Banpu, Thailand’s largest coal miner, said it planned to invest $170 million in solar power in Japan, as part of plan to boost capacity of renewable energy to 800 megawatts (MW) by 2025.

Banpu, which has diversified into the power business to minimise the impact from weak coal prices, has interests in seven solar projects in Japan with a combined capacity of 54 MW, Voravudhi Linananda, chief executive of Banpu’s power unit, told reporters.

The solar power plants will gradually start commercial operations during 2016 to 2018, he said.

The company aimed to raise more solar investment in Japan and is looking for opportunities to invest in other renewable power projects in China and Indonesia, Voravudhi said.

Based on its equity holding, Banpu has power generating capacity of 1,800 MW and aimed to boost that to 4,300 MW by 2025, he said.

Banpu has a 30 per cent stake in the Shanxi Lu Guang power project in China, with an installed-capacity of 1,320 MW and expected to start commercial operation by end-2017, he said.

The power business is expected to contribute about 40 per cent of earnings.