Long Range transmission of power by cables. Practical?

[Sarpedon]

I used to think that resistance in power lines made it uneconomical to send large masses of electricity to a consumer distant from the generator. But now I am reading about a plan to take solar power from Tunisia, and send it to Britain, via Italy and France.

Has there been some sort of breakthrough? Or is it more like the Tunisian Electricity is going to Rome, the Roman powerplants are powering Turin, Turin powers Marseille, Marseille powers Paris, and Paris powers London? Just shifting the loads, in other words. A triumph of management, not technology.

http://www.bbc.com/news/science-environment-29551063

 

[bilby]

I used to think that resistance in power lines made it uneconomical to send large masses of electricity to a consumer distant from the generator. But now I am reading about a plan to take solar power from Tunisia, and send it to Britain, via Italy and France.

Has there been some sort of breakthrough? Or is it more like the Tunisian Electricity is going to Rome, the Roman powerplants are powering Turin, Turin powers Marseille, Marseille powers Paris, and Paris powers London? Just shifting the loads, in other words. A triumph of management, not technology.

http://www.bbc.com/news/science-environment-29551063

High Voltage Direct Current lines can be a lot cheaper than traditional High Voltage Alternating Current lines, over very long distances. The cost of the transmission losses increases with the length of the link, while the cost of the converters required at one or both ends of the link are fairly static.

There hasn't so much been one breakthrough as lots of little ones - the cost of HVDC converters has fallen, and the practical voltages that can be employed have risen*, due to a variety of advances in materials and control systems.









*Higher voltages mean more power for a given current, reducing losses to heat; but need better insulators to reduce losses to ground.

 

[steve_bnk]

Transmitting mains power 1500 miles or so is not unusual.

On our west coast power from the Bonneville Dam on the Columbia River goes to California. In the USA depending on the prices of the day, availability, and demand power can come from anywhere.

High power-voltage DC is routine these days. The picture looks more like a heliostat than a solar voltaic.

The main problem in the region would be physical threats to the system and transmission lines which the article discounts.

http://en.wikipedia.org/wiki/High-voltage_direct_current#Disadvantages

For the same RMS AC voltage and DC line voltages the cable resistive losses are the same. The transmission efficiency gain would be eliminating AC capacitive line losses.