Ramaphosa said South Africa was speaking to international partners to identify additional funding sources, calling for "a significantly larger grant component" in support pledges.
The 1.5 trillion rand plan includes about 1 trillion rand of electricity financing needs, 128 billion rand for new energy vehicles and 319 billion rand for green hydrogen.
The head of South Africa's presidential climate finance task team said there was a funding gap of about 700 billion rand for the plan.
If successful, South Africa's energy transition plan could be a model for other coal-dependent emerging economies in the global fight against climate change.
($1 = 17.9540 rand)Additional reporting by Anait Miridzhanian Editing by James Macharia Chege, Kirsten DonovanOur Standards: The Thomson Reuters Trust Principles.