But she was later shocked to find the new amount due had increased to £336,865.
EDF has apologised for the estimate and said it was calculated after an “incorrect electricity meter reading was submitted”.
Emma, who was paying previously £212 per month for duel fuel, said: “I laughed to myself when I first saw the bill come through and just thought someone is having me on. It’s just a ridiculous amount of money.
"Then I worked out that I would need to work for 49 years to pay that amount and joked about it.”
Emma, who is a lollipop lady and dinner lady at Hartlepool’s Jesmond Gardens Primary School, tried contacting EDF energy to resolve the issue.
The 40-year-old said: “I’ve only had text conversations with the company because I can’t get through on the phone, the only response I’ve had was somebody from EDF asking if I wanted to split the amount over 36 months.
"I thought, that will be almost £10,000 per month for my electric. I expected my bill to increase slightly but not by this much.”
With energy bills set to rise shortly, Emma now wants to inform others who might have been hit with higher estimates to check the amount with suppliers.
She added: “This would make other people panic. Luckily we have laughed it off but some people might be running around turning off the lights and heating.
"Especially with the energy crisis because if it was a smaller amount like £1000 in comparison some people might just pay it.”
Apologising for not noticing the £336,865 figure earlier, an EDF Spokesperson said: “When setting up the direct debit online, an incorrect electricity meter reading was submitted by the customer. This resulted in the higher monthly direct debit.
"Mrs Martin has never received a bill for this amount. We’ve tried to call Mrs Martin to let her know that we’ve corrected the meter readings.”