WIEG Board Meeting Alliant Energy New Generation Plan Kim Zuhlke February 8, 2007

Nelson Dewey

Nelson Dewey Units 1 and 2

Nelson Dewey Units 1, 2 and Proposed Unit 3

Nelson Dewey #3  2003 WPL and WPS enter into joint study on technology and sites.  More than 100 sites considered.  Existing facilities and green field.  Four sites emerged as top candidates.  Early 2004, WP&L decides to focus on Columbia and Nelson Dewey.

Columbia: Our First Look  Big site – ease of construction.  Synergies with existing facilities.  Very good transportation, water and air.  Can build to an economy of scale – 600+ MW’s.  Transmission ~ $20m.  Community is receptive.

Nelson Dewey: Our First Look  Very good water and air.  Barge for transportation.  Small site.  Transmission ~ $20m.  Community and the region is enthusiastic and supportive.

 Two 100 MW units at Cassville today (Nelson Dewey #1 and #2)  Updating emissions technology has synergies with building Nelson Dewey #3  An opportunity for life extension of Units #1 and #2  Unit #3 Technology  New circulating fluidized bed (CFB) technology 300 MW’s)  Fuel flexibility (pet coke, coal, biomass)  Add rail transportation to the site  Existing rail corridor provides opportunity  New benefits to Nelson Dewey #1 and #2 Nelson Dewey: A Closer Look

The Bottom Line: The pieces align to make this the best option for customers.  River is a significant advantage in construction  Materials and labor  Great local support  Economic benefits to Cassville & Grant County  Transmission  Low cost upgrades  Enhanced river crossing  Greatly improves Wisconsin import capacity Nelson Dewey: A Closer Look

Wempletown -Paddock Base Imports Into Wisconsin (ATC) 1,913 MW 345 kV Major Pathways Eau Claire- Arpin Arrowhead-Weston Wempletown -Rockdale Zion- Pleasant Prairie Zion- Arcadia 161 kV Lore- Turkey River

Increase Import Columbia MW 56 MW Increase Eau Claire- Arpin Arrowhead-Weston Wempletown -Rockdale Wempletown -Paddock Zion- Pleasant Prairie Zion- Arcadia 345 kV Major Pathways Lore- Turkey River 161 kV

Import Increase: COL 3 vs. NED 3 2,538 MW 625 MW Increase Eau Claire- Arpin Arrowhead-Weston Wempletown -Rockdale Wempletown -Paddock Zion- Pleasant Prairie Zion- Arcadia 345 kV Major Pathways 161 kV Lore- Turkey River

Transmission Value: COL 3 vs. NED 3 Eau Claire- Arpin Arrowhead-Weston Wempletown -Rockdale Wempletown -Paddock Zion- Pleasant Prairie Zion- Arcadia 345 kV Major Pathways 161 kV Lore- Turkey River Paddock Rockdale $26.9M Annual Decrease

Major Milestones - Nelson Dewey #3

WPL = 10% RPS = 300 MW of Wind  80–100 MW’s in Wisconsin – Cedar Ridge – Ratebase Forward – PPA  200 MW’s in Iowa or Minnesota – sites under option

Project Overview  WPL to build, own & operate a 68MW - 98MW Wind Farm.  41 Wind Turbines; 1.65MW MW each  Located near Eden, WI  Rate based asset  Commercial Operation Date: 12/31/2008  Net Capacity Factor = 34%  East access to transmission  Excellent local support Project Site