LS Power and Global Infrastructure Partners Jointly Propose
Acquisition of TransAlta for C$39 per Share

Proposal would provide a 21 percent premium to TransAlta shareholders
as of the close of markets on Friday July 18, 2008

TransAlta headquarters and corporate infrastructure would remain in Alberta

Support of TransAlta Board of Directors and management sought for transaction.

New York City, U.S.A. (July 21, 2008) — LS Power Equity Partners (LS Power) and Global Infrastructure Partners (GIP) today announced that they have jointly made a proposal (see letter attached) to TransAlta Corporation (TSX:TA, NYSE:TAC) to acquire all outstanding TransAlta common stock for a price per share of C$39 in an all-cash transaction. The proposal represents a 21 percent premium above the closing price of TransAlta common stock on July 18, 2008 and a premium to the stock’s 52-week (and all time) high. 

“We have a great deal of respect for TransAlta, its employees, its Board of Directors, its management team led by Steve Snyder, and its heritage.  Furthermore, we have confidence in the underlying value proposition that TransAlta’s business provides,” said James Bartlett, President of LS Power Equity Advisors, LLC, speaking on behalf of LS Power and GIP.  “To that end, we believe that our proposal for TransAlta provides shareholders with compelling value.  It also provides continuity for the company’s customers, employees, management and communities where it operates.”

LS Power and its affiliates are shareholders of TransAlta and currently hold approximately nine (9) percent of TransAlta’s common stock.  This proposal is being made public pursuant to US securities regulations.

Compelling proposal

The proposed transaction offers TransAlta shareholders compelling value.  This fact, coupled with the commitment to maintaining TransAlta’s well-deserved status as a corporate leader in the Albertan and Canadian business communities, makes this an attractive proposal for all stakeholders.  TransAlta would continue on a business-as-usual basis, headquartered in Calgary.

LS Power and GIP are committed to working closely with TransAlta’s Board of Directors and management as they evaluate this proposal.  The goal is to successfully complete a consensual, negotiated transaction that is supported by the TransAlta Board of Directors and management.

The right partners for TransAlta

LS Power is an experienced owner and operator of power generation assets throughout the United States.  GIP is an organization that invests in infrastructure companies and assets worldwide.  In a private company structure, with owners taking a long-term view, TransAlta and its leadership would have significant flexibility in making strategic investments and plans that benefit stakeholders.

“We are convinced that we are the right partners for TransAlta, as management would have enhanced flexibility to execute longer-term strategies for growth,” concluded Mr. Bartlett.

Letter sent to the CEO of TransAlta

About LS Power
LS Power is a fully integrated power sector focused development, investment and asset management group with a proven track record of successful development activities, operations management and commercial execution. LS Power has developed gas-fired and coal-fired facilities in various jurisdictions. LS Power currently owns and is developing a diverse mix of power generation facilities fueled by natural gas, coal, and renewable resources, including wind and solar.

About Global Infrastructure Partners
Global Infrastructure Partners is an independent fund that invests worldwide in infrastructure assets in both OECD and select emerging market countries. GIP targets investments in single assets, portfolios of assets, and companies in the energy, transport, water, and waste management sectors. GIP has offices in New York, London and Hong Kong and Operational Headquarters in Stamford, Connecticut. Credit Suisse and General Electric are the founding investors of GIP. 

For more information please visit: www.global-infra.com

Cautionary Statement Regarding Forward Looking Statements and Regarding the Nature and Legal Effect of the Proposal

Some information in this news release may be forward-looking. Implicit in that information are assumptions and expectations which, although considered reasonable by us, may prove to be incorrect. Actual future outcomes and results, including whether our proposal is acted upon by TransAlta, whether a transaction and the definitive documentation relating thereto are agreed to by the parties and whether the conditions relating to such transaction are satisfied, are subject to a number of risks and uncertainties, and could differ materially from what is currently proposed or planned as described herein.  You should not place undue importance on forward-looking information. While we may elect to, we are under no obligation and do not undertake to update this information at any particular time.

The non-binding proposal is subject to, among other things, the satisfactory completion of confirmatory due diligence, the negotiation and execution of a definitive agreement on mutually agreeable terms and the receipt of any necessary corporate and other third party approvals, including the approval of TransAlta's Board of Directors and shareholders. No binding obligation will arise with respect to the proposed transaction unless and until a definitive agreement with TransAlta has been executed and delivered.