Shanghai plans to use cold energy released during vaporization of liquefied natural gas (LNG) for power generation and other industrial uses at its Yangshan Deep-Water Port.

The project is expected to save the city about 750 million kilowatts per hour, with a minimum value of 75 million yuan (US$9.9 million), after its first phase is completed in 2009, port managers told the city's top advisory body members yesterday.

"It's a terrific project, not only because it's energy saving but most importantly, it complies with the global strategy of CO2 emission reduction and environmental protection," said Ren Xianzheng, senior port engineer.

LNG, which is minus 162 degree Celsius under normal air pressure, sends out large amounts of cold energy when it is vaporized.

Average cold energy released by each ton of LNG reaches 830 kilojoules, equaling to about 240 kilowatts per hour, according to Gu Anzhong, low-temperature studies professor at Jiao Tong University.

However, common vaporization practice nowadays is to heat the liquid gas via heat exchange with ocean water. But that simply discharges the cold energy into oceans without being used.

Earlier this year, members of the Shanghai Committee of the Chinese People's Political Consultative Conference put forward a proposal calling on the city government to make use of possible LNG energy.

Shanghai, which has signed an agreement with Malaysia for LNG imports, is building a liquefied gas receiving station with an annual capacity of six million tons at the eastern part of the Yangshan Deep-Water Port.

Once the LNG cold energy project works, low-temperature cold energy can be used for power generation without any fuel needed.

It can be used in other industrial applications such as separating air into nitrogen and oxygen, desalinating seawater and making dry ice.

(Shanghai Daily September 6, 2007)