Wednesday, January 5, 2011

Jacobson: Beyond Cherry Picking

In a previous pos
I looked at Mark Z. Jacobson's decision to exclude nuclear power as an future energy source in a recent paper. In that post I reviewed Jacobson's assertions that the global spread of nuclear generated electrical power would cause nuclear proliferation and nuclear war. In the course of my investigating of actual instances of proliferation, I found that nations which lacked civilian nuclear power facilities were more likely to undertake the development of nuclear weapons than nations which possess civilian nuclear power facilities. Thus arguably the spread of nuclear power generation facilities may lead to a decline in nuclear proliferation risks.

In this post I intend to consider other arguments which Jacobson uses to justify the exclusion of nuclear power from future energy plans. A second part of Jacobson's argument for the exclusion of nuclear power claims that wind generated electricity leads to significantly lower CO2 emissions than would be the case with nuclear generated electricity. Jaacobson claims:
nuclear energy results in 9-25 times more carbon emissions than wind energy, in part due to emissions from uranium refining and transport and reactor construction (e.g., Lenzen, 2008; Sovacool, 2008), in part due to the longer time required to site, permit, and construct a nuclear plant compared with a wind farm (resulting in greater emissions from the fossil-fuel electricity sector during this period; Jacobson, 2009), and in part due to the greater loss of soil carbon due to the greater loss in vegetation resulting from covering the ground with nuclear facilities relative to wind turbine towers, which cover little ground. Although recent construction times worldwide are shorter than the 9-year median construction times in the U.S. since 1970 (Koomey and Hultman, 2007), they still averaged 6.5 years worldwide in 2007 (Ramana, 2009), and this time must be added to the site permit time (~3 years in the U.S.) and construction permit and issue time (~3 years). The overall historic and present range of nuclear planning-to-operation times for new nuclear plants has been 11-19 years, compared with an average of 2-5 years for wind and solar installations (Jacobson, 2009). Feiveson (2009) observes that “because wind turbines can be installed much faster than could nuclear, the cumulative greenhouse gas savings per capital invested appear likely to be greater for wind” (p. 67).
A careful examination of Jacobson's statement will reveal many problems. Jacobson makes claims about the relative emissions of CO2 from wind and nuclear power (9-25 times more carbon emissions). in support of this assertion Jacobson references papers by Lenzen and Sovacool. Both papers offer meta analyses of the life cycle CO2 emissions of CO2 by nuclear power. Both papers reach similar conclusions, which reflect an estimated life cycle CO2 emissions from nuclear power that is several times greater than that found by Dones. in several previous posts, most recently "Honor the Truth" (December 26, 2010), I set out the criticisms by Dones and others that studies of the lifecycle CO2 emissions associated with nuclear power reported by Jan Willem Storm van Leeuwen and Philip Smith contain numerous and serious flaws. Thus the "Stormsmith" CO2 emissions estimates cannot be considered reliable. Dones wrote that "Stormsmith's"
results are definitively outliers.
Yet both Lenzen and Sovacool rely heavily on "Stormsmith" for their conclusions. At any rate neither Lenzen nor Sovacool support Jacobson's claim of nuclear lifecycle emissions 25 time greater than wind lifecycle emissions, and indeed not even "Stormsmith" supports anything close to this claim. Where does the 25 times claim then come from? In his paper Review of solutions to global warming, air pollution, and energy security, Jacobson wrote:
In this section, the CO2-equivalent (CO2e) emissions (emissions of CO2 plus those of other greenhouse gases multiplied by their global warming potentials) of each energy technology are reviewed. We also examine CO2e emissions of each technology due to planning and construction delays relative to those from the technology with the least delays (opportunity-cost emissions), leakage from geological formations of CO2 sequestered by coal-CCS, and the emissions from the burning of cities resulting from nuclear weapons explosions potentially resulting from nuclear energy expansion.
The inclusion of carbon from burning cities ignited by nuclear weapons as nuclear power emissions, explains the 25 times carbon emission claim, but it is wacky, and needless to say utterly without scientific validity.

