How much to pump the water back (either fresh water from the bottom lock or replace the whole flight with salt)? 200,000 tons of water per ship, 26 metres abov

How much to pump the water back (either fresh water from the bottom lock or replace the whole flight with salt)? 200,000 tons of water per ship, 26 metres above sea level, about 200MWh, so call it 500MWh. With 20,000 ships a year that's 50 a day, or 25GWh. A 2GW solar plant A large solar farm would can reach that capacity (you don't need to run the pumps 24/7, so Solar is perfect)