They use hot air warmed by gas burners.

Since we're using electricity here, and this was mentioned in the study linked elsewhere, they used ceramic heaters.

I can buy all of it, near perfect heating, but 2% for their forced air circulation combined with turbine and generation losses? Seems too good to be true.

Chatgpt (because we're all lazy) :

Total Thermal to Electrical Efficiency

The overall thermal-to-electrical efficiency of a power plant, often referred to as plant efficiency, is the product of the steam turbine efficiency and the generator efficiency. Typical overall efficiencies for fossil-fuel-based steam turbine power plants (e.g., coal, natural gas) range from 33% to 40%.

In more advanced configurations like combined cycle power plants, which recover waste heat from the steam turbine exhaust to generate additional electricity, efficiencies can reach 50% to 60%.

Calculation Example:

If the steam turbine has an efficiency of 40%, and the generator has an efficiency of 98%, the total thermal-to-electrical efficiency would be:

\text{Total Efficiency} = 0.40 \times 0.98 = 0.392 \text{ or } 39.2%

So, for every 100 units of thermal energy input, 39.2 units are converted into electrical energy.

And that's if you're just heating the water before it hits the turbine, including the air circulation and basic entropy (there's a limit to how much you can pull out via heat differential), it seems like it should go down from there.