Scientists have invented a new environmentally-friendly "electricity bank" that enables people to collect and store surplus energy at night to curb electricity consumption peaks and power shortages.

The "bank" is a sodium-sulfur battery jointly produced by the Shanghai Institute of Ceramics, the Chinese Academy of Sciences and local electric power supplier.

It is different from ordinary batteries as it has sodium for its negative pole and sulfur at the positive pole.

It has a lower manufacturing cost and a service life of 10 years. Researchers said the strength of the single sodium-sulfur battery was 125 watts.

It could be charged at night, when power demand was small, to save surplus electricity and could discharge that stored power during day time peaks.

Joining 400 such batteries together could make up a 50-kilowatt module, equal to the driving force of eight to nine mopeds, according to Wen Zhaoyin, researcher with the institute's energy material center.

He added the battery modules could be joined to become larger power suppliers for enterprises and families.

(Shanghai Daily April 1, 2008)