Nguyen Cong Bac, owner of a pig farm with over 10,000 sows in Son La, said that all systems at the farm, from cooling systems, fans, and water pumps to lighting, need electricity to run. Before 2020, the farm's electricity bill hovered around VND150 million per month. The total VND1.8 billion a year on electricity was a major cost, so in 2020 he decided to install a rooftop solar system to power farm operations.

"About 50 percent of the roof area across the pig houses was covered with solar panels, with a total capacity of 1.4 MW. The total investment was nearly VND16 billion," he said.

Since he did not invest in a battery energy storage system (BESS), Bac signed a contract to sell surplus electricity back to the power company.

During the day, the entire farm runs on solar power. At night, it switches to the national grid. The results were clear: his electricity bill dropped significantly to about VND75 million per month, half of what it used to be.

In addition, he earns VND180-200 million per month by selling surplus electricity to the grid.

Since 2020, Bac’s pig farm has operated 24/7 without spending a single dong on electricity. He also pockets over VND100 million monthly from selling excess power.

"At this rate, I’ll recover the initial investment in about eight years," Bac said, explaining that bank interest slows the payback period; otherwise, it would take just around 5.5 years.

Similarly, all 13 chicken houses at Nguyen Van Duc’s poultry farm in Ea Tul commune, Dak Lak, are fully covered with rooftop solar panels. His system was installed at the end of 2020.

"Back then, the government was encouraging rooftop solar development. I immediately did some research and went ahead with it," he recalled. It took nearly a year, from paperwork to full operation.

Duc said he used to pay around VND60 million per month for electricity because the chicken houses used cold-house systems. After switching to rooftop solar, the monthly electricity cost dropped to VND30 million.

His rooftop solar system has a capacity of 2.4 MW. During the day, the farm uses only 5-10 percent of this capacity. The surplus is sold to the grid under a formal contract. Each month, he earns about VND600 million from the excess power.

However, to achieve this, Duc had to spend nearly VND30 billion in the rooftop solar system. Since 70 percent of the capital was borrowed from banks, the payback period is estimated at around eight years.

Rooftop solar is becoming more popular in many countries, including Vietnam. It not only delivers direct economic benefits but also contributes to environmental protection, creating a dual impact that supports sustainable energy transition.

Amid rising electricity prices and increasing pressure on the national grid, the energy sector encourages households to invest in rooftop solar under a self-generation, self-consumption model to reduce electricity bills and protect the environment.

In the third draft of the Prime Minister's decision on policies supporting households in installing rooftop solar and BESS systems, the Ministry of Industry and Trade has proposed a subsidy of VND1-1.5 million for installing rooftop solar and VND1-1.5 million for BESS systems (subject to minimum capacity requirements).

Additionally, there is a proposed loan support of VND4 million per kWp for rooftop solar systems (up to 5 kWp) and a minimum of VND2 million per kWh for BESS investment (up to 10 kWh).

The ministry estimates that with around 14 million households installing rooftop solar under the revised eighth national power development plan (Plan 8), the total direct subsidy from 2025-2030 could reach up to VND42 trillion.

If each household installs an average of about 3 kWp, the annual electricity production could exceed 50 billion kWh, equivalent to 16 percent of the national electricity demand in 2024.

The Ministry of Finance, citing data, stated that the investment cost for rooftop solar systems is VND12-15 million per kWp, equivalent to VND60-150 million for systems of 5-10 kWp, with an expected payback period of about five years. Therefore, the initially proposed direct support of VND500,000 per kWp (up to a maximum of VND2.5 million per household) lacks a clear basis for calculation.

Tam An