Exelon (NYSE:EXC) reported earnings (link saves as PDF) today, beating analyst estimates on both top-line and bottom-line numbers.

First-quarter 2013 sales clocked in at $6.89 billion, 11% above analyst expectations of $6.2 billion. This quarter's results are 9.7% higher than Q4 2012, and up 47% from 2012's first quarter (before the company's Constellation merger).

On the bottom line, adjusted EPS fell 17.6% year over year to $0.70, but still managed to beat analyst estimates by $0.02.

CEO Christopher Crane pointed to solid nuclear fleet capacity, improving power prices, and increasingly large synergies from last year's merger as reasons for Exelon's success.

Looking ahead, the utility reaffirmed its Q2 $0.50 to $0.60 guidance, as well as its 2013 $2.35 to $2.65 EPS, despite lower expected margins for its Constellation segment.

Fool contributor Justin Loiseau has no position in any stocks mentioned, but he does use electricity. You can follow him on Twitter, @TMFJLo, and on Motley Fool CAPS, @TMFJLo.

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