SPP

Central United States.

Wholesale design: nodal Integrated Marketplace with day-ahead, reliability-unit-commitment, and real-time balancing markets; decentralized resource adequacy.

Operator
Southwest Power Pool
Nominal frequency
60 Hz
Where energy trades

Where does energy trade in SPP?

Energy in SPP trades in 2 layers: Day-Ahead Market and Real-Time Balancing Market. Participation in Real-Time Balancing Market is mandatory. Scheduling and settlement, where the official sources state them, are in the table below.

Layer Scheduling Settlement
Day-Ahead Market hourly locational marginal pricing and market-clearing prices for operating reserve
Real-Time Balancing Market (mandatory) five-minute dispatch real-time locational marginal pricing and operating-reserve market-clearing prices
What a battery can sell

What ancillary services can a battery sell in SPP?

SPP has 8 ancillary-service products, across 4 families — regulation, contingency reserve, ramping reserve and replacement reserve: Ramp Capability Down, Ramp Capability Up, Regulation-Down, Regulation-Up, Spinning Reserve, Supplemental Reserve, Uncertainty Reserve Down, Uncertainty Reserve Up. Response timing, direction and eligibility for each are in the cards below, as the official sources state them.

Facts below are stated as the official sources state them. A missing line means the source does not state that value — never that the value is zero.

Regulation

  • Regulation-Down

    Correct downward area-control error through automatic dispatch around a resource base point.

    Activation
    automatic generation control, with setpoint signals transmitted every four seconds
    Trigger / range
    continuous regulation deployment within the cleared regulation range
    Typical procurement
    Dynamic or not publicly stated
    Pricing
    regulation capacity and mileage compensation

  • Regulation-Up

    Correct upward area-control error through automatic dispatch around a resource base point.

    Activation
    automatic generation control, with setpoint signals transmitted every four seconds
    Trigger / range
    continuous regulation deployment within the cleared regulation range
    Typical procurement
    Dynamic or not publicly stated
    Pricing
    regulation capacity and mileage compensation

Contingency reserve

  • Spinning Reserve

    Provide synchronized contingency reserve.

    Activation
    SPP contingency-reserve deployment instruction
    Expected within
    10 minutes
    Trigger / range
    online capacity available within the contingency-reserve deployment period
    Typical procurement
    Dynamic or not publicly stated
    Pricing
    operating-reserve market-clearing price

  • Uncertainty Reserve Down

    Hold downward capability for forecast uncertainty over a one-hour look-ahead.

    Activation
    market commitment and dispatch positioning
    Stated response
    The one-hour value defined for this product is a procurement and capability horizon, not a universal instruction-to-full-response deadline.
    Trigger / range
    one-hour uncertainty horizon; eligible online resources
    Typical procurement
    Dynamic or not publicly stated
    Pricing
    market compensation under Integrated Marketplace rules

  • Uncertainty Reserve Up

    Hold upward capability for forecast uncertainty over a one-hour look-ahead.

    Activation
    market commitment and dispatch positioning
    Stated response
    The one-hour value defined for this product is a procurement and capability horizon, not a universal instruction-to-full-response deadline.
    Trigger / range
    one-hour uncertainty horizon; eligible online and qualified offline resources
    Typical procurement
    Dynamic or not publicly stated
    Pricing
    market compensation under Integrated Marketplace rules

Ramping reserve

  • Ramp Capability Down

    Preserve downward ramp capability for expected net-load movement beyond the immediate dispatch interval.

    Activation
    co-optimized positioning in the real-time market
    Expected within
    10 minutes
    Trigger / range
    ten-minute future dispatch horizon; only online resources are eligible
    Typical procurement
    Dynamic or not publicly stated
    Pricing
    no submitted offer; compensation is based on calculated opportunity cost under market rules

  • Ramp Capability Up

    Preserve upward ramp capability for expected net-load movement beyond the immediate dispatch interval.

    Activation
    co-optimized positioning in the real-time market
    Expected within
    10 minutes
    Trigger / range
    ten-minute future dispatch horizon; only online resources are eligible
    Typical procurement
    Dynamic or not publicly stated
    Pricing
    no submitted offer; compensation is based on calculated opportunity cost under market rules

Replacement reserve

  • Supplemental Reserve

    Provide additional ten-minute contingency reserve from qualified online or quick-start resources.

    Activation
    SPP contingency-reserve deployment instruction
    Expected within
    10 minutes
    Trigger / range
    qualified capability available within ten minutes; may include quick-start resources
    Typical procurement
    Dynamic or not publicly stated
    Pricing
    operating-reserve market-clearing price
Getting paid to exist

Does SPP have a capacity mechanism?

No central capacity market. SPP has 1 capacity/adequacy arrangement — Resource Adequacy Requirement — and it works differently.

Resource Adequacy Requirement

Load-responsible entities self-supply or arrange capacity bilaterally; SPP applies deficiency-payment and compliance provisions rather than clearing a centralized capacity auction. A winter-season requirement began in 2025.

Unit of obligation
accredited capacity sufficient to meet each load-responsible entity's forecast peak demand plus planning reserve margin
Auction held in 2025
No — No capacity auction for this market was found to have been held during 2025 in the sources reviewed.
Where this comes from

Official sources

Rules

Service specification

Capacity-mechanism explainer

Current as of · from the Global Electricity Market Catalogue v1.2.0 (compiled to , CC BY 4.0). Facts belong to the linked official authorities; verify the current rules before design or bidding decisions.

Questions

Common questions about SPP

Who operates SPP?
Southwest Power Pool operates SPP, covering Central United States.
Was a qualifying capacity event held in SPP in 2025?
No. Resource Adequacy Requirement: no qualifying 2025 event is recorded. No capacity auction for this market was found to have been held during 2025 in the sources reviewed.
How is energy traded, priced and settled in SPP?
SPP: nodal Integrated Marketplace with day-ahead, reliability-unit-commitment, and real-time balancing markets; decentralized resource adequacy.
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