But despite the industrys history of huge cost over-runs, and the shadow of the Fukushima nuclear disaster, the issue has sparked almost no debate in the current election campaign.
While noisy demonstrations and debates occur regularly about wind power, nuclear has slid beneath the surface.
In fact, the nuclear issue is no farther away than your latest hydro bill, with its much-loathed Debt Retirement Charge.
Thats the legacy of Ontarios previous nuclear building campaign, which saw the former Ontario Hydro ring up billions of dollars in debt with no revenue stream to maintain it.
Ontarians have been paying off that debt ever since.
Yet despite a long history of cost over-runs and delays with previous nuclear projects, both of the two front-running parties promise a vigorous new nuclear program.
And they do so without knowing who will build the new reactors, or what they will cost.
Their commitment, however, is clear.
The Conservatives Change Book is solidly in favour of nuclear, in preference to renewables.
We will focus on the proven technologies that are effective, efficient, and clean like natural gas, hydroelectric, and nuclear, it says.
In a speech a year ago to the Ontario Energy Association, Conservative leader Tim Hudak accused the Liberals of dragging their fee and dodging important decisions on issues like Ontarios aging nuclear capacity.
Nuclear facilities supplied more than 50 per cent of our electricity last year and given the 10-year lead time for a nuclear facility, we cannot afford to wait any longer and a PC government will make that decision immediately, he vowed.
Whether or not they are acting quickly enough, the Liberals long term energy plan forsees a nuclear future as well. The long term energy plan prepared by the Liberals has received most attention for its commitment to renewable power.
But it would keep 50 per cent of Ontarios power coming from nuclear.
That means two huge projects.
One, starting about 2016, is overhauling each of the four existing reactors at Darlington for mid-life refits.
The other is building two big new reactors at Darlington to come on stream early in the next decade, as the existing Pickering reactors reach the end of their expected lives.
The Liberal position is contained in their long term energy plan, which forsees the province continuing to get half its power from nuclear.
A federal panel has given Ontario Power Generation permission to proceed with building new reactors, but big questions remain.
The biggest: Who will build them? And, even bigger: What will they cost?
The province has already tried once and failed to get the new-build project going.
It invited bids from competing firms in 2009, but received only one that complied with the terms of the competition. That bid, from Atomic Energy of Canada Ltd., was an eye-popping $26 billion for two reactors of 1,200 megawatts each.
The province had hoped for a price tag about one-third that size, and swiftly rejected the proposal as billions too high.
The fact that no one knows who will build the reactors, or what they will cost, hasnt deterred Ontario Power Generation from starting to plan for them.
Last month, they received conditional approval from a federal regulatory panel to proceed with site preparation and other preliminary steps toward building new reactors.
The New Democratic Party is the only one of the three major parties to call for a slowdown on nuclear.
We will not build new nuclear reactors and we will carefully assess the need for further refurbs, their platform states.
The Green Party is also flat-out opposed to new nuclear plants.
But the issue hasnt taken root on the campaign trail, taking a back seat to debate over renewable energy.
Mark Mattson of Lake Ontario Waterkeeper, who questioned the need for the new reactors at the panel hearings, is puzzled by the lack of interest in the nuclear issue.
He speculates that the nuclear issue is too big and complex to grasp easily: People get lost and focus on the minutiae they can understand.
But he wishes there were some debate about the basic premise about why Ontario feels obligated to produce all its own power. Hed like to see more debate about options such as importing more from neighbours with surplus capacity, or locking up more contracts for gas-fired generation at todays low natural gas prices.
The Ontario Clean Air Alliance is also questioning the commitment to nuclear, which it says opens Ontario ratepayers to a risk of big cost over-runs.
It has sent questionnaires to the four parties asking them to promise that future nuclear cost over-runs wont be passed on to consumers in the form of higher prices. Only the Conservatives have balked, says alliance chair Jack Gibbons.
Gibbons says that if the nuclear designers and builders are forced to accept all the project risks, theyll price their projects so high that nuclear will become the most expensive option on the table.