Swiss voters head to the polls Sunday to decide whether or not to speed up the Alpine nation's phaseout of nuclear power.

Polls suggest a tight race in a referendum that would, if passed, close all five of Switzerland's nuclear reactors by 2029.

The opposition Swiss Greens have pushed for the referendum since the 2011 Fukushima nuclear disaster in Japan, when many countries like Germany reevaluated their nuclear energy policies. Germany responded by immediately shuttering 40 percent of its nuclear reactors and moved quickly to build up renewables ahead of a deadline to close all nuclear power plants by 2022.

Switzerland gets about 33 percent of its electricity from nuclear power, around 60 percent from hydroelectric power and little more than 4 percent from renewable sources like wind and solar. 

Switzerland vowed to abandon nuclear power after Fukishima, but without setting a timeline. Instead, the government's long-term energy plan calls for existing nuclear reactors to run until the end of their operational lifespans. But all the country's nuclear plants have open-ended licenses and can operate so long as they are considered safe.

Impact to hit next year

The Greens, backed by all the left-leaning parties, say Switzerland's nuclear plants are aging and unsafe. Opened in 1969, the Beznau I reactor (seen above) is the oldest operating nuclear plant in the world.

A "Yes" vote in the referendum would set the life of a nuclear reactor at 45 years, meaning Benzau I and its sister reactor Benzau II would close down next year alongside a third nuclear reactor, Mühleberg. Two other nuclear plants would close down by 2029: Gösgen in 2024 and Leibstadt in 2029.

Both chambers of the Swiss legislature, the executive Federal Council and right-leaning parties are against the referendum, arguing the country is unprepared for a swift move away from nuclear power. Taking three nuclear reactors offline in 2017 means about one-third of electricity generated from nuclear power would be lacking.

Importing dirty-coal energy from Germany

The net effect of shutting down the nuclear reactors under a quick timeline would be more pollution or continued reliance on nuclear power from neighboring countries, opponents say. They argue Switzerland would need to make up for lost production by importing electricity from dirty-coal powered plants in Germany or from France, which gets about three-quarters of its electricity from nuclear power.

The government says it would be unable to quickly replace nuclear power supplies with renewable sources. Energy Minister Doris Leuthard has even warned that a positive referendum could trigger blackouts. Swiss power network operator Swissgrid has cautioned that its grid infrastructure would not be ready for a switch by 2017.

Those supporting the referendum argue that going off nuclear would force Switzerland to quickly build up renewable energy and kick-start green projects. Nearly 40,000 green energy projects that could double or triple energy production are awaiting authorization, according to public broadcaster RTS.

Closing down the nuclear reactors is unlikely to have a major impact on energy costs, since Germany has inexpensive excess capacity, according to Poyry Management Consulting Switzerland.

However, Swiss utilities have warned that if the referendum passes they would seek nearly 7 billion euros ($7.4 billion) in "economic damages" for having to shut down nuclear reactors before the end of their lifespans.

cw/cmk (AFP, AP, Reuters)