A CPA laser system for high pulse energy at high average power has been developed. The system is based on Yb:YAG thin-disk technology. It provides two laser beams with more than 500 mJ pulse energy each at 100 Hz repetition rate and 2 ps pulse duration. The system consists of a common oscillator, a grating stretcher and compressor and two identical amplifier chains that are both equipped with a regenerative amplifier and a ring amplifier. The compressor supports an individual alignment of the dispersion for the two laser channels.