ED: bne IntelliNews has launched a beta version of our AI assisted analysis tool “IntelliNews Lambda” that makes use of sophisticated mathematical modelling to identify causal links in both reporting and statistics that gives more accurate analysis and can make forward predictions with quantifiable probability. In this case, IntelliNews Lambda used a Fourier-smoothed harmonic model for the last 15 years of gas storage data (excluding the crisis years of 2022, 2023) to create a climatic baseline based on the sinusoidal nature of filling and emptying Europe’s tanks.

 

 

Europe’s gas storage is back to normal as LNG prices have dropped to their lowest levels in 18 months, thanks to surging supply and subdued demand across the continent. That has led to comfortably full gas tanks and the lowest deviation from the baseline in 15 years.

According to Gas Infrastructure Europe data, EU underground gas storage stood at 77.02% on November 27. That compares with a 2011–2024 average of roughly 86–87% for this point in the heating season and is the second-lowest level in the series after 2021, when storage dipped to about 72%. By contrast, stocks stood close to 94–97% in 2022–2023 and around 87% last year.

However, 77% is not a low level as it puts Europe on track to end the heating season with just under 40% left in the tanks – comfortably above the technical rock bottom minimum of 10% full, below which storage cannot go.

From its early-October peak of about 83.15%, EU storage has already fallen by roughly 6.1 percentage points to 77.02%. Historically, stocks over the same period have tended to decline by around 4 percentage points, suggesting a somewhat faster-than-usual start to the winter drawdown, even if overall inventories remain very healthy by past standards.

 

Setting the seasons dates

According to the baseline, typically the start of the injection season appears on February 7, when the storage curve begins bending upward. Withdrawals are still occurring, but at a slowing pace vs injections giving a net gain, as milder weather and rising supply gradually narrow the winter deficit.

The seasonal apex is on October 18 and the completion of Europe’s summer refilling. Storage peaks here before injections fall away and withdrawals dominate ending the injection season.

The end of the heating season falls on April 2, when gas storage reaches its annual nadir. By early April, heating demand collapses and withdrawals stabilise, before injections begin in earnest to refill the tanks for the next season.

 

2025 standard deviation from baseline exceptionally low

Across the 13 baseline years, deviations from the harmonic storage curve typically range between 2 and 6 percentage points, with most years clustering around 3–5.

Lower values indicate a year whose seasonal behaviour closely follows the structural pattern of injections and withdrawals, while the higher values reflect unusual weather, supply shocks or atypical stocking behaviour.

A standard deviation of about 2pp means storage typically adds or subtracts about  ±3–4 points to the seasonal baseline, making the year highly predictable. When volatility rises to 6pp, the uncertainty widens to ±10–12 points, sharply reducing forecasting confidence. 

The smallest deviations occur in steady, uneventful years such as 2012, 2016 and 2011, all with standard deviations below 3. At the other end, years like 2018, 2019, 2020 and especially 2024 show much larger variance from the baseline, reflecting volatile storage strategies, irregular withdrawal patterns, and the lingering effects of crisis-year supply disruptions.

By contrast, 2025 stands out as exceptionally close to the harmonic baseline, with a standard deviation of just 1.75, the lowest in the entire dataset. This implies that 2025’s storage trajectory has been unusually smooth, following the long-term seasonal rhythm more closely than any previous non-crisis year.

For comparison, a typical year such as 2015 deviated by nearly 4 percentage points, while 2024 deviated by more than 6, driven by sharp shifts in refilling rates and irregular winter drawdowns.

The calm behaviour in 2025 suggests that supply, demand and weather conditions have aligned unusually well, producing one of the most stable storage paths seen in over a decade.

 

End of the 2026 heating season forecasts

The harmonic baseline places the seasonal nadir on April 2, marking the statistical end of the heating season.

Because 2025 has the lowest variance of any year in the dataset (1.75 percentage points) relative to the baseline the timing uncertainty is unusually small. Based on historical timing shifts in low-variance years, the most probable real-world date for the 2025 nadir is March 31 to April 4, with April 2 the single most likely day.

Using the observed spread of turning-point deviations in comparable years (2011, 2012 and 2016), this five-day window carries roughly 90–95% confidence, making 2025 one of the few years in which the end of the heating season can be predicted with high statistical precision.

The harmonic baseline gives a storage level of 37.86% on April 2, which is the structural expectation for the lowest point of the cycle. With 2025 tracking the baseline closely, the expected error band is narrow with a realistic range of 36.1% to 39.6%, again with an estimated 90–95% probability of the actual nadir falling within this interval.

In practical terms, this means Europe is likely to bottom out at just under 40% capacity, with an unusually small chance of a significantly deeper or shallower trough compared with more volatile years such as 2018, 2020 or 2024.

In historical context, a storage nadir in the 36.1–39.6% range would place 2025 firmly back in the band of what might be called Europe’s “normal storage levels”.

In the calmest years of the last decade — notably 2011, 2012, and 2016 — end-of-season levels typically settled between 37% and 42%, just a tad higher than the projected 2025 storage interval.

The unusually stressed years stand out clearly against this baseline: 2021, ahead of the crisis, bottomed out near 29–30%, while the chaotic volatility of 2022 and its aftermath produced nadirs ranging between the low 20s and mid-30s depending on timing and market conditions.