For >= 2048 eV/t links a microwave power TX/RX unit that operates on (dead on) line of site only would be wonderful. The highly focused beam could be used as both a power transmission method and for building a wall of death.
Likely it would cost an HV-TF, a diamond, and an advanced circuit or two to construct; sending and receiving units would have (slightly) different recipes. The device would constantly send power (disabled via redstone signal), and the receiver would be optional. Possibly some kind of reflector could be added to divert the signal without regenerating it.