Flexibility, the New Strategic Variable in Power Markets Electricity markets rest on two realities. The first is prices, which fluctuate hour to hour and open gaps — spreads — between periods of abund

Flexibility, the New Strategic Variable in Power Markets

Electricity markets rest on two realities. The first is prices, which fluctuate hour to hour and open gaps — spreads — between periods of abundance and scarcity. The second is physical: a system's actual capacity to store energy when it is in surplus and release it when it is scarce. The heavier the weight of intermittent renewables in the mix, the more these two dimensions are linked. Storage becomes the junction point between the price signal and effective availability.

The decision taken in Italy on September 24, 2026, illuminates this link. Through resolution 332/2026, an eleven-page document, the energy regulator Arera set the parameters for the next Macse auction, the national mechanism for procuring storage capacity. The premium cap rises from €22,000 to €27,000 per MWh — a €5,000 increase, nearly 23%. The auction covers a 2029 delivery year.

A Swap Between Market Spreads and Guaranteed Revenue

The Logic of the Mechanism

How Macse works helps explain the scope of this revision. A bid submitted to the auction amounts to setting the price of a financial exchange: the operator receives a fixed premium for fifteen years. In return, it forgoes the commercial revenues its battery would have earned from the capacity committed to the scheme.

Those revenues come mainly from arbitrage — the ability to buy or store electricity when it is cheap, then release it when it is expensive. In other words, the spreads. Macse converts volatile exposure to price gaps into a contractual, predictable annuity. The state buys the physical availability of storage and recovers in exchange the market value associated with it.

What the Cap Increase Says

Raising the cap means accepting to pay more for this insurance. Several readings are possible, none of them settled by the available evidence. The first concerns costs: financing, equipment, or grid connection costs may have made the old cap insufficient to attract enough bids. The second stems from a reassessment of arbitrage. If project developers anticipate wider or more frequent spreads by 2029, the revenues they forgo gain value. The compensation demanded then rises mechanically.

In both cases, the conclusion is the same: the price of flexibility is trending upward. For a regulator, the premium cap reflects its willingness to pay to guarantee the system's future physical availability. Raising it by nearly a quarter sends a clear signal about the perceived scarcity of this resource.

From Price Signal to Physical Indicator

The angle of correlation between benchmark prices and physical availability finds a concrete illustration here. In gas or oil markets, regional inventory levels classically serve as a leading indicator: low reserves signal price tensions and a widening of gaps between zones or maturities. In electricity, storage plays a comparable role. But it is built through multi-year investment decisions, not seasonal injections.

This is where mechanisms like Macse become structural. By securing storage capacity over fifteen years, they lock in part of the grid's physical availability in advance. They may also help, over time, to shave the spreads from which batteries derive their value. The paradox is familiar to analysts: the more storage develops, the more it compresses the gaps that make it profitable on a purely market basis. A long-term fixed premium breaks this circle — at the cost of transferring risk to the community.

Beyond Batteries: The Stakes of Physical Efficiency

Compressed Air, a Long-Duration Storage

The question of availability is not limited to batteries. Work by a team at Hunan University of Technology in China focuses on compressed air energy storage (CAES) in underground caverns. The researchers studied how different air injection strategies alter the thermodynamic behavior and storage performance of these caverns.

The study incorporates two phenomena that are often simplified. First, heat transfers during air transport in the well. Second, thermal exchanges between the cavern and the surrounding rock. The main finding: higher injection flow rates improve storage efficiency.

Why It Is Strategic

This technical result has economic reach. The value of a storage asset against spreads depends on the amount of energy stored, but also on the share actually returned. Every efficiency gain improves the economics of arbitrage and reduces the level of public support needed to make a project viable. In an environment where premium caps are rising, operational optimization becomes a competitiveness lever in its own right.

CAES also remains a mass, long-duration storage technology, complementary to batteries. For power systems facing imbalances lasting several days rather than a few hours, such solutions could play a role analogous to strategic reserves in hydrocarbon markets.

Demand Under Pressure, a Burdened Macroeconomic Backdrop

This rising value of flexibility fits into a broader context. Announced investments in artificial intelligence would reach ?.3 trillion within seven years. For Léa Dauphas, chief economist at TAC Economics, this technological revolution must be placed within a set of self-reinforcing factors: strategic rivalries between major powers and the end of conventional monetary policies. For energy systems, such a wave of investment raises the question of grids' capacity to absorb new, concentrated demand. It thus reinforces the value of any resource capable of balancing supply and demand in real time.

What to Watch

Three points will merit particular attention in the coming months. First, the results of the Macse auction for 2029 delivery: a clearing price close to the new cap would confirm tension over the cost of flexibility, while a significantly lower price would temper the diagnosis. Second, the possible spread of comparable mechanisms to other European markets, which would institutionalize the exchange between volatile spreads and guaranteed revenues. Finally, the industrial translation of advances in long-duration storage, whose physical efficiency will determine its place in the mix.

One trend stands out: physical availability is becoming an asset that regulators buy forward, at a rising price. Benchmark prices remain the market's thermometer. But contracted storage capacity already sketches the structure of tensions to come.

This article was written with the assistance of artificial intelligence and verified by our editorial team.