Investor Presentation Manchester, New Hampshire OCTOBER 14, 2008

1. Investor Presentation Manchester, New Hampshire OCTOBER 14, 2008

2. Safe Harbor Provisions This presentation contains statements concerning NU’s expectations, plans, objectives, future financial performance and other statements that are not historical facts. These statements are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. In some cases, a listener can identify these forward-looking statements by words such as “estimate”, “expect”, “anticipate”, “intend”, “plan”, “believe”, “forecast”, “should”, “could”, and similar expressions. Forward-looking statements involve risks and uncertainties that may cause actual results or outcomes to differ materially from those included in the forward-looking statements. Factors that may cause actual results to differ materially from those included in the forward-looking statements include, but are not limited to, actions or inactions by local, state and federal regulatory bodies; competition and industry restructuring; changes in economic conditions; changes in weather patterns; changes in laws, regulations or regulatory policy; changes in levels or timing of capital expenditures; developments in legal or public policy doctrines; technological developments; changes in accounting standards and financial reporting regulations; fluctuations in the value of our remaining competitive electricity positions; actions of rating agencies; subsequent recognition, derecognition and measurement of tax positions; and other presently unknown or unforeseen factors. Other risk factors are detailed from time to time in our reports to the Securities and Exchange Commission (SEC). Any forward looking statement speaks only as of the date on which such statement is made, and we undertake no obligation to update the information contained in any forward-looking statements to reflect developments or circumstances occurring after the statement is made. This presentation references our 2008 earnings and 2008 guidance excluding a significant charge associated with a litigation settlement payment made to Consolidated Edison, Inc. Due to the nature and significance of the litigation charge, management believes that this non-GAAP presentation is more representative of our performance and provides additional and useful information to investors in analyzing historical and future performance. This presentation also references our 2008 projected EPS by segment, a non-GAAP presentation which management believes is useful to investors to evaluate the actual financial performance and contribution of NU’s business segments. These non-GAAP measures should not be considered as an alternative to NU consolidated net income and EPS determined in accordance with GAAP as an indicator of NU’s operating performance. Please refer to our reports to the SEC for further details concerning the matters described in this presentation.

3. Daily Share Price and Volumes January 2, 2008 – October 8, 2008

4. NU vs. Dow Utilities vs. Philadelphia Utility Index January 2, 2008 – October 8, 2008

5. Total Shareholder Return For Comparator Companies December 31, 2007 – September 30, 2008

6. 2008: Year of Progress For NU • Earnings growth strong; initial consolidated guidance raised on August 1 • Major southwest Connecticut transmission projects on or ahead of schedule • Long Island Cable, Middletown-Norwalk overhead section placed in service • NEEWS siting process has begun • Favorable FERC rulings on transmission incentives • Major financings completed successfully • New legislation consistent with NU’s strategic initiatives

7. First Half Earnings ’07-’08 18.1% * ’07-’08 10.9% ’07-’08 83.0% In Millions * Distribution and Generation Transmission Parent/Other Competitive Consolidated *Excludes $29.8 million after-tax charge from settlement of ConEd litigation

8. First Half Distribution, Generation Earnings In Millions

9. 2008 EPS Guidance

10. Recent Earnings Growth Has Been Driven Primarily By Successful Execution Around Major Projects COMPLETE COMPLETE Waterbury LNG Middletown-Norwalk Overhead COMPLETE Bethel-Norwalk Middletown-Norwalk Underground COMPLETE COMPLETE Glenbrook Cables Long Island Replacement Cable Northern Wood

11. Transmission Earnings Growth Has Resulted From Increased Investment Rate Base in Millions Net Income in Millions

12. How NU’s Allowed Transmission ROE is Calculated 12.44% 13.10% For projects in-service before 1/1/09 and Middletown-Norwalk For projects entering service on or after 1/1/09, each specific incentive must be requested from FERC, and the project must meet certain tests. Must address some of these considerations: (Increase of 20 basis points) • Non-routine • Ensures reliability, or reduces congestion considerably • Size • Significant financing • Multi-state • Multi-pool • Multi-company • Technologically advanced

13. System Reliability: NEEWS Projects Will Improve Transmission Capability, Help Access Renewable Power From the North File Siting Applications: Early fall 2008; municipal consultations under way Estimated Cost: $714M Greater Springfield Reliability Project SPRINGFIELD File Siting Application: End of 2008; municipal consultations under way Estimated Cost: $250M Interstate Reliability Project HARTFORD Central Connecticut Reliability Project File Siting Application: Mid-2009 Estimated Cost: $315M 345-kV Substation Generation Station 345-kV ROW 115-kV ROW *Total NEEWS costs projected to be $1.49 billion including $210 million of additional reliability-related expenditures.

