Uns Energy (UNS) 8-K Regulation FD Disclosure

Exhibit 99.1

UniSource Energy Corporation NYSE: UNS September 2010

2 Contact Information & Safe Harbor Paul J. Bonavia, Chairman, President and CEO Kevin P. Larson, SVP, CFO and Treasurer Investor Relations Contact Information M. Jo Smith, Director Chris Norman, Lead Analyst (520) 884.3650 (520) 884.3649 josmith@uns.com cnorman@uns.com Investor Information http://ir.uns.com Safe Harbor and Non-GAAP Measures This document contains forward-looking information that involves risks and uncertainties, that include, but are not limited to: state and federal regulatory and legislative decisions and actions; regional economic and market conditions which could affect customer growth and energy usage; weather variations affecting energy usage; the cost of debt and equity capital and access to capital markets; the performance of the stock market and changing interest rate environment, which affect the value of the company's pension and other postretirement benefit plan assets and the related contribution requirements and expense; unexpected increases in O&M expense; resolution of pending litigation matters; changes in accounting standards; changes in critical accounting estimates; the ongoing restructuring of the electric industry; changes to long-term contracts; the cost of fuel and power supplies; performance of TEP's generating plants; and other factors listed in UniSource Energy's Form 10-K and 10-Q filings with the Securities and Exchange Commission. The preceding factors may cause future results to differ materially from historical results or from outcomes currently expected by UniSource Energy. The Company's press releases and other communications may include certain non-Generally Accepted Accounting Principles (GAAP) financial measures. A "non-GAAP financial measure" is defined as a numerical measure of a company's financial performance, financial position or cash flows that excludes (or includes) amounts that are included in (or excluded from) the most directly comparable measure calculated and presented in accordance with GAAP in the Company's financial statements. Non-GAAP financial measures utilized by the Company include presentations of revenues, operating expenses, operating income and earnings (loss) per share. The Company uses these non-GAAP measures to evaluate the operations of the Company. Certain non-GAAP financial measures utilized by the Company exclude: the impact of non-recurring items: the effect of accounting changes or adjustments; expenses that are reimbursed by third parties; and other items. The Company's management believes that these non-GAAP financial measures provide useful information to investors by removing the effect of variances in GAAP reported results of operations that are not indicative of fundamental changes in the earnings or cash flow capacity of the Company's operations. Management also believes that the presentation of the non-GAAP financial measures is largely consistent with its past practice, as well as industry practice in general, and will enable investors and analysts to compare current non-GAAP measures with non-GAAP measures with respect to prior periods.

Regulated Electric and Gas Utility Businesses UNS' Largest Subsidiary ~ 80% of Operating Revenues ~ 81% of Total Assets Vertically Integrated Electric Utility ~ 400,000 Electric Customers Gas & Electric T&D Businesses ~ 146,000 Gas Customers ~ 90,000 Electric Customers 3

Utility Service Areas Navajo Sundt Moenkopi Peacock Marketplace Kayenta Tucson Generating Station Coal Mine Interconnection With Other Utility Substation Solar Station TEP UNS Gas UNS Gas & Electric UNS Electric Service Areas High Voltage Transmission Lines San Juan Ship Rock Four Corners San Juan Mine Navajo McKinley McKinley Mine Coronado Springerville Luna Hidalgo Greenlee South Vail Valencia Nogales Davis Mead Black Mountain Kingman Kingman Black Mountain Griffith Griffith N. Havasu Lake Havasu City Parker Parker Saguaro West Wing Liberty Palo Verde Phoenix Pinal West Cholla Flagstaff Lee Ranch Yavapai Prescott MEXICO NEVADA UTAH COLORADO CALIFORNIA NEW MEXICO Lake Havasu City Pinnacle Peak 4

Compelling Long-Term Value Proposition Compelling Long-Term Value Proposition 5

Attractive Dividend Yield & Growth Potential In Feb. 2010, the Board indicated its intent to reach a 60% payout level over the next few years Payout is calculated using net income or basic earnings per share; not diluted earnings per share Signals confidence in UNS' long-term financial strength and stability *Indicated annual dividend (CHART) * Dividend Yield as of Sept. 20, 2010 **6/30/10 LTM Payout Ratio (CHART) (CHART) 17% Avg. Annual Growth Rate 6

