Biomass, one of the renewable resources, is expected to play an important role in the world’s energy future. In Asia, rice straw is an abundant agricultural surplus because rice is one of the leading staple food crops in the region. Often, rice straw is burned directly in the field via uncontrolled combustion methods that emit large amounts of short-lived air pollutants, greenhouse gases, and other pollutants. In Vietnam, the energy and environment protection sectors are facing great challenges because of rapid urbanisation and industrialisation. A national strategic choice is to exploit renewable energy, including biomass-derived energy, to achieve energy security and CO2 emission reduction. This study investigates the potential of rice straw as an energy source for power plants at a local scale in Vietnam using data derived from satellite Sentinel-1 images. The results show that Vietnam can produce 2,565 MW from rice straw, for which 24 out of 63 provinces have a potential capacity higher than 30 MW, and the Kien Giang province has the highest capacity (245 MW). The study also analyses limitations and obstacles overcoming which can promote the biomass energy sector in the country.

In field survey, Pteris vittata and Pityrogramma calomelanos were only found in arsenic (As) contaminated areas with soil pH 7.2-8.8 and 2.3-4.2, respectively. In the first pot experiment, two fern species were grown on the soil amended with 300 mg kg As at soil pH of 5.1, 7.2 and 9. P. calomelanos survived all pH treatments, and had the highest frond As concentration and soil As removal efficiency at soil pH 5.1. All P. vittata plants were dead at soil pH 5.1. P. vittata had higher frond As concentration, biomass and the amount of As removed from the soil than those of P. calomelanos at soil pH of 7.2 and 9. In the second pot experiment, P. vittata was demonstrated to have greater life time, biomass, As tolerance and accumulation than those of P. calomelanos as planted on alkaline soil (pH 7.8) spiked with various concentrations of As.

This research uses the GHI (Global Horizontal Irradiation Index) raster data source of solar radiation potential map developed by The World Bank Group and the land use map data, infrastructure in 2019 of Thanh Hoa province to calculate the solar radiation technical potential in Thanh Hoa province. In addition, GIS techniques are also applied to overlay thematic maps to determine the available solar energy development area according to the method of the Institute of Energy. The results show that the available solar energy development area is 54,621.15 ha, accounting for 5% of the province's natural area, the technical potential is 21,848.46 MWp. The well-developed regions are concentrated in the lowland and midland districts due to favorable conditions of land scale and infrastructure, less affected by natural disasters such as storms, floods and landslides. Regarding the method of determining technical potential, it is required to be more specific to identify available and exclusion areas with some types of land such as water surface, forest and paddy rice land.