Tariffs Recent Filings PGA Summaries Iowa Electric Workshops Supplemental Information Electric Alternative Energy Producer Cooper Tracker Factor ECA Factors - Retail ECA Factors - Wholesale Energy Efficiency Manufactured Site Clean-Up Nuclear Decommissioning Gas RTP Illinois Rider 17 Customer Generation

Supplemental Information Electric: Energy Efficiency MidAmerican Energy Company Electric Rates Energy Efficiency (ECR) Iowa - East System ($/kWh) Effective Date (Month/Year) Residential Commercial/Small General Service Industrial Large General Service Lighting September 29, 1997 $0.00347 $0.00168 $0.00168 $0.00087 April 30, 1998 $0.00378 $0.00152 $0.00152 $0.00090 February 1, 1999 $0.00378 $0.00152 $0.00152 $0.00090 June 1, 1999 $0.00339 $0.00161 $0.00161 $0.00097 August 1, 1999 $0.00260 $0.00129 $0.00129 $0.00052 June 1, 2000 $0.00253 $0.00105 $0.00105 $0.00047 June 1, 2001 $0.00227 $0.00104 $0.00104 $0.00032 September 28, 2001 $0.00092 $0.00072 $0.00072 $0.00015 June 1, 2002 $0.00133 $0.00074 $0.00074 $0.00018 June 2, 2003 $0.00123 $0.00082 $0.00082 $0.00017 June 1, 2004 $0.00183 $0.00105 $0.00105 $0.00010 June 2, 2005 $0.00170 $0.00124 $0.00124 $0.00012 June 1, 2006 $0.00231 $0.00159 $0.00159 $0.00012 June 1, 2007 $0.00212 $0.00118 $0.00118 $0.00011 June 1, 2008 $0.00172 $0.00125 $0.00125 $0.00012 Iowa - North System ($/kWh) Effective Date (Month/Year) Residential Commercial/Small General Service Industrial Large General Service Lighting January 20, 1997 $0.00090 $0.00020 $0.00110 $0.00030 April 13, 1997 $0.00090 $0.00020 $0.00070 $0.00030 September 29, 1997 $0.00366 $0.00313 $0.00355 $0.00140 April 30, 1998 $0.00407 $0.00288 $0.00323 $0.00154 February 1, 1999 $0.00317 $0.00257 $0.00257 $0.00100 June 1, 1999 $0.00298 $0.00261 $0.00261 $0.00093 August 1, 1999 $0.00298 $0.00261 $0.00261 $0.00093 June 1, 2000 $0.00294 $0.00249 $0.00249 $0.00081 June 1, 2001 $0.00287 $0.00232 $0.00232 $0.00091 September 28, 2001 $0.00092 $0.00072 $0.00072 $0.00015 June 1, 2002 $0.00133 $0.00074 $0.00074 $0.00018 June 2, 2003 $0.00123 $0.00082 $0.00082 $0.00017 June 1, 2004 $0.00183 $0.00105 $0.00105 $0.00010 June 2, 2005 $0.00170 $0.00124 $0.00124 $0.00012 June 1, 2006 $0.00231 $0.00159 $0.00159 $0.00012 June 1, 2007 $0.00212 $0.00118 $0.00118 $0.00011 June 1, 2008 $0.00172 $0.00125 $0.00125 $0.00012 Iowa - South System ($/kWh) Effective Date (Month/Year) Residential Commercial/Small General Service Industrial Large General Service Lighting September 29, 1997 $0.00466 $0.00319 $0.00321 $0.00188 April 30, 1998 $0.00517 $0.00300 $0.00299 $0.00208 January 1, 1999 $0.00382 $0.00254 $0.00254 $0.00130 June 1, 1999 $0.00318 $0.00250 $0.00250 $0.00108 June 1, 2000 $0.00341 $0.00238 $0.00238 $0.00118 June 1, 2001 $0.00293 $0.00206 $0.00206 $0.00107 September 28, 2001 $0.00092 $0.00072 $0.00072 $0.00015 June 1, 2002 $0.00133 $0.00074 $0.00074 $0.00018 June 2, 2003 $0.00123 $0.00082 $0.00082 $0.00017 June 1, 2004 $0.00183 $0.00105 $0.00105 $0.00010 June 2, 2005 $0.00170 $0.00124 $0.00124 $0.00012 June 1, 2006 $0.00231 $0.00159 $0.00159 $0.00012 June 1, 2007 $0.00212 $0.00118 $0.00118 $0.00011 June 1, 2008 $0.00172 $0.00125 $0.00125 $0.00012 Illinois ($/kWh) Effective Date (Month/Year) Residential Commercial/Small General Service Industrial Large General Service Lighting June 1, 2008 $0.00137 $0.00121 $0.00121 $0.00000 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.