Due to the publication of fuel prices from July 2010 to September 2010 
(trade statistics prices for crude oil, liquefied natural gas (LNG) and 
coal published by Ministry of Finance Japan), a fuel cost adjusted unit 
price for December 2010 is fixed as per enclosure. 

Fuel cost adjustment system: 
"Fuel cost adjustment system" is a system designed to automatically adjust 
monthly electricity fees based on fluctuations in (actual recorded) fuel 
prices for crude oil, LNG and coal. 

 http://www.tepco.co.jp/en/customer/guide/fuelcost-e.html

Appendix: Fuel Cost Adjustment in Electricity Fees for December 2010
                                                        (PDF 18.1KB)