The Day Europe's Power Grid Almost Faced a Massive?Blackout
On Friday, 8 January 2021, a disturbance in the synchronised European high-voltage power grid resulted in the separation of European grid regions, cutting Europe’s power grid into two: a south-eastern and a north-western part — for about an hour.
This incident has been described as one of the most critical near-blackout situations since the region’s last major blackout in 2006 leading the German Association of the Industrial Energy and Power Industry (VIK) to warn EU citizens and policy makers “not to lose sight of the issue of grid stability and security of energy supply.”
The analysed sequence of events concludes that the cause of this incident was the tripping of a 400 kV busbar coupler in a Croatian substation by overcurrent protection, which resulted in the decoupling of two busbars in the substation, which in turn separated the north-west and south-east electric power flows in this substation.
As shown in the image below, North-West bound lines which remained connected to one busbar, connect Ernestinovo to Zerjavinec (Croatia) and Pecs (Hungary), while South-East bound lines which remained connected to another busbar, connect Ernestinovo to Ugljevik (Bosnia-Herzegovina) and Sremska Mitrovica (Serbia).
The separation of these energy flows in the Ernestinovo substation, lead to the shifting of electric power flows to neighbouring lines which were subsequently overloaded leading to a line trip in Serbia due to overcurrent protection, which was then followed by the further tripping of other lines due to distance protection, leading eventually to the system separation into two parts.
This system separation resulted in a deficit of power (approx. -6.3 GW) in the North-West Area and a surplus of power (approx. +6.3 GW) in the South-East Area, resulting in turn in a frequency decrease in the North-West Area and a frequency increase in the South-East Area.
Due to the low frequency in the North-West Area, contracted interruptible services in France and Italy (in total around 1.7 GW) were disconnected in order to reduce the frequency deviation. In addition, 420 MW and 60 MW of supportive power were automatically activated from the Nordic and Great Britain synchronous areas respectively. These countermeasures ensured that already at 14:09 CET the frequency deviation from the nominal value of 50 Hz was reduced to around 0.1 Hz in the North-West area.
In order to reduce the high frequency in the South-East Area, automatic and manual countermeasures were activated, including the reduction of generation output (Eg. automatic disconnection of a 975 MW generator in Turkey at 14:04:57). As a consequence, the frequency in the South-East Area returned to 50.2 Hz at 14:29 CET and remained within control limits (49.8 and 50.2 Hz) until the resynchronisation of the two separated areas took place at 15:07:31.6 CET.
While the response and the coordinated actions taken by the transmission system operators (TSOs) by ELES in Slovenia and across Continental Europe ensured that the situation was quickly restored to a close to normal operation; this incident served as a reminder that the energy sector needs a way to locally manage the electricity flows from electricity sources within short notice — needing larger amounts of local flexibility resources. Furthermore, the sector needs a solution to accurately manage on the go, record and monitor those energy transactions to ensure they actually occur as reported, and to use that information as a basis for payment.
Energy marketplaces like SunContract, which can provide energy aggregation services to the system, can support TSOs and even local distribution system operators (DSOs) with “crowd-balancing” flexibility services to control the volatility of the electricity system that decentralised generation and consumption offers and that is expected to significantly scale in the future. By tapping into distributed generation and an increasingly smarter managed load, end-point energy customers can change their need for electricity infeed/withdrawal on short notice, and at a specific point in the grid.
At SunContract, we believe that energy self-sufficiency based on renewables and in combination with locally distributed energy storage (batteries) is the right answer.
This combination can improve the national and regional connectivity of the grid promoting energy security, and yielding lower and more stable energy prices. We also understand that energy security requires the right and flexible legal framework to enable flexibility services from any consumer and producer, to be used in the energy system for both uninterrupted energy supply and affordable prices which are the basis for the implementation of our energy technology. This new energy services should be commercialized and market base on data aggregation services solution providers.
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