Net Gas Metering

Net gas metering is a concept where the total gas cost of a transaction is calculated based on the net change in state, rather than just the operations performed. This allows for the refunding of gas when an operation effectively cancels out a previous one, such as clearing a storage slot.

It provides a more accurate reflection of the resources consumed by the transaction and encourages developers to perform state-cleaning operations. By accounting for the net effect, the protocol incentivizes actions that reduce the burden on the network.

This is a key part of how gas refunds are handled within the EVM. It ensures that the cost of state changes is proportional to the actual impact on the blockchain.