NRG ENERGY, INC. / ALTER NRG CORP.

Somerset Power PlantR f li Th h Pl G ifi tiRefueling Through Plasma Gasification

GTC Annual ConferenceOctober 5 - 8, 2008

Confidentiality and Forward-Looking Statements

This presentation is confidential and for authorized use only. Under no circumstances are its contents to be reproduced or distributedto the public, media or potential investors without written authorization.to the public, media or potential investors without written authorization.

The information contained herein, while obtained from sources believed to be reliable, is not guaranteed as to its accuracy orcompleteness.

Certain statements in this disclosure may constitute “forward-looking” statements which involve known and unknown risks,uncertainties and other factors which may cause the actual results, performance or achievements of the Corporation, or industryresults, to be materially different from any future results, performance or achievements expressed or implied by such forward-lookingstatements. When used in this disclosure, such statements use such words as “may”, “would”, “could”, “will”, “intend”, “expect”,“believe”, “plan”, “anticipate”, “estimate”, and other similar terminology. These statements reflect the Corporation’s current expectationsregarding future events and operating performance and speak only as of the date of this disclosure. Forward-looking statementsinvolve significant risks and uncertainties, should not be read as guarantees of future performance or results, and will not necessarilybe accurate indications of whether or not such results will be achieved. A number of factors could cause actual results to differmaterially from the results discussed in the forward-looking statements, including, but not limited to, the factors discussed below andunder “Risk Factors” in the Corporation’s prospectus filed April 10, 2007. Although the forward-looking statements contained in thisdisclosure are based upon what Management believes are reasonable assumptions, the Corporation cannot assure investors thatactual results will be consistent with these forward-looking statements. These forward-looking statements are made as of the date ofthis disclosure, and, subject to applicable securities laws, the Corporation assumes no obligation to update or revise them to reflectnew events or circumstances. This disclosure may contain forward-looking statements pertaining to the following: capital expenditurey g p g g p pprograms; supply and demand for the Corporation’s services and industry activity levels; commodity prices; income tax considerations;treatments under governmental regulatory regimes. The Corporation has provided cost estimates and resource conversion ratios forprojects that are still in the early stages of development and are preliminary estimates only.

No securities commission or other similar regulatory authority has passed on the merits of the securities described herein nor has anysecurities commission or similar regulatory authority reviewed this presentation and any representation to the contrary is an offense.g y y p y p y

All dollar figures are Canadian unless otherwise stated.

Introduction

• Alter NRG Corp. and NRG Energy, Inc. have teamed up to provide the world’s first plasma gasification refuelingto provide the world s first plasma gasification refueling of a coal fired power plant

• The revamped facility will gasify coal and biomass toThe revamped facility will gasify coal and biomass to provide cleaner energy with reduced emissions and Carbon footprint

• The project will generate 120 MW of power from the existing facility, and will extend the life of a “legacy” power plantpower plant

• Estimated costs are less than $200 million

Alter NRG Company Overview• Company formed in 2006, headquartered in Calgary, Alberta, Canada• Common shares listed on the TSX-V: NRG

• Significant assets:468 million tonnes of coal reserves in Alberta– 468 million tonnes of coal reserves in Alberta

– Westinghouse Plasma Corporation (WPC)– Strategic partnership with NRG Energy

VISION:B S i E P d d L d i th D l t f E i t ll S t i blBecome a Senior Energy Producer and a Leader in the Development of Environmentally Sustainable and Economically Viable Gasification Projects

Westinghouse Plasma Corporation

Alter NRG purchased Westinghouse Plasma Corporation (WPC) in April 2007

WPC Strengths• WPC plasma technology developed with

an estimated $100 million in R&D funding • Over 40 years experience in the design

and application of plasma technology• WPC has completed approximately 100

pilot tests on a multitude of feedstocks

WPC Plasma Cupolap

What is Plasma Gasification?

What is plasma?• Plasma is a highly ionized or electrically charged gas. An

example in nature is lightning - capable of producing temperatures exceeding 7,000°C.temperatures exceeding 7,000 C.

What are the advantages of plasma?• Increased temperature and higher degree of temperature control

providesAbility to gasify blended feedstock including waste- Ability to gasify blended feedstock including waste

- Increased control in the process - Reduced operating and capital costs

What’s the end product?S b d f l t t l t i it t• Syngas can be used as a fuel to generate electricity or steam, or used as a basic chemical building block in the petrochemical and refining industries.

