A mobile clamp attaches to a steam pipe and converts thermal energy to electric energy. One side of the clamp is generally open to allow for insertion of the steam pipe. During insertion, opposing blocks on either side of the clamp are deflected apart. Each block includes a curved channel extending along the length of the block to receive the steam pipe. Fitting the steam pipe within the channel aligns the clamp on the steam pipe. A biasing force applied to the blocks to return each block to an initial position provides a clamping force on the steam pipe to positively retain the clamp on the pipe. Thermoelectric devices are mounted on the blocks to convert the thermal energy into electrical energy. Thermal energy is transmitted from the steam, through the steam pipe, through the block pressed against the steam pipe, and to the thermoelectric device.