Coal-fired power generators are struggling to secure coal supplies for their power plants ahead of summer, with the scarcity set to push up electricity prices for households and businesses already hurting with a doubling of prices over the past five years.

The Australian Energy Market Operator is monitoring the problem ahead of the 2017-18 summer as the NSW fleet has to catch up to fill the shortfall in the National Electricity Market after the closure of the Hazelwood power station in Victoria in March and the bulk of the state's coal is exported to international customers.