Virtual or physical?
VPPAs (financial PPA or synthetic PPA) is the usual mechanism for PPAs globally. In a VPPA there is no physical delivery of energy. The energy is sold into the wholesale market, while the buyer continues to get its electricity from its usual retail supplier.
In Physical PPAs, the offtaker and the power producer share a grid that enables the physical delivery of power.
The PPA can be structured in different manners: a fixed price, a price floor, a collar…. Sleeving PPAs allow physical delivery trough a third party when the offtaker is on a different grid site.