Nguyen Tuan Hung, owner of an internet cafe in HCMC, set up 20 mining rigs last month at a solar farm in the southern province of Tien Giang at a cost of VND25 million ($1,080) a month.

Hung said this method fetches higher profits than mining by himself using grid electricity, which is what most miners do.

"I can monitor my rigs online and ask solar farm operators to deal with errors when they occur. I have not seen any major issue in the past month."

The cryptocurrency mining trend using solar power began towards the end of last year as miners sought to increase their profit margins by reducing electricity bills, which is a major cost component of mining Bitcoin, Ethereum and other such coins.

Nguyen Quang Tuan, owner of a solar power installation company in Ho Chi Minh City, said most miners are not willing to invest large sums into setting their own solar-powered mining rigs and instead partner with solar farm operators for using their electricity.

These operators, instead of selling their power to the national utility Vietnam Electricity, sell it to miners at a price of VND1.2-1.5 million ($52-65) per rig per month with a guarantee that the rigs will be running 24/7.

Spotting the opportunity, many solar farm operators are also entering the mining game by setting up their own rigs to utilize the extra power they produce.

Sinh Le, owner of a mining rig provider in HCMC, has received many requests from solar farm operators in Tay Ninh and Tien Giang provinces in the south and Binh Thuan Province in the center to set up rigs at their farms for VND4-5 billion ($173,000-216,000) per rig.

Although using solar power costs less than traditional power, miners can only utilize this resource during the day and still have to use grid power for night-time mining.

Industry insiders say that solar power mining has the highest benefit during the dry season. In the rainy season, miners will have to go back to using national grid power.

Vietnam has the second highest rate of cryptocurrency use among 74 surveyed economies, according to market data provider Satista.

However, cryptocurrency has not been recognized as legitimate currency in Vietnam. The State Bank of Vietnam has warned that owning, trading and using cryptocurrency is risky and has no legal protection.