What is a solar power system?

Content of Circular No. 05/2019 of the Ministry of Industry and Trade issued on March 11, 2019

  • Before January 1, 2018, the electricity purchase and sale price was 2,086 VND/kWh (excluding value-added tax, equivalent to 9.35 UScents/kWh, according to the central exchange rate of Vietnamese dong against US dollar announced by the State Bank of Vietnam on April 10, 2017 is 22,316 VND/USD)
  • From January 1, 2018, the electricity purchase and sale price applied according to the provisions in Clause 1 of this Article shall be adjusted according to the central exchange rate of Vietnamese dong against US dollar announced by the State Bank of Vietnam on the date of announcing the final exchange rate of the previous year. The electricity purchase price of EVN in 2019 is 2,134 VND.

When will the government’s policies be officially implemented

Content of Circular No. 05/2019 of the Ministry of Industry and Trade issued on March 11, 2019

  • Article 3: Effective date
  • This Circular takes effect from April 25, 2019

How is the procedure for replacing a two-way meter?

  • After the system is installed and put into operation, the Company will assist customers with registration procedures with the local power company or customers can contact the power company themselves.
  • The registration dossier will include technical parameters of the system such as: Expected capacity, technical specifications of solar panels, inverter specifications.
  • The local power company will send an electrical appraisal unit down to appraise the quality of the system.
  • After appraising the electrical quality that meets the electrical connection standards. The local power company installs a two-way meter for customers
  • Depending on the number of customers requesting to replace a two-way meter at that time, the support time of the power company will vary.

Does replacing a two-way meter cost money? And how much?

Currently, the installation of a two-way electricity meter is the responsibility and managed by EVN, the company will assist customers to work with EVN and install a two-way meter.

What is a solar energy system? How does it work?

A solar energy system includes: solar panels and inverters.
The solar panels installed on the roof of the building will absorb sunlight and convert it into direct current (DC) electricity. The DC electricity will then be converted into alternating current (AC) electricity using a 220V-1 phase or 380V-3 phase inverter depending on the demand. The AC electricity generated from the solar energy system will be directly connected to the existing power grid to supply power to the loads that are operating.

  • The system will automatically calculate and adjust the parameters so that the solar power can be synchronized and connected to the grid. Then, the following cases will occur:
  • When the power from the solar power system is equal to the load power, the load will prioritize consuming electricity from the solar power system.
  • When the load power consumption is greater than the solar power system power, the system will take additional electricity from EVN’s grid to compensate.
  • When the load power consumption is less than the solar power system power, the excess electricity will be pushed up to EVN’s grid and recorded by a two-way electric meter.

The excess electricity has been regulated by the Government and the Ministry of Industry and Trade with regulations on purchase prices and standard power purchase contracts for solar power projects (sending Circular No. 05/2019 of the Ministry of Industry and Trade and Decision No. 02/2019 of the Prime Minister). This is also a remarkable effect of grid-connected solar energy systems.

Can solar energy systems be used during power outages?

The Solar Power system consists of 3 types of systems:

  • Grid-connected system: is a system that is directly connected to the national power grid and requires the use of an energy storage system , so when the power grid is lost, the system will not operate.
  • The interactive grid system: is a system that is connected to the national power grid and has an energy storage system.
  • Independent system: is a system that is connected to the national power grid and has an energy storage system.

Customers should choose the grid-connected system because:

  • The investment cost for the grid-connected system is the most economical, so the payback period is faster than the other 2 systems.
  • Using an energy storage system is not efficient because of the high investment cost and the harmful compounds inside the batteries, especially since the battery life is not high, which will affect the environment.

For areas with stable national power grids and low power outage frequency (1-2 power outages per month), installing a grid-connected system is the most economical, without using batteries to store electricity for use during power outages.

Advantages of the grid-connected solar power system?

