3.1.1. Objective Function 1: Minimum Operating Cost

The total operating costs include fuel costs for the DEs and MTs; operation and maintenance costs for DEs, MTs, and the PV power station; and transmission costs between the microgrid and the main grid. The battery degradation cost is disregarded [24,25].

$$\mathbf{C}\_{1} = \sum\_{t=1}^{T} \left[ \mathbf{C}\_{f} (P\_{i,t} + PMT\_{j,t}) + \mathbf{C}\_{OM} (P\_{i,t} + PV\_{l,t} + PMT\_{j,t}) + \mathbf{C}\_{grid,t} \right] \tag{8}$$

where *Pi*,*<sup>t</sup>* is the output power of the *i*th DE at period *t*, *PMTj*,*<sup>t</sup>* is the output power of the *j*th MT at period *t*, *PVl*,*<sup>t</sup>* is the output power of the *l*th PV power station at period *t*. *Cf*(·) is the fuel costs of the DEs and MTs [26]; *COM*(·) is the operation and maintenance costs of the DE, MTs, and the PV power station [27]; and *Cgrid*,*<sup>t</sup>* is the cost of transmission between the microgrid and the main power grid.

$$\begin{aligned} \mathbf{C}\_{f}(P\_{i,t}) &= [\mathbf{c}\_{1}P\_{i,t}^{2} + \mathbf{c}\_{2}P\_{i,t} + \mathbf{c}\_{3}]\_{\mathrm{DE}} + [\mathbf{y}\frac{PMT\_{j,t}}{\eta(PMT\_{j,t})}]\_{\mathrm{MT}} \\ \mathbf{C}\_{\mathrm{OM}}(P\_{i,t} + PV\_{l,t} + PMT\_{j,t}) &= \mathbf{K}\_{\mathrm{OM}}(P\_{i,t} + PV\_{l,t} + PMT\_{j,t}) \\ \mathbf{C}\_{\mathrm{grid},t} &= P\_{\mathrm{grid},t}M\_{t}\Delta t \end{aligned} \tag{9}$$

where *c*1, *c*2, *c*<sup>3</sup> represent fuel cost parameters of DEs, y is the cost parameter of MTs, η(*PMTj*,*t*) is the work efficiency of the *j*th MT at period *t*, *KOM* is the OM cost parameter, Δ*t* is scheduling interval, and *Mt* is the price of electricity.

### 3.1.2. Objective Function 2: Minimum Environmental Cost

The traditional output units and the power transmission process of the grid will cause environmental pollution problems, which incurs the cost of environmental protection. Three important pollutants, sulfur dioxide (SO2), carbon dioxide (CO2), and nitrogen oxide (NOX), are considered in this paper [26].

$$\mathbf{C}\_{2} = \sum\_{t=1}^{T} \sum\_{p=1}^{P} \sum\_{h=1}^{H} \left( \mathbf{C}\_{h} \mu\_{p,h} \right) P\_{p,t} + \sum\_{t=1}^{T} \sum\_{h=1}^{H} \left( \mathbf{C}\_{h} \mu\_{g\text{wid}} \right) P\_{g\text{wid},t} \tag{10}$$

where *Ch* is the treatment cost of the *h*th pollutant; μ*p*,*<sup>h</sup>* is the *h*th pollutant emission coefficients of the *p*th type power source including DE, MT, and PV; *Pp*,*<sup>t</sup>* is the output power of the *p*th power source; *Pgrid*,*<sup>t</sup>* is the transmission power between the microgrid and the main power grid at period *t*, and μ*grid* is the pollutant emission coefficients of the main power grid.

### 3.1.3. Total Cost Function

The objective of the scheduling system proposed in this paper is to minimize the system operating cost and the environmental protection cost. Therefore, the total cost function (*Ctotal*) can be expressed by

$$\min \mathcal{C}\_{total} = \min(\mathcal{C}\_1 + \mathcal{C}\_2) \tag{11}$$
