Exhibit 12A 

UniSource Energy Corporation

Computation of Ratio of Earnings to Fixed Charges

	9 Months Ended		12 Months Ended		12 Months Ended(2)
	Sept. 30		Sept. 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	$	54,733	$	73,024	$	75,039		$	76,762		$	80,968		$	80,844		$	65,620
Other Interest (1)		4,767		5,812		7,922			3,153			1,947			3,709			2,123
Interest on Capital Lease Obligations		48,390		65,929		72,586			79,098			85,912			84,080			87,801
Total Fixed Charges		107,890		144,765		155,547			159,013			168,827			168,633			155,544
Net Income		42,167		54,590		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		42,167		53,717		69,243			52,253			50,982			53,942			47,847
Add (Deduct):
(Income) Losses from Equity Investees		197		195		(210	)		(2,113	)		(7,121	)		3,051			3,047
Income Taxes		27,678		33,088		43,936			37,623			37,186			16,531			26,432
Total Fixed Charges		107,890		144,765		155,547			159,013			168,827			168,633			155,544
Total Earnings before Taxes and Fixed Charges	$	177,932	$	231,765	$	268,516		$	246,776		$	249,874		$	242,157		$	232,870
Ratio of Earnings to Fixed Charges		1.649		1.601		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.