After years of operation, the four coal-fired power plants at Vinh Tan Power Center (sited in Tuy Phong District of Binh Thuan Province) have generated and accumulated millions of tonnes of coal ash and slag. With storage facilities approaching their designed capacity, the disposal and potential utilization of this waste material remain a significant challenge.
Observations of the shared ash and slag storage facility serving the three power plants of Vinh Tan 2, Vinh Tan 4, and Vinh Tan 4 Extension in Vinh Tan Commune of Tuy Phong District in early 2025 reveal continuous operation of water spraying and automated monitoring systems designed to mitigate dust dispersion. This facility, operational since 2015, now reaches a height equivalent to five stories.
“For nearly a decade, we’ve repeatedly suffered from dust pollution emanating from the ash and slag storage, impacting our health. While dust dispersal has been mitigated in recent years, the sheer height of the stockpile now raises concerns about potential landslides, particularly during the monsoon season,” explained T.V.Đ., a resident of Vinh Phuc Village (Vinh Tan Commune).
According to the Binh Thuan Province Department of Construction, the shared storage facility, covering over 38ha, has a planned capacity of approximately 8.6 million tonnes. By the end of 2024, it had received approximately 8.1 million tonnes of ash and slag, representing over 94 percent of its designed capacity. Without prompt solutions to facilitate the utilization of this material, the facility is projected to reach full capacity within a matter of months.
Adjacent to this shared facility lies the ash and slag storage site of Vinh Tan 1 Power Plant (Tuy Phong District), covering a substantial 59.5ha and possessing a maximum capacity of approximately 7.5 million tonnes. This factory commenced depositing and burying ash and slag at its storage site in April 2018. By December 2024, the site had held approximately 4.6 million tonnes, representing nearly 62 percent of its total designed capacity.
The combined stockpile of ash and slag from the four power plants currently totals nearly 13 million tonnes. With the shared facility nearing full capacity and the Vinh Tan 1 facility projected to reach its limit within the next two to three years, the scale of the environmental challenge is considerable.
Deputy Director Do Huynh Phong of Vinh Tan Thermal Power Co. informed that current efforts are largely limited to utilising the daily output of ash and slag from the Vinh Tan 2’s power units. The consumption of the accumulated stockpile from previous years continues to present significant challenges. Representatives from Vinh Tan 1, 4, and 4 Extension power plants corroborated this, citing limited market demand for the accumulated material.
Despite efforts by Binh Thuan Province to promote the utilization of this byproduct of coal-fired power generation, including granting investment licenses for projects using ash and slag in the production of non-fired bricks and road construction materials, these projects have largely stalled.
For instance, in 2018, the Binh Thuan Province People’s Committee approved an investment by Mai Xanh Co. to establish a non-fired brick manufacturing plant using ash and slag, with a projected capacity of 3,500-4,500 tonnes per day. However, according to the Binh Thuan Province Department of Construction, this project remains non-operational after seven years and is currently suspended.
Regarding the use of ash and slag for road embankment construction, the Binh Thuan Province Department of Transport stated that no such projects have been implemented within the province to date. This is due to the constraints of TCVN (Vietnamese standards) 12660:2019, which stipulates that thermal power ash and slag can only be used for embankment at depths of 80-100cm, precluding its use in areas with underlying groundwater.
Given that the rural road network in Binh Thuan Province has largely already been established, the use of ash and slag for embankment is deemed currently impractical.
To address the issue of the millions of tonnes of accumulated ash and slag, representatives from the power plants in Binh Thuan Province have pointed out that ash and slag are classified as ordinary industrial solid waste meeting relevant technical standards and guidelines for use as raw materials in construction materials and land filling.
Therefore, local authorities have recommended that the Ministry of Construction consider revising technical guidelines to incentivize the use of ash and slag as fill material.
Furthermore, the Ministries of Transport as well as the Ministry of Agriculture and Rural Development are urged to implement policies that encourage and support project developers utilizing public or state funding (excluding public-private partnerships) to prioritize the use of ash and slag in their projects.
Only through such measures can the problem of accumulated ash and slag be effectively addressed.
