Hawaiian Electric Co. has signed an agreement to buy solar power from a developer that is building a 1-megawatt photovoltaic project on a former industrial waste site near Campbell Industrial Park.

The 12-acre project will feature 4,200 solar panels generating enough power to supply about 200 Oahu homes. The project is being developed by Forest City Hawaii and the panels will be installed by Hoku Solar.

The 12-acre site was an industrial waste site until 1986 when the Environmental Protection Agency ordered its closure, according to a news release from participants in the project. Forest City said it hopes to have the project online by the end of  2011, subject to regulatory approvals.