​Terna is consulting on new rules for Italy's capacity auction for 2028 delivery. The proposal cuts de-rating coefficients for all battery durations, driven by forecasts of 4 GW of incremental batteries in the Nord zone and 64 GW of solar nationwide. The consultation closes on 9 March 2026.

Key takeaways

• 4-hour batteries, the most common duration in Italy's capacity market, drop from 67% of nameplate to 53%, a 21% loss in qualified capacity (Metodologia, points 16-17). All durations are reduced by 20-25%.
• Italy currently has the most generous battery de-rating in Europe. The proposed values would put Italian batteries below Belgium and closer to GB at 4 hours.
• Lower de-rating shrinks the existing fleet's total qualified volume, widening the gap between supply and demand and supporting higher clearing prices. On balance, the de-rating cut outweighs the clearing price effect for batteries.
• A new bidding floor (Art. 24.2b) forces existing operators to offer full capacity from session one, compressing auction strategy alongside the 4% price-step rule (Art. 24.9).

The proposed capacity market reform cuts battery qualification across all durations

Italy's de-rating coefficients determine how much of a battery's nameplate power counts as firm capacity. A 4-hour system currently qualifies at 67% of nameplate.

Under the proposal, that drops to 53%, meaning a 100 MW project would contract 53 MW instead of 67 MW. Shorter durations face even steeper cuts, with 1-hour batteries dropping from 24% to 18% and 8-hour batteries from 90% to 69%.

The cut reflects a saturation risk. As the battery fleet grows, Terna expects batteries to discharge simultaneously during stress events and projects that each additional MW will contribute less to system reliability.

These coefficients are specific to the 2028 delivery auction and will be recalculated for future auctions as the fleet evolves.

Italy's proposed de-rating would push batteries below most European capacity markets

Italy currently tops the European range for BESS de-rating.

But the proposal would change that: at 53%, a 4-hour battery would sit below Belgium, and the gap with GB widens at longer durations.

De-rating methodologies vary significantly across markets, but directionally, Italy is moving from the top of the European range toward the middle.

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The capacity market supply curve shifts twice: less qualified capacity, more zero-price bids

​The de-rating cut works both ways. Each battery qualifies for fewer MW, but the existing fleet's total qualified capacity also shrinks. If Terna maintains the same adequacy target, the supply-demand gap widens, more auction space opens for new entrants, and clearing prices should rise.