Solar Power Inc. said problems with a planned solar-power installation project, expected to generate $23 million in revenue, could lower its 2008 revenue guidance of $60 million.

The Roseville-based company (OTCBB: SOPW) said in a press release that the Santa Rosa City School District has delayed a vote on whether to proceed with the installation of more than three megawatts of on-site solar electricity production at 10 of the district's 30 schools.

While negotiating the contract, the company and its joint venture partner Solar Power Integrators learned that many areas of the roofs were unsuitable for large solar-power systems. The companies suggested building elevated solar structures on the ground that would cover 1,000 parking spaces and provide more than 56,000 square feet of covered outdoor lunch and recreation areas for students.

The school district has reservations for rebates on four megawatts of solar power from the state of California. One megawatt is enough power to supply about 750 California homes.