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Rebuttal Storm2

by Jan Willem Storm van Leeuwen

to Response to the rebuttal

by Martin Sevior and Adrian Flitney

dated 15 February 2006

Construction of a nuclear power plant

The study Storm & Smith [Q6] describes in Chapter 3 the methods to estimate the energy requirements of construction of a reference nuclear power plant.

The construction energy requirements comprise:

•  energy consumed at the construction site, including transport;

  this component can be measured directly

•  energy embodied in the construction materials, such as concrete, steel

  and copper, but also in chemicals and other auxiliary materials:

  that is, the energy consumed in the processes to obtain that materials

•  energy needed to construct and maintain capital goods, such as machines and equipment

•  energy embodied in services and human labour.

During the 1970's and 1980's the methodology of energy analysis has been developed, maturing to a useful tool to calculate the energy requirements of a good or economic activity with reasonable accuracy, see for example IFIAS 1974 [Q99], IFIAS 1975 [Q100], Roberts 1975 [Q101], Chapman 1975 [Q113], Chapman-1 1976 [Q104], Chapman-2  1976 [Q106], Roberts PC 1976 [Q105], Reister 1977 [Q97], Bullard, Penner & Pilati 1978 [Q102], Roberts PC 1982 [Q103], Constanza & Herendeen 1984 [Q119].

The construction of a nuclear power plant is an extensive and very complex activity.

Process analysis leads to a large underestimation of the total construction energy requirements, when labour and supporting activities of the construction are discounted, see e.g. Rombough & Koen 1978 [Q120]. This is the case in a number of energy analyses published in the past. Input/output analysis is well suited to large aggregated activities, like the construction of a nuclear power plant. Chapman 1975 [Q106] concluded:

In principle this is an unsatisfactory procedure since the inputs to nuclear systems are likely to be uncharacteristic products of the sectors documented in the input-output tables. However there are grounds for believing that provided a product has a large vector of inputs, ie requires inputs from many other sectors of the economy, then the average energy intensity derived from the input-output table is fairly reliable.”

The I/O analysis may be simplified by using  the general energy/gdp ratio of a particular year in a particular country to calculate the net energy requirement of a complex activity. The general energy/gdp ratio (or energy intensity) e is defined as the quotient of the total primary energy consumption of a country (in joules) and gross domestic product (for exemple in US dollars).

This simplification gives a fairly reliable value of the energy embodied in that activity, including energy costs of labour, services, subsidies, etcetera (Tyner, Constanza & Fowler 1988 [Q124]). This is affirmed by other studies, e.g. Rombough & Koen 1978 [Q120], Roberts PC 1982 [Q103], Bullard, Penner & Pilati 1978 [Q102], Constanza & Herendeen 1984 [Q119].

As Constanza & Herendeen put it:

“Embodied energy (calculated the way we suggest) is a good, non-trivial static correlate of the economic value of the relatively large aggregates of goods and services that make up the entries in the I/O tables.”

Certainly, the construction of a nuclear power plant is a large aggregate of goods and services. Nuclear technology can be considered being high-tech, on top of an extensive industrial and economic infrastructure of other high-tech production processes.

The studies of  Rombough & Koen 1975 [Q120] and Bullard, Penner & Pilati 1978 [Q102] showed that the value calculated via a detailed I/O analysis is somewhat higher than the value found via the simplified method. Both studies concluded that construction of a power plant is somewhat more energy-intensive than the average economic activity.

The total energy requirements of construction cannot be measured directly, because of the sheer complexity of the construction activities: many different materials, activities and capital goods are involved. Therefore, the construction energy has to be estimated using the methods mentioned above and discussed in Chapter 3 of [Q6]. The results are given in Table 1.

Table 1 Energy requirements, total and lifetime specific CO2 emission of

construction of a 1 GW(e) nuclear power plant. Source: [Q6].

-------------------------------------

    low   mean  high

-----------------------------------------

energy in PJ    40  80  120 R = 4.8

CO2 emission Tg   2.5  5.0  7.5

specific CO2 emission *, g/kWh 12  24  36

-------------------------------------

1 PJ = 1 petajoule = 1015 joule

1 Tg = 1 teragram = 1012 gram = 1 million metric tonnes

R = ratio thermal energy/electric energy

* averaged on lifetime 24 FPY

Energy requirements for construction = sum of electric and thermal (=fossil) energy in PJ. In the study [Q6] no primary energy units are used.

The large range of values is due by:

•  uncertainty range in the data

•  physical differences between individual nuclear power plants.