How efficient is it?Plasma Torches use 2% to 5% of the energy inputFacility Exports 80% of the energy input into Syngas

Gasification is not incinerationG ifi ti d t i l b tiGasification does not involve combustion

Understanding Plasma Gasification

Plasma Gasification can create more renewable energy than the projected energy from solar, wind, landfill gas and geothermal energies combined”

Georgia Tech Research Institute

• Plasma gasification is technically and commercially proven and has been in commercial operation processing MSW since 2002

Th W ti h Pl T h h 500 000 h f• The Westinghouse Plasma Torch has over 500,000 hours of operation in harsh environments

• Plasma gasification is versatile and can handle most feed stocks

• Plasma gasification is economically viable and competitive with any other form of solid waste or fuel management when properly sited with syngas, electricity, heat, and/or steam customersy g , y, ,

• Plasma gasification generates baseload renewable power, providing needed clean energy and displacing fossil fuels

Application: Power Generation

Wide Variety of Feedstocks Flexible Process Wide Variety of Products

Boiler

Steam

Steam Turbine

C bi d C l

Electric Power

Combined Cycle Gas Turbine

Lo $ Cost Gasifier High $ Val e

Electric Power

Reciprocating Engine

Low $ Cost Gasifier High $ Value

Plasma: Baseload Renewable Power

“Plasma Gasification can create more renewable energy than the projected energy from solar, wind, landfill gas and geothermal energies combined”

% of US P B l d P ki I t itt t

Georgia Tech Research Institute

• 24 States in the U.S. define waste-to-energy as a renewable source of energy

Power Supply1

Baseload Peaking Intermittent

Coal 22%

Nuclear 8%

Natural Gas 23%

Wind < 0.1%

Solar < 0.4%

WTE/Biomass 3.5%

Coal Retrofits TBD

Notes: 1. US Energy Information Administration, Renewable and Alternative Fuels, 2007

Power Plant Retrofits

Market Drivers•Environmental permits expiring – retrofit or

closure•Retrofit less costly than new plantRetrofit less costly than new plant

• $1,500 to $1,800 per kW versus IGCC and supercritical coal plants of $3,000 to $6,000 per kW

•Existing site is retrofitted which hasExisting site is retrofitted which has•Quicker and easier permitting•Key agreements, labor force

•Up to 45% biomass enables 45% carbon offsets

Partnership With NRG Energy, Inc.• In April 2007 Alter NRG Corp granted NRG Energy, Inc a five-year US

license for WPC technology to retrofit coal fired power plants

• NRG Energy, Inc is a U.S. independent power producer (US$10 billion market cap)First retrofit project Somerset has received regulatory approval• First retrofit project – Somerset has received regulatory approval

Safe Harbor Statement

NRG Energy, Inc. NYSE: NRGgy,

This Presentation contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Forward-looking statements are subject to certain risks, uncertainties and assumptions and typically can be identified by the use of words such as “expect,” “estimate,” “should,” “anticipate,” “forecast,” “plan,” “guidance,” “believe,” “will” and similar terms. S h f d l ki i l d i f i l i l ifi i d h S P Such forward-looking statements include information relating to plasma gasification and the Somerset Power Station. Although NRG Energy, Inc. (NRG) believes that these expectations are reasonable, it can give no assurance that these expectations will prove to have been correct, and actual results may vary materially. Factors that could cause actual results to differ materially from those contemplated above include, among others, general economic conditions, hazards customary in the power industry, weather conditions, competition in wholesale power markets the volatility of energy and fuel prices failure of customers to competition in wholesale power markets, the volatility of energy and fuel prices, failure of customers to perform under contracts, changes in the wholesale power markets, changes in government regulation of markets and of environmental emissions, the condition of capital markets generally, and the inability to implement value enhancing improvements to plant operations and companywide processes.

NRG undertakes no obligation to update or revise any forward-looking statements, whether as a result of new g p y g ,information, future events or otherwise. The foregoing review of factors that could cause actual results to differ materially from those contemplated in the forward-looking statements included in this Presentation should be considered in connection with information regarding risks and uncertainties that may affect NRG's future results included in NRG's filings with the Securities and Exchange Commission at www.sec.gov.

NRG: Portfolio with Scale and Diversity

Ranked in Fortune 500 as 3rd Fastest Growing Co, (July 2007)Platt’s 2007 Recipient of Energy Company and Industry Leader of the Year

i l 23 000 i il i i i

Western

Northeast

Gas

Approximately 23,000 MW, Primarily in Four Domestic Regions

Western

Gas2.1GW100%

Oil3.7 GW53%

Gas1.4 GW20%

Coal1.9 GW27%

South CentralTexas

Nuclear Combined Scale1

Gas5.5 GW

Nuclear1.2 GW11%

Coal4 1 GW

Gas1.4 GW48%

Coal1.5 GW52%

Nuclear 1.2 GW 5%Coal 7.5 GW 33%

5.5 GW51%

4.1 GW38% Gas 10.5 GW 46%

Oil 3.7 GW 16%Total 22.9 GW

Asset scale and diversity of fuel and locationprovide value creation opportunities

1 MW data as of December 31, 2007

Somerset Power LLC – Somerset Station

Plant Highlights

Location: Somerset, MA

Facility: Pulverized Coal Utility Station; 380MW Total; 6 Steam Turbine Units; 2 Aircraft Derivative Peaking Units; Now IPP Merchant Plant

