Data compiled from Vietnam Electricity (EVN), Vietnam Oil and Gas Group (PVN), Vietnam National Coal - Mineral Industries Holding Corporation Limited (TKV), and other thermoelectric facilities indicates the presence of 31 operational coal-fired power plants nationally.
The quantity of ash and slag emissions exhibits a progressive annual increment from 13.6 million tonnes in 2019 to 18.07 million tonnes in 2023 and exceeding 20 million tonnes in 2024. The total annual ash and slag emission volume from these power plants approximates 20 million tonnes, with 66 percent concentrated in the Northern region. Despite consumption exceeding 65 percent of total emissions, substantial residual stockpiles persist.
Despite this positive overview, the reality of ash and slag utilization is complex. Recent reports to the Prime Minister from the Ministry of Construction reveal sluggish consumption and substantial stockpiles at facilities in Cam Pha, Dong Trieu, Mong Duong BOT, Vinh Tan 1 BOT, Vinh Tan 2, and Duyen Hai. The Dong Trieu and Cam Pha power plants face pricing challenges for ash and slag sales. At Vinh Tan 1, 2, and Duyen Hai, the distance between storage yards and consumption sites results in elevated transportation costs, deterring potential project investors.
Furthermore, gypsum waste from production plants of chemical and fertilizer, namely Diammonium Phosphate (DAP), is accumulating in significant quantities. Data from the Ministry of Industry and Trade and Vietnam Chemicals Group identifies three major gypsum waste emitters, consisting of Dinh Vu DAP Plant (Hai Phong City), Lao Cai No. 2 DAP Plant, and Duc Giang - Lao Cai DAP Plant. The aggregate gypsum waste emission approaches 1.4 million tonnes annually. These substantial industrial waste volumes necessitate extensive storage areas and impose environmental protection pressures, particularly amidst regional moratoriums on storage site expansion.
Current applications of ash and slag predominantly include fill materials and mineral additives for cement, followed by concrete additives for irrigation and transportation projects, such as rural cement concrete roads, civil construction, and partial substitution in brick manufacturing.
Economic experts highlight the waste of excluding ash and slag from construction bids, especially with dwindling natural sand. More seriously, Mekong Delta highways face sand shortages, while Tra Vinh’s Duyen Hai plant holds millions of tonnes of ash and slag.
Finance Director Nguyen Anh Vu of Hoang Son Flyash and Cement JSC. noted the lack of compliant environmental impact assessments for using these materials, urging standard promulgation. Meanwhile, Pham Viet Hung, a member of the Members’ Council of Power Generation Corporation 1 (EVNGENCO1) insists enterprises can meet ash and slag standards for construction, but stresses regional cost factors. He proposes standardized pricing norms for on-site or regional use, set by authorities.
The absence of clear legal frameworks and standardized pricing mechanisms hinders the effective utilization of industrial byproducts, creating a paradox of material abundance amidst scarcity. Vice President of the Vietnam Building Materials Association Dr Thai Duy Sam advocates for state-sponsored tax incentives and interest rate support to boost investment in recycling equipment for materials like ash, slag, and construction waste, thereby achieving cost competitiveness with natural sand.
The Ministry of Construction has proposed to the Ministry of Finance the establishment of accounting regulations for ash, slag, and gypsum from thermoelectric, chemical, and fertilizer plants, aligning with current regulations. It has also advocated for collaboration with local People’s Committees to develop specific mechanisms supporting transportation cost subsidies for projects distant from supply sources.
The Ministry has also intensified research on the utilization of ash, slag, and gypsum as building materials for transportation projects, replacing sand. Research has concluded, and the Construction Ministry proposes the Ministry of Science and Technology to promulgate standards for ash and slag materials, and specialized agencies to issue basic standards and technical guidelines for construction applications.
The Ministry of Construction has directed investors and project management boards to identify suitable project components for ash and slag utilization, either directly or with binder reinforcement.
