An advantage of gas turbines over other types of prime movers, is that gas turbines:

• A. require little to no cooling water
• B. have high thermal efficiencies
• C. are reversible
• D. need very little lubrication

Answer: (A)

Gas turbines run on the Brayton cycle using air as the working fluid, so the main cycle doesn’t require boiler or condenser cooling like a steam plant does. That means far less cooling water is needed to operate the turbine itself. The main cooling concerns for a gas turbine are limited to auxiliary systems (like lubrication and cooling of certain components), not for condensing steam or feeding a boiler.

Other options aren’t universal advantages: simply having high efficiency isn’t guaranteed for a gas turbine in basic setups (simple-cycle turbines are typically less efficient than steam plants; higher efficiency often comes from combining with a heat recovery stage). Reversibility isn’t a feature of gas turbines, and they don’t inherently need only a small amount of lubrication—lubrication systems are still required.