FRANKFURT/LONDON (Reuters) - Infrastructure investor First Sentier Investors (FSI) and fund manager Equitix have been shortlisted by waste management firm Wheelabrator to make final bids for four British power plants valued at more than $600 million (£465 million), two sources told Reuters.

Macquarie Infrastructure Partners (MIP), which controls Wheelabrator, has set a mid-December deadline for second-round bids, with a decision expected by the end of the year, the sources said, speaking on condition of anonymity as the process is confidential.

Macquarie and FSI declined to comment.

Equitix was not immediately available for comment.

MIP launched an auction process in September for the four plants that produce renewable energy from waste in Wales, Kent and Yorkshire, sources previously said.

Governments and companies around the world have committed to securing renewable energy to manage costs and reduce their carbon emissions, while boosting their credentials with the general public and customers.

Macquarie bought Wheelabrator Technologies - which ranks as the second-largest U.S. waste-to-energy business with 25 plants across the United States and Britain - in 2019 for an undisclosed price.

Two of Wheelabrator's plants for sale are in a joint venture with British renewable power generator and network operator SSE, one of which is a 300 million pound facility still under construction.

SSE last month agreed to sell its 50% stake in West Yorkshire-based Ferrybridge and Skelton Grange assets for 995 million pounds in cash.

(Reporting by Arno Schuetze and Clara Denina; editing by Barbara Lewis)

By Arno Schuetze and Clara Denina