A fault at a converter station caused Sunday's outage which was rectified on Monday night.

During a budget estimates hearing, Murchison Independent MLC Ruth Forrest questioned the minster regarding the reliability of the interconnector.

"Both the Department of State Growth and Hydro Tasmania are monitoring this very carefully and making sure energy security has not been compromised," Mr Barnett said.

"Basslink is a key part of our energy infrastructure."

The estimates committee heard the interconnector had a total of six outages in the past 12 months, four of which were unplanned.

Ms Forrest also questioned how investment in a second interconnector, Project Marinus, and Battery of the Nation projects would drive down power prices for Tasmanians.

Mr Barnett said the increased ability of Hydro Tasmania to sell power as the result of such infrastructure investments would give the government greater policy options regarding power pricing.

Mr Barnett said the government was on track to deliver its promise of providing the country's lowest regulated power prices by 2022.

Tasmania already has the lowest regulated business power price and was among the lowest for residential according to Energy Consumers Australia, he said.

"We are already in a good position going toward 2022," Mr Barnett said.

"I'm energised as the energy minister."

Ms Forrest said electricity demand was only going to increase.

"I haven't been convinced that we are looking at a situation where supply is so much higher than demand it pushes down the spot market," Ms Forrest said.

The estimates committee heard Project Marinus would potentially not go ahead if the state would not profit above the $3.1 billion it would need to invest to complete the interconnector.

Department of State Growth secretary Kim Evans said the government had made it clear it was not prepared to invest in overall project costs beyond what benefits would flow to Tasmania.

"We have a position that we are not going to pay more than we receive," Mr Evans said.

Mr Barnett said the decision regarding this investment not be made until the end of 2019 when a business case study currently being undertaken about the viability of the interconnector being profitable for Tasmania is completed.

"We need to ensure that Tasmania pays its fair share and no more," Mr Barnett said.

"We have what the nation needs with low cost, reliable energy."

Department of State Growth deputy secretary Gary Swain said the Battery of the Nation was a series of projects that would provide construction and other job opportunities for a long period of time.

"It has the potential to stimulate capacity in our industries as opposed to a single big project where you would expect the workforce to be flown in," Mr Swain said.

The Marinus link is expected to inject $1.3 billion into the Tasmania economy and create 1000 jobs in the initial build, with a further 1000 jobs created in follow-on wind and hydro pump projects.

A government spokesman said each of approximately a dozen stations, once operational, will require 30 to 40 ongoing employees.

Hobart Independent MLC Rob Valentine questioned the minister about the use of Lake Pedder in producing hydro power.

Mr Barnett said draining Lake Pedder would be "an economic and environmental disaster for Tasmania."

Lake Pedder provides 40 per cent of the water in the Gordon Power Station which provides 50,000 homes and businesses with electricity a year, Mr Barnett said.

Mr Barnett said the government was not looking to create any new dam sites on rivers but instead was focused on implementing pumped hydro facilities and upgrading existing sites.