Tariffs Recent Filings PGA Summaries Iowa Electric Workshops Supplemental Information Electric Gas Btu Factors Cost of Gas Distribution Charges Energy Efficiency Exit Fees Firm Supply Standby Service Gas Retention Factors Imbalance Cashout Rates Imbalance Charges Interruptible Commodity Prices ISR Margin Manufactured Site Clean-Up RTP Illinois Rider 17 Customer Generation

Supplemental Information Gas: Energy Efficiency MidAmerican Energy Company Gas Transportation Rates Energy Efficiency (ECR) Iowa - West System - Rider 3 Effective Date (Month/Year) Firm ($/Therm) Interruptible* ($/Therm) Small Volume Medium Volume Large Volume Seasonal General Service Small Volume Large Volume Residential Non-Residential January 1995 $0.00373 $0.00373 $0.00238 $0.00232 $0.00124 $0.00124 April 24, 1996 $0.00403 $0.00403 $0.00226 $0.00214 $0.00097 $0.00152 April 10, 1997 $0.00363 $0.00363 $0.00163 $(0.00067) $0.00118 $0.00180 Sept. 29, 1997 $0.02545 $0.00992 $0.00798 $0.00557 $0.00689 $0.00720 April 30, 1998 $0.01918 $0.00717 $0.00521 $0.00386 $0.00486 $0.00524 Feb. 1, 1999 $0.01607 $0.00406 $0.00406 $0.00406 $0.00406 $0.00406 June 1, 1999 $0.02305 $0.00585 $0.00585 $0.00585 $0.00585 $0.00585 June 1, 2000 $0.02491 $0.00656 $0.00656 $0.00656 $0.00656 $0.00656 June 1, 2001 $0.02417 $0.00691 $0.00691 $0.00691 $0.00691 $0.00691 Jan. 1, 2002 $0.01030 $0.00102 $0.00102 $0.00102 $0.00102 $0.00102 June 1, 2002 $0.02985 $0.00321 $0.00321 $0.00321 $0.00321 $0.00321 Nov. 25, 2002 $0.02985 $0.00321 $0.00321 $0.00321 $0.00321 $0.00321 $0.00321 June 2, 2003 $0.02029 $0.00767 $0.00767 $0.00767 $0.00767 $0.00767 $0.00767 June 1, 2004 $0.02659 $0.00780 $0.00780 $0.00780 $0.00780 $0.00780 $0.00780 Nov. 1, 2004* $0.02659 $0.00780 $0.00780 $0.00780 $0.00780 $0.00780 June 2, 2005 $0.03426 $0.00770 $0.00770 $0.00770 $0.00770 $0.00770 June 1, 2006 $0.05741 $0.01288 $0.01288 $0.01288 $0.01288 $0.01288 June 1, 2007 $0.03844 $0.01185 $0.01185 $0.01185 $0.01185 $0.01185 June 1, 2008 $0.02466 $0.01586 $0.01586 $0.01586 $0.01586 $0.01586 The customers' ECR rate is determined by the rate the customer moved from to transport. * The small and large volume interruptible rates were eliminated on November 1, 2004, and    replaced with an interruptible rate for customers that cannot currently be provided firm    service due to operational constraints on interstate pipeline or interstate pipeline facilities    directly serving MidAmerican's distribution system.  Iowa - East System - Rider 8 Effective Date (Month/Year) ($/Therm) Residential Rate 60 Non-Residential Rates 70, 87 & 90 January 1996 $0.01510 $0.00390 Oct. 29, 1996 $0.01560 $0.00500 Sept. 29, 1997 $0.04813 $0.01097 April 30, 1998 $0.03732 $0.00786 June 1, 1999 $0.07301 $0.00898 Aug. 1, 1999 $0.03218 $0.00456 June 1, 2000 $0.03658 $0.00492 June 1, 2001 $0.02812 $0.00479 Jan. 1, 2002 $0.01030 $0.00102 June 1, 2002 $0.02985 $0.00321 June 2, 2003 $0.02029 $0.00767 June 1, 2004 $0.02659 $0.00780 June 2, 2005 $0.03426 $0.00770 June 1, 2006 $0.05741 $0.01288 June 1, 2007 $0.03844 $0.01185 June 1, 2008 $0.02466 $0.01586 Illinois - Rider 10 Effective Date (Month/Year) ($/Therm) Residential Rate 60 Non-Residential Rates 70, 80, 87 & 85 June 1, 2008 $0.02774 $0.00627 For Your Home | For Your Business | Safety | Rates | Energy Efficiency | Economic Development | Environmental Efforts About Us | Careers | News Room | Storm Center | Wind Energy | Contact | Streetlight Repair Request | System Outage Watch | Energy Choice | For Contractors | For Landlords | ©2008 MidAmerican Energy Holdings Company. All rights reserved.