南海波浪能
Harnessing
the ocean: China’s military looks to wave farms to power radar on remote islands
as South China Sea disputes simmer
Country
has been testing one of the largest power-generating machines of its kind in the
world with maximum capacity in excess of 200 kilowatts.
30
November, 2015
China
plans to build electricity-generating wave farms near remote islands in the
South China Sea, where it is engaged in territorial disputes with several of its
neighbours, to mitigate the threat of a power blackout hitting its military
radars there, according to researchers involved in the project.
These
giant floating power stations are expected to significantly strengthen the
nation’s foothold in the disputed waters.
A
full-scale unit, about half the size of a soccer field, was deployed for a test
run in waters off the Wanshan archipelago near the city of Zhuhai in Guangdong
province earlier this month, said the researchers at the Chinese Academy of
Sciences’ Guangzhou Institute of energy Conversion.
Using
cutting-edge mechanical designs, the generator will efficiently transform the
constant movement of the sea water into electricity and stay in operation on
windless days and also in the face of a super-typhoon, they said.
China’s
breakneck rush to build civilian and military facilities in these seas has
stretched its power supply chain in recent years. One of the biggest headaches
has proven to be keeping the country’s larger-than-ever radar network in
constant operation.
“Military
radars are power-hungry beasts that must be fed all the time,” said one
researcher, who declined to be named due to the sensitivity of the
issue.
“Sending
fossil fuels to remote islands is costly and time-consuming. The shipping can
also be affected easily by bad weather or unfriendly neighbours,” the researcher
added.
More
power is needed for the radar to cast its net wider. When operating at full
power to get a bead on a distant fighter jet or unknown object, an early warning
system may require thousands of kilowatts of energy - tantamount to the total
demand of 1,000 average households in the United States.
Conventional
renewable energy sources are not suitable for small islands, the researchers
said.
Most
lack sufficient land area for the installation of solar power panels, which at
any rate are usually quickly compromised by faecal matter from birds, the team
said.
Moreover,
wind turbines cannot generate a stable enough energy supply, and their
performance is also severely affected by the weather.
The
unit that was tested is among the largest power-generating machines of its kind
in the world, capable of churning out in excess of 200 kilowatts.
Similar
power buoys deployed in the US and Australia have shown peak power outputs of
around 150kw. The largest single wave energy convertor to date was a prototype
deployed at a wave farm in Portugal, which recorded 750kw.
But
the new Chinese generator can survive even the most extreme weather conditions,
the researchers said.
In
the event of a typhoon, it would automatically partially submerge, leaving only
a small area on the surface to avoid damage caused by strong winds.
The
unit is not anchored to the ocean bed, which allows it to move freely amid
strong waves.
The
design, which resembles half a submarine, has performed well. A smaller 10-kw
prototype even survived Typhoon Haiyan in the South China Sea two years ago. The
typhoon claimed over 6,000 lives in the Philippines.
The
machine continued generating power during the typhoon even after most of it was
submerged, the researchers said.
The
wave farms that are planned have a flexible capacity with room to grow as more
converters can be added later to meet demand.
The
electricity will be channelled to nearby islands using underwater
cables.
The
enormous power requirements of military radar facilities means they cannot
operate on a full-time basis with a large and stable energy supply, so using sea
waves to provide power is a logical solution, said Li Ming. The professor of
radar technology works at the National Lab of Radar Signal Processing in Xidian
University, Xi’an in northwestern Shaanxi province.
But
Li doubted whether a wave farm would fully satisfy demand.
“A
warning radar consumes far more than 200kw of power,” he said.
Another
problem is the cost of such an operation. A wave farm needs many
power-generating units to form a grid for maximum output.
But
those who field-tested the single unit recently said it cost nearly 20 million
yuan (US$3.13 million) to design and build.
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