Well, yes and no. Power stations using local water are also made to be as efficient as possible so efficiency of the power station is probably a red herring here. It is the supply of water for cooling that is the issue. I think that the major difference is going to be the machinery installed. The Oman power station mentioned by James uses diesel engines (i.e. internal combustion engines running on the diesel cycle - not necessarily engines burning diesel fuel) while the coal burning power stations all operate with steam turbines (on the basis that you can't burn lumps of coal in a diesel cylinder...). The efficiency of diesel engines is slightly better than steam turbines, but when the steam turbine power station provides local heating it can have the edge.

The big difference between these is the cooling water for a diesel engine should be entering the engine cooling system at around 60-65 degrees Celsius, while for a steam turbine condenser you are aiming to get about a 90% vacuum and want the cooling water to be entering at 30 degrees Celsius or less. As we in Britain switch from coal to gas you will likely see a switch from steam turbines to dual fuel diesel engines and a similar switch away from cooling towers.

Alasdair

(Please note the above figures are quoted from memory so if anyone wishes to challenge or correct them, please feel free)

Well, yes and no. Power stations using local water are also made to be as efficient as possible so efficiency of the power station is probably a red herring here. It is the supply of water for cooling that is the issue. I think that the major difference is going to be the machinery installed. The Oman power station mentioned by James uses diesel engines (i.e. internal combustion engines running on the diesel cycle - not necessarily engines burning diesel fuel) while the coal burning power stations all operate with steam turbines (on the basis that you can't burn lumps of coal in a diesel cylinder...). The efficiency of diesel engines is slightly better than steam turbines, but when the steam turbine power station provides local heating it can have the edge.

The big difference between these is the cooling water for a diesel engine should be entering the engine cooling system at around 60-65 degrees Celsius, while for a steam turbine condenser you are aiming to get about a 90% vacuum and want the cooling water to be entering at 30 degrees Celsius or less. As we in Britain switch from coal to gas you will likely see a switch from steam turbines to dual fuel diesel engines and a similar switch away from cooling towers.

Alasdair

(Please note the above figures are quoted from memory so if anyone wishes to challenge or correct them, please feel free)