# Evolutionary Game Analysis of Power Generation Groups Considering Energy Price Fluctuation
## 5 Case Analysis
### Primary Energy Price Fluctuation and Power Generation Cost Analysis
In July 2020 and March 2021, the cost of gas-fired power generation is slightly higher than the cost of coal-fired power generation, which belongs to the scenario of phase 2 in Figure 2a. At this time, the bidding power of coal-fired and gas-fired power generation groups satisfies the first condition in Scenario 1.1-b, which is as stated in inequality (28):  
\[\sum_{i=1}^{n}Q_{gas,i}<\frac{\
u_{gas}-1}{\mu_{gas}-1}(Q_{DM}-\sum_{i=1}^{m} Q_{coal,i}) \tag{28}\]  
The evolution simulation results are shown in Figure 6a, the supply is relatively tight, and the coal-fired and gas-fired power generation groups all choose strategic bidding, which leads to the high electricity price. The coal-fired electricity price is \(\
u_{coal}\) times the  
Figure 5: July 2020–June 2021 Trends in power generation costs of coal-fired and gas-fired power generation groups. cost of its power generation, the gas-fired electricity price is \(v_{gas}\) times the cost of its power generation, and the market has reached an equilibrium situation. In order to alleviate the pressure of high electricity prices, the bidding volume of gas-fired power generation groups can be increased to satisfy the second condition in Scenario 1.1-b, which is as stated in inequality (29):  
\[\frac{\
u_{gas}-1}{\mu_{gas}-1}(Q_{DM}-\sum_{i=1}^{m}Q_{coal,i})<\sum_{i=1}^{n} Q_{gas,i}<Q_{DM}-\sum_{i=1}^{m}Q_{coal,i}\frac{\mu_{coal}-1}{\
u_{coal}-1} \tag{29}\]  
Let \(Q_{gas,1}\sim Q_{gas,10}=300\) MW; \(Q_{gas,11}\sim Q_{gas,30}=200\) MW. The evolution simulation results are shown in Figure 6b. The competition on the supply side has intensified. Gas-fired power generation groups that adopt strategic bidding can obtain higher unit income than gas-fired power generation groups that adopt cost bidding, but the total income decreases. After a long-term evolution, the relatively large amount of gas bidding power on the generation side cannot change the bidding behavior of the coal-fired power  
Figure 6: Evolution trend of bidding entities in phase 2 under scenario 1. (**a**) Simulation results of the evolution of coal-fired and gas-fired feed-in tariffs under “Condition 1” in Scenario 1.1-b, (**b**) Evolutionary simulation results under “Condition 2” in Scenario 1.1-b, (**c**) Simulation results for the evolution of “condition three” in scenario 1.1-b. generation groups, but it can change the bidding behavior of the gas-fired power generation groups. Therefore, the coal-fired power generation groups still adopt strategic bidding, and the gas-fired power generation groups adopt cost bidding, and the electricity price has dropped. Coal-fired electricity prices are still \(\
u_{coal}\) times the cost of its power generation. However, the gas-fired electricity price has dropped by \(\mu_{gas}\) times the cost of its power generation. The market can still reach equilibrium. Further, increase the bidding volume of gas-fired power generation groups to meet the third condition in Scenario 1.1-b, which is as stated in inequality (30):  
\[\sum_{i=1}^{n}Q_{gas,i}>\max\{Q_{DM}-\frac{\mu_{coal}-1}{\
u_{coal}-1}\sum_{i=1 }^{m}Q_{coal,i},\frac{\
u_{gas}-1}{\mu_{gas}-1}(Q_{DM}-\sum_{i=1}^{m}Q_{coal,i})\} \tag{30}\]  
Let \(Q_{gas,1}\sim Q_{gas,15}=300\) MW; \(Q_{gas,16}\sim Q_{gas,30}=200\) MW. The evolution simulation results are shown in Figure 6c. The fierce competition on the power generation side has prompted the coal-fired and gas-fired power generation groups to make strategic bidding no longer the optimal behavior after long-term evolution. The market cannot reach an equilibrium state, two kinds of bidding behaviors coexist, and the electricity prices fluctuate. The coal-fired electricity price is \(\mu_{coal}\sim\
u_{coal}\) times the cost of its power generation, and the gas-fired electricity price is \(\mu_{gas}\sim\
u_{gas}\) times the cost of its power generation.