"When a resource is scarce, the price is higher," Mr Barnett said on Wednesday.

"When the resource is plentiful, the price is lower.

" ... because Tasmania's capacity will double over the next two decades, that will put downward pressure on electricity prices in Tasmania as we export our excess electricity to the mainland."

The proposed Marinus Link electricity interconnector to the mainland, the Battery of the Nation program including pumped hydro energy storage and extra renewable energy developments including "green hydrogen" production at Bell Bay and Burnie are expected to bring a huge spike in Tasmania's energy output.

" ... we are tracking to 100 per cent self sufficiency in renewable energy by 2022 and now have a target to reach 200 per cent by 2040, and all this on the back of a world class water resource and a world class wind resource that makes Tasmania the envy of the world," Mr Barnett said.

"Because we have three renewable energy zones and have a world class wind resource, the cost of wind will be very low a lot of the time because it's windy much of the time in those renewable energy zones."

He said the lower cost would put downward pressure on electricity prices for all Tasmanians.

"Tasmanians should be paying Tasmanian prices for Tasmanian electricity, not Victorian prices for Tasmanian electricity," he said.

"We have a target of having the lowest electricity prices in Australia for both residential customers and regulated business customers by 2022 and we're on track, with a 1.38 per cent reduction commencing today."

He said renewable energy was Tasmania's greatest economic opportunity in coming decades.

"There will be a huge increase in opportunities for new jobs, new businesses and investment in the state, downward pressure on electricity prices, improved energy security and significant income generating capacity for Tasmanian government business enterprises that can be reinvested in health, education and police," he said.

Mr Barnett expected having Australia's lowest power prices would help attract new businesses and industries to the state, as earlier waves of hydro power developments attracted big industrial users.

Some argue Marinus will be superseded by other technologies, and so is not needed.

Mr Barnett said it had been prioritised by the federal government and Infrastructure Australia and was seen by the Australian Energy Market Operator as "essential to the future of the National Electricity Market".

He said it had been proven to be technically feasible and commercially viable.