On July 30, 2026, Swiss energy trading giant Axpo and Spanish IPP Zelestra announced a 10-year tolling agreement for a 207MW/830MWh BESS project in Italy's Friuli-Venezia Giulia region — Zelestra's second Italian BESS tolling deal in July alone, following a long-term offtake with German utility EnBW for 300MW of a 500MW project in Emilia-Romagna. This deal exemplifies a fundamental transformation in the Italian storage market: the shift from government-administered capacity procurement (the MACSE auction) toward private, bilateral tolling agreements — a merchant storage model where the offtaker (Axpo) leases BESS capacity and assumes market revenue risk, while the owner (Zelestra) receives a fixed, predictable revenue stream. For homeowners evaluating home battery peak shaving savings — using a battery to reduce costs by shifting consumption from high-price to low-price periods — the Italian tolling model offers the utility-scale parallel: in both cases, storage value is realized through active optimization of charging and discharging against time-varying electricity prices, whether managed by a Swiss energy trader with a 207MW BESS or a residential energy management system with a 10kWh home battery.
Overview of the Technology / News
Under the 10-year tolling structure, Axpo pays Zelestra a fixed monthly capacity payment in exchange for exclusive rights to operate, dispatch, and optimize the BESS in Italy's wholesale markets — including the day-ahead market (MGP), intraday market (MI), ancillary services market (MSD), and capacity market. Axpo, trading over 150 TWh annually across 40+ European markets, uses proprietary algorithms for multi-market optimization. Zelestra receives a stable revenue stream that de-risks the project for lenders and equity investors.
Italy is implementing MACSE — a government-administered capacity procurement for storage contracting 2-3GW through 12-15 year contracts with Terna as counterparty. Under MACSE, BESS owners receive fixed annual capacity payments, and Terna gains dispatch rights for grid services during defined hours, while owners retain energy market participation during non-Terna hours. Zelestra's choice to pursue private tolling rather than MACSE is strategic: tolling offers greater commercial flexibility, potentially higher total revenue, and faster execution — the agreement can be signed and financed immediately without waiting for a delayed auction. For consumers considering 5kWh vs 10kWh vs 16kWh home battery — choosing between 5kWh for basic time-of-use shifting, 10kWh for partial backup, or 16kWh for whole-home coverage — the tolling vs. MACSE decision mirrors a fundamental sizing question: how much capacity should be reserved for guaranteed fixed-revenue services vs. higher-upside but less predictable revenue? The optimal answer at both utility and residential scale is a portfolio approach balancing contracted and merchant streams.
Why This Development Matters
- Revenue Certainty Without Government Support: The tolling model achieves revenue certainty through a private contract with a creditworthy offtaker (Axpo, rated A- by S&P) without government involvement. This demonstrates that the commercial value of BESS — optimized arbitrage, ancillary services, and capacity — is sufficiently predictable to support a 10-year contract with an investment-grade counterparty. BESS deployment is not gated on the MACSE timeline.
- Risk Allocation Between Asset Owner and Trader: The tolling structure separates steel-in-the-ground risks (construction, equipment performance, availability — borne by Zelestra) from market risks (price volatility, regulatory changes, competition — borne by Axpo). This aligns with each party's core competency and is analogous to the opco/propco structure in infrastructure finance. It could become a template enabling developers to finance projects based on offtaker credit rather than individual project revenue projections.
- Italy as a Merchant Storage Laboratory: Italian wholesale prices are structurally EUR 110-130/MWh (vs. EUR 70-90 in Germany, EUR 50-70 in Spain), driven by gas dependence (40-45% of generation), limited interconnection (~10GW cross-border vs. 55GW peak demand), and high solar penetration (25GW+ creating EUR 80-120/MWh average daily spreads). Unlike Germany or the UK where BESS revenue is dominated by frequency services, Italy's BESS revenue stack is expected to be 60-70% energy arbitrage — making tolling agreements that monetize this arbitrage particularly attractive.
- Competition Among Tolling Counterparties: Major traders — Vitol, Gunvor, Mercuria, Statkraft — are establishing Italian BESS optimization desks, benefiting developers through more counterparties, better terms, and reduced information asymmetry. For consumers researching battery management system BMS explained — the brain that optimizes battery charging and discharging — the Italian tolling market illustrates that the value of storage lies in optimization intelligence, not hardware alone. A residential BMS forecasting load, solar generation, and time-of-use prices to optimize dispatch is the residential equivalent of Axpo's multi-market algorithms, creating $300-600/year of value for a 10kWh system.
Technical Deep Dive
Italy's electricity market (operated by GME) consists of four sequential sessions: day-ahead (MGP, ~70% of traded volume), intraday (MI, 7 sessions throughout the day), ancillary services (MSD, operated by Terna on pay-as-bid), and balancing (MB). A 207MW/830MWh BESS participating across all four requires an optimization engine that: forecasts day-ahead prices using ML models trained on historical prices, weather, generation forecasts, and outage schedules; determines optimal day-ahead charge/discharge schedule while reserving SoC for higher-value intraday and ancillary opportunities; re-optimizes every 15 minutes as conditions diverge from forecasts; and manages degradation cost ($5-10/MWh of throughput for LFP).
