​Long Island's BESS reference price reached $129/MW-day in August 2026, ahead of New York City's $119/MW-day. That is the first month this year that Long Island has led.

Long Island was also the only NYISO zone to see its reference price rise year-over-year, up 44%. Every other zone fell by between 17% and 30%.

On Long Island, both components of the reference price moved up: the Reference Capacity Price (RCP) and the Reference Energy Arbitrage Price (REAP).

Key takeaways

• Long Island's reference price hit $129/MW-day, 8.5% above New York City’s. Its UCAP price rose 68% year-over-year and its day-ahead TB4 spread rose 30%.
• Real-time TB4 spreads ran 51% higher than day-ahead at the reference node, the second-widest gap this past year. REAP credits day-ahead spreads alone, so the reference price tracked the weaker of the two markets.
• August 6 delivered 23% of the month's real-time spread in one day, when load jumped 3.2 GW and the forecast missed by 1.5 GW. Real-time energy prices reached $555/MWh in an hour that day-ahead had cleared at $108/MWh.

Long Island increased both reference price components year-over-year

Long Island's reference capacity price rose 59% year-over-year, from $42/MW-day to $68/MW-day. Its August capacity auction cleared at $10/kW-month, against $6/kW-month a year earlier.

Its reference energy arbitrage price rose 30% too, to $62/MW-day. That figure is driven by a day-ahead TB4 spread of $247/MW-day, 1.81 times the $136/MW-day average of the nine upstate and Hudson Valley zones.

The gap is driven by Long Island's peak prices (as opposed to trough prices). Its four highest-priced hours each day averaged $102/MWh, against $74/MWh in New York City and $68/MWh in West. Its four cheapest averaged $40/MWh, only $5/MWh above West.

Long Island is a load pocket with limited import capability, so local units set its evening price. The locational premium is persistent through the month rather than event-driven, beating the nine-zone average on 29 of 31 days.

Real-time spreads were even more extreme. Long Island's real-time TB4 spread reached $438/MW-day, up 164% year-over-year, and cleared above $1,600/MW-day on two days.

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Upstate reference prices stayed closer to New York City’s as capacity prices remained low

New York City's premium over the nine upstate and Hudson Valley zones fell to $54/MW-day.