But 2034 will also mark the 40th year of operations at the 1,868 megawatt facility. That’s the minimum age at which an average nuclear power plant must be decommissioned and cleaned up, a costly and complex process that many nuclear powers around the world are only recently beginning to fathom.

As the world marks the fifth anniversary of Japan’s Fukushima disaster this week, energy experts and environmentalists are debating whether there is a nuclear future in Hong Kong beyond 2034.

Pro-nuclear voices believe fission is still the most reliable and stable “baseload” energy source for Hong Kong – one that emits virtually no carbon and is neither subject to the price swings of fossil fuels nor hindered by the supply constraints of renewable energy such as solar and wind.

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Anti-nuclear groups believe the 2011 disaster gives reason enough for any country to phase out nuclear power. For Hong Kong and the densely populated Pearl River Delta region the possible impacts of a Fukushima-style breakdown are especially high.

Globally, the nuclear industry appears to be struggling. According to the World Nuclear Industry Status Report, 398 plants are now operating, down from 431 the year before Fukushima. With energy prices still bottoming out, competition from cheap coal, gas and subsidised renewables has muscled its way into the equation.

Steve Thomas, professor of energy policy at London’s University of Greenwich, said because of these issues, the prospects of nuclear, especially in America and Europe, are being limited.

In East Asia, nuclear power’s future is unclear post-Fukushima. As China and South Korea look to build more reactors, Taiwan’s new government has set a policy of phasing out nuclear by 2025.

Thomas said: “The cost of nuclear and renewables is cost neutral now. But while the cost curve for renewable energy is down, the one for nuclear will only go up.”

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Even in Hong Kong the gap in unit cost between nuclear and the likes of coal and gas has widened. Nuclear power’s unit cost rose to 50 HK cents last September, while coal and gas dropped to 22 and 83 cents per unit respectively, according to CLP, the bigger of the city’s two sole electricity providers. It cited a decline in coal prices and an increase in gas prices as a result of more expensive new sources.

Thomas also pointed to the cost of disposing of spent nuclear fuel “waste” and decommissioning plants. For example, despite a pledged permanent waste facility for Daya Bay’s spent fuel rods, they are stored in a temporary facility a few kilometres from the plant, sparking safety concerns.

“Governments don’t care too much about the decommissioning of plants or the cost of waste disposal because it so far down the line, but in the end, consumers will have to pay,” said Thomas.

CLP, the Hong Kong power company supplied by Daya Bay, said the plant included the charge for spent nuclear fuel and the cost of station decommissioning in the future, “with the intention that future consumers will not pay for today’s consumption”.

Hong Kong’s Environment Bureau remains tight-lipped on anything electricity-related beyond 2025. In an interview with the Post last November, Environment Secretary Wong Kam-sing said the government would maintain an “open attitude” to nuclear after the Daya Bay contract ends.

Last year, the government announced that half of its power needs after 2020 would come from locally generated natural gas, with an unchanged 25 per cent from nuclear power.

A spokesman for CLP said the reactors at Daya Bay were, like most others, designed to last 40 years, but the life of most modern reactors could be extended up to around 60 years.

“Given that we still have 18 years to go to 2034, it is too early to comment on its operating life or nuclear power purchase beyond that point,” he said.

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The company said the cost of nuclear was relatively stable since a large portion of it covered construction and only a small portion covered cost of nuclear fuel.

An Environment Bureau spokesman said importing power from the mainland grid remained a feasible option in the long-term. But he would not comment on specific details as it would “jeopardise” the government’s position and consumers’ interests amid discussions with the city’s two power suppliers on a new regulatory framework after 2018.

He said a study would be commissioned to look at how interconnection between the mainland’s and Hong Kong’s grids could be strengthened as well as that between the existing grids in the city.

Energy economist Dr William Yu Yuen-ping, a member of the government’s Energy Advisory Committee, said nuclear would most likely remain in the fuel mix, being the practical choice.

“From a perspective of energy policy, nuclear’s function as baseload power source will give Hong Kong impetus to keep nuclear in the mix [after 2034],” Yu said, who also heads the World Green Organisation environmental group.

Yu doubted there would be enough renewable energy, with the unpredictability of sunlight and wind speeds, to fill the shortfall without the city having to increase its reserve capacity.

He also doubted that natural gas could replace it, given its volatile prices.

Dr Luk Bing-lam, who chairs the Hong Kong Nuclear Society, an academic association that champions “nuclear literacy”, said another factor for Hong Kong to consider would be the mainland’s expansion in nuclear capacity, which the central government aims to double by 2020.

Luk said: “China will be using more nuclear so if Hong Kong doesn’t, we will be bearing all the risks but not reaping any of the benefits.”

If Daya Bay was headed for decommissioning, Luk urged the government to make a decision soon on whether or not nuclear would continue to be a part of Hong Kong’s future fuel mix.

“Competition for nuclear with other Chinese cities will heat up,” Luk said.

“Our position will get weaker as more time passes.”

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He suggested that the government and CLP could consider tapping into nuclear from four reactors at the neighbouring Ling Ao plant, which – unlike Daya Bay – CLP does not have a stake in.

Greenpeace Hong Kong argues there is no rationale for continuing nuclear in Hong Kong’s fuel mix given the dangers of a Fukushima-style collapse near a densely populated region.

They also point to the dubious safety standards and speed of construction of mainland nuclear plants. As many as 39 reactors, spread across Guangdong province could be up and running within close proximity to the city in the next few decades.

Greenpeace senior campaigner Frances Yeung Hoi-shan urged the government to boost efforts into promoting energy efficiency and to incentivise using renewables. “Hong Kong should go nuclear-free by 2034,” she said.

But how difficult would it be for a city with such a narrow portfolio of fuel choices to ween itself off nuclear as the nation supplying it with nuclear continues to boost the share of atomic energy in its fuel mix?

Yeung pointed to the example of Seoul, South Korea, a city of 10 million which, through tough action by its municipal government has been able to promote more decentralised generation, more renewable energy production and energy sharing schemes, to reduce dependency on nuclear energy from power plants across the country.

This flies in the face of the national government’s policy, which is commits it to increasing the number of nuclear reactors from 24 by the end of 2015 to 26 by 2030.

“Hong Kong officials keep saying everything is too difficult, too expensive,” said Yeung.

“But the problem is there is no perseverance and no innovation. This is something that requires a vision, political leadership, creativity. We must also make use of the autonomy we have in setting our energy policy.”