Decarbonised electricity generation will not be free. There are eight challenges ahead15.02.2022Media
For European Union to meet its climate targets by 2030 it will be necessary to accelerate the decarbonization of electricity. However, the integration of renewables into electricity generation is technically demanding and requires immense investments, innovative solutions and extraordinary cooperation at the European level.
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Author: Michal Hudec / EURACTIV.sk
Content of this article does not reflect the positions or opinions of the EU-SysFlex project or its partners. EU-SysFlex is not responsible for the information or opinions included in this article.
The production of renewable electricity fundamentally changes behaviour and functioning of the transmission network. Likewise, transmission system operators (TSO’s) must deal with issues and challenges as the deliveries are becoming more complex.
But how to adjust the transmission network to a significant share of electricity production from renewable sources? The 26-million EU-Sysflex project, co-financed by the European Horizon 2020 program, has been dealing with this question for four years. Project involved 34 organizations from universities to consulting companies, technology providers, distributors and transmission system operators in the 15 European countries.
The EU-Sysflex was based on the assumption that the share of renewable electricity production increases from today´s 37 percent to 50 percent by 2030. This rise will be driven by European climate ambitions and the growth of electricity demand associated with the electrification of heating, transport and other sectors of the economy. There were several scenarios on the table, both optimistic and pessimistic, concerning the development of renewable sources in the power industry. The discussions resulted in eight key messages which should guide the Union towards flexible, reliable, dynamic and decentralized network.
The growing share of electricity production from variable non-synchronous sources such as the solar and wind will lead to significant scarcities in the transmission network. In other words, the higher the proportion of electricity from the sun and wind, the greater the problems.
One of the weaknesses of the network is, for example, inertia, and thus the ability of rotating machines to maintain and provide kinetic energy to the system. Thus, the stability of system is at risk, if inertia decreases. The transmission network faces also a capacity issues of maintaining minimum voltage, rate of change of frequency and system overload.
In Europe, we there are three synchronous power grids – Northern Europe, Continental Europe and EirGrid but each in different condition. So even though they experience the same problems, arising from unstable sources, they deal with them differently.
Expansion of system services
To solve, or at least to mitigate, the technical scarcities identified by the EU-Sysflex, Union and the Member States will need to expand the capacity of system services of various technologies.
System services, provided by TSO’s, ensure the stability of network including frequency controls, balance of supply and demand and substitution of renewables by secondary sources if the electricity production from wind and solar decreases.
To mitigate the shortcomings, it will be necessary to find a suitable combination of technologies and measures. Apart from intensifying system services of existing technologies, the EU-Sysflex calls for developing new ones, like battery storages.
Need for funding
Development of system services will require many millions invested, which cannot be provided by market itself. The reason is simple. Solar, as well as wind power plants operate almost at zero costs, which means lower electricity prices and lower profit for power plants. As the market favours these sources over conventional ones, the price of their electricity will also decrease as they will produce less.
Based on EU-Sysflex analysis, with falling prices is the market unstable to generate sufficient profits to cover the rising costs needed to maintain stability. To do so, the Union and the Member states need additional and adequate funds in a way of preserving support of renewables.
New flexibility products
A system based on variable non-synchronous sources needs flexibility. In this regards, the grid needs to respond to external signals by adapting electricity production so that the grid remains stable. Especially in a time slot when the renewables do not produce electricity.
Although flexibility is currently provided mainly by thermal, nuclear or hydroelectric power plants, some TSO’s call for changes on the flexibility market due to regular lack of capacities of these sources. This argument is supported by the analysis of EU-Sysflex which also calls for new flexibility products that would provide a sufficient capacity of system services.
Flexibility products are understood as individual technical measures in order to stabilize the system and cope with fluctuations.
Better predictions and better optimalization
One of the most important tasks of the TSO’s is to calculate the difference between supply (electricity produced by power plants) and demand. This calculation complicates with growing share of weather-dependent power plants. A more efficient and precise predictions along with better optimalization of the used sources are the key to stable network.
TSO’s and distributors must cooperate
The electricity network consists of two main parts – transmission and distribution. Distribution is handled by DSO´s (Distribution System operator), which unlike TSO’s, there may by several.
In the classical model of centralized network, transmission grids, connected to large powerplants, transmit electricity over long distances. Followed by a distribution grid, the electricity is brought to end-users such as companies or households. However, in the new model, there are several small power plants directly connected to the distribution network which is going to require better coordination between TSO’s and DSO´s.
Virtual power plants
Reduction of network instability and improvement of predictions of demand and supply can be provided by merging several types of decentralized sources to a so-called virtual power plant. This solution is conditioned by the right combination of variable and non-variable sources supplemented by batteries or other forms of energy storage. In addition, the correct set up of a virtual power plant will enable small but numerous domestic sources to provide system services which should lead to a more stable network.