I think you have 2 mistakes. First the quantities come first, then the costs. And second, the generator cost function is a total cost function, not a marginal cost function.
So what you have specified is that at 100 MW output the total cost will be $1000/hr and that at 110MW the total cost will be the same $1000/hr. So the cost per MW that you have defined is $0/MWh as Carlos pointed out. I think you want … 1 0 0 3 0 0 1000 100000 2000 200000 This says first that the the cost of 0MW is $0/hr. The cost of operating at 1000MW is $100,000/hr or $100/MWh and the cost of operating at an output of 2000MW is $200,000/hr, which is still $100/MWh. Ray On Apr 29, 2021, at 10:27 AM, Matthias Greiml <[email protected]<mailto:[email protected]>> wrote: Dear Carlos, Thank you for your quick response. I'm a bit confused, because my understanding of the gen cost definition is as following: the generator can provide up to 1000 MW for 100 $/MWh and additional 1000 MW for 110 /MWh, provided Pmax GEN is not exceeded (in my case Pmax GEN is below 1000 MW, so only the 100 $/MWh limit should be applicable). If the flexible generator should be dispatched for a price of 100 $/MWh up to (+/-) 1000 MW (or Pmax GEN) how would I have to define the cost function? Thank you & best regards, Matthias Von: Carlos E Murillo-Sanchez <[email protected]<mailto:[email protected]>> An: MATPOWER discussion forum <[email protected]<mailto:[email protected]>> Datum: 29.04.2021 16:49 Betreff: Re: nodal prices become zero, when using flexible generators Gesendet von: [email protected]<mailto:[email protected]> ________________________________ Matthias: You are specifying piece-wise linear costs with corner points at (100, 1000) and (110,1000). That's a single flat linear segment, which of course will have a marginal cost of zero. In general, if these flexible generators are not against a limit, they will set the nodal price at the bus that they're at to zero. Carlos. Matthias Greiml wrote: Dear Matpower Community, I've been trying for several days, but I can't find the reason for following Matpower behaviour. In my generator list, there are several "flexible generators" (explaination below image), this is how GEN matrix looks like: <Mail Attachment.gif> The values in row 9 and 10 are determined based on a bus' flexibility potential (e.g. comming from pumped hydro, heat pumps, combined cycle power plants at each corresponding bus), therefore power can be consumed or produced by the generator. The associated cost function is as following: <Mail Attachment.gif> My question is: whenever I active above mentioned generators (column 8 = 1), the nodal prices of all buses are zero. If I deactivate all flexible generators, the nodal prices are nonzero. I don't understand why - can anyone explain this behaviour to me? (Note there are several other generators implemented as well, which are operated as generator only at costs between 20 to 100 $/MWh: <Mail Attachment.gif> Thank you for any idea / solution in advance. Best regrards from Austria, Matthew
