At present, The State Grid adopts an encouraging and cooperative attitude towards the application of distributed photovoltaic power generation, allowing the owners of photovoltaic power stations to adopt three settlement modes: spontaneous self-use mode, spontaneous self-use surplus power Internet access or full Internet access. The following three forms of distributed photovoltaic power generation grid to do a simple introduction.
1. Completely spontaneous self-use mode
This mode is generally applied to the situation where the user side power load is large and the power load lasts for a long time, and there is little production or semi-production in a year. Or, even during holidays, the user's power maintenance load is enough to absorb most of the power generated by the PHOTOVOLTAIC power station.
This kind of system, due to the low-voltage side of the grid, if the user can not absorb the electricity, will be sent to the upper level of the power grid through the transformer, and the distribution transformer design is not allowed to be used for reverse power transmission (can be short-time power transmission, such as debugging, but not for a long time), its initial power flow direction design is fixed. It is necessary to install counter-current devices to avoid the power back.
For some users who can not ensure their own electricity can continue to consume photovoltaic power, or production can not ensure sustainable projects, it is recommended not to adopt this method of grid connection.
It is recommended to adopt this mode for photovoltaic power stations with single cells of less than 500kW and distribution transformers on the user side, because the increased investment required by voltage boost accounts for a large proportion of investment.
2. Self-use surplus electricity Internet access mode
For the majority of users who are optimistic about distributed generation, it is the most ideal mode to choose spontaneous self-use surplus electricity to access the Internet, so that they can get higher prices for spontaneous self-use and sell electricity to the grid without using it. However, there is a lot of resistance in the actual operation process, because of the asymmetric information between photovoltaic practitioners and local power grid companies, and the lack of understanding of each other's professional knowledge, which is why this model has become the most difficult part of the photovoltaic electricity price policy and the New Deal of the state grid.
In the mode of self-use surplus electricity for photovoltaic power generation, users (or "investors") hope that the generated electricity can be consumed as much as possible within the enterprise. If it is really not used up, it can be sent to the grid to avoid wasting this part of photovoltaic power. But what power companies want most is for customers to have a simple choice of either self-use or booster access. Because, for local power companies, to increase some workload: Regional distribution network capacity calculation (allow reverse power load), increasing the management of the source (pure can reduce spontaneous for private use standard to manage), users and reversing electric meter after transforming electricity metering tedious (need 2 by 1 meter and electric meter numerical conversion user actual electricity load curve and power consumption), increase meter reading work, etc.
The biggest disadvantage of this operation model is that its income model cannot be fixed, the proportion of self-use and surplus electricity network is always changing, the assessed value of power station financing and sale will be discounted compared with the actual output, and even the capital cannot obtain a reasonable asset value because of the concern about the future operation of electricity users.
3. Complete online electricity selling mode
In the recent ten years of the great development of photovoltaic power generation, direct online selling has always been the mainstream of photovoltaic applications, because its financial model is simple and relatively reliable, and it is happy to be favored by the capital.
This type of grid connection is not only suitable for the future distributed fixed electricity price project but also a good choice to choose the direct desulfurization electricity price to sell to the power grid (of course, it requires that the desulfurization electricity price in this area is not less than 0.4 yuan). This is shorter than the payback period for future distributed power stations.
Moreover, we can not avoid one thing - photovoltaic is a capital-driven industry, belongs to fixed-income long-term investment. Most enterprises are unlikely to hold photovoltaic power stations at the stage of pursuing development, even many owners who hold some photovoltaic power stations now. Therefore, the transfer market of photovoltaic power stations will be a big enough cake in the future, and services for buyers and sellers will become hot businesses, such as insurance services, evaluation services, testing services, operation and maintenance services, third-party guarantee services, etc.
Finally, it is up to investors to decide which way to choose as the grid connection mode of photovoltaic power stations.
