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Hidden Power System Inflexibilities imposed by traditional unit commitment formulations. / Morales-Espana, G.; Ramirez Elizondo, Laura; Hobbs, Benjamin F.

In: Applied Energy, Vol. 191, 01.04.2017, p. 223-238.

Research output: Scientific - peer-reviewArticle

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Morales-Espana, G.; Ramirez Elizondo, Laura; Hobbs, Benjamin F. / Hidden Power System Inflexibilities imposed by traditional unit commitment formulations.

In: Applied Energy, Vol. 191, 01.04.2017, p. 223-238.

Research output: Scientific - peer-reviewArticle

BibTeX

@article{40a5911e14bd4ea2a854e7cc3703c966,
title = "Hidden Power System Inflexibilities imposed by traditional unit commitment formulations",
keywords = "Energy-based unit commitment, Power-based unit commitment, Reserves, Stochastic programming, Unit commitment (UC), Wind power",
author = "G. Morales-Espana and {Ramirez Elizondo}, Laura and Hobbs, {Benjamin F.}",
year = "2017",
month = "4",
doi = "10.1016/j.apenergy.2017.01.089",
volume = "191",
pages = "223--238",
journal = "Applied Energy",
issn = "0306-2619",
publisher = "Elsevier",

}

RIS

TY - JOUR

T1 - Hidden Power System Inflexibilities imposed by traditional unit commitment formulations

AU - Morales-Espana,G.

AU - Ramirez Elizondo,Laura

AU - Hobbs,Benjamin F.

PY - 2017/4/1

Y1 - 2017/4/1

N2 - Approximations made in traditional day-ahead unit commitment model formulations can result in suboptimal or even infeasible schedules for slow-start units and inaccurate predictions of actual costs and wind curtailment. With increasing wind penetration, these errors will become economically more significant. Here, we consider inaccuracies from three approximations: the use of hourly intervals in which energy production from each generator is modeled as being constant; the disregarding of startup and shutdown energy trajectories; and optimization based on expected wind profiles. The results of unit commitment formulations with those assumptions are compared to models that: (1) use a piecewise-linear power profiles of generation, load and wind, instead of the traditional stepwise energy profiles; (2) consider startup/shutdown trajectories; and (3) include many possible wind trajectories in a stochastic framework. The day-ahead hourly schedules of slow-start generators are then evaluated against actual wind and load profiles using a model real-time dispatch and quick-start unit commitment with a 5 minute time step. We find that each simplification usually causes expected generation costs to increase by several percentage points, and results in significant understatement of expected wind curtailment and, in some cases, load interruptions. The inclusion of startup and shutdown trajectories often yielded the largest improvements in schedule performance.

AB - Approximations made in traditional day-ahead unit commitment model formulations can result in suboptimal or even infeasible schedules for slow-start units and inaccurate predictions of actual costs and wind curtailment. With increasing wind penetration, these errors will become economically more significant. Here, we consider inaccuracies from three approximations: the use of hourly intervals in which energy production from each generator is modeled as being constant; the disregarding of startup and shutdown energy trajectories; and optimization based on expected wind profiles. The results of unit commitment formulations with those assumptions are compared to models that: (1) use a piecewise-linear power profiles of generation, load and wind, instead of the traditional stepwise energy profiles; (2) consider startup/shutdown trajectories; and (3) include many possible wind trajectories in a stochastic framework. The day-ahead hourly schedules of slow-start generators are then evaluated against actual wind and load profiles using a model real-time dispatch and quick-start unit commitment with a 5 minute time step. We find that each simplification usually causes expected generation costs to increase by several percentage points, and results in significant understatement of expected wind curtailment and, in some cases, load interruptions. The inclusion of startup and shutdown trajectories often yielded the largest improvements in schedule performance.

KW - Energy-based unit commitment

KW - Power-based unit commitment

KW - Reserves

KW - Stochastic programming

KW - Unit commitment (UC)

KW - Wind power

UR - http://resolver.tudelft.nl/uuid:40a5911e-14bd-4ea2-a854-e7cc3703c966

U2 - 10.1016/j.apenergy.2017.01.089

DO - 10.1016/j.apenergy.2017.01.089

M3 - Article

VL - 191

SP - 223

EP - 238

JO - Applied Energy

T2 - Applied Energy

JF - Applied Energy

SN - 0306-2619

ER -

ID: 10533182