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CLIMATE CHANGE—THE ACHILLES HEEL OF THE THERMAL POWER
INDUSTRY
Kristin Linnerud, CICERO, +47 94873338, [email protected]
Torben K. Mideksa, CICERO, +47 22858562, [email protected]
Gunnar S. Eskeland, NHH, +47 55959699, [email protected]
Overview
A warmer climate will result in lower thermal efficiency and more frequent shutdowns of thermal power plants. To
identify these two supply-side effects we estimate regression models on nuclear plant capacity utilization data. We
use different data sets and estimation strategies to control for other factors which are related with temperature and
which may affect capacity utilization. Our results indicate that a rise in temperature of 1 degree Celsius reduces
thermal power capacity with 0.1-0.5 percent through its effect on thermal efficiency; during droughts and heat
waves the capacity loss increases to 1.0-2.0 percent per degree Celsius as the operation of cooling systems is
constrained by physical laws, regulation or access to cooling water. Thus, more frequent droughts and heat waves
may in the future pose a threath to energy supply security.
Methods
A rise in temperature may influence the capacity utilization of thermal power plants in two ways:
I.
Reduced efficiency: Increased environmental temperature reduces how efficient a thermal power plant is in
turning fuel into electricity; i.e. the ratio of electricity produced to the amount of fuel used in producing it.
II.
Reduced load: For high environmental temperatures thermal power plant’s operation will be limited by a
maximum possible condenser pressure. The operation of plants with river or sea cooling will in addition be
limited by a regulated maximum allowable temperature for the return water or by reduced access to water.
The 4th Assessment report of the IPCC reports that “Climate change could have a negative impact on thermal power
production since the availability of cooling water may be reduced ...” However, while several contributions 1 identify
these climate change impacts, few have tried to quantify them. Durmayaz and Sogut (2006) design a theoretical
model for a pressurized-water reactor nuclear-power. They find that an increase in temperature with 1 oC of the
coolant extracted from environment will yield a decrease of 0.12 percentage points in efficiency and a 0.45 percent
reduction in power output. Daycock et al. (2004) measure the actual decrease in efficiencies on gas power plants
located in a desert and their results are consistent with a 0.09-0.23 percentage point decrease in efficiency and a
0.55-0.73 percent decrease in power output for an increase of 1oC. Maulbetsch and DiFilippo (2006) address the
need for alternative cooling systems as a changing climate makes water use and conservation at thermal power
plants more important. They demonstrate that these water saving comes at a price including increased capital and
operating costs, reduced thermal efficiency and reduced output.
In this paper, we take the challenge of quantifying the impact of changes in climate on the supply of thermal power.
More specifically, we estimate a regression model in which variations in thermal power plants’ capacity utilization
is explained by variations in environmental temperature. The model specification and the estimation strategy are
chosen so as to isolate the above mentioned two supply-side impacts: (I) reduced efficiency and (II) reduced load.
The major problem is to control for other factors which are related to temperature and which also influence the
thermal power plant’s capacity utilization. These factors are: 1) choice of technology which may reflect climate
conditions, 2) planned maintenance which is normally laid to the summer months and 3) seasonal changes in
demand.
1
See e.g. Arnell et al. (2005) and Bull et al (2007).
To control for these factors we use two different datasets: a plant specific dataset and a panel dataset with
aggregated observations for seven countries. In both datasets nuclear power plants are chosen as our object of study
since nuclear power plants’ low marginal costs and low operating flexibility make their production less sensitive to
temperature-induced demand shifts compared to other thermal power plants.
Results
Our plant specific estimation shows that a rise in environment temperature of 1 degrees Celsius will reduce output
with 0.1-0.2 percent due to a fall in efficiency and, for high temperatures, with 0.9-1.1 percent due to both reduced
efficiency and reduced load. Estimations on the panel data suggest an even higher temperature sensitivity of supply
in general; a rise of 1 degree Celsius will reduce output with 0.5-1.0 percent for temperatures around 0 degree
Celsius and 1.5-2.0 percent for temperatures around 15 degree Celsius.
Conclusions
These impacts may seem small. But, since 81 percent of all power worldwide is produced by conventional thermal
power and nuclear power plants, it is important to take them into consideration when estimating expected costs of
climate change. The net electricity generation from conventional thermal power and nuclear power plants was about
1,500 TWh in 2006 (EIA, 2008). A reduction in production capacity of 1-2 percent due to an increase in
environment temperature of 2 degree Celsius would represent a drop of up to 30 TWh that might need to be replaced
somewhere. This translates into the full production of 3 nuclear power plants with 1200 MW installed capacity.
But, perhaps more importantly, more frequent droughts and heat waves may, by causing partial or full shutdowns of
power plants, pose an energy supply security risk in the future. This points in the direction of investing in more
robust cooling technologies and/or in more spare production and network capacity. Climate considerations will also
become even more important when deciding where to build new thermal power plants.
References
Arnell, N., E. Tomkins, N. Adger and K. Delaney, 2005: Vulnerability to Abrupt Climate Change in
Europe. ESRC/ Tyndall Centre Technical Report No 20, Tyndall Centre for Climate Change Research,
University of East Anglia, Norwich.
Bull, S. R., D. E. Bilello, J, Ekmann, M. J. Sale, and D. K. Schmalzer, 2007: Effects of Climate change on
energy production and distribution in the United States in Effects of Climate Change on Energy
Production and Use in the United States. A Report by the U.S. Climate Change Science Program and the
subcommittee on Global change Research. Washington, DC.
Daycock, C., R. Jardins and S. Fennel (2004). Generation Cost Forecasting Using On-Line Thermodynamic Models.
Proceedings of Electric Power, March 30-April 1, 2004, Baltimore, MD.
Durmayaz, A. and O.S. Sogut (2006). Influence of Cooling Water Temperature on the Efficiency of a Pressurized
Water Reactor Nuclear-Power Plant. International Journal of Energy Research, 30, 799-810.
EIA (2006). Annual Energy Outlook 2006,with projections to 2030. DOE/EIA-0383(2006). Washington, DC:
Energy Information Administration.
Maulbetsch, J.S. and M.N. DiFilippo (2006). Cost and Value of Water Use at Combined Cycle Power Plants,
Calefornia Energy Commission, PIER Energy-Related Environmental Research , CEC-500-2006-034, April 2006.