Title of paper

3. Life-cycle analysis

The GHG emissions and other environmental impacts of different types of energy production can be calculated. Many researchers studied the nuclear life-cycle and calculated the emissions of CO₂ arising from the entire process. However, results of life-cycle analysis for nuclear energy show great variations.
A survey, here discussed in more detail, was done in 2008 by Benjamin Sovacool, a researcher of the National University of Singapore. He screened 103 life-cycle studies of GHG-equivalent emissions for nuclear power plants. In a selection process he narrowed the studies down to 19, whereby missing transparency about methodology, credibility and accessibility were his criteria.
Reflecting on all steps of the nuclear life-cycle, the Sovacool study shows great deviation of the total estimate of gCO₂-e/kWh.⁹ Statistical analysis of the 19 studies reveals a range of GHG emissions at the extremely low end of 1.36 gCO₂-e/kWh and the extremely high end of 288 gCO₂-e/kWh. Accounting for the mean values of emissions associated with each part of the nuclear life-cycle, the mean value reported for the average nuclear power plant is 66 gCO₂-e/kWh.
By assessing the disparity in life-cycle estimates, Sovacool concluded that the studies primarily differ in terms of their scope, assumptions regarding the quality of uranium ore and the type of mining, assumptions regarding the method of enrichment, whether the researchers assessed emissions for a single reactor or a fleet of reactors, assumptions regarding reactor type, site selection of the reactor and its operational life time, and the type of life-cycle analysis.
Table 1: Summary statistics of qualified studies reporting projected greenhouse gas emissions for nuclear power plant (Sovacool, 2008).

(gCO2-e/ kWh)	Frontend	Construction	Operation		Back-end		Decommissio-ning	Total gCO2-e/ kWh
Minimum	0.58	0.27	0.1	0.4		0.01		1.36
Maximum	118	35	40	40.75		54.5		288.25
Mean	25.09	8.20	11.58	9.2		12.01		66.08
No	17	19	9	15		13

Frontend includes mining and milling, conversion, enrichment, fuel fabrication and transportation.

Construction includes all materials and energy inputs for building the reactor.

Operation includes energy needed for maintenance, cooling and fuel cycles, backup generators during outages and shutdowns.

Backend includes fuel processing, conditioning, reprocessing, interim and permanent storage of nuclear waste.

Plant decommissioning includes deconstruction of reactor and land reclamation.
The frontend component of the nuclear cycle is responsible for 38% of equivalent emissions, decommissioning for 18%, operation of the nuclear plant for 17%, the backend for 15% and construction of the plant for 12% (Table 1).

Table 2: Life-cycle assessments for different electricity generation methods (Sovacool, 2008).

Source	Capacity/ configuration/ fuel	Estimate (gCO2-e/kWh)
Wind	1.5 MW, onshore	10
Biogas	Anaerobic digestion	11
Hydroelectric	300 kW, run-of-river	13
Solar thermal	80 MW, parabolic trough	13
Biomass	Forest wood steam turbine	22
Biomass	Waste wood steam turbine	31
Solar	Polycrystalline silicone	32
Geothermal	80 MW, hot dry rock	38
Nuclear	Various reactor types	66
Natural gas	Various combined cycle turbines	443
Fuel cell	Hydrogen from gas reforming	664
Diesel	Various generator and turbine types	778
Coal	Various generator types with scrubbing	960
Coal	Various generator types without scrubbing	1050

With an average of 66 gCO₂-e/kWh, nuclear energy is by no means emission-free. Although it is much better from the point of carbon-equivalent emissions than natural gas, oil and coal generators, it is worse than electricity generated from renewable sources (Table 2).

Sovacool concluded that life-cycle studies of GHG emissions associated with the nuclear fuel cycle need to become more accurate, transparent, accountable and comprehensive. Many studies have methodological shortcomings. Most GHG studies associated with the nuclear life-cycle are obscured, especially those motivated by either pro- or anti-nuclear perception.
According to Sovacool, guidance for the nuclear industry how to report their carbon-equivalent emissions does not exist. Regulators should consider developing proper standardisation and reporting criteria for the GHG emissions associated with the nuclear life-cycle.
If nuclear power would be considered as an option to replace fossil fuels, a massive construction programme for nuclear power plants would be necessary. Estimates of the Intergovernmental Panel on Climate Change (IPCC) suggest that around 2,000 reactors would need to be operational in 2100, almost five times the current level of 435 plants. This would require the completion of 20 reactors per year. Considering the enormous costs and the time of ten and more years constructing a nuclear power plant, it is impractical to imagine that nuclear power will ever play an important role in reducing human impact on the world’s climate (Earthlife Africa, 2000: 15).