SDIC Power said that it had received the green light from government regulator, the State-owned Assets Supervision and Administration Commission.
However, its plan, which corresponds to less than 678.6 million A-shares, still needs further approvals from shareholders as well as British and Chinese securities regulators, it added.
Reuters reported last month, citing sources, that SDIC Power had hired Goldman Sachs, HSBC and UBS to help it list in London via the newly-minted Stock Connect scheme, in a boost for Britain's status as a financial centre ahead of Brexit.
The sources said that SDIC Power, which has a market value of 57 billion renminbi (£7 billion) in Shanghai, was looking to raise between $500 million and $1 billion from the GDRs sale.
(Reporting by Brenda Goh; Editing by Kim Coghill)