  • The system does not use batteries, so the investment and maintenance costs are low. The system is easy to operate and upgrade;
  • The lifespan of the solar panels is high, and the peak output power of the solar panel is guaranteed for 25 years;
  • Reduce monthly electricity bills;
  • Environmentally friendly because the system directly converts solar energy into electricity, does not produce CO2 gas, thereby contributing to environmental protection and reducing greenhouse effects;
  • The system automatically stops operating in case of a power outage to ensure safety for the power grid and users;
  • The excess electricity pushed onto the grid will be repurchased by the power company according to the instructions of the Prime Minister and the Ministry of Industry and Trade.

Can the grid-connected system generate electricity for use at night?

  • In essence, solar power only generates electricity during the day, so there is no solar energy to use at night.
  • However, when installing a grid-connected solar power system, customers will have their two-way meter replaced. The amount of electricity generated during the day that is not used will be pushed onto the EVN power grid and recorded by the two-way meter. This amount of electricity will be converted into money according to the regulated electricity selling price (9.35 Cents/kWh multiplied by the exchange rate on December 31 of the previous year ~ 2.134 VND). This amount will be paid back and offset against the amount of electricity used at night (according to Circular No. 05/2019 with a sample contract).

When the power goes out, does the solar power system work? Does the system work with a diesel generator?

  • For grid-connected solar power systems, technically, when the power grid goes out, the system has no power source to supply the inverter (which converts DC to AC), so the system will stop operating to ensure safety and prevent reverse power flow onto the grid that could endanger power company employees repairing the grid (if any).
  • If customers have a diesel generator and want to run it during a daytime power outage, they must isolate the solar power system because electricity generated by the system can flow back into the generator and damage it.

On cloudy or rainy days, will there be enough electricity for daily use?

  • On cloudy or rainy days, the solar power system still works, but the amount of electricity generated depends on the intensity of the light.
  • At this time, the power grid will automatically connect to supplement the missing amount of electricity to ensure that the load is supplied. Therefore, daily life and production still take place normally and are not interrupted.

Do I have to pay for electricity when using solar energy?

It depends on the demand for electricity and the scale of solar power installed: because solar power only generates electricity during the day. At that time, at night, it is mandatory to use electricity from the grid. Therefore, solar power only provides some of the demand for electricity during the day. However, if the installed capacity is greater than the demand for daytime use, the amount of electricity sold back to the Electricity Company may be equal to or greater than the amount of electricity paid to the Electricity Company

What type of solar panel should be used for a rooftop solar system?

  • There are 2 types of panels: Mono-crystalline and Poly-crystalline. However, Mono will have higher efficiency and higher cost due to its complex production process and higher costs.
  • But with the characteristic of solar panels that the higher the temperature, the lower the power output. Therefore, in the Southwest region where the average temperature is high, Poly should be installed. In fact, it has been shown that the amount of electricity generated by Mono is only slightly higher than that of Poly even though the investment cost for Mono is higher.

What is the efficiency of NLMT solar panels? What are they used for? Is it important?

  • The efficiency (conversion) of the Panel is the ability to convert solar radiation into electricity. Currently, this conversion ability is at 16 – 19%. With the same area, the higher the conversion efficiency, the greater the power output of the panel.
  • The most commonly used panel today is the Poly 330 Wp panel with a conversion efficiency of 17.8%. Mono 360 Wp panel has an efficiency of 18.7%

How does installing a solar energy system bring economic benefits?

  • Helps reduce monthly electricity costs and may not have to pay for electricity due to the government’s preferential mechanism for buying solar power when it is generated on the grid, and especially the lifespan of the solar panel system is very high, the peak output power of the panel is warranted up to 25 years.
  • The system does not use batteries so the investment and maintenance costs are low, the operation is simple and easy to upgrade and expand the system.
  • Environmentally friendly because the system directly converts energy from sunlight into electricity, does not produce CO2 gas, thereby contributing to environmental protection and reducing greenhouse effects
  • In the context of fossil fuels being depleted, solar power can be seen as the energy source of the future and the trend of the times.
  • Reduce the load for power transmission lines before the increasing demand for electricity, thereby contributing to ensuring national energy security.

