9. Employee incentive programs

Long-Term Incentive Program

The following table summarizes the changes in LTIP notional units during the nine months ended September 30, 2013:

(Units in thousands)			Grant Date Weighted-Average Price per Unit

Outstanding at December 31, 2012	492,535		$	13.88
Granted	597,031			4.91
Reinvested	45,344			9.12
Forfeited	(138,473	)		8.88
Vested	(202,696	)		13.48

Outstanding at September 30, 2013	793,741		$	7.76

Certain awards have a market condition based on our total shareholder return during the performance period compared to a group of peer companies and, in some cases, Project Adjusted EBITDA per common share compared to budget. Compensation expense for notional units granted in 2013 is recorded net of estimated forfeitures. See Note 14 to the consolidated financial statements in our Annual Report on Form 10-K for the year ended December 31, 2012 for further details. Cash payments made for vested notional units for the nine months ended September 30, 2013 was $0.9 million. Compensation expense for LTIP was $0.4 million and $1.7 million for the three and nine months end September 30, 2013, respectively.

The calculation of simulated total shareholder return under the Monte Carlo model for the remaining time in the performance period for awards with market conditions included the following assumptions as of September 30, 2013 and December 31, 2012:

	September 30, 2013	December 31, 2012

Weighted average risk free rate of return	0.0 – 0.5%	0.1 – 0.3%
Dividend yield	9.0%	10.1%
Expected volatility—Atlantic Power	42.2%	22.5%
Expected volatility—peer companies	10.6 – 96.3%	11.9 – 97.1%
Weighted average remaining measurement period	2.1 years	1.4 years