Combined Heat and Power Dynamic Economic Emissions Dispatch with Valve Point Effects and Incentive Based Demand Response Programs

Nnamdi Nwulu

doi:10.3390/computation8040101

Abstract

In this paper, the Combined Heat and Power Dynamic Economic Emissions Dispatch (CHPDEED) problem formulation is considered. This problem is a complicated nonlinear mathematical formulation with multiple, conflicting objective functions. The aim of this mathematical problem is to obtain the optimal quantities of heat and power output for the committed generating units which includes power and heat only units. Heat and load demand are expected to be satisfied throughout the total dispatch interval. In this paper, Valve Point effects are considered in the fuel cost function of the units which lead to a non-convex cost function. Furthermore, an Incentive Based Demand Response Program formulation is also simultaneously considered with the CHPDEED problem further complicating the mathematical problem. The decision variables are thus the optimal power and heat output of the generating units and the optimal power curbed and monetary incentive for the participating demand response consumers. The resulting mathematical formulations are tested on four practical scenarios depicting different system operating conditions and obtained results show the efficacy of the developed mathematical optimization model. Obtained results indicate that, when the Incentive-Based Demand Response (IBDR) program’s operational hours is unrestricted with a residential load profile, the energy curtailed is highest (2680 MWh), the energy produced by the generators is lowest (38,008.53 MWh), power losses are lowest (840.5291 MW) and both fuel costs and emissions are lowest.

Highlights

Combined Heat and Power (CHP) generating units known as co-generation units produce electric power and heat simultaneously
In order to benchmark the CHPDEED-Incentive-Based Demand Response (IBDR) results, results from conventional CHPDEED using the data of Case 1 are provided in the second column of Table 6
For Case 1 and Case 3, when there is no restriction in IBDR operating hours, the total energy generated by both the thermal units and CHP units over 24 h is 38,008.53 MWh and 38,732.62 MWh, respectively

Summary

Introduction

Combined Heat and Power (CHP) generating units known as co-generation units produce electric power and heat simultaneously. The. Combined Heat and Power Dynamic Economic Dispatch (CHPDED) problem seeks to minimize the fuel costs of committed units by determining their optimal power and heat output whilst ensuring that both heat and power demand are satisfied during the whole scheduling interval [2]. Combined Heat and Power Dynamic Economic Dispatch (CHPDED) problem seeks to minimize the fuel costs of committed units by determining their optimal power and heat output whilst ensuring that both heat and power demand are satisfied during the whole scheduling interval [2] This mathematical problem is constrained by practical mathematical constraints like ramp rate constraints, power balance constraint, generating units constraints, etc. The CHPDEED problem determines the committed units power and heat outputs whilst minimizing the fuel costs and emissions and respecting system constraints [1,2].

Combined Heat and Power Dynamic Economic Emission Dispatch Model

Thermal Units

CHP Units

Objective Functions

Constraints

Incentive Based Demand Response Model

Numerical Simulations

Results and Discussion

Conclusions

Limitations