Exhibit 12a

UniSource Energy Corporation
Computation of Ratio of Earnings to Fixed Charges

	12 Months Ended
	Dec. 31,		Dec. 31,		Dec. 31,			Dec. 31,			Dec. 31,			Dec. 31,
	2008		2007		2006			2005			2004			2003
	- Thousands of Dollars -
Fixed Charges:
Interest on Long-Term Debt	$	70,227	$	73,095	$	75,039		$	76,762		$	80,968		$	80,844
Other Interest (1)		1,837		5,480		7,922			3,153			1,947			3,709
Interest on Capital Lease Obligations		57,272		64,499		72,586			79,098			85,912			84,080
Estimated Interest Portion of Rental Expense		188		258		326			391			453			552
Total Fixed Charges		129,524		143,332		155,873			159,404			169,280			169,185
Net Income		14,021		58,373		67,447			46,144			45,919			113,941
Less:
Discontinued Operations – Net of Tax		—		—		(1,796	)		(5,483	)		(5,063	)		(7,472	)
Extraordinary Income & Accounting Change – Net of Tax		—		—		—			(626	)		—			67,471
Net Income from Continuing Operations		14,021		58,373		69,243			52,253			50,982			53,942
Add (Deduct):
(Income) Losses from Equity Investees		713		340		(210	)		(2,113	)		(7,121	)		3,051
Income Taxes		16,976		39,079		43,936			37,623			37,186			16,531
Total Fixed Charges		129,524		143,332		155,873			159,404			169,280			169,185
Total Earnings before Taxes and Fixed Charges	$	161,234	$	241,124	$	268,842		$	247,167		$	250,327		$	242,709
Ratio of Earnings to Fixed Charges		1.245		1.682		1.725			1.551			1.479			1.435

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