Complex sentence: Studies for a competing project called CLIC the Compact Linear Collider are also underway, which would operate at higher energies (3 to 5 TeV) in a shorter-length machine than the ILC.
Split into simpler sentences: Studies for a competing project called CLIC the Compact Linear Collider are also underway. It potentially has significantly higher energies (3 to 5 TeV) in a shorter-length machine than the ILC.