03-04-2012, 12:33 PM
Generating Electricity
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The overall objective of the study is to provide reliable information on key factors affecting the
economics of electricity generation using a range of technologies. The report can serve as a resource for
policy makers and industry professionals seeking to better understand generation costs of these
technologies.
The study was carried out by an ad hoc group of officially appointed national experts. Cost data
provided by the experts were compiled and used by the joint IEA/NEA Secretariat to calculate generation
costs.
Cost data were provided for more than 130 power plants. This comprises 27 coal-fired power plants,
23 gas-fired power plants, 13 nuclear power plants, 19 wind power plants, 6 solar power plants,
24 combined heat and power (CHP) plants using various fuels and 10 plants based on other fuels or
technologies. The data provided for the study highlight the increasing interest of participating countries
in renewable energy sources for electricity generation, in particular wind power, and in combined heat and
power plants.
The technologies and plant types covered by the present study include units under construction or
planned that could be commissioned in the respondent countries between 2010 and 2015, and for which
they have developed cost estimates generally through paper studies or bids.
The calculations are based on the reference methodology adopted in previous studies, i.e., the levelised
lifetime cost approach. The calculations use generic assumptions for the main technical and economic
parameters as agreed upon in the ad hoc group of experts, e.g., economic lifetime (40 years), average load
factor for base-load plants (85%) and discount rates (5% and 10%).
Electricity generation costs calculated are busbar costs, at the station, and do not include transmission
and distribution costs. The costs associated with residual emissions – including greenhouse gases – are
not included in the costs provided and, therefore, are not reflected in the generation costs calculated in the
study.
The cost estimates do not substitute for detailed economic evaluations required by investors and
utilities at the stage of project decision and implementation that should be based on project specific
assumptions, using a framework adapted to the local conditions and a methodology adapted to the
particular context of the investors and other stakeholders.
Moreover, the reform of electricity markets has changed the decision making in the power sector and
led investors to take into account the financial risks associated with alternative options as well as their
economic performance. In view of the risks they are facing in competitive markets, investors tend to
favour less capital intensive and more flexible technologies. The used methodology for calculating
generation costs in this study does not take business risks in competitive markets adequately into account.
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Executive Summary
The introduction of liberalisation in energy markets is removing the regulatory risk shield where
integrated monopolies can transfer costs and risks from investors to consumers and taxpayers. Investors
now have additional risks to consider and manage. For example, generators are no longer guaranteed the
ability to recover all costs from power consumers. Nor is the future power price level known. Investors
now have to internalise these risks into their investment decision making. This adds to the required rates
of return and shortens the time frame that investors require to recover the capital. Private investors’
required real rates of return may be higher than the 5% and 10% discount rates used in this study and the
time required to recover the invested capital may be shorter than the 30 to 40 years generally used in this
study.
Main results
Coal-fired generating technologies
Most coal-fired power plants have specific overnight construction costs ranging between 1000 and
1 500 USD/kWe. Construction times are around four years for most plants. The fuel prices (coal, brown
coal or lignite) assumed by respondents during the economic lifetime of the plants vary widely from
country to country. Expressed in the same currency using official exchange rates, the coal prices in 2010
vary by a factor of twenty. Roughly half of the responses indicate price escalation during the economic
lifetime of the plant while the other half indicates price stability.
At 5% discount rate, levelised generation costs range between 25 and 50 USD/MWh for most coal-fired
power plants. Generally, investment costs represent slightly more than a third of the total, while O&M
costs account for some 20% and fuel for some 45%.
At 10% discount rate, the levelised generation costs of nearly all coal-fired power plants range between
35 and 60 USD/MWh. Investment costs represent around 50% in most cases. O&M cost account for some
15% or the total and fuel costs for some 35%.
