Lehman Brothers CEO Energy/Power Conference September 6, 2007

1. Lehman Brothers CEO Energy/Power Conference September 6, 2007 Energy / Growth / Leadership

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. 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.

3. A Successful First 8 Months of 2007 In Meeting Our Short-Term And Long-Term Goals • Short Term • 23% increase in Y-T-D regulated earnings, consistent with guidance • Rate settlements implemented at 3 of 4 utilities • LNG facility placed in service on budget, on schedule • Transmission projects on budget, on or ahead of schedule • CL&P rate case filed • Competitive business divestitures largely complete • Longer Term • Rate base growth expectations intact • Design of next generation of transmission projects advancing • Connecticut legislation offers new opportunities for customers, utilities

4. 2007 Results 14.2% 45.7% In Millions Distribution and Regulated Generation Transmission Competitive Total Parent/Other

5. Distribution/Regulated Generation Results 7.4% 34.4% In Millions 18.8% 62.1% CL&P PSNH WMECO Yankee Gas

6. Transmission Earnings Tracking Rate Base Investment Six Months Revenues in Millions Net Income in Millions

7. EPS Guidance Dist./Gen: $0.80-$0.90 Trans.: $0.50-$0.60 Competitive: modestly profitable Parent: $0.00-$0.05

8. Rate Settlements in Place for 3 of 4 Distribution Companies

9. CL&P Distribution Rate Case Case Timeline • Two annual increases requested • $189 million 1/1/08 • $22 million 1/1/09 • 11% requested ROE • Expected 2007 ROE 7% – 7.5% • Projected average common equity in 2008 CL&P distribution company = $1 billion • Capitalization 45% equity/55% debt (rating agency methodology) Consumer Counsel Testimony Due Case Filed Public Hearings Evidentiary Hearings Decision Scheduled 10/9-11/9/07 7/30/07 10/1-10/4/07 12/27/07 9/21/07

10. Need to address aging infrastructure as equipment costs have risen $290 million in distribution cap ex annually Pole top transformer costs are up 62% since 2003 Overhead wire cost up 80% Underground cable costs up 53% Substation transformers up 105% Tree trimming costs up 80% Reliability And Increased Costs Key Topic in CL&P Case

11. Four Major Southwest Connecticut Projects – A $1.65 Billion Investment More Than Half Complete COMPLETE Bethel-Norwalk 345-kV underground & overhead $350 Million • 21 miles 345-kV (56% underground) • 10 miles 115-kV (100% underground) • Completed October 2006 at a cost of $340 million 50% of CT Load Middletown-Norwalk 345-kV underground & overhead $1,047 Million (NU share) Glenbrook Cables 115-kV underground $183 Million Long Island Cable 138-kV cross-sound $72 Million (NU share) • 69 miles 345-kV (35% underground) • 57 miles 115-kV (1% underground) • Joint project with United Illuminating • Projected in-service date: 2009 • 38% complete at 6/30/07 • 9 miles 115-kV underground • Projected in-service date: 2008 • Under contract – construction under way, 36% complete at 6/30/07 • 11 miles 138-kV submarine cable • Joint project with LIPA • Projected in-service date: 2008 • 41% complete at 6/30/07

12. Bethel-Norwalk Line Expected To Help Reduce Connecticut Congestion Costs By $100 Million in 2007 2006 Avg. = $103/MWh 2007 Avg. = $11/MWh 2006 Average 2007 Average

13. 2007-2011 Projected Capital Expenditures $1,265* $1,126* $908* $880* $874* $779* In Millions 2006 Actual 2007 2008 2009 2010 2011 Distribution Capex Transmission Capex *Excludes approximately $18 million per year at corporate service companies

14. The Next Five Years: Transmission Capital Expenditures Historic Forecast $1,062 Million Up To $2.5 Billion $1.1 Billion of major SW CT projects in 2007-2011 forecast period; $1.65 billion in total In Millions NEEWS, Springfield projects estimated at $710 million during the 2007-2011 forecast period

15. Springfield 115-kV Projects

16. The NEEWS Family of Projects Contains Four Main Elements Springfield-115 Projects Greater Springfield Reliability Project SPRINGFIELD Interstate Reliability Project HARTFORD Central Connecticut Reliability Project 345-kV Substation Generation Station 345-kV ROW 115-kV ROW

17. Projected Transmission Year-End Rate Base Transmission Rate Base 2006-2011 CAGR of 23% $3.0B $2.8B $2.6B $1.9B In Millions $1.4B $1.1B * * * *Reflects FERC approved 50% CWIP for southwest CT projects

18. Connecticut Legislation • 2007: “An Act Concerning Electricity and Energy Efficiency” was signed by Governor Rell June 4 • Generation provisions • Requires distribution companies to file plans in January 2008 to build cost of service peaking generation • Requires DPUC to allow distribution companies to buy generation put up for sale, if in the public interest • For future identified generation needs, distribution companies can submit proposals to compete with IPP developers and will serve as builders of last resort • Ratemaking • Requires DPUC to decouple electric and natural gas distribution revenues from sales volumes • Planning and incentives • Institutes long-term integrated energy planning for state through utility filings with Energy Advisory Board and DPUC • Maintains one-time utility incentives created in 2005 “Energy Independence Act” • $200/kw to host utility for customer-side generation • $25/kw to utilities for traditional generation

19. PSNH Opportunities • Recently • Successful conversion of 50-MW Schiller unit from coal to wood in December 2006 • $74 million cost • Enhances fuel diversity, reduces sulfur, NOx, mercury emissions • Under Way • Legislation to install wet scrubber at Merrimack approved in spring 2006 • Projected completion: Mid-2013 • Estimated cost: $250 million • Future Possibilities • Connect northern New Hampshire renewables to power grid • Additional biomass opportunities Schiller Merrimack

20. Ability To Finance Growth 6/30/07 Strong balance sheet Strong cash and liquidity position • Approximately $400 million of NU parent cash • Nearly $1 billion unused bank, accounts receivable lines Strong access to capital • Solid credit ratings at parent, subsidiaries • Successful debt financings • Minimal equity requirements

21. NU’s Transformation Producing Solid Results, Prospects • Financial performance consistent with projections • Transmission business is growing rapidly to meet customer needs • Distribution results improving as reasonable rate case outcomes are implemented • Additional infrastructure needs being identified • Financial flexibility to finance the growth • Attractive total shareholder return profile