Vietnam expects to grant investment licences for three coal-fired power plants worth a combined $7.5 billion in early June, the country's investment minister said.

Although Vietnam wants to boost renewable energy output amid resources scarcity and environmental issues, it has been mostly reliant on coal-fired and hydro power plants to meet its annual electricity demand growth of around 11 percent.

The projects by Japanese, South Korean and Saudi Arabian investors are expected to receive licences ahead of Vietnamese Prime Minister Nguyen Xuan Phuc's visit to Japan next month, investment minister Nguyen Chi Dung told Reuters on Tuesday.

Details provided by the ministry showed South Korea's Taekwang Power Holdings Co. and Saudi Arabia's ACWA Power would invest $2.07 billion for a 1,200-megawatt thermal power plant.

Each investor would have a 50-percent stake in the plant and commercial operation is expected to start in 2021.

Japan's Marubeni Corp and Korea Electric Power Corp would invest $2.79 billion in a 1,200-megawatt plant, with operation expected to start in 2021. The investors will also share half of the investment each.

Japan's Sumitomo Corp would invest about $2.64 billion into a 1,320-megawatt plant, with an expected starting date of 2022, the ministry said.