MACSE: a 15-year fixed premium for storage in southern Italy.
Terna procures storage capacity for 15 years through a pay-as-bid auction. The second round on 24 November 2026 awards 16 GWh — with a lower cap than in 2025. What the numbers mean for investors.
As of 01 Oct 2026. Not legal or investment advice. Every figure is sourced below.
16 GWh
volume, 2nd auction
27,000 €
cap per MWh·yr
33 days
to the auction (24 Nov 2026)
12,959 €
avg. 2025 award per MWh·yr
How MACSE works
The swap
The owner receives its bid premium per qualified MWh per year for 15 years. In return, Terna dispatches the committed capacity every quarter-hour on its own schedule.
Claw-back
80 % of the positive balancing-market margin below the strike price is returned; 20 % stays with the owner. Unqualified MWh and the period before delivery remain merchant.
Pay-as-bid
Each winner receives its own bid. ARERA sets the cap (CONE) from a benchmark investment, fixed costs and WACC — guarantees and penalties are percentages of it.
South & islands only
Northern Italy is not eligible. Zones have volume ceilings and floors.
First auction (30 Sep 2025) — results
- Awarded
- 9,968 MWh · 1,491 MW · 15 projects
- Delivery / term
- 2028 · 15 years
- Cap
- 37,000 € per MWh·yr
- Weighted average award
- 12,959 € per MWh·yr (−65 % below cap)
- Demand
- bids more than 4× the volume
- Technology
- lithium-ion only
- Concentration
- about 70 % to Enel and Eni, about 80 % to state-backed firms
2025 awards by zone (€/MWh·yr)
Second auction (24 Nov 2026) — what changes
- Volume
- 16 GWh (2025: 10 GWh), delivery year 2029
- Cap
- 27,000 € per MWh·yr — 27 % below 2025; the July consultation proposed 22,000 € (ARERA 332/2026)
- Why higher than in July
- benchmark investment 150,500 €/MWh instead of €125,000 (lithium prices, end of Chinese export rebates), WACC 8.2 %
- Zones
- South & Calabria up to 11.5 GWh (2025: 7 GWh); Sicily at least 1 GWh (2025: 0.5 GWh)
- Four categories
- new lithium-ion systems, new non-reference technologies (max. 10 %), conversion of existing hydro, upgrades of pumped hydro
- More disclosure
- grid operator, connection request and reference code, site coordinates
- Partial merchant
- part of the capacity can stay outside the contract
- Guarantees
- 10 % of the cap in cash before the auction = 2,700 € per qualified MWh; peak after award 12,150 € per MWh
- Other rules
- anti-concentration limits, carry-forward on partial acceptance, early-completion option, staged withdrawal penalty
Timeline 2026
28 May 2026
Terna publishes the binding rules
07 Jul 2026
Admission window opens (to 27 July)
10 Sept 2026
Deadline for project data / qualified quantity
24 Sept 2026
ARERA sets the cap: €27,000/MWh·yr
20 Oct 2026
Pre-auction cash guarantee (10 % of cap)
24 Nov 2026
Auction (pay-as-bid), 16 GWh
Premium calculator: what does my bid support?
Simplified annual view without merchant revenue, tax or degradation. Fixed costs are an assumption — replace them with your own.
Qualified MWh
–
Premium per year
–
Premium over 15 years (nominal)
–
Premium per nominal MWh·yr
–
Cash guarantee by 20 Oct
–
Peak guarantee after award
–
Supportable all-in investment per nominal MWh
–
ARERA benchmark (incl. construction charges): 189,790 €/MWh
What it means for investors
- The cap falls, but 2025 awards cleared at roughly a third of it anyway. What matters is your own floor: the higher of “the premium that pays back the plant” and “the premium that replaces the merchant revenue you give up”.
- Qualification costs capacity: an 8-hour asset keeps about 92 % of nameplate as qualified MWh. The premium is paid on qualified MWh, costs are incurred on nominal MWh.
- Guarantees are real cash before the auction. Bidders need liquidity and an exit calculation (withdrawal schedule).
- The pipeline is large: the energy ministry reports 447 permitting proceedings with about 73 GW; more than 7 GW are authorised. Competition for the 16 GWh is likely to stay high.
- New capacity in the south compresses the merchant spreads measured today. Model uncontracted capacity conservatively.
Sources
- Terna — Disciplina MACSE (Regeln, Relazione tecnica) · 28 May 2026
- pv magazine — Italy raises MACSE premium cap to €27,000/MWh (ARERA 332/2026) · 28 Sept 2026
- Modo Energy — Italy’s MACSE 2026: bigger volumes, same rules · 29 May 2026
- DLA Piper — MACSE 2026: What’s new in Terna’s updated storage auction rules · 25 Jun 2026
- ESS News — ARERA sets auction premium cap at €27,000/MWh · 28 Sept 2026
- ESS News — Italy sets November date for 16 GWh MACSE auction · 02 Jun 2026
- ESS News — 2025 cap raised to €37,000/MWh·yr · 01 Aug 2025
Assessing a project in Italy or Germany?
The ROI calculator has its own Italy tab: premium, 20% market share, guarantees and your bid floor. For MACSE projects, get in touch.