(Bloomberg) --

An unusual scuffle broke out last summer about what role nuclear energy should play at next week’s United Nations climate summit hosted by the U.K.

The tiff began in August when organizers invited the International Atomic Energy Agency and other industry advocates to set up shop in the meeting’s quieter Blue Zone instead of the public Green Zone, where companies enjoy higher visibility. “Every application on nuclear energy for the Green Zone at the upcoming COP26 conference has been rejected,” London-based lobbyists at the World Nuclear Association complained in a letter to COP President Alok Sharma. “We are deeply concerned.”

The kerfuffle over colors underscores the awkward position nuclear power occupies in discussions about the best way to decarbonize the global economy. Anti-nuclear nations from Austria to New Zealand have opposed attempts to label atomic technology with the same credentials as wind or solar power. The industry is also excluded from multilateral financial aid for clean energy at places such as the World Bank.

“At COP25 I was warned not to even attend,” said Rafael Mariano Grossi, director general of the Vienna-based IAEA, the UN body tasked with promoting the peaceful uses of nuclear technology. His group declined to get involved in the industry’s spat with organizers this year, quietly announcing they’d set up tent in the Blue Zone. “Now, it is obvious that we have a place. The message to the public is that nuclear will be a very useful element in the equation, whether you like it or not.”

Beyond the optics of the Glasgow summit, atomic power continues to be one of the world’s great sources of emissions-free electricity. Like cathedrals of industrialization, many reactors built a half-century ago are still reliably generating electricity 24 hours a day, rain or shine. Coordinated construction programs across Europe, Japan and the U.S. over the 1970s and 1980s avoided billions of tons of carbon dioxide that might otherwise have been emitted by oil, coal and gas plants.

But the act of conjuring the immense power induced by splitting atoms – creating energy so dense that whole cities can be powered with minuscule volumes of fuel – is an uncomfortable reminder for humankind of the risks carried by dabbling with dangerous science.

Leaving aside the possible military dimensions (just ask Iran), atomic energy has been dogged by safety mishaps since its inception. Commercial accidents from Three Mile Island in 1979, to Chernobyl in 1986 and Fukushima Dai-Ichi in 2011, repeatedly shook public and investor confidence, leaving a global nuclear renaissance seemingly out of reach — forever just behind the next corner.

Today China is the only nation building a fleet of new reactors at large scale, while there are individual plants in countries from the United Arab Emirates to Bangladesh. Russia exports and finances the most new builds. The few projects in Europe and the U.S. are almost uniformly past schedule and over budget. More reactors are being permanently retired than put online in western economies. As for the future, engineers are trying to downsize the technology into a new generation of small-modular reactors, which they hope might hit the market in the next decade.

Recent energy-market fluctuations show there’s still plentiful demand for reliable power. When the price of electricity spikes, even reactors that cost billions of dollars each start looking attractive. But price isn’t necessarily atomic power’s biggest downfall. Its larger, perhaps insurmountable, hurdle is time.

Emissions need to drop dramatically in the industrialized world by 2030, and the nuclear industry hasn’t shown it can coordinate resources quickly enough. Shovel-ready projects are few and far between. Most need at least a decade to complete. More than 70 contestants have entered the race to build small modular reactors. That sprawling competition risks bogging down efforts to standardize crucial licensing and manufacturing processes.

There are some signs that atomic officials are coming to grips with the urgency of the climate crisis. Attacks on wind and solar that used to be common at forums such as IAEA conferences have become much more rare. The agency has also recently started advocating for a bigger nuclear role in displacing the dirtiest fuel. It’s a modest symbolic step for a multilateral agency answerable to many member countries who still rely on fossil fuels.

But the agency still draws a red line when it comes to backing a price for carbon pollution, which many experts say is the key to accelerating atomic growth. “You have to go into these things gradually,” the IAEA’s Grossi said in an interview on Monday. “Coal replacement will not happen overnight and the same applies to gas.”

Ultimately, the nuclear industry’s most productive role in the next decade might be to continue generating electricity with its old reactors as long as they can safely be operated, while developing a new generation of technologies that can be rapidly scaled up and economically plugged into decentralized grids after 2030.

The message of the Blue Zone designation to those fighting for nuclear power is thus: While the world might need existing nuclear generation to avoid the worst impacts of global warming, it’s not yet sold on industry solutions pitched for the critical decade ahead.

©2021 Bloomberg L.P.