Can nuclear power extend the economic expansion?

Also published at Resilience.org and BiophysEco.

Richard Rhodes’ new book Energy: A Human History does an excellent job of describing the scientific and technological hurdles that had to be cleared in the development of, for example, an internal combustion engine which can convert refined petroleum into forward motion.

But he gives short shrift to the social and political forces that have been equally important in determining how technological advances shape our world. That internal combustion engine might be a wonder of ingenuity, but was there any scientific reason we should make multi-tonne vehicles the primary mode of transportation for single passengers in cities, drastically reconfiguring urban landscapes in the process? When assiduous research resulted in more efficient engines, did science also dictate that we should use those engines to drive bigger and heavier SUV’s, and then four-wheel-drive, four-door pick-up trucks, to our suburban grocery superstores?

Unfortunately, Rhodes presents the benefits of modern science as if they are all inextricably wrapped up in our current high-energy-consumption economy, implying that human prosperity must end unless we find ways to maintain this high-energy system.

In this second part of a look at Energy (first installment here), we’ll delve into these questions as they relate to Rhodes’ strident defense of nuclear power.

To set the context, Rhodes argues that the only realistic – and the most ethical – way forward is a gradual progression on the path we are already taking, and that means an “all energy sources except coal and oil” strategy:

“Every energy system has its advantages and disadvantages …. And given the scale of global warming and human development, we will need them all if we are to finish the centuries-long process of decarbonizing our energy supply – wind, solar, hydro, nuclear, natural gas.”1

Three key points here: First, Rhodes recognizes the severity and urgency of the climate problem.

Second, he believes we have been “decarbonizing our energy supply” for centuries. That is true with respect to intensity: we now release fewer units of carbon for each unit of energy than we did in the 19th century.2 But in an overall sense, we emit vastly more carbon cumulatively (and vastly more carbon per capita) than we used to. It is the overall carbon emissions, not the carbon/energy intensity ratio, that matters to the climate.

Third, while energy production via natural gas has relatively low carbon emissions at the point of combustion, there is wide recognition that methane leaks throughout the production/transmission chain are major sources of greenhouse gas emissions, which may counteract the benefits of switching from coal to gas. Rhodes makes only an oblique reference to this critical problem in current natural gas usage.

It’s the issue of nuclear power, though, that really brings out Rhodes’ rhetorical heat. Consider this ad hominem attack:

“Antinuclear activists, whose agendas originated in a misinformed neo-Malthusian foreboding of overpopulation (and a willingness at the margin to condemn millions of their fellow human beings to death from disease and starvation), may fairly be accused of disingenuousness in their successive arguments against the safest, least polluting, least warming, and most reliable energy source humanity has yet devised.3

If someone warns that a social or technological development is likely to result in mass death, does that logically mean they want mass death, or that they are indifferent to it? Obviously not. They may well be sincerely motivated by a desire to save lives – just as those who promote the same social or technological development might sincerely believe that is the best way to save lives and promote prosperity.

So I think it is Rhodes who is being disingenuous with his ad hominem argument – even though I happen to agree with some of his substantive points on the relative safety of nuclear power.

What could go wrong?

As one who has lived for fifteen years just downwind of major nuclear facilities – first a uranium processing plant, more recently a nuclear power generator – I’ve had lots of incentive to study the potential safety hazards of the nuclear power industry. And on the issue of the relative operating safety of nuclear power generation, my conclusions have been much the same as those Rhodes puts forth.

I frequently take a short bike ride along the Lake Ontario Waterfront Trail through the buffer zone around the Darlington Nuclear Generating Station. Is this a significant hazard to my health? Yes it is, but only because this route also requires me to share the road with trucks and cars for a few kilometers, and to ride right beside a stream of pollution-emitting traffic on Ontario’s busiest expressway.

As a close neighbour of nuclear facilities, my risk of death due to sudden catastrophic nuclear power accident is several orders of magnitude lower than my risk of death due to sudden catastrophic traffic accident. (Worldwide, well over a million people are killed in traffic accidents per year.4)

As for the health risk due to chronic exposure to the amounts of radiation that are emitted by a current Canadian nuclear generating plant, I fully concur with Rhodes’ more general conclusion: “Low doses of radiation are not only low risk; they’re also lost in the noise of other sources of environmental insult.”5

Likewise, I share Rhodes’ conclusion that shutting down our existing nuclear power plants for environmental reasons, while continuing to rely on coal for a significant part of electricity generation, is daft6 – we should replace carbon-emitting generating systems first.

