If rooftop solar power is not “self-produced and self-consumed”, it must be connected to the grid, which will incur system operating costs, so it is not recommended, according to the Ministry of Industry and Trade.
In the draft Decree on the mechanism to encourage the development of self-consumed rooftop solar power, the Ministry of Industry and Trade proposed that if this type is not connected to the grid, it will be developed without limit. In case of grid connection, people have the right to distribute or not distribute excess output into the system but pay 0 VND. The total capacity in this form does not exceed the capacity allocated in the implementation plan of Power Planning VIII (2,600 MW).
The above regulations are considered by some experts to be not attractive enough to encourage people to invest because they are not allowed to sell or sell at 0 VND which would be economically ineffective.
In information released on the afternoon of April 30, the Electricity Regulatory Authority (Ministry of Industry and Trade) continued to emphasize a cautious stance in developing rooftop solar power. According to the regulatory agency, this energy source should only be available for on-site consumption, and should not be encouraged or even limited from being released into the system.
“If massively developed on a large scale, it will greatly affect the balance of the system, causing unnecessary costs,” the agency said.
According to updated data, rooftop solar capacity is currently about 7,660 MW, accounting for more than 9% of total capacity and output of nearly 4% of the entire national electricity system. In terms of installed capacity, this power source has a higher proportion than other renewable energies such as wind power and biomass, surpassing even small hydropower and gas turbines – which used to account for a large proportion in the previous source structure.
According to the Ministry of Industry and Trade, rooftop solar energy is unstable due to its dependence on solar radiation. When there is no radiation (cloudy, rainy or at night), the national grid must still ensure adequate electricity supply. Therefore, to stabilize the source, suitable storage sources need to be taken into account. That is, people and the electricity industry have to pay for this storage and backup.
Specifically, on a small scale, organizations and individuals will have to equip storage battery packs. The prices of these devices are trending down but are still high.
On a large scale, the backup plan is pumped storage hydropower sources or traditional sources (hydropower, coal thermal, gas turbines). However, the uncertainty of rooftop solar power causes these sources to operate in an intermittent state. This both reduces output and harms the equipment due to constantly having to adjust up and down or having to start and stop many times.
The electricity industry regulator believes that at times of high solar radiation, this type of capacity is at risk of exceeding the absorption capacity of the regional grid. At that time, the dispatching unit must choose: cutting the capacity of traditional power plants or renewable energy sources.
In particular, the first option will be “very dangerous” because if the traditional controllable power source is reduced, the system will no longer have the source to respond when renewable energy fluctuates. Therefore, the popular and inevitable choice, according to the Ministry of Industry and Trade, is “cutting renewable energy”. According to them, this option also increases operating costs and wastes social resources.
At the same time, this agency assesses that rooftop solar sources are scattered, small-scale and very small, making it difficult to collect data and control when operating the system. To achieve balance, the dispatcher must collect capacity data from all power sources. But this can only be done with sources of large enough scale, such as in industrial parks and large factories.
With small-scale household-level systems, accurate data collection is not possible. The dispatching agency will only forecast this amount of capacity, leading to difficulties in system operation. Not to mention, data collection and forecasting requires a flexible system and costs additional operating costs.
The final reason stated by the authorities is that the development of rooftop solar power brings “great worry about the overall cost of the system” for dispatching agencies and investors of traditional power plants.
This cost comes from the need for availability of traditional power sources to meet the uncertainty of renewable energies. The dispatching unit will have to maintain a certain amount of traditional power source operating in a standby or low power state continuously. Therefore, they still have to pay for the power sources maintained in this state instead of the electricity generated.
At the same time, power companies still have to invest in grids to supply electricity to customers at night or when it is dark but cannot sell electricity during the day. “The power company’s sales output decreases but the investment remains unchanged, the grid investment rate will increase,” the Ministry of Industry and Trade said, adding that this cost will be charged to all customers, including non-installers. install renewable electricity.
Not to mention, if we follow the viewpoint of “costs due to any cause must be calculated for that cause”, the Ministry of Industry and Trade believes that investors of rooftop solar power sources actually have to pay costs for the system to maintain operation. operates normally while still receiving stable power supply. Thus, in general, the more volatile the renewable energy source, the larger the cost scale.
Since 2017, to encourage renewable energy, the Government has a mechanism to buy back rooftop solar power invested by people at a preferential price (FIT price) of 9.35 cents per kWh, then reduced to 7 cents per kWh. .09 cents per kWh for transitional projects. This policy encourages people to massively spend money investing in rooftop solar power systems to use and sell excess capacity to EVN. Data from EVN shows that, as of December 31, 2020 – the time the FIT price policy expired, nationwide there were about 101,029 projects of this type connected to the power system with a total installed capacity of up to to 9,296 MW.