Who actually buys my power?
Utilities, businesses on your local grid, and neighbours who'd rather pay you than the utility. They bid; you win.
Three kinds of buyer show up on the board.
Utilities
The same company that pays you $0.07 today will bid for your power when it needs it, which is most afternoons. They are the largest buyers by volume and usually bid close to the market price.
Businesses
Bakeries, data centres, transit depots, cold stores. Anyone with a big daytime load on your local grid would rather buy local surplus than pay peak rates. They tend to bid a little above the utility because it is still cheaper for them.
Neighbours
Households on your street who do not have panels can buy directly from you. They bid the highest per kWh, because they are comparing against retail prices, but they buy the least.
Whoever bids highest wins the block. You never pick a buyer, and every sale is logged with who bought it.