Battersea Power Station tube station opened Monday 20th September

From TFL:

Tube services on the extension will start on Monday 20 September, running from Kennington station on the Charing Cross branch. There will be an initial peak time service of six trains per hour on the extension, increasing to 12 trains per hour by mid-2022. There will be five trains per hour during off-peak times, doubling to 10 trains per hour next year.

The Northern Line Extension is the first major Tube extension this century and is supporting around 25,000 new jobs and more than 20,000 new homes. In addition, construction of the extension boosted the UK economy and supported around 1,000 jobs, including 79 apprenticeships.

From Sadiq Khan, Mayor of London:

The two new stations at Nine Elms and Battersea Power Station are the first new stations on the Northern line for 80 years. They will hugely improve connectivity between these two areas and the rest of London, and play a major part in the capital's recovery from the pandemic by supporting thousands of new jobs, homes and businesses.