Even if "Stormsmith" could be considered a reliable source, Jacobson derives arguments from the Lenzen and Sovacool papers that cannot be supported from those papers. First a meta analysis is not a scientific study, and its conclusions are not scientific. Secondly, meta analysis can be manipulated to produce highly biased results. The Wikipedia observes:
The most severe weakness and abuse of meta-analysis often occurs when the person or persons doing the meta-analysis have an economic, social,or political agenda such as the passage or defeat of legislation. Those persons with these types of agenda have a high likelihood to abuse meta-analysis due to personal bias. For example, researchers favorable to the author's agenda are likely to have their studies "cherry picked" while those not favorable will be ignored or labeled as "not credible". In addition, the favored authors may themselves be biased or paid to produce results that support their overall political, social, or economic goals in ways such as selecting small favorable data sets and not incorporating larger unfavorable data sets.
If a meta-analysis is conducted by an individual or organization with a bias or predetermined desired outcome, it should be treated as highly suspect or having a high likelihood of being "junk science". From an integrity perspective, researchers with a bias should avoid meta-analysis and use a less abuse-prone (or independent) form of research.
There is abundant evidence that both the Sovacool and the Lanzen studies were biased. Both studies rely heavily on "Stormsmith" despite Dones's critique of "Stormsmith's" methods and conclusions. There is added evidence that Sovacool was engaged in cherry picking, he found fault with most of the peer reviewed studies of life cycle emissions from nuclear power, and excluded them from his analysis. Thus neither Sovacool nor Lanzen offer credible evidence on the life cycle emissions of nuclear power plants, and both studies are likely to reflect the biases of their authors. Thus Jacobson lacks credible sources for his assertions about the life cycle CO2 emissions of nuclear power plants, and therefor there are no credible data to make comparisons between the lifecycle CO2 emissions of wind and nuclear.

But what of Jacobson's claims about soil loss in connection with nuclear facilities? Uranium mines use a variety of mining technologies, and in a variety of settings, but in the United States all uranium mines use a technology called in situ leaching. In situ leaching does not disturb the soil, thus uranium mining in the United States cannot be regarded as creating a soil loss problem. Underground mines in other countries do not, for the most part create soil loss problems. New Canadian uranium mines tend to be underground. Many surface open pit uranium mines are located in desert country where soil loss to uranium mining would lead to only a very limited loss of ground covering vegetation, hence an insignificant impact on the global carbon cycle. Further, a review of recent mining practices indicates that played out open pit uranium mines are used for tailings disposal, thus limiting the impact of uranium mining tailings on ground covering vegetation and the carbon cycle. Of the world's 10 largest uranium mines only three, representing 20% of the global uranium mining total were open pit mines. Of those three, two, representing over 11% of the global uranium mining total, are located in desert environments. The number of in situ mines and their percentage of the global uranium mining total is rapidly increasing, and is currently running at 32% of the uranium mining total.

Uranium mills and uranium separation facilities occupy a tiny fraction of the global industrial infrastructure. Thus arguments attributing a displacement of ground cover so large as to impact the global carbon cycles are simply absurd. Finally reactor have small footprints. Most land dedicated to reactors constitute buffers designed to protect the public from any possible release of gaseous and volatile radioisotopes in the event of a reactor accident. The soil in reactor buffers is typically undisturbed, and and ground cover assumes natural forms. The developed area of reactor facilities is relatively small and thus the impact of even thousands of power producing reactors on the global carbon cycle through vegetation displacement would be insignificant.

Thus Jacobson's claim that nuclear power plants
nuclear energy results in 9-25 times more carbon emissions than wind energy,
is partially based on arguably unscientific and bias sources and partially based on an highly exaggerated account of the impact of the nuclear power cycle on ground cover vegetation and the global carbon cycle. Even the sources

What of Jacobson's claim that
The overall historic and present range of nuclear planning-to-operation times for new nuclear plants has been 11-19 years, . . .
Jacobson exaggerates the time scale required to build a large number of reactors. The French decision to convert its electrical system too nuclear power was made in 1973. The whole project was completed by 1992 19 years after the decision was made.

The French example is appropriate here because France was able to convert 3/4ths of its electrical industry to nuclear power very quickly. One group of 34 900 MW French reactors was completed between 1977 and 1988. A second group of 20 1300 MW reactors was completed between 1985 and 1992.

