ENTSO-E warns EU on transit flows’ threat to electricity grid security
Decisions on grid investments in central Europe are progressing too slowly as the risk of supply disruptions grow, European network of transmission system operators for electricity (ENTSO-E) president Daniel Dobbeni warned European energy commissioner Günther Oettinger in a letter dated 17 April and published this week.
So-called transit flows, the result of rising levels of intermittent generation delivered by renewable sources, are a growing problem in central Europe nations bordering Germany such as Poland,the Czech Republic, Hungary and Slovakia, ENTSO-E said in a briefing paper to the European Commission.
These unplanned power flows result in physical and scheduled flows travelling in opposite directions more than 90% of the time on the Polish/German and Polish/Czech borders, and more than 80% of the time on the Polish/Slovakian border.
As a result, the grid operational security criteria were compromised.
Decisions 'much too slow'
"I remain deeply concerned about the difference in speed between the connection of very large capacities of renewable energy resources and the realisation in due time of the grid investments needed to support the massive increase of power flows these new resources bring," Dobbeni wrote. "Even more worrying is the very slow progress in permitting procedures for the new transmission lines that have for years been identified as needed by [transmission system operators (TSOs)], for example for North-South transmission in central Europe."
"In other words, regulatory and government decision-making on any measures the TSOs propose to reduce risks to electricity security of supply are much too slow in comparison to the speed with which the operational risks are now increasing," he continued.
Grid failure fear
Czech grid operator CEPS has previously warned of possible grid failures with excessive wind power generation in Germany (see EDEM 27 February 2012), and last year, the German energy agency warned that the lack of grid investment has pushed Germany to use neighbouring grids for balancing and could unbalance the German grid (see EDEM 12 December 2011).
Overloading on cross-border interconnectors further south, including the Slovak-Hungarian and Slovak-Ukrainian borders, was also caused by transit flows, the ENTSO-E paper added.
ENTSO-E called for the installation of phase shifting transformers (PSTs) to reduce congestion on the Czech and Slovak borders with Germany, Poland and Hungary.
"This will partially unload the networks of PSE Operator and CEPS, but will increase the flows inside Germany," the ENTSO-E briefing said.
The paper also recommended redefining bidding areas within the region in advance of the move to a single Day-ahead electricity market in 2015.
ENTSO-E noted efforts by Polish TSO PSE-Operator and German counterpart 50 Hertz Transmission in developing a common list of remedial actions to use on windy days. KB
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