When multiple units are available, which one runs and which one sets the price?

How generators stack by cost to form the supply curve, and why the marginal unit determines the Market Clearing Price.

Why can't the cheapest unit always set the price?

How reserve obligations lock a unit's spare capacity, preventing it from responding to marginal demand, and therefore from setting the MCP.

What happens when a coal unit is the only one that can respond to demand?

The regulatory rule that excludes coal from setting the MCP, and why it exists: to prevent prices from dropping as demand increases.

What happens when the cheapest unit can't increase output fast enough?

How the MCP can be a blended cost across multiple intervals when ramp constraints bind, computed via the LP dual variable.

What is the MCP when all gas units are exhausted and diesel must run?

When gas capacity is fully used, diesel sets the MCP at its very high price, signaling extreme system stress.

Does it matter why diesel is dispatched?

When diesel runs due to gas supply constraints (not capacity), the MCP is capped at the highest purchased gas price, a completely different outcome.

How do zero-cost renewables affect the market?

Renewables dispatch first at near-zero cost but don't set the MCP. The marginal thermal unit still determines the price.

What happens when generators offer multiple price bands?

How price bands from different generators interleave in the merit order, and why this affects dispatch and pricing.

How does a battery make money in the auction?

Temporal arbitrage: charge when prices are low, discharge when high. Storage couples decisions across time periods.

Why can't generators just turn on and off freely?

How minimum up/down time requirements create multi-interval commitment consequences.

Why might it be cheaper to keep a generator running than to restart it?

How startup costs create stickiness in unit commitment decisions.

What happens when demand exceeds all available capacity?

The MCP rises to the Value of Lost Load (VOLL), the maximum price, representing the cost of not serving demand.

4 gas units over a full day (48 intervals). See how demand shapes dispatch and unit commitment.

10 diverse units (Gas, Coal, Solar, Wind) in a realistic fuel mix scenario.

Full complexity: 10 units, time-varying renewables, unit commitment dynamics over 48 intervals.