Among the "urgent events" that President Obama said he discussed Monday with Chilean President Sebastián Piñera was the unfolding nuclear crisis in Japan that began March 11 when a magnitude 9.0 earthquake and resulting tsunami along the northeast coast.

While the crisis only appeared to be mentioned in passing during a press conference in Santiago during Mr. Obama's five-day regional tour, it has set off a firestorm of criticism against Mr. Piñera and caused a major rethink over energy policy here.

Yesterday, some 2,000 people marched through the capital to protest a new US-Chile nuclear power cooperation agreement signed Friday as radiation leaked from Japan's Fukushima nuclear plant. The agreement promises cooperation in operating research reactors, handling civilian nuclear training and safety measures. It seemed a natural extension of Piñera's steady push for nuclear power to ensure electricity for Chile's world-leading copper industry.

But recent events appear to have caused Piñera to pivot.

Like Japan, Chile is seismic – its 9.5-magnitude quake in 1960 was the most powerful of the 20th century. And Chile's risk management culture is not as mature as Japan's. Now, this mineral-rich nation faces an energy dilemma: whether to choose earthquake-prone nuclear power plants or greenhouse gas-emitting coal-fired power plants.

Walking the fence

Ditching nuclear power would mark a sharp shift for Chile's government. Piñera said in an energy policy address in November that the country should build small nuclear plants like those found on nuclear submarines – an idea also promoted by the US Commerce Department. And last month, Energy Minister Laurence Golborne visited France and signed a nuclear cooperation agreement. The signing was announced with a press release, unlike the silence around Friday's closed-doors ceremony.

Then on Friday, Mr. Golborne said on Twitter: "I've been clear. We don't have nuclear plants in Chile, there are no plans to build them, and there's a commitment not to make a decision during this government."

Former President Ricardo Lagos, who supported nuclear power while in office, told local newspaper La Tercera: "Today the conditions don't exist to think about nuclear power. A lot of time will pass before it can be reconsidered."

US hunts for nuclear markets

If it doesn't use nuclear energy, then how will Chile power its growing copper extraction industry? Coal.

Chile has already approved almost a dozen new coal-fired power plants to allow its metals industry to grow to meet world demand. The country approved in February a 2,400-megawatt plant for the coast, which if built will be the biggest coal-fired plant in South America.

But there's a heavy price to pay environmentally for that. Growth of coal and diesel-fired electricity to power copper mines and smelters was one of the reasons that copper produced more greenhouse gases per ton in 2008 than in 2004, according to the Chilean Copper Commission.

That, as well as the US's hunt for new markets for its nuclear technology, could keep Chile on a nuclear course.

In a November report, the US General Accounting Office called on the Commerce Department to identify new markets, saying the US has lost much of its share in the global nuclear marketplace.

"US exports of sensitive nuclear material such as natural and enriched uranium remained stable, while the US share of global exports for these materials decreased significantly, from 29 percent to 10 percent, from 1994 through 2008," the agency said.