Re: nodal prices become zero, when using flexible generators

[Carlos E Murillo-Sanchez]

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: 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: 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: Thank you for any idea / solution in advance. Best regrards from Austria, Matthew �