French nuclear power reactors

ClassReactorMWe net, eachCommercial operation
900 MWeBlayais 1-4
12/81, 2/83, 11/83, 10/83
Bugey 2-3
3/79, 3/79
Bugey 4-5
Chinon B 1-4
2/84, 8/84, 3/87, 4/88
Cruas 1-4
4/84, 4/85, 9/84, 2/85
Dampierre 1-4
9/80, 2/81, 5/81, 11/81
Fessenheim 1-2
12/77, 3/78
Gravelines B 1-4
11/80, 12/80, 6/81, 10/81
Gravelines C 5-6
1/85, 10/85
Saint-Laurent B 1-2
8/83, 8/83
Tricastin 1-4
12/80, 12/80, 5/81, 11/81
1300 MWeBelleville 1 & 2
6/88, 1/89
Cattenom 1-4
4/87, 2/88, 2/91, 1/92
Flamanville 1-2
12/86, 3/87
Golfech 1-2
2/91, 3/94
Nogent s/Seine 1-2
2/88, 5/89
Paluel 1-4
12/85, 12/85, 2/86, 6/86
Penly 1-2
12/90, 11/92
Saint-Alban 1-2
5/86, 3/87
N4 - 1450 MWeChooz B 1-2
12/96, 1999
Civaux 1-2


1999, 2000
Total (58)

it would appear then that France offers a model to any nation which wished to rapidly convert its electrical generating system to post carbon energy sources. It should be noted that French reactors are as safe as reactors anywhere in the world, so the rapid development of nuclear power in France was not accomplished at the cost of nuclear safety.

It should also be added that newer reactor construction technologies have emerged since the French Reactor building program was completed. These include factory construction of reactor modules, with field assembly of modules, and the introduction of time and labor saving construction/assembly equipment. In addition, refinements of reactor construction planning have emerged from asian countries such as South Korea and Japan. This improvement in reactor construction planning has significantly lowered reactor construction costs. China has adopted the best construction practices with a consequent decrease in construction costs of 40% compared to the construction practices of French reactor constructors. Any attempt to convert the American energy economy to post carbon nuclear power should take advantage of all possible cost and time saving technologies and techniques.

Thus Jacobson lacks objective, scientifically valid grounds for his a priori exclusion of nuclear power from consideration as a future post carbon energy source. He objects to nuclear power on the basis of
* Nuclear proliferation
* Nuclear CO2 emissions
* Nuclear effects f the Global Carbon Cycle
* The time scale of nuclear construction
My conclusions are that none of these objections have merit.
* The evidence from the study of actual instances of nuclear proliferation suggests the spread of nuclear power appears to inhibit rather than encourage nuclear proliferation.
* Jacobson uses biased and inaccurate sources in making his claims about nuclear CO2 emissions.
* Jacobson goes beyond his sources and concocts highly unscientific arguments that extend well beyond any scientific evidence, in order to justify his exaggerated carbon emissions estimate.
* Jacobson greatly exaggerates the impact of nuclear facilities on ground cover vegetation and the Global carbon cycle.
* France was able to convert 75% of its electrical industry to nuclear powered generation in the same time scale that Jacobson claims is required to build a single nuclear plant.
One must conclude that Jacobson's anti-nuclear arguments suffer from confirmation bias. Jacobson simply ignores sources that contradict his viewpoint. When supportive sources are available, Jacobson cherry picks, but his claim that
nuclear energy results in 9-25 times more carbon emissions than wind energy,
is not truly supported even by cherry picking. Thus Jacobson's exclusion from consideration of nuclear power as a post carbon energy source is not supported by judgements that can in any way be characterized as scientific and is the products of a personal bias.


donb said...

Jacobson claimed:
...and in part due to the greater loss of soil carbon due to the greater loss in vegetation resulting from covering the ground with nuclear facilities relative to wind turbine towers, which cover little ground.

While the wind turbine towers do cover little ground, the access roads needed to maintain them cover quite a bit of ground. Add in the area covered by access roads, and compare the amount of ground actually covered by a nuclear facility (not including the buffer zone, which becomes wildlife habitat), and you will find that per unit of energy produced, wind turbines cover more ground.

Finrod said...

When I first heard of Jacobson's proliferation objections, I did some quick back-of-the-envelope calculations based on his assumptions about how much CO2 would be released in a nuclear attack on a modern city. If a modern first-world city using coal as its power source were to be attacked and destroyed, the results would be carbon-neutral after four years, and carbon negative thereafter.


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