FORT MCMURRAY, Canada (AFP) - Petroleum companies are eyeing nuclear power to feed burgeoning oil production in Canada's oil patch, pitting ecologists against ecologists unable to agree on its climate change impact.

Squeezing one barrel of oil from the Athabasca, Peace River and Cold Lake Oil Sands in western Canada requires twice as much energy as pumping it from a conventional well, according to the industry, or three times as much energy, say environmentalists.

While crude is pumped from the ground, oil sands must be mined and bitumen separated from the sand and water, then upgraded and refined.

At an estimated 173 billion barrels, Canada's oil sands rank second behind Saudi Arabia in petroleum reserves. However, due to high extraction costs, the deposits were long neglected, except by local companies.

Since 2000, skyrocketing crude prices and improved extraction technology have persuaded several foreign companies to invest billions of dollars in projects, relying on copious amounts of natural gas to power the machinery.

Officials say oil sands production is expected to triple to 3.0 million barrels per day over the next decade.

But with wide fluctuations in natural gas prices and pressure from the government and environmentalists to reduce their greenhouse gas emissions, some petroleum companies are contemplating switching to cleaner and stable nuclear energy to fuel the oil sands boom.

"We're looking to cut our power needs and eventually turn to another source, and nuclear energy is a possible alternative," said Michael Borrell, president of Total Canada, a subsidiary of French oil firm Total SA.

Some ecologists acknowledge nuclear power is without emissions versus burning fossil fuels.

But others see inherent "risks" in sparking up nuclear reactors, raise security issues, and lament disposing of radioactive waste.

In September 2005, Total rebuffed the atomic option following its purchase of Canadian oil company Deer Creek, but its tone has since softened.

Pierre Alvarez, president of the Canadian Association of Petroleum Producers commented that nuclear energy is certainly among the "bouquet" of options for oil sands companies.

Possible alternatives in Alberta are coal plants, thermal energy, or connecting the province to rich natural gas reserves in the far north through a proposed 16-billion-dollar pipeline.

Of note, neighboring Saskatchewan province is one of the top producers of uranium in the world.

In December, Natural Resources Minister Gary Lunn shocked observers by saying: "I think nuclear can play a very significant role in the oil sands. I'm very, very keen. ... It's not a question of if, it's a question of when in my mind."

"It's absolutely emission free. It's CO2 free," he said. "On this specific file, I've had discussions this week."

Since then, Atomic Energy of Canada and French nuclear giant Areva have multiplied their lobbying of oil sands companies and local energy officials.

"We've had interest from investors who would like more information about the possibility of using nuclear energy in Alberta for extraction and refining of oil, Armand Laferrere, president of Areva Canada, told AFP.

"The most likely scenario is that several oil companies each needing a few hundred megawatts join together (tapping into one nuclear plant)," he said.

However, regulatory approvals, environmental studies and construction of a reactor would take almost a decade.