UNS Consolidated - Positive Free Cash Flows Free cash flow provides flexibility Historically, UniSource Energy's operating cash flows have exceeded capital expenditures Annual dividend increases since 2000 Operating cash used to reduce debt and capital lease obligations by approx. $300 million over the last 10 years Invested $85 million of equity to help fund purchase of UES Positive free cash flow trend expected to continue Manageable level of capital expenditures Reduced actual and planned capital expenditures for 2008-2013 by $280 million due to weak economy Rate base growth in 2010 without regulatory lag Purchased Sundt Unit 4 in 2010 for $52 million $14 million of renewable energy investments in 2010 with cost recovery through the renewable energy surcharge (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) (REST) Note: Capital expenditure estimates for 2011-2014 from 2009 10-K; 2011-2014 excludes proposed investments in solar projects (up to $28 million per year for TEP and $5 million per year for UNS Electric, beginning in 2011). See p. 13 for further detail. 7

TEP - Diverse Retail Customer Base TEP - Diverse Retail Customer Base TEP - Diverse Retail Customer Base 2009 Retail kWh Sales Mix University of Arizona Davis Monthan Air Force Base Freeport -McMoRan (CHART) Customer Sector Freeport McMoRan Copper Mining Asarco Copper Mining University of Arizona Education Fort Huachuca, US Army Intelligence Center Military Raytheon Defense IBM Technology Davis Monthan Air Force Base Military Arizona Portland Cement Construction Liquid Air Manufacturing Largest Retail Customers 8

TEP - Retail Customers TEP customer base continues to grow at a modest pace Long-term outlook positive with a customer growth rate of more than 1.5% in 2014 Expect local economy to gradually improve Positive indicators in home sales and inventories University of Arizona Economic and Business Research Center indicates that the recession in Arizona has ended and expects growth to gradually resume Tucson unemployment rate 8.7% vs. national average of 9.6% (as of August 2010) Retail Customer Growth (CHART) 9 Possible addition of Rosemont Copper mine in late 2010 or 2013 with usage of ~ 100MW Support from local business organizations; opposition from local government and environmental groups Requires a U.S. Forest Service Record of Decision Process includes issuance of Environmental Impact Statement [EIS] Draft EIS expected by year-end 2010

Long-Term Economic Outlook Remains Strong *According to University of Arizona Economic and Business Research Center as of July 2010 (CHART) (CHART) 10

TEP - Energy Resources Provide Optionality 2009 Resource Mix - GWh Generating Capacity - 2,229 MW Owned Coal - 1,061 MW (incl. 14% of Springerville Unit 1) Luna Combined Cycle Gas Turbine Purchased Power Simple Cycle Gas Units Gas CCCT 190 MW - 9% Coal/Gas 156 MW - 7% Simple Cycle Gas 484 MW - 22% Solar 5 MW - 0.2% Leased Coal - 86% of 387 MW Springerville Unit 1 Coal / Gas - Sundt Unit 4 Leased Coal 334 MW - 15% 334 MW - 15% 334 MW - 15% Solar (CHART) Owned Coal 1,061 MW - 47% Leased and duel fuel plants provide optionality Springerville Unit 1 lease (expires Jan. 2015) has fair market value purchase and lease renewal options No near-term new base load generation requirements Substation and transmission line additions are expanding access to the Palo Verde hub Limited commodity price exposure for retail fuel & purchased power costs Long-term coal contracts provide price and supply stability PPFAC allows for full recovery PPFAC allows for full recovery Protection against carbon-related costs Carbon costs are a fuel-related cost and can be recovered through the PPFAC TEP's 2008 Rate Order provisions allow for base rate and adjustor mechanism change in emergency conditions, subject to ACC approval 11

UniSource Energy Services UNS Gas T&D retail gas business More than 146,000 retail customers 2009 retail sales - 110 million therms $215 million net plant in-service at 12/31/09 Rate Case Activity Base rate increase of $3.5 million effective April 1, 2010 UNS Electric T&D retail electric business More than 90,000 retail customers 2009 retail sales - 1,780 GWh $238 million net plant in-service at 12/31/09 Rate Case Activity Base rate increase of $7.4 million effective October 1, 2010 (UNS Electric requested increase of $13.5 million) Rate increase includes acquisition of Black Mountain Generating Station $4 $4 $8 $5 $5 $4 $ - $ 2 $ 4 $ 6 $ 8 $10 $12 $14 2006 2007 2008 UES Net Income ($ millions) UNS Gas UNS Electric Estimated Capital Expenditures ($ millions) $7 $6 2009 Note: -Capital expenditure estimates for 2010-2014 from 2009 10-K -UNS Electric excludes renewable energy investments of up to $5 million per year beginning in 2011. See p. 13 for further details. (CHART) 12

