A filing with the state from Cape Wind officials identifies several companies interested in participating in the controversial energy project, including a leading Spanish energy engineering firm.
The filing, made Friday by attorney David S. Rosenzweig, argues against Attorney General Martha Coakley’s attempt to review cost and profit estimates for the proposed offshore wind farm. The information, Rosenzweig wrote, is “irrelevant to, and outside the proper scope’’ of the state’s scrutiny of a proposed contract between Cape Wind and utility company National Grid.
Cape Wind’s developers have previously said they feel the information is proprietary and should remain confidential. In its Friday filing, Cape Wind also argued that giving Coakley the data she seeks would be “inconsistent with department precedent,’’ as well as federal and state supreme court case law.
The filing includes letters of support from a division of the Spanish firm Iberdrola; Siemens Energy Inc., which has an agreement to provide the turbines for Cape Wind; the insurance advisory firm Willis of Massachusetts Inc. that is hoping to become Cape Wind’s insurance broker; and a joint venture called Kiewit/Weeks/Cashman that is hoping to help construct the project.
In May, the utility National Grid agreed to purchase power from Cape Wind, which recently gained federal approval to build turbines in Nantucket Sound. The agreement was seen as a crucial step to attract financing to build Cape Wind. The contract agreement is subject to approval by the state Department of Public Utilities. As the state’s advocate for ratepayers, the attorney general is reviewing the deal.
Coakley argues that the cost and profit estimates she requested are necessary to determine whether power generated by the 130-turbine wind farm is cost effective — one of the criteria state officials must consider.
Erin Ailworth can be reached at eailworth@globe.com. 
