The types of sugar produced in Vietnam include RS Sugar (Refined Standard), RE Sugar (Refined Extra), and Raw Sugar. Currently, only nine companies can produce RE sugar. The production of RE sugar accounts for approximately 50% of the total national sugar output; it is supplied mainly to industrial customers, thus leading to high demand, less volatile prices and less competition from smuggled RS and Raw sugar.
At present, the revenue from co-products (electricity, fertilizers, alcohol, MSG, aminal feeds) from sugar factories contributes 6.4–9.6% of the total revenue of sugar industry; this is an important factor in the production and business of sugar mills. The quantity of materials from which co-products could be developed by sugar mills is currently very large (Table 3). In addition, the level of utilization of secondary materials is not high: about 83% of the bagasse, 48% of the molasses and 61% of the filter cake are converted into co-products. The amounts of secondary materials that are not consumed are often sold or released into the environment. Previously, 80% of the bagasse was used in the sugar factories boilers; the remaining 20% was used to produce plywood. Molasses was fermented to produce alcohol, MSG (monosodium glutamate) and animal feeds. Recently, more sugar mills have invested in technologies to develop co-products from by-products in sugar processing which means to convert the available by-products beside the main products as sugars of different qualities. The benefit of co-products is that their production reduces the impact of reject streams discharged in the environment.
Cogeneration from cane bagasse for electricity: One tonne of cane can provide 0.3 tonnes of bagasse that produce 100–120 kWh of electricity (MARD 2016a). The sugar miller using this source of electricity can export 50–60 kWh to the national grid. In 2016–2017, the sugarcane industry had about 200 MW of generating capacity for export to the national electricity grid. Large sugar mills, such as Lam Son, Cam Ranh, TTC Tay Ninh, Quang Ngai and An Khe, with high capacities have invested in large generators for electricity production. However, due to the unfavourable price of electricity, those millers could not invest in high efficiency boilers and generators. For the 2017–2018 season, 28 power plants in Vietnam have invested in technology to utilize bagasse to improve the efficiency of sugar production and trading with total capacity of 351.6 MW and producing 186.3 GWh of electricity.
Animal feeds: Beside the usage in power generators, bagasse is also a good feedstock for animal feeds, especially for buffalo and cattle raising. The survey results showed that bagasse was sold by sugar factories in Nghe An, Dak Lak, Hau Giang to livestock businesses with an output of 23,784 tons, accounting for 0.89% of total bagasse processed in the surveyed provinces. In Nghe An, the bagasse of Nghe An Sugar Company was sold to TH Dairy Company for processing as cow feed. In Hau Giang, a Japanese company has invested in animal feed processing factory using fermented bagasse with a capacity of about 20,000 tons of raw materials/year. Currently, bagasse is naturally fermented, and pressed and purchased by Japanese and Korean businesses at a price of 500,000 VND/ton (approximately USD 22/ton).
Fertilizers: Filter cake (mud) and ash are often used to produce biofertilizers, most sugar mills often provide to sugarcane growers or sell to collectors in need. In 2015–2016, there were 19 sugar mills having a complete fertilizer production line from filter cake to supply fertilizers to its sugarcane growers. The total ratio of using filter cake and ash to produce fertilizer is summarized in Table 4. The percentage of filter cake converted to produce fertilizers was 59.1 in the season 2013/2014. Survey results at 10 factories with production lines of microbiological fertilizers from filter cake and ash show that the output of mud and kiln ash put into the production of compost is 188,564 tons, accounting for 43.61% of the total production of sludge and ash generated in sugar processing. The obtained products are mainly invested in the sugarcane material areas of the power plants.
Monosodium glutamate: there is about 0.5 million tonnes of molasses annually provided to monosodium glutamate production.
Alcohol: Molasses products have very low financial margins (less than 1%), while ethanol production can yield up to 30%. Refined alcohol products are made from molasses by fermentation followed by distillation. In 2016, only 6 of the 41 sugar mills produce alcohol from molasses. The volume of molasses used in alcohol production varied from 13 to 32% of the total amount produced (Table 5). The excess amount of molasses is sold or mixed with bagasse as animal feeds. The production of ethanol from molasses is not yet common in Vietnam mainly due to economic and competitive reasons. However, the price of ethanol is currently high and varies according to market’s trend. If more sugar mills adopt ethanol production technology, the increased revenue can compensate for the higher production cost of sugar. Under the current low sugar price, sugar plants that can also produce ethanol from sugarcane will be effective in production and business.
Yeast production and other co-products: Beside the above-mentioned co-products in sugar mills, there is product development in producing yeast from molasses. The Vietnam-Taiwan Sugar Company has recently invested in food-grade yeast production line. In addition, bagasse can be used as a medium for mushroom production which is also cost-effective. These special, smaller, less development cost, but profitable co-products are very important contribution to the added value of sugarcane. They introduce the concept of developing simple co-products and financially attractive. This model will eventually expand to larger developments and gradually improve financial issues of the industry.
Sugar-containing commodities: Sugar is a main raw material for confectionary, candy, beverage, and soft drinks. These products have recently been developed by sugar millers, according to the market demand and the availability of sugar. A good example is the Quang Ngai sugar factory with well-known brand products such as soymilk, beer, candy, biscuits and mineral water. In the period of 2012–2016, the total income of the company increased 22% each year, reaching 8,223 billion VND (i.e. 360 million US dollars), in which the income from sugar was only 20% of the total. This is an excellent example of a diversification project which used sugar directly for an important and lucrative market.