Power plant performance

Load factors to end December 2011

1 June 2012

Review of nuclear power plant performance in 2011, by Caroline Peachey

The Fukushima accident dominated the nuclear industry during 2011, prompting safety re-evaluations and reviews of the lessons learned across the world, as well as the permanent closure of 12 reactors (eight in Germany and four in Japan) in the second quarter of 2011. The accident has also had a notable impact on nuclear electricity generation, which fell by more than 3% compared with 2010.

Performance (height) correlates with operating experience (width) within reactor type. Bar width indicates electricity generated; totals listed above.

Data were available for 398 units (371.8 GW) with more than a year’s operating experience on 31 December 2011, and they generated just over 2500 TWh of electricity during the year. In comparison, 407 units (379.5 GW) generated 2581.6 TWh of electricity in 2010. (Note that the 12 units closed in response to Fukushima generated an additional 15.2 TWh of electricity in 2011.)

fig 2
The 2011 annual load factor for boiling water reactors dipped below the lifetime load factor for the first time since 2003

A slight overall decrease in performance in 2011 is evident. Overall, the average annual load factor for all reactors fell from 77.0% at the end of 2010 to 76.0% in 2011. But the decline is magnified at the bottom end. When the reactors are grouped in quartiles, the lowest annual load factor in the top 25%, 50% and 75% changes little from 2010 to 2011 (91.8, 83.2 and 70.8 for 2011, respectively). But the lowest annual load factor in the top 90% in 2011, 37.6%, is a third lower than in 2010.

Year on year load factors comparison

The fall in average annual load factor was the most prominent for BWR designs, dropping from 75.5% for 2010 to 67.7% for 2011. The BWR figure is affected most significantly by the operation of reactors in Japan, which is home to 30% of the BWRs listed in our main table. The average annual load factor for PWRs dropped less markedly from 81.1% in 2010 to 79.5%. However, it was a good year for RBMK and PHWR reactors, which improved from 60.3% to 80.6% and from 64.3% to 72.8%.

The effect that Fukushima has had on the operation of nuclear power plants in Japan is unprecedented. There was a similar fall in performance of US nuclear plants following the 1979 Three Mile Island accident, but this was much less marked. Interestingly though, performance in most countries was not largely affected by Fukushima with drops in generation only in Japan, Germany and the USA in 2011 compared to the prior year.

Wide disparities in performance are visible between countries

The average load factor for Japanese reactors dropped from 69.5% at the end of 2010 to just 39.5% at the end of 2011. The respective figures for PWRs fell from 82.0% to 55.1% and for BWRs from 61.3% to 25.0%.

Top three performers as of December 2011

Takahama 3 (Japan): 106.2% load factor in 2011

Quad Cities 2 (USA): 104.8% load factor in 2011

Shearon Harris (USA): 102.3% load factor in 2011

Top three lifetime electricity generators as of December 2011:

Grohnde (Germany): 304 TWh

Grafenrheinfeld (Germany): 297.6 TWh

Philippsburg 2 (Germany): 295.4 TWh

Top three lifetime performers as of December 2011:

Wolsong 3 (South Korea): 93.8% lifetime load factor

Wolsong 4 (South Korea): 93.4% lifetime load factor

Emsland (Germany): 93.2% lifetime load factor

Top three achievers in equivalent full power years output as of December 2011

Beznau 1 (Switzerland): 35.6 equivalent full power years’ output

Beznau 2 (Switzerland): 35.2 equivalent full power years’ output

Ginna (USA): 34.9 equivalent full power years’ output

Author Info:

Adapted from an article first published in the May 2012 issue of Nuclear Engineering International magazine

Related Articles
Review of units in long-term shutdown in 2011

comparison comparison
country country
Wolsong Wolsong
Fig1 Fig1
fig 2 fig 2
Takahama 3 Takahama 3

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