The Hazelwood brown coal plant in the Latrobe Valley provides 25 per cent of Victoria’s base load electricity.

On Thursday the plant’s owner Engie announced it would close the station in March next year rather than pay for upgrades to reduce its emissions, make it more economically viable and improve safety.

State government modelling show the plant’s closer would increase power prices by between four and eight per cent, costing consumers an extra $44 to $86 per year.

Ms Kealy said the increase in the cost of living and doing business would hit hard in the Wimmera.

“It’s going to have an enormous impact,” she said. 

“Eight per cent increases will have an impact on local pensioners and there isn’t going to be an increase in the pension.

“It’s going to have an impact on local manufacturing and businesses that are already struggling after years of drought.”

Chris Jones, owner of Mitre 10 in Horsham and Rocks Apartments in Halls Gap, said electricity was one of his biggest costs and an increase would hit hard.

“We’re going to have to look at all our operating costs and that may affect employment,” he said.

“Electricity is one of our biggest costs at both sites. We use it during the day so there’s no off-peak savings.”

Mr Jones said he believed an increase in power costs would hit accommodation businesses really hard across the Wimmera.

Energy Minister Lily D'Ambrosio said it was a sad fact of reality that Hazelwood's closure would affect prices, but the analysis showed the rise may be less than $1 a week.

"While that seems small, we know there are Victorian families already doing it tough," she said.

Ms Kealy said the state government had taken the wrong approach to transitioning away from reliance on Hazelwood.

“We know Hazelwood is 60 years old but last budget put in hundreds of millions of dollars more taxes on power generation, making it harder to continue,” she said.

“Premier Daniel Andrews and Lily D’Ambrosio have been talking about closing Hazelwood since 2011 and lobbying for it to close would not have helped.”

“I’ts hard to say what we would do, given we are not in government, but there shouldn’t have been an immediate shutdown without a plan for transitioning workers and avoiding a power price spike.”

The state government has announced a $266 million support package for Hazelwood workers and Latrobe Valley.