According to Decree No. 135/2024/ND-CP, off-grid self-produced and self-consumed solar power (self-produced and self-consumed) is encouraged to develop without registration procedures. People, business households and enterprises wishing to install a system with a capacity of less than 100kWp only need to notify the Department of Industry and Trade, the electricity unit and the local construction and fire prevention and fighting management agency of the installation capacity and location.
This is a policy that opens up great opportunities for businesses and people to have easier access to this trending renewable energy option. With rooftop solar power systems, individuals or businesses can achieve dual benefits of “sustainable development” and “increasing economic efficiency” in the long term. So what are the economic benefits that rooftop solar power brings? Through this article, energy expert Tran Dinh Sinh will analyze so that readers can have a deeper insight.
What is the structure of a self-generating and self-consuming rooftop solar power system?
The figure below is a diagram of a self-generating and self-consuming rooftop solar power system. The system consists of solar panels, an inverter (also known as a stimulator, power converter, inverter), a load-tracking device (load-tracking meter) to prevent solar power from being pumped into the national grid along with wires. Solar panels and inverters are the most important devices in a solar power system.
Solar panels can be installed directly on corrugated iron roofs. For tiled or concrete flat roofs, solar panels must be mounted on racks. For solar power systems installed in places with high corrosion potential such as livestock farms or coastal areas, the application of anti-corrosion solar panels is necessary to ensure service life and maximize operating capacity.
Currently, the capacity of each solar panel is about 500Wp. Each panel is usually about 2m long and about 1m wide. Thus, about 4 m2 is needed to install 1 kWp.
Normally, in addition to the area for installing solar panels, the roof area is also needed for walkways to check and clean the solar panels. The actual roof area for 1kWp is about 5 m2 to 6 m2 for 1 kWp. For example, if your family has a 50 m2 roof, you can install 10 kWp and each year will get about 10.000 kWh in the North and about 14.000kWh in the South. To optimize the usage, solar panels should be installed in places without shade, especially from 8am to 16pm every day.
How can rooftop solar power optimize costs?
The application of solar power to reduce daily electricity consumption of individuals and businesses is an essential need to protect the environment and save costs. However, differences in geography and climate are sometimes also a reason affecting the capacity of the device.
In fact, when installing rooftop solar power, households are often advised by solar power contractors on how much capacity to install. GREEN IN will estimate based on a monthly electricity bill in the summer. Because solar radiation in the South (from Da Nang and below) is 150% higher than radiation in the North (from Hue and above), it is calculated separately for the North and the South.
Electricity bill for 1 summer month (million VND) | 2,0 | 3,0 | 5,0 | 7,0 | 10,0 | 15,0 |
Solar power installation capacity (kWp) | 3 | 4 | 7 | 9 | 13 | 20 |
Monthly savings in the North (million VND) | 0,6 | 0,8 | 1,4 | 1,9 | 2,8 | 4,2 |
Monthly savings in the South (million VND) | 0,8 | 1,2 | 2,0 | 2,8 | 4,0 | 6,0 |
With the above installed capacity, the North will save about 30% and the South will save about 40% of monthly electricity bills. According to economic calculations, a solar power system of about 9kWp in the North of Vietnam will save approximately 24 million VND in electricity bills per year compared to when not installed. The amount of savings will be greater if the system is installed in the southern region. In the long term, this option brings both environmental and economic benefits to households and businesses.
However, if the installation capacity is large, when the sun is strong, the solar power produced is large but not fully used. On the contrary, when the sun is weak, the solar power produced is not enough to meet the needs of the family. So how much capacity should be installed to be able to use it all without being wasted?
Stay tuned to GREEN IN for more expert opinions in the next article.