The purchaser is ENSTOR, Inc., the Houston-based natural gas storage unit of Spanish-listed IBERDROLA RENEWABLES, part of the Spanish utility Iberdrola, S.A., group of companies. Credit Suisse acted as financial advisor to the sellers. The transaction is expected to close in the second quarter of 2008.

TPF, a private equity limited partnership, has been joint owner of CEP since 2006. A portion of CEP also is owned by the original sponsors of the project along with certain individuals who have been involved in the development and operation of the facility throughout its history. Pacesetter Energy, Inc., a Flower Mound, Texas-based integrated energy company, led the design, engineering and operations of the Caledonia Gas Storage Field.

The Caledonia gas storage facility currently is permitted to store 11.7 billion cubic feet (0.33 billion cubic meters) of working natural gas. A permit to expand the facility to 16.9 billion cubic feet (0.48 billion cubic meters) of working gas is currently pending approval by the Federal Energy Regulatory Commission.

The facility is fully subscribed on firm storage through March 2010, and is strategically interconnected with Tennessee Gas Pipeline in Mississippi. This pipeline provides 2 billion cubic feet per day (0.06 billion cubic meters per day) of gas supplies to growing natural gas demand markets in the Northeast, Southeast and Ohio Valley regions of the U.S. and can provide customers with firm and interruptible storage opportunities.

"TPF and its partners in CEP have taken what was a depleted natural gas reservoir in 2006 and converted it into one of the most modern and efficient gas storage facilities in the U.S.," said Paul Smith, Tenaska Capital senior managing director. "The purchase of CEP by ENSTOR indicates the growing need for and value of storage in the natural gas industry."

Matt Morrow, ENSTOR president and a senior vice president at IBERDROLA RENEWABLES, Inc., said the Caledonia facility, combined with ENSTOR's Freebird Gas Storage Facility, will enhance the company's ability to give customers superior services, rapid injection and withdrawal capacity, and a range of contract options. "We are committed to providing storage services with the operational flexibility demanded by volatile North American natural gas markets, and Caledonia will help us meet those needs."

About Tenaska Power Fund, L.P.

Tenaska Power Fund, L.P. (TPF) is a stand-alone private equity partnership of institutional investors. TPF invests in a diverse group of energy and power companies and assets in the United States, and has in excess of $3 billion of assets under management. For more information, please visit http://www.tenaska.com

About Caledonia Energy Partners, L.L.C.

Caledonia Energy Partners, L.L.C. (CEP) is a privately-held company based in Dallas, Texas. The original sponsors, Bob Millard and Tony Roosevelt, are two proven energy industry executives with combined experience in excess of 50 years. They have held senior management positions in both public and private energy companies of all sizes and are part of CEP's executive management team. CEP is jointly owned by Tenaska Power Fund, L.P., the two original sponsors of the project and other individual members.

About Pacesetter Energy, Inc.

Pacesetter Energy, Inc. (Pacesetter) is involved in the design, development and operations of midstream energy assets, oil field services and oil and gas exploration. Pacesetter was established in 1993 by Bob Millard. Its principals and managers have extensive experience in all aspects of the oil and gas industry.

About ENSTOR, Inc.

ENSTOR, Inc., a subsidiary of IBERDROLA RENEWABLES, through its subsidiaries manages operations and the development of IBERDROLA RENEWABLES' owned natural gas storage business. ENSTOR provides operational flexibility and reliability of supply that its natural gas and cogeneration customers increasingly demand throughout North America. At December 31, 2007, the company's natural gas storage capacity in the United States stood at approximately 1.7 billion cubic meters and an additional capacity of 1.3 bcm of storage capacity was under development.

About IBERDROLA RENEWABLES

IBERDROLA RENEWABLES engages in the development, construction and operation of power plants that use renewable energy sources, as well as the sale of the electric energy that they produce. The company's business activity is currently centered on wind energy and on small hydroelectric power stations, as well as solar photovoltaic energy. In addition, it has started to develop other technologies such as thermal solar energy and the energy coming from biomass and from tides. IBERDROLA RENEWABLES is supported by Iberdrola, S.A., one of the five biggest electricity companies in the world, which has placed the environment and sustainable development at the centre of its strategic plans.