Finally. We are starting to get the high-voltage direct current (HVDC) transmission system we need to shift massive amounts of wind power from all those empty states where all the wind is, to all the full ones where all the people are. Green Car Congress reports that Siemens is starting to build the much-needed grid that doing that will take.
The world has mostly used alternating current (AC) for above-ground cross-country transmission ever since the dawn of the electrical age, only because Thomas Edison – who advocated for DC – was not able to out-argue Nicola Tesla, who favored AC. But AC has high losses over distances, and would lose even more in cables underground or under water, which is where we need them, for example for off-shore wind.
DC, by contrast loses up to 40% less in transmission, so using DC transmission, wind farms can be spread over large geographic areas to produce a more even supply of power (as it’s always blowing somewhere). Since distance transmission is key to desert solar and lonely-state wind, DC is better for renewables.
In 2010, Siemens had $41.6 billion in sales of its high voltage DC systems.
Beginning in 2013, its new HVDC PLUS technology will transmit 2,000 MW as direct current underground connecting the Spanish grid with that of France.
A 1,000-MW HVDC cable was recently put into operation along a 260-kilometer underwater line between the Netherlands and the UK.
Desertec (Half a Trillion Dollars to Build Huge Desertec Plan) the ambitious plan to ship power from the deserts of North Africa and the Middle East to Europe will definitely need HVDC.
But Siemens is not only building renewable-friendly transmission in the EU. The company has built HVDC here too, and right in my neck of the woods, the San Francisco Bay Area: “Transbay, likewise erected by Siemens Energy, transmits 400 MW of electrical output at a transmission voltage of ±200 kV with low losses and high energy efficiency via an 88-kilometer marine cable link from Pittsburg, California, to San Francisco.”
There are wind farms in Pittsburg, and people in San Francisco.
- UK-Netherlands power cable begins transmission (guardian.co.uk)
- Why Japan’s Fragmented Grid Can’t Cope (spectrum.ieee.org)