Estonia grid frequency
Real-time AC frequency on the Estonian grid, which has been part of the Continental European Synchronous Area since 9 February 2025. The whole CESA shares one frequency in real time — Estonia and Portugal see the same number. Sourced from Elering, downsampled to 5-min mean and refreshed hourly.
Last refresh: 28 Apr 2026, 00:35 UTC
Source: Elering via Volton, CC-BY-4.0.
Methodology
AC frequency is the heartbeat of the grid: nominal 50 Hz means generation exactly matches consumption. When generation exceeds consumption, frequency rises; shortage pushes it down. FCR responds within 30 s to keep the system inside ±200 mHz; aFRR brings it back to 50.000.
Sample rate here is downsampled to 5-min averages so the page is light to load. Volton samples at higher resolution internally for trading; the public feed is the 5-min mean.
FAQ
- Why is the value sometimes a few mHz off 50?
- Even tiny imbalances move frequency: a 100 MW shortage in CESA shifts it about 5 mHz. FCR / aFRR continuously correct, so the value stays in a tight band around 50 Hz under normal conditions.
- Why is this Estonia-only when CESA shares one frequency?
- CESA is synchronous, so any one PMU in the area gives a representative number. We publish the Estonian PMU value (sourced from Elering); Portugal would publish a virtually identical curve.
Get this data
JSON download and stable URL pattern available on the developer API page.