Renewable Energy Leadership Arizona Renewable Energy Standard and Tariff REST requires 15% of all retail energy needs from renewable resources by 2025 Customer surcharge funds above market cost renewable energy Proposals to invest $146 million in solar photovoltaic projects over next 5 years TEP ACC approved two new solar photovoltaic projects totaling 3.4 MW Capital cost of projects ~$14 million Estimated completion by end of 2010 Cost recovery, including ROI, through REST surcharge ACC approval pending for annual investments of up to $28 million for ~ 7 MW from 2011- 2014 UNS Electric ACC approved annual investments of up to $5 million for ~1.25 MW from 2011-2014 Purchase Options Included in Solar PPAs 136 MW of TEP's solar Purchased Power Agreements (PPA) include purchase options that can be exercised after the 5th year (CHART) (CHART) 13

TEP & UNSE Renewable Contracts and Projects Resource/ Counterparty Resource/ Counterparty Technology Location Operator Completion Date Term (Years) Purchase Option Capacity MW Solar Solar Amonix Concentrating PV Tucson, AZ Amonix 2011 20 On or after yr. 6 at FMV 1.5 Swan Solar Concentrating PV Tucson, AZ Amonix 2011 20 12 Avalon Solar Fixed PV Marana, AZ Avalon 2012 20 35 First Light Fixed PV Tucson, AZ CTC 2011 20 5 Emcore Solar Concentrating PV Tucson, AZ Emcore 2012 20 1.5 FSP Solar One Single-Axis Tracking PV Tucson, AZ Foresight Solar 2012 20 4 FSP Solar Two Single-Axis Tracking PV Tucson, AZ Foresight Solar 2012 20 12 NRG Solar Fixed PV Tucson, AZ NRG Solar 2011 20 25 FRV Tucson Solar Single-Axis Tracking PV Tucson, AZ Renewable Ventures 2011-2012 20 20 Renewable Fuel Solar Thermal Tucson, AZ Bell IPC 2012-2013 20 5.5 Wind Wind Western Wind Energy US Corp Wind Kingman, AZ Western Wind 2011 20 None 7-11 Macho Springs Wind Deming, NM Torch Energy 2011 20 None 50 Landfill Gas Landfill Gas Sexton Energy Landfill Gas Tucson, AZ Sexton Energy 2012-2013 15 None 2.2 Total 184.7 PPAs Fuel/ Plant Fuel/ Plant Technology Status Completion Date Net Capacity MW Solar Solar Springerville Solar Station Fixed PV Complete 2002 4.6 Springerville Solar Station Expansion Fixed PV In Progress Year End, 2010 1.8 Tucson Airport Project Single-Axis Tracking PV In Progress Year End, 2010 1.6 Total 8.0 Owned / Under Construction

Key Earnings Drivers and Rule of Thumb Sensitivities Driver - Full Year Pre-Tax Amount Potential Change in Diluted EPS 1% change in TEP Retail Sales(2009 TEP total retail sales = 9,371 GWh; Avg. non-fuel rate approx. 6 cents / kWh) $5.6 million +/- $0.08 100 bps increase in rates on un-hedged TEP Variable Rate Debt ($279 million outstanding at 9/30/2010)* $2.8 million ($0.04) 100 bps increase in pricing on $621 million of bank facilities $6.2 million ($0.09) 1% change in UNS Base O&M (based on 2010 estimate of $275 million) $2.8 million +/- $0.04 *Current average rate on underlying debt was less than 0.30% as of Sept. 15, 2010 15 15 Agreement Amount Undrawn Pricing* Expiration UNS Revolver $70 million 1.25% Aug. 2011 TEP Revolver $150 million 0.45% TEP LOC Facility $341 million 0.60% UES Joint Revolver $60 million 1.00% *Borrowed amounts are LIBOR + undrawn spread