Energy requirements estimated in other known studies: see Table 11 from Chapter 3 of Storm & Smith 2005 [Q6].

Materials

A clue of some kind of a physical/chemical minimum of the construction energy can be estimated starting with the main construction materials: concrete and steel.

Table 2 Construction masses * of a 1 GW(e) nuclear power plant

------------------------------------

 steel    concrete  total

 Gg   Gg   Gg

------------------------------------

low  119   681   800

mean  150   850   1000  

high  179   1021   1200

------------------------------------

*  excluding piping, wiring and other materials

1 Gg = 1 gigagram = 1000 metric tonnes

This table is based on Crowley & Griffith 1982 [Q229] and Shaw 1979 [Q230]. Uchiyama 2002 [Q205] cites a total construction mass of 1291 Gg.

Production of cement

Cement is made by heating CaCO3 (calciumcarbonate, limestone) with a siliceous material:

5 CaCO3  +  2 SiO2  -> (3CaO.SiO2) + (2CaO.SiO2) + 5 CO2

From this equation a stoichiometric ratio of 0.55 gram CO2 released per gram cement can be calculated, by the calcination reaction alone.

The specific energy consumption of concrete is 1.83 MJ/kg, according to IAEA-TecDoc-753 1994 [Q148]. If that amount of energy is generated by burning oil (75 g CO2/MJ), the specific CO2 emission is 137 g CO2/kg concrete. Assuming cement makes up 15% of high-density concrete - used in construction of nuclear power plants - the calcination process adds 83 g CO2/kg to the specific emission concrete. The total amounts to 220 g CO2/kg concrete.

Production of steel

Stoichiometrically calculated CO2 release from blast furnaces (including slag forming) is about 2 g CO2 per g iron. Excluding coke production. IAEA-TecDoc-753 1994 [Q148] cites a value of 29.54 MJ/kg. Assumed this energy is mainly generated by burning coal (coke) with a specific CO2 emission of 92 g/MJ, the specific CO2 emission of steel production would be 2.7 kg CO2 per kg steel, somewhat higher than the stoichiometric minimum.

Table 3 Total CO2 emission from the production of the construction

materials iron and cement of a 1 GW(e) nuclear power plant,

and specific CO2 emission averaged on lifetime of 24 FPY

(210 billion kWh)

-----------------------------------

  concrete steel  total  lifetime (24 FPY)

 Gg CO2  Gg CO2 Gg CO2 g CO2/kWh

-----------------------------------

low  150  321  471  2.2  

mean  187  405  592  2.8

high  225  483  708  3.4

-----------------------------------

The figures in Table 3 should be seen as little more than an indication:

•  Energy requirements of mining sand, gravel, iron ore, coal and slag and transport of iron and concrete may be not included in these figures.

•  Production of other materials, such as stainless steel, copper, etc., are not included either.

•  The figures relate to raw materials only, without processing them into components of buildings or equipment.

Rombough & Koen 1974 [Q96] and 1975 [Q120] demonstrated in their studies that the embodied energy in the raw construction materials of a nuclear power plant makes up less than 5% of the total energy requirements of construction, as calculated via an elaborate I/O analysis.

The figures of Table 3 are included in the figures of the total and specific CO2 emission, mentioned in Storm & Smith 2005 [Q6] and in Table 1.

Rebuttal (construction)

To my knowledge the figures of the Vattenfall EPD [Q152] are measured values. As pointed out above, the total energy requirements of construction cannot be measured directly.

I don't dispute the figures, nor the intention of Vattenfall. I dispute the use of the Vattenfall figures for purposes they aren't meant for.

How are the results of Table 3 to be reconciled with the 150 Gg stated by Vattenfall?

Do I understand Sevior and Flitney correctly that they dismiss the figures found by ExternE UK [Q308] (see p 5 of their response)?

If so, that's because the authors of ExternE UK problably used a similar method to estimate the CO2 emission like ours?

In my view some scientific arguments would be appropiate here.

Rebuttal (uranium)

Sevior and Flitney incorrectly state that Storm & Smith used only two studies from the 1970s and ignored later studies.

In Table 2 of Chapter 2 of our study [Q6] we listed the known studies with estimates of the energy requirements of mining and milling. We explained our choices. As any reader may learn from Table 2 of Chapter 2 of our study, more recent studies than we used cite much higher figures. Sevior and Flitney seem still to misread our study.

Studies from the 1970s and 1980s are not necessarely outdated or invalid. If so, it should be proven in a scientific way.

Digging up rock from the ground seems not very liable to advances in technology, with respect to the specific  energy consumption.

