Commonwealth Edison S-3ASR Automatic shelf registration

Exhibit 12.4

PECO Energy Company

Ratio of Earnings to Fixed Charges

	2009			2010			2011			2012			2013			3 Months Ended March 31, 2014
Pre-tax income from continuing operations		499			476			535			508			557			123
Plus: Loss from equity investees		24			—			—			—			—			—
Less: Capitalized interest		(2	)		(4	)		(4	)		(2	)		(2	)		(1	)
Pre-tax income from continuing operations after adjustment for income or loss from equity investees and capitalized interest		521			472			531			506			555			122
Fixed Charges:
Interest expensed and capitalized, amortization of debt discount and premium on all indebtedness		185			193			135			122			114			28
Interest component of rental expense (a)		9			10			9			9			7			2
Total fixed charges		194			203			144			131			121			30
Pre-tax income from continuing operations after adjustment for income or loss from equity investees and capitalized interest plus fixed charges		715			675			675			637			676			152
Ratio of earnings to combined fixed charges		3.7			3.3			4.7			4.9			5.6			5.1

(a) Represents one-third of rental expense relating to operating leases, which is a reasonable approximation of the interest factor.

PECO Energy Company

Ratio of Earnings to Fixed Charges and Preferred Stock Dividends

	2009			2010			2011			2012			2013
Pre-tax income from continuing operations		499			476			535			508			557
Plus: Loss from equity investees		24			—			—			—			—
Less: Capitalized interest		(2	)		(4	)		(4	)		(2	)		(2	)
Preference security dividend requirements		(6	)		(6	)		(6	)		(5	)		(10	)
Pre-tax income from continuing operations after adjustment for income or loss from equity investees, capitalized interest and preference security dividend requirements		515			466			525			501			545
Fixed Charges:
Interest expensed and capitalized, amortization of debt discount and premium on all indebtedness		185			193			135			122			114
Interest component of rental expense (a)		9			10			9			9			7
Preference security dividend requirements		6			6			6			5			10
Total fixed charges		200			209			150			136			131
Pre-tax income from continuing operations after adjustment for income or loss from equity investees, capitalized interest and preference security dividend requirements plus fixed charges		715			675			675			637			676
Ratio of earnings to fixed charges and preferred stock dividends		3.6			3.2			4.5			4.7			5.2

(a) Represents one-third of rental expense relating to operating leases, which is a reasonable approximation of the interest factor.