AltaGas Ltd. Receives Final Approval From Michigan Public Service Commission for SEMCO Acquisition

CALGARY, ALBERTA--(Marketwire - May 24, 2012) - AltaGas Ltd. ("AltaGas") (TSX:ALA) (TSX:ALA.PR.A) (TSX:ALA.R) and Continental Energy Systems LLC ("Continental") today announced that the Michigan Public Service Commission ("MPSC") approved the Settlement Agreement for AltaGas' acquisition of Semco Holding Corporation ("SEMCO").

AltaGas previously announced the proposed acquisition of SEMCO on February 1, 2012, subject to receipt of all regulatory approvals. SEMCO is the sole shareholder of SEMCO Energy Inc., a privately held regulated public utility company headquartered in Port Huron, Michigan. SEMCO indirectly holds a regulated natural gas distribution utility in Alaska through ENSTAR Natural Gas Company and an interest in a regulated natural gas storage utility in Alaska under construction called Cook Inlet Natural Gas Storage Alaska, LLC. SEMCO also indirectly holds a regulated natural gas distribution utility and an interest in a natural gas storage facility in Michigan.

The process for obtaining regulatory approval from the Regulatory Commission of Alaska is progressing with a hearing date scheduled for May 30, 2012.

Closing of the transaction is expected in third quarter 2012 after receipt of all regulatory approvals.

AltaGas is an energy infrastructure business with a focus on natural gas, power and regulated utilities. AltaGas creates value by acquiring, growing and optimizing its energy infrastructure, including a focus on renewable energy sources. For more information visit: www.altagas.ca.

This news release contains forward-looking statements. When used in this news release, the words "may", "would", "could", "will", "intend", "plan", "anticipate", "believe", "seek", "propose", "estimate", "expect", and similar expressions, as they relate to AltaGas or an affiliate of AltaGas, are intended to identify forward-looking statements. In particular, this news release contains forward-looking statements with respect to, among other things, business objectives, expected growth, results of operations, performance, business projects and opportunities and financial results. These statements involve known and unknown risks, uncertainties and other factors that may cause actual results or events to differ materially from those anticipated in such forward-looking statements. Such statements reflect AltaGas' current views with respect to future events based on certain material factors and assumptions and are subject to certain risks and uncertainties, including without limitation, changes in market, competition, governmental or regulatory developments, general economic conditions and other factors set out in AltaGas' public disclosure documents. Many factors could cause AltaGas' actual results, performance or achievements to vary from those described in this news release, including without limitation those listed above. These factors should not be construed as exhaustive. Should one or more of these risks or uncertainties materialize, or should assumptions underlying forward-looking statements prove incorrect, actual results may vary materially from those described in this news release as intended, planned, anticipated, believed, sought, proposed, estimated or expected, and such forward-looking statements included in, or incorporated by reference in this news release, should not be unduly relied upon. Such statements speak only as of the date of this news release. AltaGas does not intend, and does not assume any obligation, to update these forward-looking statements. The forward-looking statements contained in this news release are expressly qualified by this cautionary statement.