Northern Natural Gas Company Western Canadian Basin Montana

Northern Natural Gas Company Western Canadian Basin Montana Minnesota North 1. 3 Dakota Bc Michigan f/d Wyoming Rocky Mountain Basins Extensive Access to Major Utilities and Industrials in the Upper Midwest Flexible Operations – Interconnections with 4 Major Pipelines in Market Area – Storage Capacity of 56 Bcf – Bi-Directional Flow Capabilities Wisconsin South Dakota . 3 Bcf/d Nebraska Illinois Kansas Hugoton Basin Market Area Iowa Supply Area Missouri Oklahoma 1. 9 Bc f/d Enron Assets Over 85% of Revenues Comprised of Demand Charges Anadarko Basin New Mexico Permian Basin Storage Northern Natural Pipeline Market Area Volumes (BBtu/d) Full Year Texas 2, 173 Major Pipeline Interconnects Great Lakes Viking Northern Border Trailblazer 2000 Average Flows Draft 01/11/01 1999 December 3, 483 2, 775 No New Rate Case Until November 2003 2, 202 2000 1999 95% of Market Area Capacity Contracted Through 2003 2000

Northern Natural Gas Company Market Area Initiatives Completed Agreement Minnesota Great River Energy Peaking Plant May 2001 In-Service 463 MW Enron Solution No-Notice, Flexible Supply Average Service of 50 MMcf/d Peak Use 2. 4 Times Average 3 -Year Term Enron Benefits Adds Demand During Off-Peak, Summer Season Establishes Long-Term Customer Wisconsin 250 MW Customer Profile Gas-Fired Merchant Plant 120 MMcf/d Peak Requirement Situated Close to Main Pipeline Michigan 275 MW South Dakota 445 MW 2001 200 MW 2002 300 MW Nebraska 2003 372 MW Storage Iowa 150 MW Kansas 500 MW Illinois Missouri Supply Area 3, 000 MW of Gas-Fired Power Plants Under Development in Close Proximity to Northern’s System Innovative Tariffs in Place to Provide Flexible Gas Supply-Related Services Draft 01/11/01 Market Area