Due to the publication of fuel prices from July 2012 to September 2012 (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 2012 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 Rates for December 2012 (PDF 21.6KB)
Attachment 1: Calculation of Fuel Cost Adjusted Unit Price and Electricity Rates for December 2012 (PDF 48.7KB)
Attachment 2: Calculating Electricity Rate for each contract ampere in December 2012 (PDF 17.1KB)