In my region, I would be sorry to see Darlington Nuclear Station shut down if Ontario were still significantly reliant on gas-powered peaker plants, as it is now. And given that we have a very long way to go in electrifying personal transportation and home heating, our electricity demand may increase significantly, making the transition to a fully renewable electricity generation system that much farther down the road. In that context, I think our existing nuclear power plants are a better option environmentally than continued or increasing use of any fossil fuel, natural gas included, for generation of electricity.

But should we commission and build new nuclear power plants? That is a very different question. Rhodes recognizes that the economic viability of the nuclear power industry is very much in question, but he makes no significant attempt in Energy to resolve the economic question.

To adequately answer the economic viability question, we would need a much wider conception of science than the one that comes through in Rhodes’ book.7

Beyond physics and chemistry

The science Rhodes celebrates in Energy: A Human History falls almost entirely within very basic physics and chemistry. The discoveries and developments Rhodes discusses are highly significant, and they will always remain foundational – but they are not sufficient for a clear understanding of technological systems, which are also social phenomena.

A more recent scientific advance is essential in coming to grips with our current energy challenges. This is the concept of Energy Return on Investment (EROI). Over his long and distinguished career, ecologist Charles A.S. Hall posited that organisms, ecological communities, and human societies must derive more usable energy from their activities than the energy they invest in those activities. With this simple insight8, Hall gave economics a foundation in the very principles of thermodynamics that Rhodes reveres.

The resulting field of biophysical economics provides a deeper understanding of the socio-technological revolutions that Rhodes simply ascribes to “science”. After studying the Energy Return on Investment of major energy sources over the past 200 years, we can understand how the rapid exploitation of fossil fuels provided a huge boost in the the energy available to society, while simultaneously freeing the great majority of people from energy-procuring activities so that they could work instead at a wide variety of new activities and industries. We can understand that if any society is to use a high quantity of energy per person, while employing only a small number of people in its energy sector, then its energy sector needs a high rate of Energy Return on Investment.

With readily accessible supplies of coal, oil and natural gas, industrial civilization in the past 200 years has benefitted from a very high Energy Return on Investment. But with “sweet spots” exhausted or in depletion phases, the EROI of the fossil fuel economy has been in marked decline for the past few decades.

Thus one of the key questions about a supposed nuclear renaissance is, can the nuclear power industry achieve an EROI comparable to that of the fossil fuel economy we have known to date? Most published analyses say no9 – from an Energy Return On Investment standpoint, nuclear power generation is (at worst) not worth doing at all, or (at best) worth doing even though it will produce much more expensive energy than the energy we came to depend on during the twentieth century.

If nuclear power generation has a low EROI, in sum, it cannot and will not fuel a continued economic expansion.

Rhodes argues that nuclear power is vitally important because we really need it to extend our current model of prosperity to billions more people now and in coming generations, and he claims the mantle of science for this position. But a broader and deeper application of scientific analysis can deal with the economic viability questions about nuclear power that he simply sidesteps.

Illustration at top: high-voltage transmission lines on grounds of Darlington Nuclear Station, on north shore of Lake Ontario east of Toronto

 

NOTES

1Energy: A Human History, page 337 (return to text)

2This is a point explained in more detail by Vaclav Smil, who also gives a perspective on the relative degree of decarbonization. From 1900 to 2000, he says, “the average carbon intensity of the world’s fossil fuel supply kept on declining: when expressed in terms of carbon per unit of the global total primary energy supply, it fell from nearly 28 kg C/GJ [GigaJoule] in 1900 to just below 25 in 1950 and to just over 19 in 2010, roughly a 30% decrease; subsequently, as a result of China’s rapidly rising coal output, it rose a bit during the first decade of the twenty-first century.” Smil, Energy and Civilization: A History, page 270. (return to text)

3Energy: A Human History, page 336 (return to text)

4World Health Organization says there were 1.25 million traffic deaths in 2013. (return to text)

