PORTLAND — Concerned about the future of the planned Ocean Avenue elementary school, an energy-conscious philanthropist has increased his planned donation to the project.

Fred Padula, a retired University of Southern Maine history professor, had planned to give $20,000 to the project to ensure that it would be LEED certified for energy efficiency.

In an e-mail sent yesterday to Mayor Edward Suslovic, Padula said he would increase his donation to $75,000 to add a solar heating system to the school. He did the same for East End Elementary School and Lincoln Middle School.

On Monday, a plan to borrow $19.6 million to build the new school failed to win council approval on a 6-3 vote. Suslovic and Councilors David Marshall and Kevin Donoghue were opposed.

The council needs seven votes to issue bonds. The state would reimburse the money.

The council's action also scuttled a planned June 10 referendum on the school project, removing an opportunity for citizens to consider the issue.

"I strongly support the notion that (there) should be a public referendum," Padula wrote to Suslovic. "I don't understand why certain councilors are opposed to the project."