# Research on Optimal Dispatching Strategy for Micro-Energy-Grid of Protected Agriculture
## 5 Optimal Dispatching of Micro-Energy-Grid
### Parameter Settings  
Our target is the micro-energy-grid of an agriculture greenhouse in a region of Gansu Province, China. The temperature inside and outside of a typical greenhouse is shown in Figure 5. The temperature inside the greenhouse is controlled at a constant temperature 25 \({}^{\circ}\)C. The data of the temperature outside the greenhouse were from National Meteorological Information Center of China. We put the data into Equation (8), and obtained the heat load of the greenhouse at each moment in a scheduling cycle. The heat transfer coefficients of the greenhouse film, wall and ground are 1.12, 0.62 and 0.24 W/(m\({}^{2}\).k), respectively; the corresponding measures of area are 720, 170 and 640 m\({}^{2}\); the air volume is 1360 m\({}^{3}\); and the ventilation frequency is 1.2 times/h. Using 150 kWp PV cells, the PV output and its probability of each scenario in a typical day are shown in Tables 3 and 4. Electric load is the sum of time-shifting load and non-time-shifting load. We considered 13 types of electric load objects in this study. Their time-shifting characteristics and the input time of non-time-shifting load at initial state from state grid science and technology project are shown in Table 9. Combining the above results, the PV output, thermal load, time-shifting load and non-time-shifting load in greenhouse are shown in Figure 6.  
Figure 5: The temperature inside and outside of a typical greenhouse. The time-of-use tariff of agricultural electricity in Gansu power grid is shown in Table 10. The data were from Gansu Development and Reform Commission [32]. Emission coefficients of gaseous pollutants and corresponding environmental costs are shown in Table 11. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Time Period** & **Purchasing Price (Yuan/kWh)** & **Selling Price (Yuan/kWh)** \\ \hline High (8:00–11:00, 15:00–16:00, & 0.6414 & 0.4617 \\
19:00–22:00) & 0.6414 & 0.4617 \\ Flat (12:00–14:00, 17:00–18:00) & 0.4289 & 0.3078 \\ Low (23:00–7:00) & 0.2165 & 0.1539 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Time-of-use tariff of agricultural electricity in Gansu. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Load Type** & **Time-Shifting Characteristic** & **Power Rating/kW** & **Initial Input Time** \\ \hline LED plant growth lighting & 6:00–20:00 continuous & 5 & 6:00–20:00 \\ Plasma nitrogen fixation and water treatment & 10:00–14:00 intermittent & 2 & 12:00, 14:00 \\ Biogas pool heat pump & 20:00–6:00 intermittent & 3 & 6:00, 21:00 \\ Far Infrared Heating & 20:00–6:00 continuous & 4 & 20:00–6:00 \\ Physical insecticide & 00–00:24:00 intermittent & 6 & 3:00, 500, 10:00, 13:00, 16:00 \\ Water and fertilizer integration & 8.00–10:00, 15:00–18:00 intermittent & 5 & 9:00, 16:00 \\ Space electric field & 0.00–24:00 intermittent & 0.3 & 7:00–9:00, 15:00–1:00 \\ Gehumification & Curtain rolling motor & Short time at morning and evening & 2 & 8:00, 19:00 \\ Lighting in shed & 20:00–6:00 intermittent & 0.15 & 1:00, 4:00, 6:00, 21:00, 23:00 \\ Intelligent Agricultural & 0.00–24:00 continuous & 0.2 & 1:00–14:00 \\ Monitoring System & Nutrient solution & 10:00–18:00 intermittent & 0.2 & 10:00–12:00 \\ circulation system & & & 1:00, 4:00, 6:00, 8:00, 11:00, \\ Acoustic wave facilitation & 6:00–19:00 intermittent & 0.2 & 12:00, 14:00, 19:00, 21:00, 24:00 \\ Unitlator & 0.00–24:00 intermittent & 2 & 8:00–9:00, 12:00–17:00 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Time-shifting characteristics and the input time of non-time-shifting load at initial state for 13 types of electric load. Figure 6: The PV output and three loads in greenhouse. The greenhouse includes microturbine, absorption heat pump, ASHP, storage battery, phase change heat storage device and PV power generation equipment. The upper and lower operating limits, conversion coefficients, capacity and operating costs of the equipment are shown in Table 12.  
We selected five cases as examples to analyze.