5Energy: A Human History, page 324 (return to text)

6This general statement must be qualified, of course, by noting that some particular nuclear plants should be shut down because their designs were inherently flawed to begin with, or because they have aged beyond the point where they can be maintained and operated safely. (return to text)

7Even if one accepts that the operating safety record of nuclear power stations is exemplary, there are the major issues of nuclear weapons proliferation, and the long-term storage of highly radioactive wastes. Rhodes doesn’t mention weapons proliferation, and he cavalierly dismisses the long-term disposal issue: “The notion that such waste must be successfully protected from exposure for hundreds of thousands of years is counter to how humans handle every other kind of toxic material we produce. We usually bury it, but we also discount its future risk, on the reasonable grounds that we owe concern to one or, at best, two generations beyond our own …” (Energy: A Human History, page 337, emphasis mine). Yes, that’s what we usually do, but in what sense is that “reasonable”? (return to text)

8Though the basic insight is simple, measuring and calculating EROI can be anything but simple. A key issue is deciding how far out to draw the boundaries of an analysis. As Hall, Lambert and Balogh noted in “EROI of different fuels and the implications for society” in 2014, “Societal EROI is the overall EROI that might be derived for all of a nation’s or society’s fuels by summing all gains from fuels and all costs of obtaining them. To our knowledge this calculation has yet to be undertaken because it is difficult, if not impossible, to include all the variables necessary to generate an all-encompassing societal EROI value”. (return to text)

9In Scientific American (April 2013) Mason Inman cited an EROI of 5 for nuclear electricity generation – lower than photovoltaic or wind generators, and only a small fraction of the EROI of 69 that Inman cited for global conventional oil production in 2011. In 2014 a meta-review of studies, EROI of different fuels and the implications for society, gave a mean EROI of 14 for nuclear power. A paper by the World Nuclear Association cites outliers among the published studies, highlighting a conclusion that nuclear generation of electricity has a higher average EROI than hydro or fossil fuel generating systems, and is “one order of magnitude more effective than photovoltaics and wind power”. (return to text)

Wind turbine on site of Pickering Nuclear Generating Station.

How big is that hectare? It depends.

Also published at Resilience.org.

link to Accounting For Energy seriesThe Pickering Nuclear Generating Station, on the east edge of Canada’s largest city, Toronto, is a good take-off point for a discussion of the strengths and limitations of Vaclav Smil’s power density framework.

The Pickering complex is one of the older nuclear power plants operating in North America. Brought on line in 1971, the plant includes eight CANDU reactors (two of which are now permanently shut down). The complex also includes a single wind turbine, brought online in 2001.

Wonkometer-225The CANDU reactors are rated, at full power, at about 3100 Megawatts (MW). The wind turbine, which at 117 meters high was one of North America’s largest when it was installed, is rated at 1.8 MW at full power. (Because the nuclear reactor runs at full power for many more hours in a year, the disparity in actual output is even greater than the above figures suggest.)

How do these figures translate to power density, or power per unit of land?

The Pickering nuclear station stands cheek-by-jowl with other industrial sites and with well-used Lake Ontario waterfront parks. With a small land footprint, its power density is likely towards the high end – 7,600 W/m2 – of the range of nuclear generating stations Smil considers in Power Density. Had it been built with a substantial buffer zone, as is the case with many newer nuclear power plants, the power density might only be half as high.

A nuclear power plant, of course, requires a complex fuel supply chain that starts at a uranium mine. To arrive at more realistic power density estimates, Smil considers a range of mining and processing scenarios. When a nuclear station’s output is prorated over all the land used – land for the plant site itself, plus land for mining, processing and spent fuel storage – Smil estimates a power density of about 500 W/m2 in what he considers the most representative, mid-range of several examples.

Cameco uranium processing plant in Port Hope, Ontario

The Cameco facility in Port Hope, Ontario processes uranium for nuclear reactors. With no significant buffer around the plant, its land area is small and its power density high. Smil calculates its conversion power density at approximately 100,000 W / square meter, with the plant running at 50% capacity.

And wind turbines? Smil looks at average outputs from a variety of wind farm sites, and arrives at an estimated power density of about 1 W/m2.

