STOCKHOLM (Reuters) - Sweden’s parliament voided a 30-year-old ban on building new nuclear reactors on Thursday after a debate pitting the country’s need for low-carbon energy sources against environmental concerns over atomic energy.

The new legislation will allow construction of new reactors at existing plants from Jan. 1 next year to replace the 10 ageing reactors that still produce roughly 40 percent of the Nordic country’s electricity.

The vote was passed with a majority of two with 174 voting for the bill and 172 against. Three legislators were absent.

Opinion polls now suggest most Swedes favour keeping nuclear plants, but Thursday’s vote does not necessarily secure a future for the country’s reactors.

The centre-left opposition, currently running neck and neck with the ruling centre-right in polls before a September election, will rescind the new law if they win the vote, said Tomas Eneroth, Social Democratic spokesman on energy issues.

“Of course we will tear it up,” he said, speaking before Thursday’s decision.

Efforts to combat the dangers of global warming have led to a revival of interest in nuclear power with European countries such as Britain, Italy and Sweden’s Nordic neighbour Finland planning to bring new reactors on line.

During a sometimes heated parliament session, Environment Minister Andreas Carlgren said the bill was a “unique chance” to leave decades of acrimonious political debate behind and stressed the need to ensure the future of Swedish industry.

“A few months ago, the climate threat dominated the environmental debate. Now it is the oil disaster in the Mexican Gulf that is sparking the world’s interest and horror,” he said.

“Both are really two sides of the same coin, namely, we must leave the dependency on oil and fossil energy behind.”

In 1980, Swedes voted in a referendum to phase out existing reactors by 2010, and fears of nuclear power were heightened by the 1986 Chernobyl disaster.

In 1997, however, Sweden scrapped plans for a phase-out of atomic energy, citing the need for cost-effective energy to service its large manufacturing and processing industries.