PJM Market Primer: Written for Readers Familiar with China's Power Market

Working document — v0.1 (July 2026) Positioning: the mirror of Section 1 of ../markets/china/market_vendor_dd_en.md (the China market primer) — it explains PJM for readers who know China's market, with Chinese concepts as the constant point of comparison. Chinese version: market_pjm_zh.md.

1. Institutional frame: who governs, who plays

PJM Interconnection is the largest US Regional Transmission Organization (RTO), spanning 13 eastern states plus Washington DC, serving ~65 million people, with peak load on the order of 150 GW and installed capacity above 180 GW. The frame differs fundamentally from China's "provincial markets + national push":

The regulator is FERC (federal), not provinces/states — PJM's market rules (tariff/operating agreement) are FERC-approved, and rule changes go through a federal legal process (stakeholder proceedings + FERC rulings): public, slow, litigable. Contrast: Chinese rules issue as NDRC/NEA and provincial documents — fast and flexible.
PJM itself is a member-governed nonprofit: generators, transmission owners, retailers, state consumer advocates — and, crucially, financial institutions are a formal market-participant category. That single fact is the key to most PJM–China differences.
One market, one rulebook: 13 states share the same clearing engine and price system. There is no "one province, one policy." Inter-RTO trade (PJM–MISO, PJM–NYISO) resembles China's inter-provincial layer, but with greater volume and mechanism maturity.

2. Market architecture: spot-native

China is "MLT as ballast, spot as corrector"; PJM is the inverse — the spot market IS the market, and all forward arrangements are off-exchange financial contracts settling against it.

Day-ahead (DA): closes 10:30 AM ET daily, clears all 24 hours of tomorrow via SCUC + economic dispatch, hourly prices. Analog: the DA declaration/clearing in Chinese spot provinces — but with no "physical" MLT volume occupying space; the DA market reprices everything.
Real-time (RT): 5-minute dispatch and settlement. DA + RT form the two-settlement system: DA positions settle at DA prices; deviations of actuals from DA settle at RT — the same logic as Chinese spot provinces' DA settlement + RT deviation settlement.
Nodal prices (LMP): ~13,000 pricing nodes, each decomposed into energy + congestion + loss. Contrast: most Chinese provinces clear at a unified provincial price or coarse zones (generation-side nodal in Guangdong/Shanxi excepted) — PJM's spatial granularity is two orders of magnitude finer, which is why "congestion" is a standalone business (see FTR).
Caps and scarcity pricing: offer cap $1,000/MWh (to $2,000 with cost justification), plus the Operating Reserve Demand Curve (ORDC) — an administrative adder that drives RT prices up when reserves run short. Negative prices are fully legal and common. Contrast: China's declaration caps anchor to industrial peak retail rates (~¥1–1.5/kWh) with administratively compressed tails; PJM scarcity spikes reach an order of magnitude higher — which is precisely why US volatility can fund optimization fees.

3. The financial layer: species absent from China

PJM's DA market is open to purely financial participation — the deepest structural difference from China:

Virtual transactions (INC/DEC/UTC): entities with no physical assets submit virtual supply (INCs) or virtual demand (DECs) into DA, clearing DA and mandatorily unwinding at RT — speculation/arbitrage on the DA–RT spread, at meaningful volume shares. Effect: any persistent, predictable DA–RT gap gets arbitraged away; the spread's mean is pinned near zero. Contrast: China has no such mechanism — the core reason the MLT–spot basis can persistently diverge (see China report §1.5).
FTRs (Financial Transmission Rights): financial rights on DA congestion differences between two nodes, auctioned by PJM — the hedging and speculation instrument for congestion risk. Contrast: China's unified provincial pricing makes the instrument largely unnecessary; inter-provincial congestion rents flow to grid/government mechanisms.
OTC forwards/futures: Nodal Exchange and ICE list PJM hub power futures (peak/off-peak, monthly, years out), liquidity concentrated at Western Hub; plus bilateral PPAs/virtual PPAs (CfDs against hub or node prices) and bank hedge structures (proxy revenue swaps, etc.). Contrast: functionally equivalent to China's MLT contracts, but (a) fully voluntary, no coverage-ratio mandates; (b) priced by financial traders with arbitraged basis convergence; (c) settled outside the market operator — PJM doesn't know your hedge exists. China's MLT lives inside the exchange: quasi-mandatory, priced by physical counterparties, settlement-integrated, and — a silver lining — visible in disclosure data.

4. Capacity market and ancillary services

RPM capacity market: rolling three-year-forward auctions procure capacity obligations; cleared resources carry a must-offer obligation (must bid into DA) and performance assessment in scarcity hours (Capacity Performance — underperformance penalties are substantial). Contrast: China's coal capacity payment (容量电价, from 2024) is administratively priced availability compensation — no auction, no symmetric performance penalty; similar function (a revenue pillar outside the energy market), very different mechanism.
Ancillary services: regulation and synchronized/primary reserves co-optimized with energy in DA/RT with endogenous prices. Contrast: Document 394 pushes China the same direction, but product scope and co-clearing depth are still evolving.

