In the late 1880s Thomas Edison and George Westinghouse waged “the War of Currents”, each battling to demonstrate the merits and advantages of Edison’s Direct Current distribution system and Westinghouse’s preferred Alternating Current distribution system.
The quite bizarre antics that followed are the stuff of history now (and some pretty hilarious if dis-tasteful, short films) but Edison would be smiling today if he was still around, despite the proliferation of AC distribution systems.
Why? Because DC distribution is starting to find a new place in the world.
I’ve got to hand it to China, they don’t do anything by halves it seems, and announced on Sunday that construction had started on the worlds largest Ultra High Voltage Direct Current (UHVDC) power line. Oh, and they started on a second 750kV HVDC one on the same day, just for good measure.
Operating at 800 kV, the system will connect Hami prefecture in eastern Xinjiang with the central city of Zhengzhou, along a 2,210-km-long, $US$3.7B power line and is designed to handle 8million kW of power.
Up-size that, Mr Westinghouse!
What’s arguably most interesting are the drivers behind the selection and use of UHVDC . The State Grid Corporation of China claimed: ”We can reduce 317,000 tonnes of sulphur dioxide and 267,000 tonnes of nitrogen oxide which would otherwise be produced during the transportation,” a signal that energy losses are finally being recognised as the low hanging fruit, at least in one part of the world.
By comparison, a 2011 MIT report on the US issues of grid design highlighted just where Australia sits in this regard; ranked the third worst of surveyed countries in energy losses in the following graph (China ranked 7th) . In Australia’s case this is equivalent to losses of 6.6TWh of energy in 2009-2010 and roughly the same as the entire annual generation of all of Australia’s Hydro generation in the same year; or approximately 5GW of PV.
Secondly, it is the need to efficiently connect and distribute the increasingly prolific solar and wind generation plants in the country’s east, to the areas of growing demand. China is confident that time and technology has solved the issue of DC power transformation it seems, (the bug bear of Edison’s DC dream) and renewables fit the bill very nicely.
This is truly ground breaking stuff; it will be fascinating to see how the project pans out and to read the implications for energy distribution at a scale we have never seen before.
Perhaps using the sun to make energy and exporting electrons to our neighbours is closer to reality than we think?
FOOTNOTE: A kind reader suggested that in this article I had implied that UHVDC was new and highly uncommon, which I did not intend to do. Although it is far less common than AC, there are a good number of projects around the world, listed here, and ABB have a list of Google map references here.
I’d also like to highlight that Australia has several UHVDC connections:
-- Basslink between Tasmania and the mainland
-- Murraylink connection between Victoria and South Australia
-- Terranora inter connector between NSW and Queensland
-- Broken Hill back to back network