Can a solar energy system cool the roof?

  • Because the solar panels come into direct contact and absorb all sunlight, they will help the roof be cooler.
  • If customers ask if solar panels can be used instead of tiles or not: Because there must be a minimum distance between the panels for ventilation-heat dissipation, it cannot prevent rainwater and dust like tiles or metal roofs

What equipment does a solar power system include?

Currently, the solar power system solution package is a complete grid-connected system that includes:

  • Solar panels.
  • Inverter (Power converter).
  • Solar energy monitoring system.
  • Frame support system for all types of roofs (flat roofs, metal roofs, tile roofs).
  • Electric cables and accessories.

What type of solar panel is used in the solar power system?

Currently, the company has 3 product lines:

  • Hanwha_Qcell solar panel: Korean brand, manufactured in Malaysia, warranty for 12 years, performance warranty over 80% for 25 years.
  • RECOM solar panel: German brand, manufactured in China, warranty for 15 years, performance warranty over 80% for 25 years.
  • Risen solar panel: American brand, warranty for 12 years, performance warranty over 80% for 25 years.

Can solar panels withstand hail and storms?

Solar panels are designed to withstand snow and ice loads up to 5400 Pa (5400 N per square meter) and wind loads up to 2400 Pa.

However, in the event of a large-scale storm or hail that damages the solar panel due to natural disasters, it will not be covered by the company’s or manufacturer’s warranty.

What type of inverter is used in the solar power system?

To meet the diverse needs of customers, the company currently has 02 options:

  • Sungrow inverter, Taiwanese brand, manufactured in China.
  • SMA inverter, German brand.

All inverters meet many reliable certification standards and meet the connection requirements for single-phase and three-phase power grid systems for customers to use and are accepted by EVN to replace two-way electricity meters.

What is the monitoring system?

The monitoring system will record the system parameters so that customers can remotely monitor them, such as: the instantaneous power of the system, the amount of electricity generated in a day, in a month.

What is the cost of the system?

The complete cost of the solar power system includes:

  • Survey, installation and completion of the system.
  • Solar panels, inverters, electrical cabinets, monitoring systems, frame support systems, accessory wiring systems.
  • Maintenance and warranty.

The total cost is calculated based on the capacity of the system (Price = system capacity * unit price/kWp) with a reference price (according to the current price list).
The actual price may increase for additional costs incurred during actual construction (customer requests additional installation) and transportation costs for customers far away.

Is the grid-connected solar power system for households cost-effective (how long does it take to recover the investment)?

The solar power system provided by the company will help customers recover their investment in just 4.5-5 years (refer to product packages in the price list).

And because the performance of the solar panel is guaranteed up to the 25th year and still reaches over 80%, the system can generate profits for up to 20 years.

The system is not only suitable for customers who want long-term investment with low risk but also demonstrates customers’ responsibility to the community in reducing CO2 emissions and protecting the environment.”

How is the system capacity calculated?

System capacity = solar panel capacity * number of solar panels
For example: Poly 345 Wp solar panel capacity * 9 solar panels = 3105 Wp = 3.1 kWp

How is the system output calculated?

Vietnam is located in the Northern Hemisphere, and the equatorial region is a location with a relatively high number of sunny days in a year and is suitable for installing solar power systems. Depending on the geographical area, there will be different sunshine hours throughout the country. But the average number can be used for calculation is 4 hours of maximum sunshine, meaning that if customers install 1 kWp, they will receive 4 kWh/day (this is an average number/day calculated in 01 year, in fact, there are days that can reach up to 5.5-6 hours of maximum sunshine)

The formula for calculating output is as follows: Electricity output (kWh) = system capacity (kWp) * sunshine hours coefficient

For example: Solar power system installed in Ho Chi Minh City, with a capacity of 3.1 kWp * 4h = 12.4 kWh. This means that the 3.1 kWp solar power system has the ability to generate 12.4 kWh/day in Ho Chi Minh City.

How is the roof area needed for the system?

