specified by different grid codes. The outcomes presented will certainly be beneficial to the countries, which are in the process of enacting their own grid code. Result: We have reviewed different grid codes in terms of Low Voltage Ride-Through (LVRT) requirement, operating voltage and frequency range, active power control (frequency regulation) and reactive power support (voltage regulation). Conclusion: The present study envisages helping wind turbine manufacturers and WPP developers, as it would provide them a clear insight into the regulations imposed on WPPs as included/ updated in different grid codes.