These FAQs cover the Eastern Interconnection model framework, followed by market-specific questions (capacity mechanisms, ancillary products, storage subsidies) for each ISO: NYISO, MISO, PJM.
General
How often is the forecast updated?
The Eastern Interconnection forecast is updated quarterly, incorporating the latest commodity price data, interconnection queue updates, and structural model improvements.
Can the forecast support BESS financing?
Yes. Model outputs include hourly prices, BESS dispatch profiles, and revenue breakdowns (energy arbitrage and ancillary services) across scenarios. These are suitable for financial models, due diligence, and bankability assessments.
Which ISOs are covered and at what granularity?
NYISO (11 zones, A through K), MISO (Local Resource Zones), and PJM (transmission zones / Locational Deliverability Areas) are documented; ISO-NE is planned. All ISOs are modeled at the zonal level.
What scenarios are available?
The central scenario reflects base-case assumptions for demand growth, commodity prices, policy, and capacity buildout. Sensitivity scenarios can be configured for commodity price shocks, accelerated electrification, and policy changes (e.g., RGGI cap tightening).
Are the forecasts in real or nominal terms?
Forecast results are expressed in a real 2025 currency base. This base is stated in the forecast revenues output CSV and is subject to updates. You need to apply your own inflation assumptions to uplift to nominal.
Fundamentals Model
Is this a fundamental or statistical model?
Fundamental. The model solves a cost-minimization optimization for each hour, subject to physics and policy constraints. Scenario analysis and sensitivity testing are used to explore uncertainty, rather than stochastic simulation or Monte Carlo methods.
How is RGGI modeled?
RGGI is a declining regional CO2 budget constraint on generators in member states, with a Cost Containment Reserve that releases additional allowances when the carbon shadow price clears trigger levels. See Emissions & Policy for the cap schedule and which ISOs are affected.
How is the operating reserve modeled?
The model enforces a minimum reserve requirement at each node, adding a reserve penalty price to locational prices when available reserves fall short. See Overview for how this fits the dispatch framework.
How are negative prices modeled?
Negative prices arise endogenously when oversupply occurs or when PTC-backed renewables bid below zero to maintain dispatch. Must-run generators (nuclear, certain hydro) can also bid negative to reflect reliability requirements and incentive structures.
Can the model simulate curtailment?
Yes. Curtailment occurs endogenously when transmission constraints or oversupply prevent full renewable dispatch. A spill variable with a small penalty allows the solver to curtail renewables when it is cheaper than re-dispatching thermal generation.
How is unit commitment handled?
A two-stage solve: a first MIP stage commits thermal generators, then a second LP stage fixes those decisions and re-optimizes dispatch for clean LMP shadow prices. See Overview for the full two-stage dispatch framework.
NYISO
NYISO-specific questions on market design, capacity, ancillary services, and the Indexed Storage Credit.
Fundamentals Model
How are gas prices differentiated across NYISO?
Each NYISO zone is mapped to a specific pipeline gas hub based on physical infrastructure. See Commodity Prices for the zone-to-hub mapping.
What is the NYISO capacity market modeling?
ICAP demand curve-based capacity prices are derived from supply-demand equilibrium across four localities (NYCA, G-J, NYC, Long Island), using technology-specific Capacity Accreditation Factors (CAFs). See Capacity Prices for CAF tables and demand curve parameters.
How is storage cannibalization modeled?
Three mechanisms: (1) spread compression: as more batteries compete for the same arbitrage windows, daily price spreads narrow; (2) declining CAFs: NYISO BESS capacity credits decline over time as storage penetration increases, reducing capacity revenue; (3) ancillary services saturation: a growing battery fleet competing for a fixed volume of AS products depresses AS clearing prices, reducing per-asset AS revenue.
How are ancillary services modeled?
AS prices for the four NYISO products are derived post-processing from historical relationships, not co-optimized with energy: the dispatch holds reserve-margin headroom and AS revenue is applied post-solve. See Dispatch Model.
Dispatch Model
What is a capacity price?
A payment for being available to meet peak demand, separate from energy revenues, set monthly across four localities via the ICAP demand curve and scaled by each asset’s Capacity Accreditation Factor (CAF). See Capacity Prices.
