Battery Revenue Stacking

A grid-scale battery that earns revenue from only one source (say, energy arbitrage) is often uneconomic. The same battery earning from three sources simultaneously can be highly profitable. This is revenue stacking: combining multiple market revenue streams from a single asset.

A typical 100 MW / 400 MWh battery can stack three revenue streams. Energy arbitrage: charge low, discharge high ($30,000-60,000/day in CAISO). Frequency regulation: provide fast response during non-arbitrage hours ($5,000-15,000/day). Capacity payments: sell availability during peak periods, through a resource adequacy contract in California or the capacity auction in PJM, at $50-150/kW-year ($5-15 million/year). A battery sells its availability once; RA contracts and capacity auctions are the same product in different markets, not two stackable streams.

Stack the revenue. Arbitrage: $15M/year. Regulation: $3M/year. Capacity: $10M/year. Total: $28M/year. A 400 MWh battery costs roughly $134M at NREL's 2024 benchmark of $334/kWh installed, a conservative modeled estimate (BNEF's observed 2024 market prices for installed systems run lower, around $165-220/kWh). At $28M/year revenue, the simple payback is roughly 5 years, well within the 15-20 year project life.

Can a battery provide all these services simultaneously?

Not simultaneously, but sequentially within a day. A battery might provide regulation from midnight to 10 AM, charge during midday solar surplus, and discharge for arbitrage and capacity during evening peak. Sophisticated battery management systems optimize revenue across these windows, switching between services in real time based on which market pays the most at each moment.

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