Gas-fired generating technologies
For the gas-fired power plants the specific overnight construction costs in most cases range between
400 and 800 USD/kWe. In all countries, the construction costs of gas-fired plants are lower than those of
coal-fired and nuclear power plants. Gas-fired power plants are built rapidly and in most cases expenditures
are spread over two to three years. The O&M costs of gas-fired power plants are significantly lower
than those of coal-fired or nuclear power plants. Most gas prices assumed in 2010 are ranging between
3.5 and 4.5 USD/GJ. A majority of respondents are expecting gas price escalation.
At a 5% discount rate, the levelised costs of generating electricity from gas-fired power plants vary
between 37 and 60 USD/MWh but in most cases it is lower than 55 USD/MWh. The investment cost
represents less than 15% of total levelised costs; while O&M cost accounts for less than 10% in most
cases. Fuel cost represents on average nearly 80% of the total levelised cost and up to nearly 90% in some
cases. Consequently, the assumptions made by respondents on gas prices at the date of commissioning
and their escalation rates are driving factors in the estimated levelised costs of gas generated electricity.
The current gas prices are on a relatively high level. The gas price projections in 2010 of some of the
respondents in the study are higher than the current level and a few are lower than the current level. The
IEA gas price assumptions given in World Energy Outlook 2004 (IEA, 2004) are markedly different.
At a 10% discount rate, levelised costs of gas-fired plants range between 40 and 63 USD/MWh. They
are barely higher than at the 5% discount rate owing to their low overnight investment costs and very short
construction periods. Fuel cost remains the major contributor representing 73% of total levelised
generation cost, while investment and O&M shares are around 20% and 7% respectively.
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Nuclear generating technologies
For the nuclear power plants the specific overnight investment costs, not including refurbishment or
decommissioning, vary between 1 000 and 2000 USD/kWe for most plants. The total levelised investment
costs calculated in the study include refurbishment and decommissioning costs and interest during
construction. The total expense period ranges from five years in three countries to ten years in one country.
In nearly all countries 90% or more of the expenses are incurred within five years or less.
At a 5% discount rate, the levelised costs of nuclear electricity generation ranges between 21 and
31 USD/MWh except in two cases. Investment costs represent the largest share of total levelised costs,
around 50% on average, while O&M costs represent around 30% and fuel cycle costs around 20%.
At a 10% discount rate, the levelised costs of nuclear electricity generation are in the range between 30
and 50 USD/MWh except in two cases. The share of investment in total levelised generation cost is
around 70% while the other cost elements, O&M and fuel cycle, represent in average 20% and 10%
respectively.
Wind generating technologies
For wind power plants the specific overnight construction costs range between 1 000 and 2 000 USD/kWe
except for one offshore plant. The expense schedules reported indicate a construction period of between
one to two years in most cases.
The costs calculated and presented in this report for wind power plants are based on the levelised
lifetime methodology used throughout the study for consistency sake. This approach does not reflect
specific costs associated with wind or other intermittent renewable energy source for power generation
and in particular it ignores the need for backup power to compensate for the low average availability
factor as compared to base-load plants.
For intermittent renewable sources such as wind, the availability/capacity of the plant is a driving factor
for levelised cost of generating electricity. The reported availability/capacity factors of wind power plants
range between 17 and 38% for onshore plants, and between 40 and 45% for offshore plants except in one
case.
At a 5% discount rate, levelised costs for wind power plants considered in the study range between 35
and 95 USD/MWh, but for a large number of plants the costs are below 60 USD/MWh. The share of
O&M in total costs ranges between 13% and nearly 40% in one case.
At a 10% discount rate, the levelised costs of wind generated electricity range between 45 and more
than 140 USD/MWh.
Micro-hydro generating technologies
The hydro power plants considered in the study are small or very small units. At a 5% discount rate,
hydroelectricity generation costs range between some 40 and 80 USD/MWh for all plants except one.
At a 10% discount rate, hydroelectricity generation costs range between some 65 and 100 USD/MWh
for most plants. The predominant share of investment in total levelised generation costs explains the large
difference between costs at 5 and 10% discount rate.