Duluth's three Edison Schools will keep their charter for three more years. Last night the Duluth school board narrowly voted to renew the contract after more than two hours of contentious debate. Critics -- and even some allies -- of Edison Schools, Inc., a for-profit company based in New York, said the vote was premature because the contract does not expire until next summer. New school board members set to take office in January are known to oppose the Edisons schools. But Edison proponents said they need to know where they stand with the Duluth board in order to properly plan for the next school year.