Can you explain possible aggregation procurement methods in more detail?

With a Physical PPA, buyers purchase electricity from a utility-scale, off-site renewable energy generator to use at their facilities. For “physical delivery” to be possible, the renewable resource needs to be located in the same wholesale market as the buyers and each buyer needs to be in a retail choice state or convince their traditional utility to deliver the energy to their facilities. Local governments in states without retail choice that want to physically receive the renewable electricity will need to work with their local utility, as it is the only entity that can legally deliver electricity to their facilities. This delivery can be achieved through special contracts with their utility in which the utility takes the power produced at the project site and delivers, or sleeves, it to the buyer.

A Virtual PPA (VPPA) is a financial arrangement between a renewable energy project developer and a buyer in which a buyer (1) pays the developer the positive difference between a fixed PPA price ($/MWh) for the generated renewable electricity and a floating market price ($/MWh) when the floating price is lower, and (2) receives from the developer the positive difference between the floating price and the fixed price when the floating price is higher. The buyer also receives ownership of the project’s associated Renewable Energy Certificates (RECs).