Constellation Energy Group Selects InSITE SERVICES, Leading Energy Billing Services ASP.

Business Editors

NEW YORK--(BUSINESS WIRE)--April 25, 2000

Constellation Energy Source to market InSITE's Utility Navigator(R)

to commercial and industrial customers

InSITE SERVICES LLC, the pioneering application service provider that fosters next-generation utilities, announced today that Constellation Energy Source (NYSE: CEG), a subsidiary of Constellation Energy Group, will market InSITE's Utility Navigator(R) bill payment and information analysis service to its large commercial and industrial customer base.

Completely Web-based, Utility Navigator's comprehensive utility bill payment, reporting and analysis tools examine utility usage of all types. Hosted by InSITE, Utility Navigator is a proven strategic resource and business planning tool that enables commercial and industrial customers to understand--and then optimize--their energy usage and costs. By offering instant access to usage information, metrics and benchmarks, Utility Navigator positions ESPs as the key resource to large customers that need to manage utility usage and costs for all their locations.

"InSITE's Utility Navigator service helps our engineers to understand our customers' energy needs better. We have become the key resource our customers rely on to control their energy costs and to manage bill processing and payment. This is an especially critical need as competition heats up in newly deregulated areas of the country," said Jack Disney, vice president of Operations for Constellation Energy Source. "By understanding our customers' utility consumption patterns, we become a more valuable knowledge partner."

"As a premier energy service provider in the Mid-Atlantic region, Constellation Energy Source fully appreciates the market dynamics powering the changes in the energy industry," said Ben Blumberg, executive vice president and general manager of Utility Navigator. "With Navigator as a part of its competitive arsenal, Constellation Energy Source can provide enhanced value to its large customers while simultaneously differentiating itself from competitors."

Last month, InSITE announced that it will process more than $1 billion in utility bills through its Utility Navigator service.

About Constellation Energy Source

Constellation Energy Source is a subsidiary of Constellation Energy Group (CEG), Inc. CEG was formed in 1999 and is a holding company whose subsidiaries include energy related businesses focused on power marketing and generation and nuclear license renewal services, plus Baltimore Gas and Electric, which provides service to more than 1.1 million electric customers and some 570,000 natural gas customers in Central Maryland. For more information about the Company, please visit www.cesource.com.

About InSITE SERVICES

InSITE SERVICES is the pioneering application service provider fostering next-generation utilities through strategic, customer-focused and Web-enabled billing solutions. Founded in 1995 to provide billing and energy information services to an increasingly competitive energy industry, InSITE's sole focus is on energy information and billing applications, with a commitment to delivering the highest quality and value services in the industry. With EnerEDI(TM), EnerBill(TM), and Utility Navigator(R), InSITE provides innovative and best-of-breed billing and information services to companies throughout North America, focusing much of its efforts on states in the midst of deregulation. For more information about InSITE SERVICES, visit www.insiteservices.com.