Exhibit 99.1

Niska Gas Storage Partners LLC Announces Results for the Fourth Quarter and Fiscal Year ended March 31, 2011

Houston, Texas — May 18, 2011 - Niska Gas Storage Partners LLC (“Niska”) (NYSE: NKA) reported today Adjusted EBITDA (as defined below) for its fiscal year ended March 31, 2011 of $195.5 million, consistent with the Company’s previous guidance and compared to Adjusted EBITDA of $223.8 million for the fiscal year ended March 31, 2010.  Adjusted EBITDA for the quarter ended March 31, 2011 was $61.2 million compared to $78.8 million in the same period last year.  Cash Available for Distribution (as defined below) was $117.5 million and $38.7 million for the fiscal year and quarter ended March 31, 2011, respectively.  Net earnings for Niska’s fiscal year ended March 31, 2011 were $57.5 million compared to $53.2 million in the fiscal year ended March 31, 2010.  Net earnings for the quarter ended March 31, 2011 were $27.9 million compared to $50.0 million in the quarter ended March 31, 2010.  Earnings per common and subordinated unit were $0.40 for the quarter ended March 31, 2011 and $0.31 for the period May 17, 2010 (the completion of Niska’s initial public offering) to March 31, 2011.

“We are very pleased with our results for the fourth quarter and fiscal year ended March 31, 2011,” said Dave Pope, President and CEO of Niska.  “Our Adjusted EBITDA for the year was within our guidance of $190 million to $205 million, and our Cash Available for Distribution produced a coverage ratio of 1.13 to 1.0. Beyond our financial results, we were able to organically add 19 billion cubic feet (“Bcf”) of working gas capacity at an extremely low average cost of $1.86 per thousand cubic feet (“Mcf”). The ability to add capacity at this cost is a reflection on how well we know our assets and the depth of our engineering capabilities. We were able to produce these results in a weaker storage spread environment, which reflects the advantages of our diversified commercial model as well as the skill and expertise of our employees.”

“We remain confident in our ability to pay our distribution and will continue our organic expansion plans for fiscal 2012,” added Mr. Pope, “These plans include the expansion of our Wild Goose facility by 15 Bcf up to its maximum permitted capacity of 50 Bcf. However, the continuation of a weaker storage spread environment limits our current visibility with respect to short-term firm and optimization revenues and, accordingly, our ability to make reliable predictions of these amounts.  Therefore, we are not providing guidance for fiscal 2012 at this time.”

As announced April 26, 2011, Niska paid a cash distribution of $0.35 per unit on May 13, 2011 to unitholders of record at the close of business on May 6, 2011.

Earnings Call

Niska will host a conference call with members of our executive management on Thursday, May 19, 2011, at 10:00 a.m. Eastern Time. Interested parties may access the call via our website at www.niskapartners.com. A webcast is also available on the Thomson Reuters Street Events network at www.earnings.com.

If you are unable to participate in the webcast, you may access the live conference call by dialing the following numbers:

A telephonic replay can be accessed until midnight, May 26, 2011 at the following numbers:

In addition, an electronic replay and PDF transcript will be available on the Niska website in the Investor Center section under the Presentations and Webcasts Tab.

About Niska

Niska is the largest independent owner and operator of natural gas storage in North America, with strategically located assets in key natural gas producing and consuming regions. Niska owns and operates three facilities, including the AECO Hub™ in Alberta, Canada; Wild Goose in California; and Salt Plains in Oklahoma. Niska also contracts gas storage capacity on the Natural Gas Pipeline Company of America system. In total, Niska owns or contracts approximately 204.5 Bcf of gas storage capacity.

Forward Looking Statements

This press release includes “forward-looking statements” — that is, statements related to future, not past, events. Forward-looking statements are based on current expectations and include any statement that does not directly relate to a current or historical fact.  In this context, forward-looking statements often address our expected future business and financial performance, and often contain words such as “anticipate,” “believe,” “intend,” “expect,” “plan,” “will” or other similar words. These forward-looking statements involve certain risks and uncertainties that ultimately may not prove to be accurate. Actual results and future events could differ materially from those anticipated in such statements. For further discussion of risks and uncertainties, you should refer to Niska’s SEC filings. Niska undertakes no obligation and does not intend to update these forward-looking statements to reflect events or circumstances occurring after this press release. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release. All forward-looking statements are qualified in their entirety by this cautionary statement.

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Non-GAAP Financial Measures

Niska uses and discloses the financial measures “Adjusted EBITDA” and “Cash Available for Distribution” in this press release.  Niska defines Adjusted EBITDA as net earnings before interest, income taxes, depreciation and amortization, unrealized risk management gains and losses, foreign exchange gains and losses, unrealized inventory impairment write-downs, gains and losses on asset dispositions, asset impairments and other income.  Niska defines Cash Available for Distribution as Adjusted EBITDA reduced by interest expense (excluding amortization of deferred financing costs and the effects of unrealized gains or losses on interest rate swaps), income taxes paid and maintenance capital expenditures.  Niska’s Adjusted EBITDA and Cash Available for Distribution are not presentations made in accordance with Generally Accepted Accounting Principles in the United States (“GAAP”).  Niska’s management utilizes Adjusted EBITDA and Cash Available for Distribution as key performance measures in order to assess:

·                  The financial performance of our assets, operations and return on capital without regard to financing methods, capital structure or historical cost basis;

·                  The ability of our assets to generate cash sufficient to pay interest on our indebtedness and make distributions to our equity holders;

·                  Repeatable operating performance that is not distorted by non-recurring items or market volatility; and

·                  The viability of acquisitions and capital expenditure projects.

The GAAP measure most directly comparable to Adjusted EBITDA and Cash Available for Distribution is net earnings. For a reconciliation of Adjusted EBITDA to net earnings, please see the schedule provided in the attached pages.

Niska believes that investors benefit from having access to the same financial measures used by Niska’s management. Further, Niska believes that these measures are useful to investors because they are one of the bases for comparing Niska’s operating performance with that of other companies with similar operations, although Niska’s measures may not be directly comparable to similar measures used by other companies.

Contact

Niska Gas Storage Partners LLC

Investor Relations:

Brandon Tran or Vance Powers

(403) 513-8600

NISKA GAS STORAGE PARTNERS LLC

CONSOLIDATED STATEMENTS OF EARNINGS

(in thousands of U.S. dollars)

(unaudited)

NISKA GAS STORAGE PARTNERS LLC

SELECTED FINANCIAL DATA AND NON-GAAP RECONCILIATIONS

(in thousands of U.S. dollars, except capacity amounts)

(unaudited)