Tucson Electric Power 10-Q 2007 Q2 Quarterly report

Exhibit 12(a)

UniSource Energy Corporation

Computation of Ratio of Earnings to Fixed Charges

	6 Months Ended		12 Months Ended			12 Months Ended(2)
	Jun. 30		Jun. 30			Dec. 31,			Dec. 31,			Dec. 31,			Dec. 31,			Dec. 31,
	2007		2007			2006			2005			2004			2003			2002
						- Thousands of Dollars -
Fixed Charges:
Interest on Long-Term Debt	$	36,265	$	74,492		$	75,039		$	76,762		$	80,968		$	80,844		$	65,620
Other Interest (1)		3,412		8,760			7,922			3,153			1,947			3,709			2,123
Interest on Capital Lease Obligations		32,278		67,790			72,586			79,098			85,912			84,080			87,801
Total Fixed Charges		71,955		151,042			155,547			159,013			168,827			168,633			155,544
Net Income		16,749		57,376			67,447			46,144			45,919			113,941			34,928
Less:
Discontinued Operations - Net of Tax		-		873			(1,796	)		(5,483	)		(5,063	)		(7,472	)		(12,919	)
Accounting Change - Net of Tax		-		-			-			(626	)		-			67,471			-
Net Income from Continuing Operations		16,749		56,503			69,243			52,253			50,982			53,942			47,847
Add (Deduct):
(Income) Losses from Equity Investees		174		(60	)		(210	)		(2,113	)		(7,121	)		3,051			3,047
Income Taxes		11,947		35,072			43,936			37,623			37,186			16,531			26,432
Total Fixed Charges		71,955		151,042			155,547			159,013			168,827			168,633			155,544
Total Earnings before Taxes and Fixed Charges	$	100,825	$	242,557		$	268,516		$	246,776		$	249,874		$	242,157		$	232,870
Ratio of Earnings to Fixed Charges		1.401		1.606			1.726			1.552			1.480			1.436			1.497

(1)  Excludes recognition of Allowance for Borrowed Funds Used During Construction.

(2)  The information previously reported has been reclassified for the discontinued operations of Global Solar, Inc.