A new nuclear age is dawning. The second most prolific source of low-emission energy after hydropower has caught the attention and imagination of countries around the world eager to ensure stability of supply and meet decarbonisation targets.

Interest in nuclear energy has been sharpened by a new report from the International Energy Agency (IEA) which says the carbon-free energy source can play a significant role in complementing renewables in the transition to net-zero emission systems.

The report concludes nuclear energy can help countries reduce their reliance on imported fossil fuels, cut carbon dioxide emissions, and enable electricity systems to integrate a higher share of renewable energy sources, such as solar and wind power.

Security in uncertain times

Experts including Professor Pan Chin, Head of Department of Mechanical Engineering at the City University of Hong Kong and CLP Power Chair Professor of Nuclear Engineering, believe nuclear energy could help ensure energy security amid mounting geopolitical tensions.

“Extreme weather around the world signals the global warming effect due to the increasing concentration of carbon dioxide in the atmosphere. Like renewables, nuclear power does not emit carbon dioxide directly and could play a significant role in achieving the carbon neutrality goal,” Professor Pan explains.

Nuclear power provides very stable electricity output under normal operating conditions and is commonly employed for the base load. “The extra electricity generated by nuclear power reactors in off-peak hours can be stored through pumped storage, and then used to provide electricity in peak hours,” he says.

Nuclear power can also be used to charge batteries for electric vehicles, or to produce hydrogen through electrolysis. “The hydrogen produced may generate electricity through hydrogen-fueled gas turbines and power the fuel cell vehicles directly,” Professor Pan says.

“If high temperature reactors are employed, hydrogen may also be produced through a series of thermal chemical reactions, resulting in higher energy efficiency.”

Lessons from a dark past

The shadow of past disasters still lingers over the nuclear energy industry and public concerns about its safety must be fully addressed, Professor Pan acknowledges.

He believes the world learned important lessons from Three Mile Island in 1979, Chernobyl in 1986, and Fukushima in 2011, and says safety enhancements after each of the disasters have made today’s nuclear power plants far safer.

People must be convinced the industry remains safe, however, and the International Atomic Energy Agency (IAEA) has established a taskforce to review the proposed discharge of nuclear wastewater from the Fukushima plant amid concerns over safety and handling of nuclear waste and emissions. 

While nuclear energy is a clean energy source, it produces radioactive waste that must be stored safely. Its sustainability has also been questioned given the limited supply of uranium needed for its production, and the mining and processing involved which can generate radioactive waste and hazardous chemicals.

However, advanced fuel recycling and reprocessing can not only reduce the amount of waste to be stored but also diminish the radioactivity of the remaining waste. Some advanced reactor designs in development could see reactors running on spent fuel in future.

Under this scenario, Professor Pan argues, “spent fuels will not be waste but potential fuel”.

By converting waste to fuel, uranium reserves could potentially sustain the operation of nuclear power plants for thousands or even tens of thousands of years, he argues, adding that the thorium cycle is another option that could make nuclear power sustainable.

Nuclear power has the potential to play a significant role in the global transition to carbon neutrality over the next 40 years, Professor Pan believes. With advances in fast breeder reactor technology, nuclear power could be a green oasis in an energy-starved world, he argues.

At the heart of a global debate

The debate is close to home for Hong Kong, where nuclear power has become an indispensable element of the city’s electricity generation system since Daya Bay – Mainland China’s first commercial nuclear plant – went into operation nearly three decades ago.

Today, nuclear energy meets a quarter of Hong Kong’s electricity demand in a safe, reliable way, and at a reasonable cost. With its benefits and potential to help Hong Kong achieve its decarbonisation target, CLP envisages a growing role for nuclear energy in the city’s future energy mix.

Globally, the nuclear energy debate spreading around the tables of governments and energy companies is more than environmental considerations, as they face rising threats of volatile supply, global warming, and geopolitical conflict.

As energy security becomes an almost existential issue, nuclear power is firmly back on the agenda as a possible means to stabilise an uncertain future and support a smooth transition to a greener, more sustainable future.