Regulatory Overview 16

Regulatory Framework Commissioner Term Expires Kristin Mayes (R) Jan 2011* Sandra Kennedy (D) Jan 2013 Paul Newman (D) Jan 2013 Gary Pierce (R) Jan 2011 Bob Stump (R) Jan 2013 * Unable to run for re-election - two term limit Arizona Corporation Commission Constitutionally created branch of Arizona government Five commissioners elected state-wide Limited to serve two consecutive four year terms Two ACC seats are up for election in November 2010 ACC Candidates Experience Gary Pierce (R)Mesa Incumbent Brenda Burns (R) Scottsdale Lobbyist, former State Legislator David Bradley (D)Tucson Director of Social Services, State Legislator Jorge Luis Garcia (D)Tucson Social worker, State Legislator Federal Energy Regulatory Commission Transmission rates Long-term wholesale transactions 17

Good Regulatory Foundation 18

2008 TEP Rate Order Key Provisions Methodology Cost-of-service Test year 12/31/2006 Rate base $1.02 billion 2006 Retail Sales (GWh) 9,320 Allowed ROE 10.25% Capital Structure 42.5% equity / 57.5% debt (Actual capital structure was 40% equity, excluding capital leases, and 60% debt) Non-fuel base rate increase 6% (approx. $47 million). Effective Dec. 1, 2008. Purchased Power and Fuel Adjustment Clause (PPFAC) Effective Jan. 1, 2009Forward lookingEnergy, capacity and transmission Springerville Unit 1 - 387 MW coal-fired plant leased by TEP. Lease expires Jan. 1, 2015. Non-fuel recovery of $25.67 per kW per month or approx. $117 millionApproximates levelized cost through the remainder of the term of the lease Average base retail rate 8.9 cents / kWh (base non-fuel rate of 6.0 cents) Rate case moratorium Cannot file new case before 6/30/2012 with a test year no earlier than 12/31/11 19

2008 TEP Rate Order - Rate Base $1.02 billion ACC jurisdictional rate base as of 12/31/2006 Excludes FERC-regulated assets High voltage transmission assets of $205 million Generation assets dedicated to long-term wholesale sales of approximately $63 million Excludes adjustments of $134 million for deferred income taxes, working capital and other items other items other items other items other items other items other items other items other items other items other items other items 20 (CHART) *Excludes assets under capital leases (CHART) TEP Net Plant in Service* (millions) 12/31/06 12/31/09 (CHART) Note: Capital expenditure estimates for 2011-2014 from 2009 10-K; 2011-2014 excludes proposed investments in solar projects of up to $28 million per year for TEP. See p. 13 for further details.

TEP Rate Case & Springerville Unit 1 Timeline 2008 2009 2010 2011 2012 2013 2014 2015 12/1/2008 Effective date of 2008 TEP Rate Order 12/31/2011 Earliest test year 6/30/2012 Earliest filing date 6/30/2013 Earliest effective date of rate case 1/1/2015 Expiration of Springerville Unit 1 Lease 21 9/1/2013 Notify lessor of intent to purchase or renew Springerville Unit 1 Lease

2008 TEP Rate Order - Key Provisions 22 ACC Decision No. 70628 II. Rate increase 2.2 TEP's rates, including generation, will be determined using a cost-of-service methodology. ...TEP shall withdraw its proposed market and hybrid rate methodologies. Original cost rate base: $1.02B (net of $134M of adjustments, including deferred income taxes of $119M) Average base rate increase of 6% (avg. base retail rate of 8.9 cents/kWh) Includes base cost of fuel & purchased power of 2.8896 cents/kWh Revenue increase of $47.1M III. Ratemaking treatment of generation assets 3.1 For ratemaking purposes, SGS Unit 1 and Luna shall be included in TEP's rate base at their respective original costs. All other generation assets acquired by TEP after December 31, 2006, but before December 31, 2012, shall be included in TEP's rate base at their respective original costs, subject to the Commission's subsequent regulatory and ratemaking review and approval. 3.2 Recovery of SGS Unit 1 non-fuel costs shall reflect a cost of $25.67 per KW per month which approximates the levelized cost of SGS Unit 1 through the remainder of the primary lease term for this generating facility. In addition, SGS Unit 1 leasehold improvements shall be included in TEP's original cost rate base at net book value as of December 31, 2006. 3.3 Luna shall be included in TEP's original cost rate base at net book value as of December 31, 2006. 22

