Please forgive me, as I'm a complete layman. For decades, various bridges and tunnels have been proposed for the Long Island Sound, which is ~21 miles (33.8 km) wide. Residents worry about the unsightliness of a bridge and the tall exhaust towers that would be needed for a tunnel. You could also build islands and alternate like the Chesapeake Bay Bridge-Tunnel. Are hyperloops energy efficient enough to be completely submerged/beneath bedrock without the need for exhaust towers or evidence of their presence and hidden from sight?