The European Union (EU) has reshaped its gas storage regime by shifting from very strict emergency obligations to a more flexible framework, while maintaining a high legal filling target. Member States now have broader room to decide on the pace and level of filling, under the continuous oversight of the European Commission (EC). This development aims to reconcile security of supply with the functioning of the internal market without reproducing the price tensions seen at the peak of the last gas crisis. For suppliers, traders and storage operators, these rules redefine how to balance regulatory constraints, price signals and commercial risk management.
From emergency instrument to extended framework
The initial scheme was based on a legal obligation for every Member State with underground storage capacity to bring its filling level close to full use before each heating season. On top of this volume obligation, intermediate milestones set minimum levels to be reached on several dates throughout the year, which very tightly framed the injection profile. The EU’s total storage capacity represents slightly more than one quarter of annual gas consumption, but it is concentrated in a limited number of countries, making regulatory signals particularly decisive for certain markets. In practice, the simultaneous obligation to fill led market players to buy gas over the same time window, fuelling price tensions at a moment when market liquidity was already under strain.
The regulation provided several derogation mechanisms in order to adjust targets to national consumption profiles. Countries whose underground storage volume is far higher than their annual demand could cap their obligation at a predefined fraction of that demand, which was notably the case for Slovakia, Austria, Czechia, Hungary and Latvia. A specific mechanism allowed the target to be adjusted for States exporting significant volumes to neighbouring markets, such as the Netherlands in light of its historical flows to the United Kingdom. In addition, some States with large liquefied natural gas (LNG) terminal capacities, notably Spain and Portugal, were allowed to count part of the volumes stored in those facilities towards their target, complementing the role of conventional underground storage.
Pressure from interim targets and reversal of the seasonal spread
During the last winter season, storage withdrawals increased compared with the previous year under the combined effect of cold spells, lower renewable generation and flexibility needs for neighbouring markets. However, the trajectory set at EU level imposed high minimum levels from the middle of winter onwards, so that several Member States quickly drifted away from their intermediate targets. At the same time, the price differential between summer and winter contracts turned negative, with a spread of around eight euros per megawatt-hour observed at the end of the first quarter, removing the classic economic incentive to inject gas in summer and sell it in winter. Faced with this signal, operators were reluctant to rebuild stocks, and governments had to consider directed purchases or compensation schemes to cover uneconomic injections.
This combination of physical and economic constraints led several States and market participants to call for an easing of the obligations. The European Commission responded with a recommendation allowing greater tolerance for deviations from the trajectories while maintaining, on paper, the final and intermediate objectives. The text opened the way to treating certain unfavourable market conditions in the same way as technical constraints in order to justify shifting the moment when the maximum filling target is reached, potentially towards the start of winter rather than strictly at the beginning of November. At the same time, the Commission proposed to extend the initial emergency framework by two additional years with unchanged obligations, which reignited debate over its impact on price formation and the need for a detailed impact assessment.
An institutional compromise in favour of more flexible targets
The Council of the European Union supported a more flexible approach, keeping a legal 90% storage filling target but allowing that level to be reached at any time between the beginning of October and the beginning of December. In this logic, intermediate targets are no longer presented as firm obligations, but as a series of indicative goals designed to guide planning rather than mechanically triggering gas purchases. Member States are granted the possibility to deviate from the final objective within certain limits when conditions deemed difficult restrict their ability to fill storage, with a margin that can reach ten percentage points and, in specific cases, an additional five points linked to the structure of national production or technical constraints at the largest sites. States without underground facilities remain required to secure, through access or burden-sharing agreements with neighbouring countries, storage volumes representing at least fifteen per cent of their average consumption, with a deadline now aligned to the new window for reaching the final target.
The amended regulation gives Member States responsibility for defining their own annual filling trajectory based on the profiles observed over the previous five years, with milestones set in February, May, July and September. These milestones remain indicative at EU level, even if a national authority may decide to make them binding on its territory in order to steer operator behaviour. Once the 90% threshold is reached within the permitted window, there is no requirement to maintain that level, which allows withdrawals if prices or demand justify them while preserving a minimum safety buffer. For monitoring, the Commission relies on the Gas Coordination Group (GCG) and the Agency for the Cooperation of Energy Regulators (ACER), tasked with consolidating storage data, identifying persistent deviations and, where appropriate, proposing corrective measures without directly imposing binding decisions at EU level.
Impacts on commercial storage, flows and price formation
On the ground, this new framework alters the risk profile for storage operators and for suppliers of liquefied natural gas (LNG) and pipeline gas. The disappearance of legally binding intermediate targets reduces the likelihood of synchronised purchasing peaks in spring and summer, which had contributed to price tensions during the acute phase of the crisis. The possibility for States to make targeted use of derogations, within a range that can reach twenty percentage points when the Commission fully exercises its room for manoeuvre, mitigates the risk of filling storage at a loss in an environment of inverted seasonal spreads. Storage data observed in autumn already show a less stretched profile than in previous years, with an average filling rate of around eighty-two per cent in mid-November, compared with more than ninety-two per cent a year earlier, a level reflecting the strictest application of the earlier emergency rules.
For companies, the challenge is gradually shifting from mechanically complying with a regulatory timetable to optimising portfolios in an environment where security of supply remains framed by a common target, but where the use of flexibility margins varies from one country to another. Some States could fully exploit the scope for deviation to limit storage-related costs, while others may maintain more ambitious internal targets or keep binding national milestones, creating differences in storage pricing and valuation between market areas. At the same time, the prospect of rising global LNG supply from the middle of the decade, combined with more stable European demand, points to an environment in which filling obligations will weigh less heavily on overall prices than during the previous crisis. Each market participant must now factor this framework into its scenarios for prices, hedging and capacity management, and assess how national choices on the use of regulatory flexibilities could reshape the hierarchy of gas hubs and the strategic role of storage in its business models.
