Market Performance and Planning Forum (examples) March 23, 2011 - PowerPoint PPT Presentation

Market Performance and Planning Forum (examples) March 23, 2011

How Would Flexible Ramping Constraint Affect LMP? • Partially loading 2 generators where 1 alone would seem to be sufficient. • Two generators in the market to fill a 100MW load. • Assume each generator has a range of 40-105 and one has a cost of $30 while the other has a cost of $35 • Without any flexible ramping constraints the solution would be for the $30 generator to fill the 100MWs by itself. • With the flexible ramping constraint that each would be dispatched; presumably the $35 unit would be dispatched to 40 while the cheaper one would be dispatched to 60. • Are the LMPs of each generator correct? Slide 2

Example 1 • Flexi-Ramp constraint enforced in RTPD. • Forecast Load: 100MW • Forecast uncertainty (Flexible ramp req.): +50MW • Resources Available • Unit 1: Pmin=40MW, Pmax=105MW, Energy Bid=$30 • Unit 2: Pmin=40MW, Pmax=105MW, Energy Bid=$35 • The following two constraints are enforced: – ENgen-ENload = 0 (Power balance constraint Ignoring losses) – FRonlinegen-up >= FRreq-up (Flexi-ramp constraint) Page 3

Example 1 (cont.) • Without Flexi-ramp Constraint: – Unit 1: Committed and loaded to 100MW at price of $30 – Unit 2: Remains Un-committed • With Flexi-ramp Constraint enforced in RTPD: – Unit 1: Committed and loaded to 60MW at price of $30 • Contributing 45MW of online capacity to Flexi-ramp constraint – Unit 2: Committed at Pmin= 40MW • Contributing 5MW of online capacity to Flexi-ramp constraint • Note the energy prices in RTPD are not binding. Only RTD prices are binding. Page 4

Example 1 (cont.) • In RTD binding interval no flexi-ramp constraint is enforced. • Assuming actual load in RTD is 100MW – Unit 1: Dispatched to 60MW at a marginal price of $30 – Unit 2: Dispatched to 40MW at a marginal price of $30 • Assuming actual load in RTD is 150MW – Unit 1: Dispatched to 105MW at a marginal price of $35 – Unit 2: Dispatched to 45MW at marginal price of $35 Page 5

Example 2 • Flexi-Ramp constraint enforced in RTPD. • Forecast Load: 100MW • Forecast uncertainty (Flexible ramp req.): + 100 MW • Resources Available • Unit 1: Pmin=40MW, Pmax=105MW, Energy Bid=$30 • Unit 2: Pmin=40MW, Pmax=105MW, Energy Bid=$35 • The following two constraints are enforced: – ENgen-ENload = 0 (Power balance constraint Ignoring losses) – FRonlinegen-up >= FRreq-up (Flexi-ramp constraint) Page 6

Example 2 (cont.) • Without Flexi-ramp Constraint: – Unit 1: Committed and loaded to 100MW at price of $30 – Unit 2: Remains Un-committed • With Flexi-ramp Constraint enforced in RTPD: – Unit 1: Committed and loaded to 60MW at price of $30 • Contributing 45MW of online capacity to Flexi-ramp constraint – Unit 2: Committed at Pmin= 40MW • Contributing 55MW of online capacity to Flexi-ramp constraint • Note the energy prices in RTPD are not binding. Only RTD prices are binding. Slide 7

Example 2 (cont.) • In RTD binding interval no flexi-ramp constraint is enforced. • Assuming actual load in RTD is 100MW – Unit 1: Dispatched to 60MW at a marginal price of $30 – Unit 2: Dispatched to 40MW at a marginal price of $30 • Assuming actual load in RTD is 200MW – Unit 1: Dispatched to 105MW at a marginal price of $35 – Unit 2: Dispatched to 95MW at marginal price of $35 Slide 8