5. Settlement and deviations: BORD vs. the Two Detailed Rules

PJM disciplines deviations through Balancing Operating Reserve Deviation (BORD) charges: real-time balancing uplift is allocated by cost causation to parties who deviated from DA positions (generation deviations, load deviations, virtuals), at a daily rate scaled to actual costs incurred. China disciplines forecast accuracy and schedule compliance through the administrative 两个细则 assessments, decoupled from actual daily system cost. One-line contrast: PJM prices the externality; China grades the homework. Product implication: in PJM, deviations are optimized against a forecastable stochastic price; in China, forecasts are engineered against a fixed rulebook — which is why China developed a compliance-procurement forecasting market and the US never did. (Details: ../markets/us/pjm/design_models_en.md §4.1.)

6. Renewables: tax credits, not mechanism prices

The US never had "guaranteed volume, guaranteed price": renewables were always market-absorbed (PPAs are voluntary commercial contracts, not policy procurement). Policy support flows through tax credits:

PTC: ~$27.5–30/MWh of generation for 10 years ⇒ a rational negative offer floor (≈ −$25 to −$35/MWh) — the plant pays to generate because the credit outweighs the negative price.
ITC: a one-time 30%+ credit on capex ⇒ no effect on marginal cost; offer floor ≈ $0.
Contrast with China's mechanism price: both are revenue stabilizers, but the mechanism price is a price-type instrument (a CfD stabilizing the realized price) while tax credits are tax-type (leaving price formation untouched but distorting offer floors). A neat mirror: China's mechanism auctions (lowest bids win) and America's PTC-shaped negative floors each create a distinctive supply-curve signature at the low end of their respective markets.
Curtailment in PJM is economic (you're dispatched down when price falls below your offer floor — a market-clearing outcome), not an administrative quota; "curtailment rate" statistics are therefore not directly comparable across the two systems.

7. Data and access: the transparency gap

Data Miner 2: PJM's public data platform — full nodal DA/RT LMPs with component decomposition, load and forecasts, fleet wind/solar forecasts and actuals, outages, binding constraints — web access without login, API with free registration. Contrast: China has no equivalent; provincial disclosures vary and sit behind member portals. In China, data acquisition is a moat; in PJM data is free and insight is the moat.
Bid submission uses the separately authenticated Markets Gateway; participant status involves registration and credit/collateral (logic parallel to Chinese exchange membership + performance bonds).
Note the asymmetry, though: PJM unit offers publish only at a 4-month lag, masked, and the network model is CEII-restricted — "transparent" is not "fully transparent."

8. Quick-reference comparison table

Dimension	PJM	China (spot provinces)
Regulator	FERC (federal); procedural, slow rule change	NDRC/NEA + provincial; document-driven, fast
Market scope	One market, one rulebook across 13 states	One province one policy; 31 provincial markets
Dominant settlement layer	Spot (DA+RT two-settlement)	MLT majority; spot settles deviations
Forwards/MLT	Voluntary OTC financial contracts (PPA/futures), outside the operator	Quasi-mandatory exchange contracts, curved, settlement-integrated
Forward price formation	Financial traders, arbitraged convergence	Physical counterparties inside coal-benchmark ±20%; persistent basis
Financial participants	Formal category (virtuals, FTR, futures)	Essentially absent
Spatial pricing	~13,000 nodal LMPs	Unified provincial / zonal mostly
Price tails	$1,000–2,000/MWh caps + ORDC adders; negative common	~¥1–1.5/kWh caps; floors at 0 or slightly negative
Capacity compensation	RPM auctions + must-offer + performance penalties	Capacity payment (administered, coal-centric)
Deviation discipline	BORD cost-causation allocation (priced)	Two Detailed Rules administrative assessment (ruled)
Renewable support	PTC/ITC tax credits (shaping negative floors)	Mechanism-price CfD (auction-set)
Public data	Data Miner, free and comprehensive	Provincial, member-gated, inconsistent
Service-provider moat	Nodal congestion insight + point-in-time archive	Provincial rules library + data acquisition + relationships

9. Three counter-intuitive notes for readers coming from China

"No MLT market" does not mean "no hedging" — hedging is everywhere, just grown outside the market operator and carried by the financial system. Analyzing a PJM plant's revenue requires asking about its PPA/hedge structure, which public data won't show (contrast China: the contracts live inside the exchange, so aggregate data is visible).
Price volatility is a feature, not a bug — ORDC scarcity adders are deliberate design, paying for reliability through a few extreme hours. The Chinese instinct of "caps for stability" misreads where the commercial opportunity comes from in PJM: optimization fees are ultimately funded by volatility.
Slow rules reshape the moat — PJM rules evolve on a multi-year cycle with precedent to consult, so model risk is dominated by market risk; Chinese rules evolve quarterly, making rule risk itself a modeling object. The same company needs different organizational muscles in the two markets.

Glossary: appendix of ../markets/us/pjm/design_models_en.md; China-side concepts: appendix of ../markets/china/market_vendor_dd_en.md.

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