NZE: One More Thing

The IEA has been endorsed as the foremost forum on world energy by participating nations, and its leadership on aggressive clean energy progress and climate action has been sought by many stakeholders.

Oscar Archer
4 min readMay 30, 2021

The recently released NZE special report was hailed as an ambitious roadmap towards rapid phaseout of unmitigated fossil fuel consumption and a future dominated by renewable energy sources.

Many celebrating the envisaged clean energy future may not necessarily have been so enthusiastic about the asserted need to more than double worldwide nuclear energy output, if it were presented in isolation. Perhaps this merely belies the value of addressing the climate challenge with an all of the above clean energy approach, albeit in this case with the weight of ambition placed squarely on solar and wind.

Ambition shouldn’t be scorned. To illustrate, NZE anticipates no less than 8,265 gigawatts of wind capacity operating in 2050 (the 2020 value is 737 GW). The global wind industry could treat this as the long range target to shoot for, maximising deployment to most beneficially displace considerable amounts of fossil fuel combustion (rather than generation from hydro, nuclear etc).

Such ambition shouldn’t necessarily be constrained by current perceptions, either. The IEA’s special report and others like it serve to convince of the extraordinary efforts expected from every sector. The industries underpinning various energy technologies, in particular, will need to deliver far higher rates of deployment than ever before.

Yet counter to this is an immediate, dramatic improvement in annual global energy intensity to achieve NZE. The IEA sets this at -4.2% per year for the current decade, then -2.7% until 2050. The weighted average of -3.2% is just shy of the extreme range of values examined by Loftus and co-workers in a 2014 critical review of the feasibility of decarbonisation scenarios, which described them as:

…roughly double the most rapid rates observed over the past 40 years. These rates fall far outside the range of historical experience and also significantly exceed the fastest sustained rates of energy intensity decline observed in any individual OECD nation from 1971 to 2006.

Herculean energy efficiency — especially neglecting the impact of rebound — is inarguably a nice-to-have but it’s frankly easier to see annual additions of wind capacity nearly quadruple than these energy intensity percentages being sustained. So, the future will likely be one of higher energy consumption. How much higher?

The IEA’s STEPS (Stated Policies Scenario) illustrates the consequences of existing and stated policies for the energy sector (Figure 1.5 in NZE). Global final consumption universally increases, and “all the growth is in emerging market and developing economies”, dominated by electricity.

The difference between STEPS and NZE isn’t all down to the energy intensity difference, but for the sake of this exercise, STEPS’ total consumption curve will replace NZE’s, i.e. final consumption in 2050 ends up being almost 760 exajoules rather than only 543.

Thus, with the dramatic growth in solar and wind maintained, and the cessation of all coal consumption, the expanded requirements for modern nuclear energy can be speculatively illustrated.

Note: for illustration only. This is not modelling output.

It looks like a lot because it is: it’s more than the substantial increases forecast by the IPCC, UNEP, even the World Nuclear Association. The corresponding 2050 solar and wind capacities are larger than IRENA forecast in their own roadmap, too.

This is all for a substantial share of future world electricity — it would be the equivalent of maybe 2,500 EPR plants. But it also represents the intended role that advanced reactors will serve in industrial heat production, and so designs which operate at much higher temperatures — such as the Xe-100 planned for Washington state in 2027 and the Integral Molten Salt Reactor intended for Ontario’s grid around 2028 — will be suitable as emission-free heat sources to directly replace much coal and gas outside of electricity demand. This is a role unfortunately neglected in the NZE scenario, but taken quite seriously by the industry.

The IEA’s roadmap already sets daunting targets for renewable technologies which the solar and wind sectors in particular have to take deadly seriously, and will need all the momentum and policy support they can get. But it tells us that without concurrent (arguable) miracles in energy efficiency, nuclear needs to step up too, and with its track record it deserves the same goodwill.

Oscar Archer holds a PhD in chemistry and has been analysing energy issues for over 15 years, focusing on nuclear technology for seven, with a background in manufacturing and QA. He helps out at Adelaide-based Bright New World as Senior Advisor (we want your support!) and writes for The Fourth Generation. Find him @OskaArcher on Twitter.



Oscar Archer

Eco-modernism, clean energy abundance and enhanced opportunity for future generations.