BrightSource Energy and Edison Intl. cancelled a power purchase agreement for the planned Rio Mesa solar field, throwing the future of the 500 MW project into limbo. Three months after the California Public Utilities Commission denied a purchase agreement between BrightSource and Edison for half of the Rio Mesa solar site, the developer and utility cancelled a deal for 200 MW for a planned adjoining field. \u201cAfter more than a year of permitting review, we concluded that there remained a number of areas at the Rio Mesa site which required additional analysis,\u201d BrightSource explained in a prepared release. The full project is now on hold. The project\u2019s suspension is the latest setback for Rio Mesa, which had been conceptually downsized and retooled since BrightSource\u2019s initial application in October 2011. The facility was originally designed as a 7,500 acre, 750 MW project and would have sat on the Palo Verde Mesa, 13 miles southwest of Blythe. It then was downsized in mid-2012, to consist of two 250 MW solar concentration thermal power plants instead of three. The two plants, Rio Mesa 1 and Rio Mesa 2, were set to generate a combined 500 MW on about 3,805 acres of private land leased from the Metropolitan Water District of Southern California. Each plant was supposed to utilize a solar power boiler on top of a 750-foot high concrete tower surrounded by fields of about 85,000 heliostat mirrors focusing solar energy on the boiler. The facility was to interconnect with Southern California Edison\u2019s grid through a 220 kV line that would be built as part of the project. It would have run north about 10 miles to link with the Colorado River Substation. On Oct. 25, 2012, the commission denied Edison\u2019s power purchase agreement for the Rio Mesa 1 solar plant but approved the other half. Regulators said that the full project compared \u201cpoorly on price and value relative to other solar thermal projects.\u201d The smaller, approved, project is now delayed for at least a year. At the request of the Oakland-based BrightSource the project\u2019s on hold for 12 months, but on the condition it be monitored.