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Bank of America Merrill Lynch

September 20,

2011

David McHaleExecutive Vice President and CFO

2011 Power and Gas Leaders Conference

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This presentation contains statements concerning NU’s expectations, beliefs, plans, objectives, goals, strategies, assumptions of future events, future financial performance or growth 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 or reader can identify these forward-looking statements through the use of words or phrases such as “estimate”, “expect”, “anticipate”, “intend”, “plan”, “project”, “believe”, “forecast”, “should”, “could”, and other similar expressions. Forward-looking statements are based on the current expectations, estimates, assumptions or projections of management and are not guarantees of future performance. These expectations, estimates, assumptions or projections may vary materially from actual results. Accordingly, any such statements are qualified in their entirety by reference to, and are accompanied by, the following important factors that could cause our actual results to differ materially from those contained in our forward-looking statements, including, but not limited to, actions or inaction of local, state and federal regulatory and taxing bodies; changes in business and economic conditions, including their impact on interest rates, bad debt expense and demand for our products and services; changes in weather patterns; changes in laws, regulations or regulatory policy; changes in levels and timing of capital expenditures; disruptions in the capital markets or other events that make our access to necessary capital more difficult or costly; 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 contracts; actions of rating agencies; the effects and outcome of our pending merger with NSTAR; 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 or to reflect the occurrence of unanticipated events.

NU Safe Harbor Provisions

3

Two of NU’s Primary Infrastructure Growth Initiatives

ELECTRIC TRANSMISSIONELECTRIC TRANSMISSION NATURAL GAS DISTRIBUTIONNATURAL GAS DISTRIBUTION

• Significant growth in recent years driven by reliability needs

• Siting regulated by states

• Economics regulated by FERC

• New projects focus on economics, environment, and public policy directives

• Very attractive opportunities in New England due to low saturation and cost and environmental advantages over competing fuels

• Siting and economics regulated by states

• Delivery and regulatory model constraints need to be addressed in Connecticut to increase penetration

PRIMARYPRIMARY EMERGINGEMERGING

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Increased Transmission Investment Has Led to Increased Transmission Earnings

$170.5

$257.3

$465.5

$761.8

$714.3

$291.8$260.9

$444.0

$177.8

$164.3

$28.2

$41.1

$59.8

$82.5

$138.3

$0.0

$100.0

$200.0

$300.0

$400.0

$500.0

$600.0

$700.0

$800.0

2004 2005 2006 2007 2008 2009 2010 2011E

$0.0

$20.0

$40.0

$60.0

$80.0

$100.0

$120.0

$140.0

$160.0

$180.0

$200.0

NU Transmission Investment NU Transmission Earnings

In M

illio

ns

Transmission Capital Expenditures

Transmission Earnings

In M

illion

s

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Increased Transmission Spending in 2011 Driven by NEEWS Reliability Projects

Greater Springfield Reliability Project

• Substation construction commenced in MA in Dec. 2010; in CT in summer 2011

• Army Corps of Engineers permit received last week – full overhead construction to commence in both MA and CT

• Projected in-service: late 2013

• Total projected NU cost: $718 million

Interstate Reliability Project

• Joint project with National Grid (NU in CT; NGrid in MA & RI)

• ISO-NE confirmed need: August 2010

• File siting application in CT: late 2011

• Siting decisions: 2013

• Commence construction: late 2013/early 2014

• Projected in-service: late 2015

• Total projected NU cost: $218 million

SPRINGFIELD

HARTFORD

345-kV SubstationGeneration Station345-kV ROW

115-kV ROW

Central ConnecticutReliability Project

InterstateReliability Project

Greater SpringfieldReliability Project

Central Connecticut Reliability Project

• Expected review to be completed and needs identified in late 2011 with specific projects identified in late 2012

• Total projected NU cost: $301 million

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Northern Pass Transmission – a Non-Traditional $1.1 Billion Capital Investment

´

• To be owned by Northern Pass Transmission LLC - NU (75%) and NSTAR (25%)

• 1,200 MW transfer capability

• Northern terminus at Des Cantons (Québec), southern terminus in Franklin (New Hampshire)

• Québec terminal will convert the power from AC to DC (rectifier)

• US terminal will convert the power from DC to AC (inverter)

• 345kV AC leg from Franklin to Deerfield, NH

• TSA signed in October 2010 and accepted by FERC on February 11, 2011

• Permitting process began October 14, 2010 with U.S. DOE application – comment period extended in mid-June; U.S. Forest Service application filed June 28

• New Hampshire Senate voted June 2 to “re-refer” eminent domain bill

• Capital cost estimate for US segment: $1.1 billion – completion projected for late 2016

Des Cantons

HVDC Line

HVDC Converter Station

345-kV Line

Existing Deerfield Substation

Deerfield

Franklin

7

50%

31%

15%

4%

0%

20%

40%

60%

% C

T H

om

e H

eatin

g M

arke

t

CT Home Heating Market Penetration

Heating Oil #2

Natural Gas

Electric Heating

Propane

72%

53%48% 47%

31%

0%

20%

40%

60%

80%

% o

f p

en

etr

ati

on

of

na

tura

l ga

s

Natural gas penetration CT vs. other states

CTNJ NY RI MA

Natural Gas: A Different Type of Infrastructure Growth Opportunity

• Connecticut is significantly under-penetrated and relies on higher priced fuels for space heating

• Increasing the penetration to 50% of the state would yield long-term benefits

• Significant customer savings

• Reduced emissions

• Reduction in oil demand

• In the short-term the investment in infrastructure to support such expansion would generate additional jobs (construction and craft labor)

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Customer Economics Are Compelling, But Obstacles Exist

$0

$10

$20

$30

$40

$50

$60

2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

2021

2022

2023

2024

2025

2026

2027

2028

2029

CT Wholesale Heating Oil #2

Henry Hub + Tport

CT Wholesale Propane

No

min

al $

/MM

Btu

Difference increases from $9 to $28 per MMbtu

Price Differential Forecast $ per MMBTU

Heating Conversion Economics

Type Customer Costs

Service already available

~$7,500 for heating retrofit

Service not available, but near gas system

~$7,500 for retrofit

~$1,000 - $3,000 for service and meter

Service notavailable, line extension required

~$7,500 for retrofit

~$10,000 - $15,000 for service, meter & line extension

Frequent Conversion Obstacles

• No local gas service in place

• Upfront customer capital with long paybacks

• Requirements for upfront customer payments (CIAC) on utility portion of expansion given a “pay as you go” regulatory philosophy

Price differentials, can lead to homeowner savings in the $1,000 - $1,500 per year

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• $57.6 million Waterbury-to-Wallingford/LNG project began in April 2010; completion expected by November 2011

• Fills gaps in supply portfolio and eliminates system constraint in Cheshire area

• Increases vaporization capacity of Waterbury LNG project

• Supports area’s growing customer demand

Yankee Gas Continues to Identify Initiatives to Meet Customer Needs and Sales Growth

3.4

6.26.6

5.0

3.1

Yankee Gas (firm)

2007 2008 2009 2010 2011 YTD

We

ath

er-

No

rma

lize

d%

ch

an

ge

ye

ar-

ove

r-ye

ar

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Potential “Follow-on” Growth Initiatives

Solar / RenewablesSolar / Renewables

• Already building solar generation in Massachusetts

• Recent authorization to invest in Connecticut

Smart GridSmart Grid

• Investing in distribution automation investments across our system

• Examining feasibility of advanced metering technologies

TransportationTransportation

• Investing intellectual capital in electric vehicle infrastructure business models

• Moving forward with charging station infrastructure across our system