Older Units Retired in PlaceOlder Units Retired in Place

Date Constructed: 1923-1925

Site: 38 acres, Taunton River

Active: Unit 6, 120 MW, 1959 Bit & Sub-Bit Coal, No. 6 FO, SNCR, Gas Re-burn, SOFA & CCOFA, ESP

Active: Jet 2, 25 MW, 1972

Somerset Station - Unit 6

Somerset Station – Coal Cargo Discharge

Somerset Station – Coal Storage

Environmental Driver

Massachusetts “Powerplant Rule” (310 CMR 7.29), 2001; 4 Primary Pollutants

–SO2SO2–NOx–Hg–CO2 (Transition to RGGI)2 ( )

Economics of APC Retrofit UnfavorableRepower or Shut Down by 1/1/2010;1/1/2010;Technology & Fuel Neutral, 7.29 & RGGI CompliantPlasma Gasification Permits Issued 1/25/2008

represents NRG’s commitment to represents NRG s commitment to environmentally responsible power generation

Carbon Reduction – Biomass & Renewable Energy Credits (RECs)

Biomass; carbon neutral feedstock; self-offsetting up to 35% solid fuel clean biomass, plus 10% liquid biodiesel; 45% total on Day Oneq ; y

– Displace greenhouse gas (CO2) emissions from coal– Cap annual TPY CO2 from non-renewable fuel

Permit authorizes alternative biomass feedstock sources– Green wood; (qualifies for RECs)– Urban tree trimmings; (qualifies for RECs)– Liquid biodiesel; (qualifies for RECs)– Construction and demolition wood residue (CDW) requires Beneficial Use ( ) q

Determination (BUD); (potential future REC qualification) – Paper cubes; (potential future REC qualification)

RECs; Under MA Renewable Portfolio Standard (RPS) add considerable value to project d t i d d d f bl d tand meet increased demand for renewable energy mandates

Up to 45% biomass enables Up to 45% biomass enables 45% carbon neutral self-offsets

Somerset Unit 6 Refueling

Plasma Gasification Process

Emission Limits for the Syngas Re-fueled Unitlb/MMBtu

lb/hr Basis1-hr(a) MonthlyNOx 0.367 0.07 471 CEMsSO2 1.2 0.08 1541 CEMs

CO 0.083 0.033 107 CEMsVOC 0.0073 0.005 9.37 EPA Methods 25A and

1919PM10 0.014 None 103 EPA Method 5PM2.5 0.014 None 103 EPA Method 5 (PM2.5 =

PM )PM10)TSP 0.015 None 103 EPA Method 5

Pb 0.00039 None 0.501 EPA Method 12 or 29

H2SO4 0.003 None 3.85 EPA Method 8

HF None None None -NH3 0.0091 None 10.1 EPA CTM 27NH3 0.0091 None 10.1 EPA CTM 27Hg 2.4 x 10-7 None 3.1 x 10-4 EPA Method 29

Somerset Project Permitting Timeline

12/06: Application Submitted

9/07: Draft Permits Issued9/07: Draft Permits Issued

10/07: Public Hearing

01/08 R i d A d P it P it t C t t & R i d ECP01/08: Received Approved Permits; Permit to Construct & Revised ECP

02/08: Conservation Law Foundation (CLF) filed Appeal

06/08: CLF Appeal denied by Adjudicatory Judge

08/08: DEP Commissioner Upholds Judge’s Decision

09/08: CLF Filed Motion Requesting DEP Reconsideration

09/08: Somerset Power Filed Motion Requesting Reconsideration Denial09/08 So e set o e ed ot o equest g eco s de at o e a

In Summary: 8 Key Project Points

From a Technology Perspective:• Introduces a viable new

From an Emissions Perspective:• Has no increase in the• Introduces a viable new

transfer technology to the power generation industry via WPC Plasma Gasification;

• Has no increase in the potential to emit any criteria air pollutant; NOx, SO2, PM, PM10, PM2.5, and Pb;

Gasification;• Results in cost savings

through use of existing facility infrastructure and

• Reduces the potential emissions of non-criteria air pollutants; HCL, H2SO4, NH3, and Hg;y

revenue potential from low value solid fuels;

• Provides fuel optionality and incremental revenue through

g;

• Eliminates conventional coal combustion production of fly ash and bottom ash; andincremental revenue through

use of renewable fuels; and,• Offers the potential for

greater, broad-based

;• Offers a reduction in the CO2

footprint through use of renewable fuel offsets in lieu of fossil fuel usageg ,

application nationwide. of fossil fuel usage.

Alter NRG Corp.Suite 700, 910 – 7th Avenue S.W.

C l Alb t T2P 3N8

NRG Energy, Inc. 211 Carnegie CenterP i t NJ 08540 Calgary, Alberta T2P 3N8

Phone: 03.806.3875Fax: 403.806.3701

Princeton, NJ 08540Phone: 609.524.4500

Fax: 609.524.4501 www.alternrg.ca

TSX-V: NRGwww.nrgenergy.com

NYSE: NRG

Please visit Westinghouse Plasma Corporation g pat Booth # 36 in the Exhibit Hall