The biggest disadvantage of solar energy is its instability. If the weather is clear, the peak of power generation every day is around noon, and the demand for electricity during this period is not high. However, during the evening when the demand is highest, there is no solar energy supply. If the weather is bad for several consecutive days, the consequences can be imagined. So the amount of solar power supply fluctuates, and the higher the proportion of solar energy in the total electricity, the greater the fluctuation, and the greater the impact of solar energy on the entire power grid.
The ideal solution is to store excess electricity in other forms of energy, such as thermal energy or electrolysis of water to store hydrogen energy, and then release it when electricity is needed at night. However, this conversion technology is not mature, inefficient, and extremely expensive.
So, we have to prepare traditional power supply methods to ensure timely replenishment of power supply when solar energy supply is insufficient. So this situation becomes that the sun is strong at noon, and the excessive power supply puts pressure on the power grid (voltage is too high). At night, the solar power supply is insufficient, and traditional power supply equipment needs to be restarted. The cost of frequent shutdown and start-up is no less than the long-term power supply cost. And as the proportion of solar energy increases, this situation becomes more apparent (duck shaped curve), and the cost also increases. This situation is called deflation of solar energy value. Although solar energy is becoming cheaper and cheaper, when the proportion of solar energy reaches a certain level, its value declines faster than its cost, and development will stagnate or even regress.