For a typical summer weekday, the optimization might: charge 500MWh during midday solar surplus (EUR 20-40/MWh), reserving 330MWh for ancillary services; discharge 400MWh during evening peak (EUR 150-200/MWh), generating EUR 60,000-80,000 in day-ahead arbitrage; and participate in MSD secondary and tertiary reserve, earning availability (EUR/MW/hour) plus utilization (EUR/MWh) payments. On high-volatility days with EUR 300-500/MWh intraday spikes, the optimization discharges into the MI and MB markets — balancing market optionality. Total annual revenue is estimated at EUR 40-60 million (EUR 200,000-300,000/MW/year), supporting a tolling fee of EUR 15-25 million/year to Zelestra (8-12% unlevered IRR on EUR 180-220 million project cost) while leaving Axpo EUR 15-35 million annual margin.
Axpo's competitive advantage lies in its approximate dynamic programming algorithms — reinforcement learning techniques developed over 20+ years of European power trading — that approximate the optimal dispatch policy by learning from millions of simulated market scenarios. The state space (4 markets x 96 15-minute steps x 10 SoC states = 10^96 possibilities) is far too large for exact optimization, making algorithmic sophistication a genuine barrier to entry. For residential system owners using energy storage inverter compatibility — where inverter, battery voltage, and communication protocols must work seamlessly — the grid-scale BESS faces an analogous integration challenge: optimization algorithm, physical characteristics, market rules, and grid conditions must all be precisely matched. A misaligned tolling agreement will underperform significantly.
Real-world Applications
- Virtual Power Plants and Aggregated Residential Storage: The tolling model provides a template for aggregating residential BESS into VPPs — a VPP aggregator (like Axpo) contracts with homeowners (like Zelestra) for battery dispatch rights, paying a fixed monthly fee per kWh of enrolled capacity. For a 10kWh battery, this could translate to EUR 50-100/month (EUR 600-1,200/year) in VPP revenue — a material contribution to total cost of ownership.
- C&I BESS Tolling for Energy-Intensive Industries: Italian industrial consumers in ceramics, steel, and paper face EUR 140-180/MWh electricity prices and strong BESS deployment incentives but lack energy trading expertise. The tolling model solves this: an industrial company installs on-site BESS and tolls capacity to a trader for a fixed payment that reduces net electricity cost, while the trader optimizes across a geographically and electrically diverse portfolio.
- Cross-Border BESS Tolling: Friuli-Venezia Giulia's location near the Slovenian border enables cross-border arbitrage — capturing EUR 20-50/MWh spreads between Italian and Slovenian/Austrian day-ahead markets. This geographic revenue stream is additive to temporal arbitrage and provides natural diversification. For system owners evaluating home battery cost per kWh — where upfront cost is the primary consideration — Italy demonstrates that BESS value is a function of market access (the number and diversity of revenue streams), not just battery specifications. A battery in a market with multiple revenue streams generates higher returns than an identical battery in a single-revenue-stream market.
Industry Impact / Market Implications
- Global Tolling Template: BESS tolling could become as standardized as PPAs are for renewables. The key elements — fixed capacity payment, exclusive dispatch rights, defined 10+ year term — are directly analogous, and PPA legal frameworks can be adapted. Standardization would reduce transaction costs, increase liquidity, and enable pension funds and insurance companies to participate in BESS financing without in-house energy trading expertise.
- MACSE vs. Tolling — Complementary: Zelestra's choice reflects a portfolio approach, not a rejection of MACSE. MACSE provides highest revenue certainty (12-15 year Terna contract, government-backed) at the cost of reduced commercial flexibility. Tolling provides more flexibility and potentially higher revenue, at the cost of Axpo credit risk and market volatility. The optimal strategy allocates some projects to MACSE (revenue floor) and some to tolling (upside).
- Trader Competition Driving Innovation: Multiple active traders create a positive feedback loop: competition drives investment in more sophisticated optimization algorithms, which improves BESS revenue capture and reduces project cost of capital. This is the same dynamic that drove 90%+ cost reductions in solar PV and lithium-ion batteries.
- Offtaker Credit Risk: The tolling model introduces a new risk dimension: if Axpo experienced financial distress, Zelestra's revenue stream would be at risk, potentially triggering loan default. Solutions — parent company guarantees, letters of credit, third-party credit insurance — will be prerequisites for the model to scale beyond investment-grade offtakers.
Future Outlook
The Axpo-Zelestra deal is a leading indicator of where the global BESS industry is headed: toward private commercial contracts for financing, ownership, and operation — like natural gas storage, LNG, and renewables before it. Italy's combination of high spreads, strong solar penetration, limited interconnection, and competitive trading makes it the ideal laboratory. Key developments to watch: (1) the MACSE auction results establishing the government benchmark for tolling pricing; (2) the first portfolio-level BESS financing based on tolling contracts — demonstrating scalability; and (3) cross-border tolling capturing geographic price spreads. For residential storage — where home battery peak shaving savings is increasingly recognized as a core household energy management function — the Italy tolling precedent validates that storage value is created by optimization, not the physical asset alone. A 10kWh battery can save $300/year through simple time-of-use shifting, or $600-1,200/year through sophisticated multi-market VPP optimization — the difference is not the battery, but the intelligence that controls it.
