atw 2017-09

atw Vol. 62 (2017) | Issue 8/9 ı August/September
ENERGY POLICY, ECONOMY AND LAW 516
commercial reactor in the US at the time. Ikata 1 was due
to end its 40-year operating period in September 2017.
Novovoronezh 3 was the oldest VVER 440 reactor in
­operation, first producing electricity 45 years previously.
| | Fig. 3.
Regional generation of nuclear electricity, North America, South America,
Africa, West & Central Europe, East Europe & Russia, Asia.
In 2016 nuclear generation was higher in all regions
­except Western and Central Europe, compared to the
­average annual generation in the preceding five years
(Figure 3). Nuclear output rose most markedly in Asia,
with generation 72 TWh higher than the 2011-2015
average.
In 2014 the share of nuclear generation in the global
electricity generation mix held steady at 10.6%, ­unchanged
from 2013. In those countries that have nuclear generation
the share supplied by nuclear rose from 12.3 % in 2013 to
13.6 % in 2014 (Figure 4).
­total electricity supply has stabilized. The continuing
increase in nuclear generation seen over the last two years
should see these trends continue.
Operational performance
The World Nuclear Performance Report assesses reactors
capacity factors based on the performance of those ­reactors
that generated electricity during each calendar year
(Figure 5). This omits those reactors, such as those
­awaiting restart in Japan, that are classed as operable, but
did not generate. This treatment gives a better indication
of the long term performance trends of operating reactors.
There have been two phases in the trends for reactor
performance in terms of global average capacity factor.
Since around 2001 the global average capacity factor has
held at around 80 %. Prior to this phase there was an
­approximately 30 year period of steady improvement.
In 2016 the global average capacity factor was 80.5 %, in
comparison to 81.0 % in 2015.
Although the global overage average has stabilized
there are variations, with some regions achieving higher
capacity factors (Figure 6). In North America capacity
­factors approached 90 %, for example.
| | Fig. 6.
Capacity factor by region, North America, South America, Africa,
West & Central Europe, East Europe & Russia, Asia.
Since 1996 the share of nuclear generation in the global
energy mix has fallen from a peak of around 17 % to just
over 10 %. This decline in the overall share is in part due to
an increase in global electricity demand and in part
­because a decline in nuclear generation, particularly in
2011 and 2012, in response to the Fukushima accident.
However, as nuclear generation started to increase
again from 2012 the share of nuclear generation in the
| | Fig. 5.
Global average capacity factor 1970 to 2016.
| | Fig. 4.
Share of nuclear generation in total electricity supply.
Capacity factors are also broadly consistent with the
­average achieved in the preceding five years for reactors in
different regions. The greatest variation is seen in regions
represented by a smaller number of reactors where the
­regular schedule of outages results in variations in average
regional capacity factors.
The percentage of reactors reaching specific capacity
factors in 2016, compared to the average for each year over
the preceding five years has remained fairly consistent
over this period and there has been no significant change
to the spread of capacity factors achieved across the fleet
either (Figure 7).
The chart shows that there remains some scope for
improvements in the performance of those reactors with
lower than average capacity factors. However, in some
­cases reactors are being used in a load-following mode that
means their output is reduced to help balance variations in
demand and supply from other generators, with a ­resulting
reduction in capacity factor.
There has been ongoing improvement of reactors
­reaching higher capacity factors over the last 40 years
(­Figure 8). For example, 64 % of reactors achieved
­capacity factor higher than 80 % in 2016, compared to
24 % in 1976, whereas only 8 % of reactors had a capacity
factor lower than 50 % in 2016, compared to 22 % in 1976.
One area of interest is the performance of reactors over
their lifetime. Extended operations are increasingly
Energy Policy, Economy and Law
World Nuclear Performance Report 2017 ı Jonathan Cobb