The Vietnamese Mekong river delta (MD) is recognised as the biggest agriculture and aquaculture region of Vietnam. The MD plays an important role in ensuring food security for the country. The MD also has many sensitive ecosystems reliant on the ecology of the Mekong river basin. However, during the last decade, many electricity generation plants, both renewable and non-renewable power projects, have been built and some will be built in the near future in the MD. These energy plants' construction and operation may prove to be a challenge to the national energy strategy. This paper is a monograph review of two sides of energy sector industrialisation in the MD with a focus on 'green' and 'grey' socio-economic development (as 'xanh' and 'xam' in Vietnamese respectively). 'Green' energy is understood as the electricity generated from inexhaustible sources and known as renewable energy. It emits fewer greenhouse gases and causes less harm to habitats in comparison to traditional fossil fuels and hydropower. 'Grey' energy is another word for non-renewable energy or polluting energy, which can have negative effects on human health, environment, and climate. This paper finds that the MD's energy development plans at present might not be as 'green' as expected, due to more 'grey' power plans in the planning pipeline. This paper also considers an outlook on energy prices and impacts on long-term sustainable development of the MD.