The nuclear industry is delighted; environmentalists are divided. Twenty countries signed a pledge last weekend at the COP28 climate summit in Dubai to triple their nuclear energy capacity by 2050.

The decision, by mostly European and North American countries, will mean that nuclear energy could go from meeting 10% of the world's current electricity needs to almost a third within 25 years.

The signature nations said they believe the world will not get to Net Zero without building more nuclear power stations, while the industry body World Nuclear Association hailed the move as “very significant.”

“This is the first time that heads of state have come together at a COP summit to set such a goal and stand up and tell the world the importance of nuclear in the transition to Net Zero,” Henry Preston, a spokesman for the World Nuclear Association. told DW.

Dozens of new power plants

Under the pledge, countries will adopt several measures, including extending the life of existing nuclear reactors up to 80 years. Between them, they'll also build both new large-scale reactors and advanced small modular reactors (SMR) as touted by TerraPower, the nuclear firm backed by Microsoft founder Bill Gates and British jet engine firm Rolls Royce.

But the tripling of nuclear capacity is no easy feat. It will require governments to speed up approvals for new nuclear plants and huge financial commitments. Existing nuclear reactors have often faced long construction delays and were delivered way over budget. So naturally, many nuclear watchers are somewhat skeptical about whether the plan is workable.

"It's very challenging, but not impossible," Jim Smith, a professor of environmental science at the UK's University of Portsmouth, told DW. "The French did it from the late 1960s to 1980 or so, but it's very difficult given how long modern reactors seem to take to get online."

Smith said the scaling up of nuclear is still more likely than nuclear fusion or green hydrogen over the next two decades as the two other technologies have several hurdles to overcome.

Nuclear backs up winds and solar power

Supporters of nuclear power say it plays a vital role as a backup for renewable energies like wind and solar when the sun doesn't shine and the wind doesn't blow. They say the more a country transitions to renewables, the more its intermittency poses a threat to the security of the power grid.

Environmentalists, meanwhile, often tout wind and solar energy as much cheaper than nuclear, but Smith called this "disingenuous" as it doesn't take into account the vital backup role that nuclear plays.

"The bigger the proportion of your electricity grid intermittent renewables become, the more expensive it is, because you need more backup, either in terms of battery or pump storage," Smith said, citing a report from the Organisation for Economic Co-operation and Development (OECD).

The European Union's labeling last year of nuclear as a green and clean energy was a major boon for the sector's renewal, despite the lack of a permanent site for the safe disposal of radioactive waste. Indeed, European countries make up 13 of the 20 signatories to the COP28 nuclear pledge, including France, Britain, Bulgaria, Ukraine, Poland, Hungary and Sweden.

Last year, France alone said it planned to build six new nuclear reactors and is considering building a further eight.

Advances in radioactive waste management touted

Nuclear for Climate, a grassroots initiative of over 150 associations set up to push for nuclear's involvement in the green transition, believes nuclear is among the safest sources of energy and increasingly so.

"Radioactive waste management also experienced dramatic improvements and innovations in recent years," Mattia Baldoni, a spokesperson for Nuclear for Climate, told DW. "The volume of waste is very limited. And the world's first deep geological repository, which will be operative in the next years, confirms that all radioactive waste can be safely managed and stored."

Will Germany U-turn on nuclear?

Even if some environmentalists can be persuaded about nuclear's utility, the German government could be more tricky to convince. Earlier this year, Germany switched off its three remaining nuclear power plants as part of a decade-long commitment to denuclearize its electricity supply.

The strategy was pushed through after fierce pressure from the Green movement in the wake of the 2011 Fukushima nuclear disaster, following a 9.1 magnitude earthquake and tsunami.

Although the German government did delay the decommissioning of the last nuclear plants due to last year's energy crisis, ministers say they remain committed to life without nuclear energy.

"As long as the Greens are in the federal government, it will not move a single micrometer in the direction of nuclear energy," Rainer Klute, chairman of Nuklearia, a German campaign group for nuclear energy. "It has ignored economic realities and scientific findings in the past, and will not suddenly start paying attention."

Klute believes Germany's opposition to nuclear will be shortlived and that by 2028, the Atomic Energy Act will be revised, especially if the Greens won't be part of the next coalition government.

He noted how Germany has increased the burning of coal power plants even as it transitions to renewables and believes the country's energy-intensive export industry has been harmed by the policy, due to much higher power prices.

"When companies go bankrupt or relocate to countries where energy is cheaper, it costs us jobs, tax revenues, and prosperity," he warned.

Edited by: Kristie Pladson