From the Introduction:

By Michael Shellenberger

This report was born from an ongoing effort by the staff and research fellows of Environmental Progress and other researchers to understand the fastest way to decarbonize national economies (i.e., reduce emissions per unit of gross domestic product) in order to mitigate anthropogenic climate change. We publish it to fill a gap in the scientific literature and the regularly issued reports by the Intergovernmental Panel on Climate Change (IPCC), which are overwhelmingly focused on modeling future scenarios with little regard for real-world historical trends.

My own involvement in analyzing decarbonization began a half-decade ago when I was president of Breakthrough Institute. In 2012, we published an analysis that decomposed the two drivers of carbon intensity of the economy: changes to the energy intensity of the economy and changes to carbon intensity of energy. The study found that five nations decarbonized their economies at rates double the global historic average. Sweden and France did so mostly by decarbonizing energy supply, while the United Kingdom and Ireland did so mostly by reducing the energy intensity of their economies. Belgium did so through a roughly equal contribution of the two.

The Breakthrough study concluded that state-led efforts to deploy nuclear energy caused the decarbonization of energy in France and Sweden while the shift to service economies caused the decline in energy intensity in the UK and Ireland. Contrary to widespread opinion at the time, the decline in energy intensity was driven not through increased energy efficiency but sectoral shifts largely independent of state policies. Moreover, those nations that had decarbonized rapidly by reducing energy intensity were outliers. “[E]xcepting Ireland,” the Breakthrough analysis concluded, “in no cases are sustained energy intensity improvement rates observed much in excess of 2 percent per year, with most nations experiencing rates ranging from 1 to 1.5 percent per year.”

As such, the Breakthrough analysis reached a conclusion that was, at least at the time, surprising: state-led efforts to deploy nuclear power plants are the only proven way for governments to deliberately and rapidly decarbonize economies. If there were other ways for governments to achieve the same outcome, they hadn’t been proven. The analysis reads:

While sectoral economic transitions are largely outside the domain and impact of energy policy, and deindustrialization is hardly a global strategy for rapid decarbonization, it appears that history presents at least one replicable strategy to accelerate the pace of decarbonization: the directed decarbonization of global energy supplies via the state-led development and deployment of scalable zero-carbon energy technologies.

The analysis was surprising to me for a different reason. The data appeared to contradict what Breakthrough and I had been arguing for several years. Until then, we had been calling for state-led efforts to accelerate technological innovation to make clean energy — principally renewables like solar and wind, but also nuclear — cheap. But the analysis concluded that what mattered most was “standardization, economies of scale, rapid construction and quick installation” of nuclear plants.

Renewable energy advocates responded that the Breakthrough findings had to be wrong because it takes so much longer to build a nuclear power plant—with much of the protracted timeframes owing to construction delays—than, say, a solar or wind farm. This response was specious, since it compared solar and wind farms that generated far less electricity than nuclear plants—a point that would be made one year later in a then-novel analysis by Geoff Russell, a mathematician in South Australia, for Breakthrough.

Russell’s analysis compared the total amount of clean, electrical energy added by different nations during 11-year periods of peak deployment. (Russell calculated per-capita added energy to control for population.) He found that Sweden, France, and Belgium produced seven, two, and five times more electrical energy, respectively, with nuclear during their 11-year peak deployment periods than did Germany during its own 11-year peak deployment period with solar. As such, Russell noted, it could be said that nuclear was “faster” in decarbonizing than solar or wind.

Part of the power of these studies was the fact that no complex modeling was required to reach their conclusions and thus could be easily replicated by lay analysts without need for publication in peer-reviewed scientific journals. Even so, a team of six respected scientists, including Environmental Progress (EP) Senior Science Advisor, James Hansen, published a bar chart of “Average annual increase of carbon-free electricity per-capita during decade of peak scale-up” in Science in August last year. (See Figure II.) That chart used more recent data than Russell and, generously, combined solar and wind into a single bar. But even then the chart showed the peak deployment of nuclear was up to 12 times faster than the peak deployment of solar and wind.

Then, in the summer of 2017, EP Senior Analyst Mark Nelson and EP Research Fellow Arun Ramamurthy took these analyses of energy decarbonization a step further. Where I had simply sought to update existing analyses, Mark and Arun were after something far more ambitious. Why only compare decades of peak deployment between a small set of countries, they reasoned, when there was publicly available data covering 68 nations over 52 years (1965 - 2016)? And why only look at solar, wind, and nuclear? Why not include hydroelectricity, which is the largest source of clean electricity globally?

I was both surprised and unsurprised when they showed me an early version of the four-square chart (See Figure IV.) that aggregated the national cases depicting the relationship, or lack thereof, between the per-capita deployment of nuclear, hydro, wind, and solar and carbon intensity of energy. I was unsurprised in that it showed what I had come to expect: the deployment of nuclear was strongly correlated with declining carbon intensity of energy. I also wasn’t particularly surprised by the correlation between the deployment of hydroelectricity and energy decarbonization, given how much power large dams generate.

On the other hand, I was surprised to see no correlation between solar or wind and the carbon intensity of energy at an aggregated level. After all, both clean energy sources are associated with the decarbonization of electricity, and the deployment of wind appears to have caused the decarbonization of energy in Denmark. Additionally, the decadal “peak deployment” bar graphs had suggested some correlation between solar and wind deployment and decarbonization, albeit a far more modest correlation than that between nuclear and hydro deployment and decarbonization. (I was further surprised nobody had conducted a similar analysis before — something we address directly in this report.)

While the deployment of nuclear (and hydro) at national scales for some countries can be safely said to have caused reductions in carbon intensity, we err on the side of caution and refrain from claiming a causal connection at aggregated national levels. In the context of a single nation like France, the deployment of nuclear energy very clearly drives energy decarbonization.

The causal relationship between nuclear and changes to carbon intensity are further demonstrated when nuclear plants are closed, as they were in Japan following the 2011 Fukushima accident. When their nuclear plants were closed, the Japanese energy supply recarbonized immediately, and there is no doubt as to why. There are too many other factors that could confound such a strong claim of causality at aggregated national levels, however.

Sample from national carbon intensity appendix

In service of transparency, we have reproduced all 68 national carbon intensity of energy charts used in this analysis in our appendix, in addition to publishing the aggregated national charts.

Ten years after my initial forays into this subject area I am more than ever of the view that a future-facing climate policy must be informed by backward-facing energy analysis. The attention given by energy analysts, policymakers, and the IPCC to scenarios ungrounded from history is wildly disproportionate to the attention given to the real world experience of deploying clean energy technologies and their impact, or lack thereof, on carbon intensity and emissions. Given what’s at stake, this constitutes a grave error. Those who insist on ignoring the past, to modify Santayana, should not be allowed to force the rest of us to repeat it.

The Power to Decarbonize