TRON energy

Tron meters two resources instead of charging a simple fee: bandwidth for a transaction's size, and energy for running contract code. A USDT (TRC-20) transfer runs the token contract, so it needs energy: tens of thousands of units for a typical transfer, and noticeably more when the recipient has never held the token. Exact amounts depend on network parameters, which change.

Three ways to get energy:

1. Burn TRX. With no energy, the network burns the sender's TRX to cover it. Always available, usually the most expensive.
2. Stake TRX. Staking gives an account a daily energy allowance. It locks up capital and suits steady volume.
3. Rent it. Rental services delegate energy to your address for a fee, often for much less than burning.

Each transaction also sets a fee limit, the most TRX it may burn.

On Valtu

Before each TRC-20 payout or sweep, Valtu estimates the energy it needs. If you've connected an energy provider key in the gas station and renting is cheaper, it rents energy for that transfer. Otherwise your gas wallet tops the sending address up with the TRX it will burn. Either way the transfer carries a fee limit. See Tron on Valtu.