What should we make of the claim that "there is an available savings surplus worldwide to finance the energy transition"?

Complying with international climate agreements (which is not at all the case currently) would require increasing global investments in renewable energies from around USD 300 billion to USD 800 billion per year . It is sometimes claimed that increasing these investments would be no problem, since the very low real interest rates show that there is a savings surplus worldwide that could be used to finance these investments. We have to be far more specific; global savings are currently being used to finance investments: the low interest rates have reduced savings and increased investment to the point where they are equal. There are then two scenarios: Either the rise in investments in renewable energies is accompanied by a reduction in other investments (and this cannot only include investments in fossil energies), and real interest rates will remain very low; Or the rise in investments in renewable energies is not accompanied by a reduction in other investments, and, at equilibrium, real interest rates will rise to stimulate savings, with negative effects of this rise in interest rates on government solvency, for example.