ARERA sets maximum premium (price cap) of €27,000/MWh/year for Italy's second MACSE battery storage auction (delivery year 2029)

ARERA (Delibera 332/2026/R/eel) fixed the 'premio massimo' (maximum bid premium/price cap) for the second MACSE battery-storage auction at €27,000/MWh/year, based on an updated CONE calculation (WACC 8.2%, investment cost INV €189,790/MWh, OPEX €4,486/MWh/year, CAPEX €150,500/MWh), and amended Annex A of deliberazione 247/2023/R/eel to require Terna to update the underlying technology cost study annually (with ≥30-day consultation) and submit it to ARERA at least 180 days before each auction.

The price cap directly determines the maximum revenue battery storage developers can bid for in Italy's long-term storage capacity mechanism (MACSE), shaping investment economics for the 2029 delivery-year battery fleet ahead of the auction scheduled for 24 November 2026. The decision also rejects industry calls to index the cap to volatile lithium carbonate prices or to further increase CAPEX assumptions, setting a precedent for how ARERA balances cost-recovery risk, Chinese export tax/commodity volatility, and consumer cost containment in capacity procurement design.

This decision is a concrete parameterization event within an established long-term storage capacity mechanism (MACSE) rather than a new market design, but it has material design implications: ARERA partially accepted industry CAPEX increase requests (raising battery cost assumptions to €72,000/MWh from the consultation's €61,000/MWh to reflect lithium carbonate price swings and the announced Chinese export tax rebate removal) while firmly rejecting indexation of the cap to commodity prices, oversizing coefficient increases, and beta risk-premium adjustments. This signals ARERA's preference for periodic (annual) recalibration via a formal technology study over dynamic/indexed mechanisms, and reinforces procedural rigidity (60-day pre-auction premium disclosure requirement) as the reason indexation was rejected. The codified annual update cadence for Terna's technology cost study (with 180-day pre-auction lead time) institutionalizes a recurring design-review cycle relevant to future MACSE auctions, including potential expansion to pumped-hydro and long-duration storage (LDES) technologies still pending separate auction design.

Decreto legislativo 210/21 (art.18) establishing MACSE; ARERA deliberazione 247/2023/R/eel (MACSE criteria/Annex A, now amended); European Commission State aid decision C(2023)9226 (CONE calculation criteria); ARERA deliberazione 362/2025/R/eel (first auction price cap precedent); ARERA consultation document 283/2026/R/eel; MASE decrees of 10 Oct 2024, 27 Feb 2025, 27 Mar 2026 and 20 May 2026 approving MACSE scheme and demand forecasts.

Second MACSE battery storage auction (delivery year 2029) · 24 Nov 2026

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