A head teacher said his school could no longer afford new text books after its gas bill went up by more than £100,000.
Vic Goddard, the head of a trust made up of four schools in Harlow, Essex, said he was struggling to sleep because of the "frightening" situation.
"I came into this job to make a difference, but how can I do that when we have no resources?" he said.
The government said it was increasing budgets for schools and recommending energy deals.
Mr Goddard, the chief executive officer of Passmores Cooperative Learning Community, said the trust would not be able to subsidise school trips in the future and had stopped providing pupils with laptops.
"If a teacher comes to me and says we need new text books, I will have to say no because we can't afford it," he said.
