Aries Power Project available to dispatch 320 MW of power

PLEASANT HILL, Mo., July 16, 2001 — Calpine Corporation and Aquila, Inc., the energy services subsidiary of UtiliCorp United, announced the Aries Power Project has entered simple-cycle operations.

Located near Pleasant Hill, Mo., Aries is a new, highly efficient natural gas-fired power project intended to serve the growing demand for electricity in the region. Initially, the facility will be able to respond to peak summer demand by operating in a simple-cycle phase. The simple cycle configuration utilizes two natural gas fueled combustion turbines and generates 320 megawatts of electricity.

Beginning October 1, the project will temporarily cease operations to complete the construction necessary to bring a steam turbine online in January 2002. Upon completion, Aries will become a combined-cycle plant providing a total of 600 MW of power to Missouri and the surrounding area.

Aries Power Project is a joint venture between Calpine Corporation and Aquila, Inc. Calpine is responsible for operations and maintenance, and Aquila is responsible for commercial optimization and power sales.

Throughout simple-cycle operation, all of the electrical output of the Aries Power Project will be sold under contract to Missouri Public Service, providing reliability to its customer base and meeting the increasing power demands of the area. Missouri Public Service is also owned by UtiliCorp United. Once the project is converted to combined-cycle in 2002, additional energy will be sold into the Southwest Power Pool (SPP) wholesale power market.

“As a result of this collaborative effort, the Aries Power Project will provide clean, reliable power for years to come,” commented Bob Bingham, Calpine’s plant manager. “The geographic location of this new facility enables us to meet the increasing power demands of Missouri and the SPP with the most innovative and reliable technology available.”

“From concept to the first day of operation we knew this project was a winner,” stated Brad Nordholm, senior vice president and general manager of Aquila’s Capacity Services. “This is a combined effort that will benefit many people in the years ahead.”

Aquila, Inc. is a provider of risk management services and a wholesaler of electricity and natural gas in North America. It also provides wholesale energy services in the U.K. and has a presence in Bermuda, Scandinavia and Germany. Aquila is 80 percent owned by UtiliCorp United, an international energy company with more than 4 million customers across the U.S. and in Canada, Great Britain, New Zealand and Australia.

Based in San Jose, Calif., Calpine Corporation is dedicated to providing customers with reliable and competitively priced electricity. Calpine is focused on clean, efficient, natural gas-fired generation and is the world’s largest producer of renewable geothermal energy. Calpine has launched the largest power development program in North America. To date, the company has approximately 34,000 megawatts of base load capacity and 7,380 megawatts of peaking capacity in operation, under construction, pending acquisition and in announced development in 29 states, the UK and Canada. The company was founded in 1984 and is publicly traded on the New York Stock Exchange under the symbol CPN. For more information about Calpine, visit its Website at www.calpine.com.