2008 TEP Rate Order - Key Provisions 23 X. Rate case moratorium 10.1 TEP's base rates shall remain frozen through December 31, 2012. 10.2 TEP shall not submit a rate application sooner than June 30, 2012. ...test year ending no earlier than December 31, 2011. 10.2 Signatories agree to use their best efforts to have post-moratorium rates in place no later than thirteen months after TEP's rate application is filed with the Commission. XI. Emergency Clause 11.1 ...TEP shall not be prevented from requesting a change to its base rates, or necessary changes to the PPFAC mechanism, the DSM or REST, that would take effect prior to January 1, 2013, in the event of conditions or circumstances that constitute an emergency. ...emergency is limited to an extraordinary event that is beyond TEP's control and that, in the Commission's judgment, requires rate relief in order to protect the public interest. This provision is not intended to preclude TEP from seeing rate relief pursuant to this paragraph in the event of the imposition of a federal carbon tax or related federal cap and trade system. 23

Supplemental Information Appendix TEP L-T Wholesale Contracts 25 TEP Operating Plant Performance 26 TEP Generation Portfolio 27 Credit Ratings and Liquidity 28 TEP Long-Term Debt Summary 29 24

TEP - Long-Term Wholesale Sales Margin on long-term wholesale sales benefits shareholders Gross margin on 2009 sales was $24 million Salt River Project (SRP) 100MW Annual demand charge $22 million; energy charge @ TEP's average generation cost Contract modifications effective June 2011 No demand charge; energy charge based on slight discount to Palo Verde Index SRP annual purchase requirement of 876 GWh Contract expires May 2016 Navajo Tribal Utility Authority (NTUA) No demand charge; energy priced in mid - $50 per MWh range No minimum purchase requirement Contract modifications effective 2010 Energy charge for 50% of sales (June-Sept) based on Palo Verde Index (~30 GWhs) Contract expires December 2015 (CHART) (CHART) 25

Strong Coal Plant Operating Performance Average Equivalent Availability Factor Baghouse - - Low NOx Environmental Equipment Operator TEP's Share (MW) Coal Delivery In Service Dates TEP's Share (%) TEP 156 MW rail 1967 100% TEP 770 MW rail Unit 1 - 1985 Unit 2 - 1990 100% Arizona Public Service 110 MW mine mouth Unit 4 - 1969 Unit 5 - 1970 7% Salt River Project 168 MW mine mouth Unit 1 - 1974 Unit 2 - 1975 Unit 3 - 1976 7.5% Public Service of New Mexico 322 MW mine mouth Unit 1 - 1976 Unit 2 - 1973 50% Coal Supplier Contract Term Peabody 2020 BHP Billiton 2016 Peabody 2011 San Juan Coal 2017 Rio Tinto Chevron Mining 2009 Annual Expected Coal Usage 350 k tons 3.2 mil. tons 400k tons 500k tons 1.3 mil. tons Baghouse Scrubbers Low NOx Baghouse Scrubbers - - Precipitators Scrubbers - - Baghouse Scrubbers LowNOx Mercury removal Sundt Unit 4 coal/gas Navajo Units 1,2&3 coal Industry Avg. coal Four Corners Units 4&5 coal San Juan Units 1&2 coal Springerville Units 1&2 coal (CHART) 93% 87% 87% 83% 05 06 07 08 09 90.9% (CHART) 89.4% (CHART) 84.4% (CHART) 89.5% (CHART) 83.8% (CHART) 85.0% 05 06 07 08 09 05 06 07 08 09 05 06 07 08 09 05 06 07 08 09 05 06 07 08 09 26

TEP Generation Portfolio Fuel/ Plant Fuel/ Plant Unit No. Location Date In Service Operator TEP's Share % TEP Share Net Capacity MW Coal Coal Springerville Station 1 Springerville, AZ 1985 TEP 100 387 Springerville Station 2 Springerville, AZ 1990 TEP 100 390 San Juan Station 1 Farmington, NM 1976 PNM 50 170 San Juan Station 2 Farmington, NM 1973 PNM 50 170 Navajo Station 1 Page, AZ 1974 SRP 7.5 56 Navajo Station 2 Page, AZ 1975 SRP 7.5 56 Navajo Station 3 Page, AZ 1976 SRP 7.5 56 Four Corners Station 4 Farmington, NM 1969 APS 7 55 Four Corners Station 5 Farmington, NM 1970 APS 7 55 Gas Gas Luna Energy Facility 1 Deming, NM 2006 PNM 33.3 190 North Loop Tucson, AZ 2001 TEP 100 95 Gas/Oil Gas/Oil Sundt Station 1 Tucson, AZ 1958 TEP 100 81 Sundt Station 2 Tucson, AZ 1960 TEP 100 81 Sundt Station 3 Tucson, AZ 1962 TEP 100 104 DeMoss Petrie Tucson, AZ 1972 TEP 100 122 Coal/Gas Coal/Gas Sundt Station 4 Tucson, AZ 1967 TEP 100 156 Total 2,224 27

