Power system flexibility in a variable climate

Our report “Power system flexibility in a variable climate” assesses the impact of the annual variation of meteorological factors – the climate variability – on the operations of the power systems in 34 European countries that jointly constitute the interconnected European electricity systems. It covers important aspects such as CO2 emissions and use of freshwater for cooling of power plants, and estimates their sensitivity to the changing climatic conditions. Changing weather conditions affect the operation of the European power systems. The output of renewable energy sources fluctuates depending on the availability of wind, cloud cover, or water levels in reservoirs, while the output of dispatchable generators, such as gas turbines, must be adapted accordingly to ensure that supply and demand are balanced at all times. The link between meteorology and power systems also manifests itself through other aspects such as the demand for electricity, affecting the operation of power markets, and thus power prices, emissions, and use of resources (fuels, fresh water etc). Today more than 40% of the European electricity generation capacity is heavily dependent on climatic factors. This dependence is expected to increase in the future as Europe is transitioning to a carbon-neutral economy by mid-century.JRC.C.7-Knowledge for the Energy Unio

Wind power integration, negative prices and power system flexibility - An empirical analysis of extreme events in Germany

This article analyses the flexibility of the German power market with respect to the integration of an increasing share of electricity from renewable energy sources. Flexibility limiting system components, which cause negative prices are explained and illustrated for the German market. Then, the decision of the European Energy Exchange in Leipzig (EEX) to allow negative price bids is explained. Empirical data show the flexibility of conventional generating capacities in Germany during the considered time frame from October 2008 until November 2009. Of the 71 hours with negative spot prices, ten hours were significantly negative with prices of at least -100€/MWh. These extreme hours are analysed in greater detail by the examination of the different system components. Thereby, load, wind power infeed and conventional generation by fuel type are observed as well as the market for negative tertiary reserve as indicators for market tightness. It will be shown that although the market situations were severe, under current conditions it could have been much worse under certain circumstances. Furthermore, the long-run implications of an increasing RES-E share on the conventional generation capacity are discussed. The article concludes with an outlook on additional power system flexibility options.Electricity markets, negative prices, renewable electricity integration, wind power

A coordinated control of offshore wind power and bess to provide power system flexibility

Article number 4650The massive integration of variable renewable energy (VRE) in modern power systems is imposing several challenges; one of them is the increased need for balancing services. Coping with the high variability of the future generation mix with incredible high shares of VER, the power system requires developing and enabling sources of flexibility. This paper proposes and demonstrates a single layer control system for coordinating the steady‐state operation of battery energy storage system (BESS) and wind power plants via multi‐terminal high voltage direct current (HVDC). The proposed coordinated controller is a single layer controller on the top of the power converter‐based technologies. Specifically, the coordinated controller uses the capabilities of the distributed battery energy storage systems (BESS) to store electricity when a logic function is fulfilled. The proposed approach has been implemented considering a control logic based on the power flow in the DC undersea cables and coordinated to charging distributed‐BESS assets. The implemented coordinated controller has been tested using numerical simulations in a modified version of the classical IEEE 14‐bus test system, including tree‐HVDC converter stations. A 24‐h (1‐min resolution) quasi-dynamic simulation was used to demonstrate the suitability of the proposed coordinated control. The controller demonstrated the capacity of fulfilling the defined control logic. Finally, the instan-taneous flexibility power was calculated, demonstrating the suitability of the proposed coordinated controller to provide flexibility and decreased requirements for balancing power

Power system flexibility improvement with a focus on demand response and wind power variability

Unpredictable system component contingencies have imposed vulnerability on power systems, which are under high renewables penetration nowadays. Intermittent nature of renewable energy sources has made this unpredictability even worse than before and calls for excellent adaptability. This paper proposes a flexible security-constrained structure to meet the superior flexibility by coordination of generation and demand sides. In the suggested model, demand-side flexibility is enabled via an optimum real-time (RT) pricing program, while the commitment of conventional units through providing up and down operational reserves improves the flexibility of supply-side. The behaviour of two types of customers is characterized to define an accurate model of demand response and the effect of customers' preferences on the optimal operation of power networks. Conclusively, the proposed model optimizes RT prices in the face of contingency events as well as wind power penetration. System operators together with customers could benefit from the proposed method to schedule generation and consumption units reliably.fi=vertaisarvioitu|en=peerReviewed

Flexibility Characterization, Aggregation, and Market Design Trends with a High Share of Renewables: a Review

Purpose of Review Balancing a large share of solar and wind power generation in the power system will require a well synchronized coordination of all possible flexibility sources. This entails developing market designs that incentivize flexibility providers, and define new flexibility products. To this end, the paper reviews latest trends in the characterization of flexibility by understanding its dimensions in terms of time, spatiality, resource type, and associated risks. Also, as aggregators have emerged as important actors to deliver, and to reward end-user flexibility, the paper reviews latest trends in the topic. Recent Findings The review reports latest trends and discussions on power system flexibility and their relations to market design. The current academic literature indicates that there are open question and limited research on how to reward shortterm flexibility while considering its long-term economic viability. Demand-side flexibility through aggregation holds great potential to integrate renewables. Summary Research in power system flexibility has to put effort on analysing new time-structures of electricity markets and define new marketplaces that consider the integration of new flexibility products, actors (e.g. aggregators, end-users), and mechanisms (e.g. TSO-DSO coordination).Flexibility Characterization, Aggregation, and Market Design Trends with a High Share of Renewables: a ReviewpublishedVersio