As important renewable energy, wind power and photovoltaic have always had unlimited "scenery", but wind power and photovoltaic face multiple challenges when they are connected to the grid in time and effectively. The biggest problem is "willfulness".
The "willfulness" mentioned here does not mean unlimited development scale, but their power generation, which is high and low, does not play cards according to common sense. According to "global photovoltaic", India is introducing the most severe restrictive policy in the history of unlimited "scenery".
1. Uncertainty of wind and solar energy
If the biggest advantage of wind and solar energy resources is infinity, and the biggest disadvantage is uncertainty.
The weather is unpredictable, the moon is cloudy, clear and round, the wind is not always there, and the sun is not always there every day. For a long time, wind and solar energy have been regarded as relying on heaven. Only when there is wind and sunlight can we use wind and solar energy. Even if there is wind and sunshine, there is still a problem of wind size and sunlight irradiance. Even on a very normal day, there are differences in power generation caused by different irradiation angles from sunrise to sunset.
It is this kind of change from big to small, from occasional to occasional, from strong to weak, which leads to the unstable voltage, current and power generation of wind power and photovoltaic power generation. Therefore, the power generation incorporated into the power grid is also discontinuous, which undoubtedly increases the difficulty and operation risk for the power grid that needs safe and stable operation control.
The inherent randomness, intermittence and volatility of wind and solar energy not only limit the development and utilization of renewable energy to a certain extent, but also make it difficult to connect to the grid. Over the years, the phenomenon of abandoning wind and light often exists in areas rich in wind and light resources.
2. How to make the wind and light no longer capricious
Depending on the weather, it is impossible for us to control the wind and light like controlling coal-fired power, nuclear power and natural gas power generation, nor to regulate the wind and light like controlling hydropower.
What we can do is to make better meteorological prediction, regulate wind and light power generation with easily controlled power sources, and realize peak shaving and valley filling with energy storage technology.
What we can also do is to increase the power grid capacity and transmission capacity, and use the global smart energy Internet to realize the complementarity of scenery in different regions. Because in a broad sense, the sunrise in the west, the rain in the East, the sunshine and the evening wind at noon, even the night in the eastern hemisphere, the day in the Western Hemisphere, the winter in the southern hemisphere and the summer in the northern hemisphere.
But in any case, only by doing a good job in the prediction of wind and light power generation, can it be adjusted more reasonably and scientifically.
3. India imposes taxes on out of gauge power generation
The installed capacity of photovoltaic is based on the sum of the nameplate nominal power of each solar panel, and the illumination is lower than the standard value most of the time. Therefore, the photovoltaic power station generates power under the standard capacity for a lot of time. For example, the photovoltaic power station usually generates power at full load only two or three hours before and after noon.
Therefore, many power stations are overloaded during construction. Even if the power generation during peak hours is wasted, more points can be generated in other periods in order to enjoy the government subsidies to the greatest extent.
The Indian government stipulates that there is no need to pay additional grid connection fees for the deviation of power generation capacity of wind power and photovoltaic power stations within ± 15% of the standard value; If it exceeds this range, if the excess power generation needs to be connected to the grid, it needs to pay 10% of the normal rate to the grid company.
The standard value here is not the standard capacity of the photovoltaic power station, but the predicted power generation reported by the power station operator to the power grid in advance. The power grid arranges power dispatching according to the reported predicted power generation, and optimizes the power grid power of the next day.
4. New regulations make operation more difficult
With the increasing installed capacity and higher goal of non fossil energy such as wind power and photovoltaic, the volatility of wind power and photovoltaic poses an increasing challenge to grid connection. In the view of India's Central Electricity Regulatory Commission (CERC), the generation deviation of ± 15% has posed a threat to the security of the power grid.
In September 2021, the Central Electricity Regulatory Commission (CERC) drafted a new draft regulation on deviation resolution mechanism (DSM), which may bring great setbacks to power station operators if implemented.
According to the proposed regulation, the fluctuation of power generation capacity of wind and solar power generators will be reduced from the original ± 15% to 10%, and it refers to the deviation from - 10% to + 0%. If the deviation is lower than - 10%, 10% of the grid connection fee of the normal rate will be paid, while if the positive deviation is higher than 0%, this part of power generation capacity will not receive any electricity charge.
The reason behind the newly proposed DSM regulation is grid security and stability. In the view of power grid companies, they must accurately dispatch online power, otherwise discom must give up other power, because renewable energy must be consumed according to regulations.
If the extra power generation cannot be compensated by any electricity charge, the power station operator will give higher power generation than the normal predicted value to reduce the loss. On the other hand, the proposed regulations can not only urge operators to provide more accurate forecasts, but also promote the wind and solar energy industries to make more use of energy storage and peak shaving of power generation.
