NYISO Capacity Market (ICAP Demand Curve)
NYISO’s capacity market uses a downward-sloping demand curve — as surplus capacity increases, the clearing price decreases. This creates a market signal: tight systems drive high prices incentivising new builds; flush systems depress prices.
Prices clear monthly for four nested localities (a Zone J generator contributes to NYC, G-J, and NYCA simultaneously):
| Locality | Zones | 2025 Summer Req (MW) | 2025 Winter Req (MW) | Surplus (%) | Zero-Crossing |
|---|---|---|---|---|---|
| NYCA | All 11 | 34,059 | 33,648 | 4.5% | 12% excess |
| G-J Locality | G, H, I, J | 11,192 | 10,897 | 14.7% | 15% excess |
| NYC | J | 8,191 | 8,051 | 6.0% | 18% excess |
| Long Island | K | 4,922 | 4,897 | 10.5% | 18% excess |
BESS Capacity Accreditation Factors (CAFs)
CAFs are duration-dependent and decline over time as storage penetration increases:
| Year | NYCA (2hr) | G-J (2hr) | NYC (2hr) | LI (2hr) |
|---|---|---|---|---|
| 2026 | 0.686 | 0.696 | 0.580 | 0.476 |
| 2030 | 0.450 | 0.460 | 0.330 | 0.270 |
| 2034 | 0.300 | 0.310 | 0.220 | 0.180 |
| 2038 | 0.180 | 0.180 | 0.120 | 0.100 |
Longer durations receive higher CAFs (NYCA 2026: 2hr=0.69, 4hr=0.81, 6hr=0.89, 8hr=0.93).
Renewable CAFs (iCAF Set 1)
| Technology | Rest of State | GHI Locality | J Locality | K Locality |
|---|---|---|---|---|
| Solar PV | 8.5% | 8.5% | 13.1% | 12.0% |
| Onshore wind | 16.2% | 15.2% | 18.7% | 17.9% |
| Offshore wind | 35.3% | 35.3% | 35.3% | 35.3% |
Offshore wind TSL floor
Offshore wind in constrained localities has RA availability (37.6%) exceeding transmission security availability (10.0%). The 27.6% gap is added to local requirements as a “TSL floor” — a 1,000 MW offshore wind farm in NYC adds 353 MW supply but increases NYC requirement by 276 MW, yielding only 77 MW net benefit.
Data sources
| Input | Source | Link |
|---|---|---|
| Demand curve parameters, Gross CONE | NYISO 2025-2029 DCR Final Report | NYISO DCR |
| 2025-26 spot auction clearing (requirements, surplus) | NYISO ICAP Market Reports | NYISO ICAP |
| 2025-2026 Final CAFs | NYISO ICAPWG | NYISO ICAPWG |
| 2026-2027 iCAF Set 1 | NYISO ICAPWG | NYISO ICAPWG |
| TSL floor methodology | NYISO ICAPWG | NYISO ICAPWG |
| Zero-crossing percentages | NYISO ICAP Demand Curve filings | NYISO ICAP |