1. All of the plaintiffs' claims are dismissed.

2. The costs of lawsuit are assessed against the plaintiffs.

1. Basic facts

A. The plaintiffs are the parties. 1) Since March 29, 2001, when the Incheon International Airport opened an open port, the plaintiffs are running private investment projects for hotel business, etc. in the Incheon International Airport area. The defendant Incheon Airport Energy Corporation (hereinafter "Defendant Airport Energy Corporation") through the defendant Airport Corporation.

2) The Defendant Airport Corporation is a corporation incorporated by the Incheon International Airport Corporation, constructing a new airport in the Seoul metropolitan area and operating the airport management, operation, maintenance and repair project.

3) The Defendant Airport Energy was a corporation established to supply electricity, etc. to the Incheon Airport area through the co-development of heat, which was licensed as an integrated energy supplier pursuant to the Integrated Energy Supply Act, and supplied electricity to business operators in the Incheon Airport area including the Plaintiffs through the Defendant Airport Corporation from March 29, 2001, when the supply of electricity to the Incheon Airport area was completed, from March 22, 201, as an operator of the district electric business. B. The instant concession agreement between the Ministry of Land, Infrastructure and Transport and the Defendant Airport Energy (hereinafter “the present Ministry of Land, Infrastructure and Transport”) was concluded on February 21, 1997 as a private business operator selected as a private business operator who supplies electricity, etc. to the Incheon Airport area in preparation for the open port of the Incheon Airport supplied by the Ministry of Land, Infrastructure and Transport on February 21, 1997.

2. Article 27 of the concession agreement of this case provides that "Energy user fees shall be the amount presented by the project operator, and energy user fees shall be lower than the unit price of the energy user fees of the Korea Electric Power Corporation, the Korea District Heating Corporation, and the Korea Energy Corporation, even if energy user fees are adjusted in the future."