Les approvisionnements d’électricité en Chine | The Economist
▻http://www.economist.com/news/science-and-technology/21714325-transmitting-power-over-thousands-kilometres-requires-new-electricity?fsrc=scn/tw_ec/electricity_now_flows_across_continents_courtesy_of_direct_current
Transmitting power over thousands of kilometres requires a new electricity infrastructure.
THE winds of the Oklahoma panhandle have a bad reputation. In the 1930s they whipped its over-tilled topsoil up into the billowing black blizzards of the Dust Bowl. The winds drove people, Steinbeck’s dispossessed, away from their livelihoods and west, to California. Today, the panhandle’s steady winds are a force for creation, not destruction. Wind turbines can generate electricity from them at rock-bottom prices. Unfortunately, the local electrical grid does not serve enough people to match this potential supply. The towns and cities which could use it are far away.
So Oklahoma’s wind electricity is to be exported. Later this year, lawsuits permitting, work will begin on a special cable, 1,100km (700 miles) long, between the panhandle and the western tip of Tennessee. There, it will connect with the Tennessee Valley Authority and its 9m electricity customers. The Plains and Eastern Line, as it is to be known, will carry 4,000MW. That is almost enough electricity to power Greater London. It will do so using direct current (DC), rather than the alternating current (AC) that electricity grids usually employ. And it will run at a higher voltage than such grids use—600,000 volts, rather than 400,000.