14. Estimated Schedules For Major NEEWS Projects

15. Regional Energy Policy Continues To Be Shaped By State Legislation • 2005 Energy Independence Act • Distributed generation • Generation RFP • 2007 Energy Efficiency Act • Integrated resource plan • Peaking generation • Increased DSM incentives • Required decoupling • Advanced metering • Long-term bilateral contracts • RPS standards increased • 2008 RGGI regulations adopted • 2008 Green Communities Act • Adopted RGGI • Removed caps on utility energy efficiency/demand response • Long-term contracts for renewable resources • Utility-owned solar generation • Smart grid pilot • Green power offering • 2006 Mercury Reduction Bill • Merrimack Scrubber • 2007 Renewable Portfolio Standards • 2008 RGGI regulations adopted • 2008 distributed generation authorization

16. Reduced Emissions -- Merrimack Clean Air Project • Scrubber required by New Hampshire statute for mercury emissions reductions • Revised estimate of $457 million • Engineering, Procurement & Construction contract secured with Washington Group International in fall 2007 • Estimated construction start: 2009 • Estimated project completion: 2013 • Expected to reduce sulfur emissions by more than 90% • Expected to reduce mercury emissions by 85% • Investment to be recovered through PSNH generation rates per legislation • Merrimack a key source of low-cost power for PSNH • Two coal units supply about 35% of PSNH’s energy requirements • PSNH energy costs now about 25% below region’s rates • Scrubber will add estimated 0.3 cents/kWh to PSNH bills

17. Investments Required to Serve Customers Will Increase Rate Base Target Utility Capitalization Structure = 45% equity, 55% debt Projected Rate Base 2008-2012 CAGR of 12% $9,314 $8,592 $7,885 $7,339 $6,469 Projected Distribution & Generation Rate Base CAGR of 7% $5,278 Rate Base in Millions $4,475 Projected Transmission Rate Base CAGR of 22% Note: 50% CWIP approved for major southwest Connecticut investment until projects enter service. 100% CWIP in rate base assumed for NEEWS projects. Rate base estimates not yet updated for 5/13/08 NEEWS projections or for 8/1/08 Merrimack Clean Air Project update.

18. New England’s Environmental Targets 22-24 million MWh of new renewable generation needed to meet 2025 RPS requirements • Energy Efficiency • Renewable Resource Development • Low carbon imports (Canada) Keys to Solution 25-38 million MWh of new non-carbon emitting generation needed to meet 2024 RGGI requirements 71 54

19. B W B W B W B W Additional New England and Eastern Canadian Resources Will Help Meet New England’s Needs Eastern Canadian Resources New England’s Most Attractive Renewable Energy Locations Newfoundland & Labrador Exploring development of large Hydro facilities H Quebec Hydro Quebec plans to develop a portfolio of hydroelectric projects totaling 4,500 MW and integrate 4,000 MW of planned wind power by 2015 H W H W S Solar Biomass B S New Brunswick Exploring development of 1 or 2 nuclear units Hydro H N Nuclear N Wind W General Movement Of Power

20. Inject 1,200 MW Hydro-Quebec power at Webster (NH) Inject 400 MW of Northern New Hampshire renewable resources • Possible Hydro-Quebec – Webster HVDC • 1,200 MW Transfer • Proposed Northern Loop Upgrades • 115 kV or 230 kV AC • Connection for renewable resources Enhanced Northern New England Transmission Key to Meeting Regional Needs Power Injection Points Tier 1 – Reliability Upgrades Multiple Projects in Maine Tier 2 – Regional Economic Projects Tier 3 – Cross Regional Economic Projects North-South Interface • Key to allowing northern power to flow to load centers in MA/CT • Multiple configurations possible (overland AC, submarine DC, others) NEEWS project provides strong path for delivery into CT