So nuclear power has about 500 times the power density of wind turbines? If only it were that simple.

Inside and outside the boundary

In Power Density, Smil takes care to explain the “boundary problem”: defining what is being included or excluded in an analysis. With wind farms, for example, which land area is used in the calculation? Is it just the area of the turbine’s concrete base, or should it be all the land around and between turbines (in the common scenario of a large cluster of turbines spaced throughout a wind farm)?  There is no obviously correct answer to this question.

On the one hand, land between turbines can be and often is used as pasture or as crop land. On the other hand, access roads may break up the landscape and make some human uses impractical, as well as reducing the viability of the land for species that require larger uninterrupted spaces. Finally, there is considerable controversy about how close to wind turbines people can safely live, leading to buffer zones of varying sizes around turbine sites. Thus in this case the power output side of the quotient is relatively easy to determine, but the land area is not.

Wind turbines in southwestern Minnesota

Wind turbines line the horizon in Murray County, Minnesota, 2012.

Smil emphasizes the importance of clearly stating the boundary assumptions used in a particular analysis. For the average wind turbine power density of 1 W/m2, he is including the whole land area of a wind farm.

That approach is useful in giving us a sense of how much area would need to be occupied by wind farms to produce the equivalent power of a single nuclear power plant. The mid-range power station cited above (with overall power density of 500 W/m2) takes up about 1360 hectares in the uranium mining-processing-generating station chain. A wind farm of equivalent total power output would sprawl across 680,000 hectares of land, or 6,800 square kilometers, or a square with 82 km per side.

A wind power evangelist, on the other hand, could argue that the wind farms remain mostly devoted to agriculture, and with the concrete bases of the towers only taking 1% of the wind farm area, the power density should be calculated at 100 instead of 1W/m2.

Similar questions apply in many power density calculations. A hydro transmission corridor takes a broad stripe of countryside, but the area fenced off for the pylons is small. Most land in the corridor may continue to be used for grazing, though many other land uses will be off-limits. So you could use the area of the whole corridor in calculating power density – plus, perhaps, another buffer on each side if you believe that electromagnetic fields near power lines make those areas unsafe for living creatures. Or you could use just the area fenced off directly around the pylons. The respective power densities will vary by orders of magnitude.

If the land area is not simple to quantify when things go right, it is even more difficult when things go wrong. A drilling pad for a fracked shale gas may only be a hectare or two, so during the brief decade or two of the well’s productive life, the power density is quite high. But if fracking water leaks into an aquifer, the gas well may have drastic impacts on a far greater area of land – and that impact may continue even when the fracking boom is history.

The boundary problem is most tangled when resource extraction and consumption effects have uncertain extents in both space and time. As mentioned in the previous installment in this series, sometimes non-renewable energy facilities can be reclaimed for a full range of other uses. But the best-case scenario doesn’t always apply.

In mountain-top removal coal mining, there is a wide area of ecological devastation during the mining. But once the energy extraction drops to 0 and the mining corporation files bankruptcy, how much time will pass before the flattened mountains and filled-in valleys become healthy ecosystems again?

Or take the Pickering Nuclear Generation Station. The plant is scheduled to shut down about 2020, but its operators, Ontario Power Generation, say they will need to allow the interior radioactivity to cool for 15 years before they can begin to dismantle the reactor. By their own estimates the power plant buildings won’t be available for other uses until around 2060. Those placing bets on whether this will all go according to schedule can check back in 45 years.

In the meantime the plant will occupy land but produce no power; should the years of non-production be included in calculating an average power density? If decommissioning fails to make the site safe for a century or more, the overall power density will be paltry indeed.

In summary, Smil’s power density framework helps explain why it has taken high-power-density technologies to fuel our high-energy-consumption society, even for a single century. It helps explain why low power density technologies, such as solar and wind power, will not replace our current energy infrastructure or current demand for decades, if ever.

But the boundary problem is a window on the inherent limitations of the approach. For the past century our energy has appeared cheap and power densities have appeared high. Perhaps the low cost and the high power density are both due, in significant part, to important externalities that were not included in calculations.

Top photo: Pickering Nuclear Generating Station site, including wind turbine, on the shoreline of Lake Ontario near Toronto.