As with the Vattenfall EPD, the environmental assessments of Ranger and Olympic Dam mines are not necessarely energy analyses.

The method of Sevior and Flitney based on financial data appears to me full of hidden assumptions, bookkeeping problems, statistical pitfalls and uncertainties.

In my view Sevior and Flitney could contribute significantly to the discussion on mining and milling of uranium if they would be able to prove in a physical way which figures are right. The  figures of Ranger, Olympic Dam, Rφssing and any other mine, should be analyzed to make them fully comparable with the figures from the studies we listed. This implies knowledge of the physical flows of fuel, electricity, materials, etcetera, which are attributable to the mining and milling, directly and indirectly.

If the figures from the studies we used are not correct anymore, there must be an unambiguous physical explanation.

Remains the question of the dependency on the ore grade of the mining and milling operations.

References

Q6

Storm & Smith 2005

Storm van Leeuwen J W & Smith Ph B,

Nuclear power - the energy balance

August 2005

www.stormsmith.nl

Q96

Rombough & Koen 1974

Rombough C T & Koen B V,

The total energy investment in nuclear power plants,

Technical Report ESL-31

Energy Systems Laboratories, College of Engineering, The University of Texas at Austin, November 1974.

Q97

Reister 1977

Reister, D.B.,

The energy embodied in goods,

ORAU/IEA(M)-77-6,

Institute for Energy Analysis, Oak Ridge Associated Universities, February 1977.

Q99

IFIAS 1974

Energy analysis workshop on methodology and convention,

IFIAS, International Federation of Institutes for Advanced Study,

Guldsmedshyttan, Sweden, August 1974. Stockholm.

Q100

IFIAS 1975

Workshop on energy analysis and economics,

IFIAS, International Federation of Institutes for Advanced Study,

Lidengo, Sweden, June 1975. Stockholm.

Q101

Roberts 1975

Roberts F,

'The convention conventions',

Energy Policy, December 1975, pp.345-347.

Q102

Bullard Penner Pilati 1978

Bullard C W, Penner P S & Pilati D A,

'Net energy analysis, Handbook for combining process and input/output analysis',

Resources and Energy, vol. 1, 1978, pp.267-313.

Q103

Roberts PC 1982

Roberts, P.C.,

'Energy and value',

Energy Policy, September 1982, pp.171-180.

Q104

Chapman-1 1976

Chapman P F,

Methods of energy analysis,

part of: Aspects of Energy Conversion,

Proceedings of a Summer School held at Lincoln College, Oxford, UK,

14-15 July 1975, pp 739-758.

Q105

Roberts PC 1976

Roberts P C,

Energy analysis in modelling,

part of: Aspects of Energy Conversion,

Proceedings of a Summer School held at Lincoln College, Oxford, UK,

14-15 July 1975, pp 759-771.

Q106

Chapman-2 1976

Chapman P F,

Principles of energy analysis,

part of: Aspects of Energy Conversion,

Proceedings of a Summer School held at Lincoln College, Oxford, UK,

14-15 July 1975, pp 715-737.

Q113

Chapman 1975

Chapman P F,

'Energy Analysis of Nuclear Power Stations',

Energy Policy, December 1975, pp 285-298.

Q119

Constanza R & Herendeen RA,

'Embodied energy and economic value in the United States economy, 1963, 1967 and 1972',

Resources and Energy, vol.6, June 1984, pp. 129-163.

Q120

Rombough & Koen 1975

Rombough C T & Koen B V,

'Total energy investment in nuclear power plants',

Nuclear Technology, Vol.26 May 1975, pp.5-11.

Q124

Tyner et al. 1988

Tyner Sr G, Constanza R & Fowler R G,

'Net energy yield of nuclear power',

Energy, vol.13, no.1, 1988, pp.73-81.

Q148

IAEA TecDoc-753 1994

Net energy analysis of different electricity generation systems,

IAEA TecDoc-753

IAEA, Vienna, 1994.

Q205

Uchiyama 20020

Uchiyama Y,

LCA informastion, personal communication, fax dated 8 Febr 2002.

Q229

Crowley & Griffith 1982

Crowley J H & Griffith J D,

US construction cost rise threatens nuclear option,

Nuclear Engineering International, June 1982, pp 25-28

Q230

Shaw 1979

Shaw K R,

Capital cost escalation and the choice of power stations,

Energy Policy, December 1979, pp 321-328.

Q308

AEAT3776 1998

Power Generation and the Environment - a UK Perspective,

Volume 1, June 1998

AEAT 3776

ExternE-UK

http://externe.jrc.es/uk.pdf


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