The NLMT solar panel in the solar power system is currently used with an area of about 1m*2m: (72 Cells panel: 1956 x 990 x 40mm)

The average area required for installing a 1 kWp system is from 7m2 to 8m2.

The 3.1 kWp system occupies an area of about: 24m2

How is the solar power system installed?

Solar power system will achieve maximum efficiency when the system is installed:

  • The mounting direction of the plate pin is not more than ±45º from the main direction South
  • Panel tilt angle (for inclined plate mounted panels): the panel tilt angle between 5º and 30º
  • For flat roof: the tilt angle of the panel according to the design of the support frame from 12º to 18º

The most important: around the system must be open, no obstructions appear to cover the system.

Can a solar power system be installed on a slanted roof (corrugated iron/tile) or a flat roof?

Solar power systems can be installed on flat roofs, tile roofs and corrugated iron roofs. For each type of roof, there will be a different construction method and frame truss system. Since then, the price is also different, so it is necessary to go to the actual survey to be able to quote the exact price.

Based on where can I know if I can install a solar power system? And how much capacity must be installed, the investment value?

In order to install a solar energy system suitable to their needs, customers should pay attention to:

  • Monthly cost of electricity usage
  • Monthly electricity saving needs
  • Type of housing and available roof area

In addition, in order for the system to achieve maximum performance, it is also necessary to survey the direction of sunshine, shade of surrounding high-rise buildings, …

What is the maintenance policy?

The solar power system is maintained for free every 6 months for 02 years.

The maintenance works are as follows:

  • Check the operating status of equipment:
  • Inverter, solar panels, monitoring system.
  • Check connection points, wires.
  • Check the structure of truss systems, frames, racks.
  • Check the amount of power generation of the system.
  • Clean and clean solar panels.

What is the warranty policy?

The warranty policy is as follows:

  • 05-year warranty equipment: Inverter, Monitoring system, frame truss.
  • 12-year warranty for solar panels.
  • The output capacity warranty is always over 80% for 25 years.
  • 05-year warranty with electrical cables and auxiliary equipment.

How do I need to maintain and operate the system?

The system works fully automatically. However, it is necessary to periodically clean the surface of solar panels to remove dirt on the surface, helping to improve light absorption to optimize and maximize the power output of the system.

The system should also be checked periodically: extension cords, fasteners, equipment,… to ensure best performance.

If the device is damaged in the 6th year, how to handle it?

Currently, the warranty policy for panels is 12-15 years, while the warranty policy for inverters is 5 years. There are 2 ways to handle this problem:

  • It is possible to buy an additional warranty package for this whole system, instead of the original 5 years, it is increased to 10 years. However, at present, the Company has not issued a specific policy, which may be issued in the near future.
  • Another treatment method is not to increase the warranty period, but when the inverter is damaged in the 6th year, the customer can replace it with a new inverter with the same capacity as the newer technology and the price can be cheaper. The dealer is committed to supporting customers in handling these issues, because the dealer is a local person, so customers can feel secure when they need maintenance support or system warranty.

The reason why I should choose Hoa Binh company's solar power products.

Customers should choose Solar Power products because:

  • The legal representative for Hoa Binh Company is currently a lecturer at the University of Technology, establishing the company with the goal of consulting and designing for solar power plants. The total capacity of the consulted solar power plant is up to 1,350 MWp equivalent to 30 plants. And based on the strength of good relationship with equipment suppliers, the Company has a source of quality goods with equipment purchase price equal to the wholesale and large-scale purchase price of 01 solar power plant.
  • The company not only operates in the field of consultancy and design but also provides maintenance and operation services for power plants throughout the project life cycle (about 20 years), so customers can be assured of warranty and maintenance services for the solar power system that the company installs in accordance with the commitments in the contract.
  • The design team of the Company are experts who have a lot of experience when consulting and designing for solar power plants, so customers will be provided by the company with the most professional services at the lowest price in the market.
  • The company has a very good relationship with local Electricity, so the procedures for installing 2-way meters will be done quickly, customers do not need to worry about administrative procedures.