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How to install solar power efficiently without considering the power price of EVN?

According to Decision 13 of the Prime Minister, issued on April 16, 2020, the encouragement of businesses and households to invest in solar power installation has exploded the solar power market in the past year. According to the data from Vietnamese energy partners, rooftop solar power only has increased more than 25 times from 378MWp in 2019 to 9,583MWp (equal to the capacity of all systems already installed earlier). The density of solar power compared to other types of power plants: hydroelectricity, thermal power, wind power… is approximately 25%. Currently, the issue of ensuring national energy security and environmental protection is on top priority, so renewable energy projects will continue to be a growing trend to replace thermal projects using fossil energy.
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Installing solar power without consideration of EVN power price, yet it’s still efficient!

On December 31, 2020, the effect of the Prime Minister’s FIT 2’s solar power promotion mechanism expired. According to EVN, the scale model and the corresponding power price for each type of rooftop solar power are still being researched by the Department of Electricity and Renewable Energy and the Ministry of Industry and Trade. It is expected to be sent to the Ministry of Industry and Trade in the first quarter of 2021 to consider submitting to the Prime Minister for approval of the policy on encouraging rooftop solar power for the next period. According to experts forecasts, the price of electricity purchased by EVN from solar power projects is going to fall compared to 2020. When there is no new price policy, the installation of two-way meters is still beneficial for customers in need of using a lot of electric equipment and high amounts of power, such as businesses, manufacturing plants, service businesses or even households for the purpose of self-use, limiting the use of electricity from the grid and not for the purpose of selling electricity at preferential prices. These groups of customers do not need to pay attention to the power price of EVN, but they are still able to invest effectively and reduce monthly electricity costs if taking the right measures.

How to install solar power efficiently without considering the power price of EVN?

Solutions on using grid-connected solar power system without storage:

For manufacturing enterprises, service businesses and households, if having to use many devices with large capacity and high power demand during the day, calculate the generated capacity of the solar power system to meet enough demand compared to the consumption demand of the load. By this way, in daytime, the sun will make the most of the solar energy to supply electricity to the equipment, if excessive, it will be generated back to the grid to resell to EVN. However, the index generated back to the grid is negligible, so there is no need to pay much attention to the price of EVN. In the evening, when the solar power system does not generate electricity, it will automatically switch to using the national grid, which will still ensure continuous power supply.

The advantage of choosing this solution is that the initial investment cost is low. The purpose of this solution is to lower monthly electricity cost.

Solution for using grid-connected solar power system with storage:

This solution is similar to the grid system solution, but with an additional power storage system to prevent power failure. This is the solution proposed by many researchers because of its ability to make the most of solar energy and the independency in power consumption. For manufacturing businesses, business establishments and households that regularly use precise systems, it is necessary to ensure uninterrupted power supply. During a power outage, this solution will be prioritized. The solar power system generates electricity to supply electrical equipment directly, the remaining will be loaded into the storage, you can also consider taking electricity from the grid to recharge the backup storage system during the day at peak hours, or when there is little sunlight, for electricity prices are usually cheaper at night.

This solution is such an advantage making the most of the electricity generated from the solar power system and high backup level that consumers don’t have to rely on the grid for power. But it is also necessary to carefully look for a suitable storage system to avoid wasting and incurred investment costs.

Using independent solar power system for storage:

This solution will prioritize places where there is no grid power. Solar energy will be stored through independent frequency converters and storage batteries. The inverter converts the DC current from solar panels and storage batteries into AC power and supplies it to electric devices. However, it should be noted that the capacity of the panel system and the storage system must be appropriate with the capacity of the electric devices, because the storage system accounts for quite high investment costs, leading to increased investment costs.

This solution will prioritize places where there is no grid power. Solar energy will be stored through independent frequency converters and storage batteries. The inverter converts the DC current from solar panels and storage batteries into AC power and supplies it to electric devices. However, it should be noted that the capacity of the panel system and the storage system must be appropriate with the capacity of the electric devices, because the storage system accounts for quite high investment costs, leading to increased investment costs.