Friday, 24 September
China building a 2000-km line to provide power to Shanghai
We have been quibbling in Australia about the cost of bringing to market the geothermal electricity produced in Cooper Basin. I understand the concern but I think we need to put it behind us now. Every day it gets more likely that thousands of megawatts can be produced in Cooper Basin from the ample geothermal resource we are blessed to have there (for example, see my blog of 8 September for recent evidence on Geodynamics progress). The transmission distance from Cooper Basin to the present Queensland grid is about 1000 kilometers, give or take a few. When the resource risk vanishes, the cost of producing that resource to the market should start becoming manageable.
In this context, it was interesting to read a story in the latest issue of the British magazine Recharge on the Chinese project to bring power to the city of Shanghai from the hydroelectric plant being built in Xiangjiaba in Western Sichuan. A 2000-kilometer transmission line will be built to transmit 6400 megawatts. This will be a UHV (Ultra High Voltage) DC line. The power transmitted on a DC line is Voltage x Current. Doubling the voltage for a given power will halve the current. Since the losses are proportional to the square of the current, the losses will go down by a factor of four. The HVDC had meant about 500-kV. The relatively new UHV means transmission voltages of 800-kV and higher. The Recharge article says that China wants to be a leader in the UHV technology. They are planning to increase the voltage to 1000-kV. The government is planning to spend RMB300bn (A$44bn) in the next two years on UHV power lines. The rationale is simple. China's energy resources are located in western China while the demand for power is in the export-oriented manufacturing plants located close to a seaport along the coastal region. Getting the power from west to east using standard transmission lines is inefficient. Over standard AC transmission lines, losses over a distance of 1000-km amount to about 10% of the transmitted power. Using a HVDC line, this would be reduced to about 2-3%. With UHV technology at 1000-kV, China should be expecting to reduce it down to 1%. It is worth watching.
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