Indian renewable energy company Adani Green Energy Ltd said on Wednesday it would buy SoftBank Group Corp-backed SB Energy Holdings Limited for $3.5 billion.

The billionaire Gautam Adani-led company will buy the 80% stake held by SoftBank Group Capital Limited and the rest owned by Indian conglomerate Bharti Global Limited in a cash deal, the company informed the stock exchanges.

The deal would allow Adani Green to achieve its renewable energy target of 25 gigawatts (GW) four years ahead of its expected date, the company said.

SB Energy was established in 2011 and is involved in the generation, supply and sale of electricity and energy produced from renewable sources. SoftBank Chief Executive Masayoshi Son is the company's chairman.