Basic and diluted earnings (loss) per share (Tables)

6 Months Ended

Jun. 30, 2018

Basic and diluted earnings (loss) per share

Schedule of diluted net income and potentially dilutive shares utilized in the per share calculation

	Three Months Ended June 30,				Six Months Ended June 30,
Basic	2018		2017		2018		2017
Numerator:
Net (loss) income attributable to Atlantic Power Corporation	$	(0.6)	$	(21.9)	$	15.2	$	(24.6)
Denominator:
Weighted average basic shares outstanding		112.4		115.2		113.6		115.0
Basic (loss) earnings per share attributable to Atlantic Power Corporation	$	(0.01)	$	(0.19)	$	0.13	$	(0.21)
Diluted
Numerator:
Net (loss) income attributable to Atlantic Power Corporation	$	(0.6)	$	(21.9)	$	15.2	$	(24.6)
Add: convertible debenture interest expense		—		—		2.2		—
		(0.6)		(21.9)		17.4		(24.6)
Denominator:
Weighted average basic shares outstanding		112.4		115.2		113.6		115.0
Convertible debentures		—		—		26.5		—
Share-based compensation		—		—		—		—
		112.4		115.2		140.1		115.0
Diluted (loss) earnings per share attributable to Atlantic Power Corporation	$	(0.01)	$	(0.19)	$	0.13	$	(0.21)

Schedule of computation of our diluted earnings (loss) per share

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
Share-based compensation		2.6		2.6		5.4		2.6
Convertible debentures		29.1		8.1		—		8.1
Total		31.7		10.7		5.4		10.7