Credit Ratings Sufficient lines of credit TEP - $150 million; UES - $ 60 million; UNS - $ 70 million Expect to refinance all three lines prior to their maturity in August 2011 Credit ratings TEP received one notch upgrade from Fitch in Sept. 2010 TEP Fitch Secured BBB Unsecured BBB- Issuer BB+ Outlook S&P BBB+ BBB- BB+ Stable Moody's Baa1 Baa3 Baa3 Stable Stable UniSource Energy Moody's Ba1 Stable Secured Credit Facility Outlook UNS Electric Moody's Baa3 Stable Sr. Unsecured Notes (guaranteed) Outlook UNS Gas Moody's Baa3 Stable Sr. Unsecured Notes (guaranteed) Outlook 28

Long-Term Debt Summary Balances as of 6/30/010 Rates as of 9/15/10 Interest Curr. Balance Issue Maturity Current Facilities Debt Issue Rate (in millions) Date Date Call Price Security Financed TEP Unsec. Ind. Dev. Bonds 2009 Pima A 4.950% 80 Oct-09 Oct-20 N/C Unsecured San Juan PC 1997 Coconino A 7.125% 37 Apr-97 Oct-32 100% Navajo PC 2009 Coconino A 5.125% 15 Oct-09 Oct-32 N/C 10 Navajo PC 1997 Pima A 6.100% 22 Sep-97 Sep-25 100% Local T&D 1998 Apache A 5.850% 84 Mar-98 Mar-28 100% SGS 1 PC 1998 Apache B 5.875% 100 Mar-98 Mar-33 100% SGS 2 PC 1998 Apache C 5.850% 16 Mar-98 Mar-26 100% Local T&D Subtotal $ 575 Tax-Exempt Bonds 1982 Pima A - Irvington 0.28% 39 Oct-82 Oct-22 100% Local T&D / Irvington 1982 Pima A 0.26% 40 Dec-82 Dec-22 100% Local T&D / 4 Corners PC 1983 Apache A 0.27% 100 Dec-83 Dec-18 100% SGS 2 1983 Apache B (Tranche A) 0.26% 80 Dec-83 Dec-18 100% SGS 2 1983 Apache C (Tranche A) 0.27% 50 Dec-83 Dec-18 100% SGS 2 1985 Apache A 0.27% 20 Dec-85 Dec-20 100% SGS 2 Subtotal $ 329* TEP TOTAL $ 934 2008 Pima A 6.375% 91 Mar-08 Sep-29 N/C 5 Local T&D UES UNS Gas Unsecured Notes 6.230% 50 Aug-03 Aug-11 MW + 50 Unsecured General Purpose UNS Gas Unsecured Notes 6.230% 50 Aug-03 Aug-15 MW + 50 General Purpose UNS Electric Unsecured Notes 6.500% 50 Aug-08 Aug-15 MW + 50 General Purpose UES TOTAL $ 200 UniSource Stand-Alone Sr. Unsec. Convertible Notes 4.500% 150 Mar-05 Mar-35 Par Unsecured General Purpose Term Loan / Revolver LIBOR + 1.25% 58 Aug-06 Aug-11 Par Unsecured General Purpose UNISOURCE STAND-ALONE TOTAL $ 208 UNISOURCE CONSOLIDATED TOTAL $1,377 UNS Gas / UNS Elec. Revolver LIBOR + 1% 0 Aug-06 Aug-11 N/A General Purpose 2008 Pima B 5.750% 130 Jun-08 Sep-29 N/C 5 Local T&D UNS Electric Unsecured Notes 7.100% 50 Aug-08 Aug-23 MW + 50 General Purpose var. rate Mortgage Bonds 2010 TEP Term Loan LIBOR + 2% 30 Mar-10 Sep-11 Par Sundt Unit 4 Secured UED Term Loan LIBOR + 3% 35 Feb-10 Mar-12 Par Black Mountain Mortgage Bonds *Supported by $341 million LOC facility which expires in Aug. 2011. 29