What is the ISC?
The Indexed Storage Credit is NYISO’s 15-year battery storage subsidy: monthly payments equal the difference between a fixed strike price and a market-based reference price, topping up income when markets are weak and clawing back when strong. See Dispatch Model.
Can a user set their own ISC strike price?
Yes. The strike price is configurable through the terminal to reflect a specific tender outcome or sensitivity scenario.
What storage durations are supported?
2-hour, 4-hour, 6-hour, and 8-hour BESS. Longer durations receive higher CAFs, lower ISC strike prices per unit, and wider REAP arbitrage windows. AS SOC headroom requirements are defined per product (e.g. 30 minutes at full power for 10-min reserves), so longer batteries retain a larger share of usable capacity while providing the same AS.
How are capacity market revenues calculated?
Each battery’s monthly UCAP clearing price is scaled by its duration- and locality-specific CAF and spread evenly across the month. See Capacity Prices for CAF tables and demand curve parameters.
How does the dispatch model handle AS stacking?
- 10-min spinning and 10-min non-sync are mutually exclusive (cannot both be active in same hour)
- Regulation is symmetric, must reserve equal MW up and down. NYISO pays a single capacity price regardless of direction.
- SOC headroom: must hold enough SoC to sustain full-power discharge for each product’s max call duration (30 min for 10-min products, 1 hr for 30-min)
- Regulation stacks with reserves: can provide regulation and spinning/operating simultaneously, subject to total capacity not exceeding nameplate
MISO
MISO-specific questions on market design, capacity, and ancillary services.
Fundamentals Model
How is the MISO capacity market modeled?
MISO capacity clears through the seasonal Planning Resource Auction (PRA) against a zonal Reserve-Based Demand Curve, with the model replaying, re-clearing, or rebuilding the supply stack depending on the year. See Capacity Prices.
How is capacity accredited?
MISO uses Schedule 53 class-average UCAP ratios, transitioning to Direct Loss-of-Load (DLoL) seasonal accreditation from the 2028 planning year. See Capacity Prices.
How are ancillary services modeled?
Day-ahead prices for MISO’s modeled products are derived post-processing from historical clearing prices, not co-optimized with energy: the dispatch holds reserve-margin headroom and AS revenue is applied post-solve. See Dispatch Model.
Dispatch Model
Is there a storage subsidy like NYISO’s ISC?
No. MISO has no availability-based storage subsidy comparable to the NYISO Indexed Storage Credit. Battery revenue comes from energy arbitrage, the three modeled ancillary products, and seasonal PRA capacity payments.
How are capacity market revenues calculated?
A battery’s seasonally accredited capacity is multiplied by the PRA clearing price for its zone and season. Accreditation follows the Schedule 53 / DLoL methodology described on the Capacity Prices page.
PJM
PJM-specific questions on market design, capacity, and ancillary services.
Fundamentals Model
How is the PJM capacity market modeled?
PJM capacity clears through the Reliability Pricing Model (RPM) forward auction against a Variable Resource Requirement (VRR) curve, nested by Locational Deliverability Area, using observed prices for settled auctions and a rebuilt VRR curve for forward years. See Capacity Prices.
How is capacity accredited?
PJM uses Effective Load Carrying Capability (ELCC) ratings by resource class, scaling each technology’s nameplate to its reliability contribution. See Capacity Prices.
How are ancillary services modeled?
Day-ahead prices for PJM’s storage-relevant products are derived post-processing from historical clearing prices, not co-optimized with energy: the dispatch holds reserve-margin headroom and AS revenue is applied post-solve. See Dispatch Model.
Dispatch Model
Is there a storage subsidy like NYISO’s ISC?
No. PJM has no availability-based storage subsidy comparable to the NYISO Indexed Storage Credit. Battery revenue comes from energy arbitrage, the modeled ancillary products, and forward RPM capacity payments.
How are capacity market revenues calculated?
A battery’s ELCC-accredited capacity is multiplied by the forward RPM clearing price for its LDA. Accreditation follows the ELCC methodology described on the Capacity Prices page.