# Day-Ahead Dispatch Model of Electro-Thermal Integrated Energy System with Power to Gas Function

^{*}

## Abstract

**:**

## 1. Introduction

## 2. The Concept of P2G

#### 2.1. Water Electrolysis

#### 2.2. Synthetic Natural Gas

#### 2.3. HCNG

## 3. Electro-Thermal Integrated Energy System with “P2G Function”

#### 3.1. Structure of the Integrated System

#### 3.2. Day-Ahead Dispatch Model of the Integrated System

_{2}production at period t. The gas boilers are using HCNG to produce heat. Equations (14) and (15) define the thermal power output of the natural gas part and the hydrogen part respectively. And Equation (16) sets the thermal generation limits.

#### 3.3. Solution Strategy

**x**= (x

_{1}, x

_{2}, ..., x

_{n}) to be solved as n particles without mass and volume. The position and velocity vectors of the ith particle of a two-dimensional search space can be represented as s

_{i}= (s

_{1}, s

_{2}, ..., s

_{n}) and v

**= (v**

_{i}_{1}, v

_{2}, ..., v

_{n}) respectively, After initialization, the particle tries to modify its position using the current velocity and the distance on the basis of the value of the evaluation function. The best previous position of a particle is recorded and represented as pbest. If the gth particle is the best among all particles in the group so far, it is represented as pbest = gbest. Before finding its optimal value, the particle updates its velocity and position by the following equations:

_{1}and c

_{2}are cognitive and social coefficients, rand

_{1}, rand

_{2}are random numbers between 0 and 1. The concept of time varying inertial weight was introduced in [17] per ω is given by

_{max}is the maximum number of iterations. Usually, the parameters are selected in the range of 0 to 4. The flowchart of the iterative algorithm is shown in Figure 3.

## 4. Simulation Results

#### 4.1. Example Data

#### 4.2. Interpretation of Result

^{3}of hydrogen, which can be converted to 5 billion 414 million m

^{3}natural gas on an equal heat basis. At the same time, it will also reduce 10 million 210 thousand tons of the carbon dioxide of the combustion emission produced by the same volume of natural gas and save 65 million 740 thousand tons of the standard coal.

## 5. Conclusions

## Acknowledgments

## Author Contributions

## Conflicts of Interest

## References

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**Figure 1.**Diagrams of (

**a**) alkaline electrolyzer, (

**b**) Proton exchange membrane electrolyzer and (

**c**) Solid oxide electrolyzer.

Name | Definition |
---|---|

${p}_{i,t}^{\mathrm{TU}}$ | Generation output of thermal unit i at period t. |

${p}_{i,t}^{\mathrm{CHP}}$ | Generation output of combined heat and power unit i at period t. |

${p}_{i,t}^{\mathrm{WT},\mathrm{gc}}$ | Grid-connected output of wind turbine i at period t. |

${h}_{i,t}^{\mathrm{CHP}}$ | Heat production output of combined heat and power unit i at period t. |

${h}_{i,t}^{\mathrm{GB}}$ | Heat production output of gas-fired boiler i at period t. |

${h}_{i,t}^{\mathrm{gas}}$ | Natural gas part of heat production output of gas-fired boiler i at period t. |

${h}_{i,t}^{\mathrm{hydrogen}}$ | Hydrogen part of heat production output of gas-fired boiler i at period t. |

${C}_{i,t}^{\mathrm{TU}}$ | Standard coal consumption of thermal unit i at period t. |

${C}_{i,t}^{\mathrm{CHP}}$ | Standard coal consumption of combined heat and power unit i at period t. |

${C}_{i,t}^{\mathrm{GB}}$ | Standard coal consumption of gas-fired boiler i at period t. |

λ^{TU} | Conversion coefficient of standard coal for thermal units. |

${\lambda}_{\mathrm{p}}^{\mathrm{CHP}}$ | Conversion coefficient of standard coal for the CHPs’ power supply. |

${\lambda}_{\mathrm{h}}^{\mathrm{CHP}}$ | Conversion coefficient of standard coal for the CHPs’ heat supply. |

λ^{GB} | Conversion coefficient of standard coal for gas fired boilers. |

${p}_{i,t}^{\mathrm{load}}$ | Net active load demand in node i at period t. |

${p}_{i,t}^{\mathrm{WT},\mathrm{max}}$ | Maximum generation output of wind turbine i at period t. |

${F}_{i,t}^{\mathrm{gas}}$ | Air input of natural gas at period t. |

${F}_{i,t}^{H2}$ | Air input of hydrogen at period t. |

ρ^{gas} | Density of natural gas. |

ρ^{H2} | Density of hydrogen. |

η_{F} | Electrolytic efficiency of electrolyzers. |

g^{H2} | Production of hydrogen per kilowatt hour. |

${p}_{i,t}^{\mathrm{WT},\mathrm{true}}$ | Actual generation output of wind turbine i at period t. |

η^{GB} | Efficiency of gas-fired boilers. |

${h}_{i,t}^{\mathrm{GB},\mathrm{min}}$/${h}_{i,t}^{\mathrm{GB},\mathrm{max}}$ | Maximum/minimum generation output of gas-fired boiler i at period t. |

${p}_{i}^{\mathrm{CHP},\mathrm{min}}$/${p}_{i,t}^{\mathrm{CHP},\mathrm{max}}$ | Maximum/minimum generation output of CHP i at period t. |

${h}_{i,t}^{\mathrm{EX}}$ | Residual heat of the gas displacement. |

${\eta}_{\mathrm{e}}^{\mathrm{CHP}}$ | Electrical efficiency of combined heat and power units. |

η_{L} | Cooling efficiency of combined heat and power units. |

${\eta}_{\mathrm{th}}^{\mathrm{CHP}}$ | Thermal efficiency of combined heat and power units. |

c_{OPh} | Coefficient of performance. |

RΔt | Ramping capability of combined heat and power units. |

λ^{TU} (kg/kW) | ${\mathit{\lambda}}_{\mathbf{p}}^{\mathbf{CHP}}$ (kg/kW) | ${\mathit{\lambda}}_{\mathbf{h}}^{\mathbf{CHP}}$ (kg/kW) | λ^{GB} (kg/kW) |
---|---|---|---|

0.404 | 0.379 | 0.113 | 0.142 |

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**MDPI and ACS Style**

Yang, D.; Xi, Y.; Cai, G.
Day-Ahead Dispatch Model of Electro-Thermal Integrated Energy System with Power to Gas Function. *Appl. Sci.* **2017**, *7*, 1326.
https://doi.org/10.3390/app7121326

**AMA Style**

Yang D, Xi Y, Cai G.
Day-Ahead Dispatch Model of Electro-Thermal Integrated Energy System with Power to Gas Function. *Applied Sciences*. 2017; 7(12):1326.
https://doi.org/10.3390/app7121326

**Chicago/Turabian Style**

Yang, Deyou, Yufei Xi, and Guowei Cai.
2017. "Day-Ahead Dispatch Model of Electro-Thermal Integrated Energy System with Power to Gas Function" *Applied Sciences* 7, no. 12: 1326.
https://doi.org/10.3390/app7121326