Exhibit 99.2

UniSource Energy Corporation

1st Quarter 2012 Supplemental Earnings Information

As of April 30, 2012

SAFE HARBOR AND NON-GAAP MEASURES

This document contains forward-looking information that involves risks and uncertainties, which 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 forecast assumptions and estimates below are not intended to be a full list of factors which could cause UniSource Energy’s future results to differ from current expectations. Please refer to UniSource Energy’s SEC filings for more information regarding risks and other uncertainties that could cause current expectations to differ from future results.

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.

UNISOURCE ENERGY 1ST QUARTER EARNINGS VARIANCE EXPLANATION

2 - Q1 Variance Explanation

UNISOURCE ENERGY AND TEP O&M

Base O&M, a non-GAAP financial measure, should not be considered as an alternative to Other O&M, which is determined in accordance with GAAP. We believe Base O&M provides useful information to investors because it represents the fundamental level of operating and maintenance expense related to our core utility business. Base O&M excludes expenses that are directly offset by revenues collected from customers and other third parties.

3 - O&M

TEP—OPERATING STATISTICS

4 - TEP Operating Stats

TEP—RETAIL AND WHOLESALE MARGIN REVENUES

Retail Margin Revenues, a non-GAAP financial measure, should not be considered as an alternative to Net Electric Retail Sales, which is determined in accordance with GAAP. Retail Margin Revenues excludes: (i) revenues collected from retail customers that are directly offset by expenses recorded in other line items; and (ii) revenues collected from third parties that are unrelated to kWh sales to retail customers. We believe the change in Retail Margin Revenues between periods provides useful information to investors because it demonstrates the underlying revenue trend and performance of our core utility business. Retail Margin Revenues represents the portion of retail operating revenues available to cover the operating expenses of our core utility business.

Long-Term Wholesale Margin Revenues, a non-GAAP financial measure, should not be considered as an alternative to Electric Wholesale Sales, which is determined in accordance with GAAP. We believe the change in Long-Term Wholesale Margin Revenues between periods provides useful information to investors because it demonstrates the underlying profitability of TEP’s long-term wholesale sales contracts. Long-Term Wholesale Margin Revenues represents the portion of long-term wholesale revenues available to cover the operating expenses of our core utility business.

5 - TEP Margin Revenues

UNS ELECTRIC—OPERATING STATISTICS

Retail Margin Revenues, a non-GAAP financial measure, should not be considered as an alternative to Total Retail Revenues, which is determined in accordance with GAAP. Retail Margin Revenues exclude revenues collected from retail customers that are directly offset by expenses recorded in other line items. We believe the change in Retail Margin Revenues between periods provides useful information to investors because it demonstrates the underlying revenue trend and performance of our core utility business. Retail Margin Revenues represents the portion of retail operating revenues available to cover the operating expenses of our core utility business.

6 - UNS Electric

UNS GAS —OPERATING STATISTICS

Retail Margin Revenues, a non-GAAP financial measure, should not be considered as an alternative to Total Gas Revenues, which is determined in accordance with GAAP. Retail Margin Revenues excludes revenues collected from retail customers that are directly offset by expenses recorded in other line items. We believe the change in Retail Margin Revenues between periods provides useful information to investors because it demonstrates the underlying revenue trend and performance of our core utility business. Retail Margin Revenues represents the portion of retail operating revenues available to cover the operating expenses of our core utility business.

7 - UNS Gas

BASIC AND DILUTED SHARES OUTSTANDING

Stock options to purchase 101,000 shares of Common Stock were outstanding during the three months ended March 31, 2012, but were not included in the computation of diluted EPS because the stock options’ exercise prices were greater than the average market price of the Common Stock. Similarly, for the three months ended March 31, 2011, 168,000 of stock options were not included in the diluted EPS computation.

For the three months ended March 31, 2012, 2.2 million potentially dilutive shares from the conversion of Convertible Senior Notes, and after-tax interest expense of $0.9 million were not included in the computation of diluted EPS because to do so would be anti-dilutive. In April 2012, holders of approximately $39 million of Convertible Senior Notes converted their interests into approximately 1.1 million shares of Common Stock. This conversion of Convertible Senior Notes to Common Stock had minimal impact on diluted EPS.

8 - Diluted Share Count