Atlantic Power CORRESP Correspondence with SEC

January 6, 2012

BY EDGAR

Division of Corporation Finance
United States Securities and Exchange Commission
460 Fifth Street, NW
Washington, D.C. 20549

Attention:  Adam Phippen, Staff Accountant

Re:	Atlantic Power Corporation
	Form 10-K for Fiscal Year Ended December 31, 2010
	Filed March 18, 2011
	File No. 1-34691

Dear Mr. Phippen:

This letter is submitted on behalf of Atlantic Power Corporation (the “Company”) as a supplement to our response letter, dated January 4, 2012, to comments in a letter dated December 2, 2011 (the “Comment Letter”) from William H. Thompson of the staff (the “Staff”) of the Securities and Exchange Commission (the “Commission”) to Barry E. Welch, Chief Executive Officer of the Company with respect to the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2010 filed with the Commission on March 18, 2011 (the “filed Form 10-K”).

In our response to comment #4 of the Comment Letter, we indicated that we would supplementally provide the Staff with a spreadsheet showing the Company’s significance tests performed for the years ended December 31, 2010, 2009 and 2008.  We are filing that spreadsheet as an attachment to this letter via EDGAR.

As a further supplemental response to comment #7 of the Comment Letter, the Company hereby acknowledges that the language immediately prior to the signatures as prescribed by Form 10-K was inadvertently omitted from the filed Form 10-K and the Company hereby confirms that the filed Form 10-K was signed, on behalf of the Company, by the persons indicated in the filed Form 10-K and in the capacities and on the dates so indicated (including by the Company’s then-current principal executive officer, principal financial officer and at least a majority of the Company’s board of directors).

* * *

The Company acknowledges that:

·the Company is responsible for the adequacy and accuracy of the disclosure in the filing;

·staff comments or changes to disclosure in response to staff comments do not foreclose the Commission from taking any action with respect to the filing; and

·the Company may not assert staff comments as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

If you have any questions or would like further information concerning the Company’s responses to your Comment Letter, please do not hesitate to contact me at (617) 977-2400.

Sincerely,
	/S/ Barry E. Welch
	Barry E. Welch
	President and Chief Executive Officer

2

Atlantic Power Corporation

Analsyis of Significant Subsidiaries

For the Year Ended December 31, 2010

	Selkirk						Gregory						Badger						Orlando						Rumford						Mid-Georgia
	2010		2009		2008		2010		2009		2008		2010		2009		2008		2010		2009		2008		2010		2009		2008		2010		2009		2008
Equity earnings	(3,454	)	(280	)	(6,958	)	2,162		1,791		4,621		1,932		1,948		2,477		1,882		3,152		2,920		(359	)	(1,904	)	2,922		—		(2,686	)	(2,068	)
add back Investor-level impairment	—		—				—		—		—		—		—		—		—		—		—		—		5,500		—		—		—		—
Total	(3,454	)	(280	)	(6,958	)	2,162		1,791		4,621		1,932		1,948		2,477		1,882		3,152		2,920		(359	)	3,596		2,922		—		(2,686	)	(2,068	)
Consolidated pre-tax Income	15,069		(54,179	)	34,541		15,069		(54,179	)	34,541		15,069		(54,179	)	34,541		15,069		(54,179	)	34,541		15,069		(54,179	)	34,541		15,069		(54,179	)	34,541
Adjustment for loss periods, if applicable	3,454		—		6,958		—		(1,791	)	—		—		(1,948	)	—		—		(3,152	)			359		(3,596	)			—		—		2,068
Consolidated pre-tax income for purpose of test	18,523		(54,179	)	41,499		15,069		(55,970	)	34,541		15,069		(56,127	)	34,541		15,069		(57,331	)	34,541		15,428		(57,775	)	34,541		15,069		(54,179	)	36,609
Significance of investment (income test)	18.6	%	0.5	%	16.8	%	14.3	%	3.2	%	13.4	%	12.8	%	3.5	%	7.2	%	12.5	%	5.5	%	8.5	%	2.3	%	3.3	%	8.5	%	0.0	%	5.0	%	5.6	%
Equity investment balance	55,146		57,030		60,307		3,662		2,931		3,381		9,022		9,949		11,677		31,394		36,387		45,910		—		845		5,649		—		—		15,340
Consolidated assets	1,011,437		869,576		907,955		1,011,437		869,576		907,955		1,011,437		869,576		907,955		1,011,437		869,576		907,955		1,011,437		869,576		907,955		1,011,437		869,576		907,955
Significance of investment (investment test)	5.5	%	6.6	%	6.6	%	0.4	%	0.3	%	0.4	%	0.9	%	1.1	%	1.3	%	3.1	%	4.2	%	5.1	%	0.0	%	0.1	%	0.6	%	0.0	%	0.0	%	1.7	%
Financial statement requirement	None		None		None		None		None		None		None		None		None		None		None		None		None		None		None		None		None		None

Thresholds = 20% of pretax income or total assets
5 Year Average Net Income	2010	15,069
	2009	—
	2008	34,541
	2007	—
	2006	—
		49,610
	years	5
	Average	9,922	use current year net income as it is greater than the 5 year average