Renewable power is capable of reducing more carbon emissions per dollar and per year than nuclear energy, according to the recently released World Nuclear Industry Status Report (WNISR). The WNISR is about the nuclear industry, not by the nuclear industry—it's actually produced by an anti-nuclear activist. Naturally, the actual-nuclear industry disagrees strongly with the report's conclusions.

While the report does reflect the reality that renewable power is now faster and cheaper to build and operate, what that means for limiting carbon emissions is substantially more complicated.

Slow nukes

The WNISR has been compiled annually since 1992 by Mycle Schneider, along with a range of other contributors. It has consistently made the case against investing in nuclear power.

This year's edition attracted wider attention after it was covered by Reuters. It argues that new nuclear power is both costlier and slower to build than new renewable capacity. "Costly and slow options avoid less carbon per dollar and per year than cheaper and faster options could have," the report says. These options "thus make climate change worse than it should have been: even though they are low-carbon, they still reduce and retard achievable climate protection compared to what was achievable." That is, spending on nuclear power wastes time and resources that would have been better spent on renewables, ultimately delaying decarbonization.

Saying that both renewables and nuclear are necessary for decarbonization is equivalent to saying that since "filet mignon and rice are both food, both are essential to combatting hunger," the report argues.

The World Nuclear Association—which does represent the global nuclear industry—released a statement arguing that this analysis of the situation misses crucial details.

For instance, the WNISR argues that nuclear reactors are slow to build. Of the 63 units that have started running since 2009, the WNISR reports that the average construction time was 9.8 years. But that average time includes a large range of results—some took as little as 4.1 years, and some as much as 43.5 years. The slowest was the Tennessee-based Watts Bar 2 plant. Construction began in 1973 and was connected to the grid in 2016, but it faced long periods of delays, and construction halted for over 20 years.

"Inclusion of such outliers skews the average construction times reported upwards," says the World Nuclear Association statement. On the other hand, at the speedy end of the scale, reactors have been built in four years as a result of learning from "first-of-a-kind projects" and building subsequent projects more swiftly, it argues. So, while renewable capacity will still go on line more quickly, the gap doesn't have to be as severe as this report indicates.

Climate benefits?

Market forces are in favor of faster, cheaper renewables, says the WNISR, making them the obvious choice instead of nuclear power. And that has generally been accurate; renewable costs have plunged in most markets, making them some of the cheapest options available. However, a step away from nuclear does not necessarily mean a step toward renewables in locations where natural gas can also provide a cheap alternative.

In May this year, the International Energy Agency (IEA) published a report warning that a lack of new nuclear power and support for existing nuclear plants could result in a step backwards for climate goals. Cheap natural gas could potentially step into the gap instead of renewables, and that would commit us to emitting billions of additional tonnes of CO2. The IEA is an intergovernmental organization that advises on energy policy to its member states as well as a range of non-member states. While the data the IEA provides is solid, it has been criticized for consistently underestimating the growth in our renewable capacity.

In this case, data seems to back up the IEA's concerns: natural gas has been increasing in capacity. In Europe, nuclear capacity decreased by 18.7GW between 2000 and 2018, along with a 42.7GW reduction in coal capacity and 41.1GW in fuel oil capacity, the WNISR reports. A lot of that was replaced by renewables, which saw 310GW of growth. But in the same period, gas power plant capacity increased by 97GW. In the US, natural gas accounted for more than 60% of the new capacity installed in 2018, according to the EIA, with the remainder being renewables. Natural gas clearly is playing a growing role in the energy economy.

"Renewables, and often natural gas, outcompete new and even existing nuclear plants," the WNISR reports. But where the WNISR sees this as an argument to focus funding on renewables, the IEA points to efforts to extend the lives of existing nuclear facilities. These facilities are a crucial factor in reducing greenhouse emissions, as well as a cost-effective alternative to building new reactors.