Uranium, Electricity and Climate Change
Updated December 2012
- Uranium can supply energy for
the world's electricity with less greenhouse effect than virtually
any other energy source.
effect' is not a new concept. In 1863 Irish-born
scientist John Tyndall was writing about 'greenhouse gases' and
some 30 years later Swedish scientist Svante Arrehenius made the
first known attempt to calculate the impact of increased carbon
dioxide in the Earth's atmosphere.
Today there is no question about the
existence of the greenhouse effect. Without it our planet would be
vastly colder (by 33°C on average), and present life forms would be
very different. Water vapour is the main greenhouse gas, accounting
for some three quarters of the greenhouse effect, and nothing we do
is likely to change it very much.
But second to that, and much more
related to human activity, is carbon dioxide. A major source of
this today is the burning of fossil fuels to provide energy,
particularly electricity. Human activity, particularly since the
beginning of the Industrial Revolution, seems to be turning up the
Each year well over 28 billion tonnes
of carbon dioxide are put into the atmosphere by human activity.
This is only about 3% of the natural flux between atmosphere and
oceans or land. But its balance is critical. Carbon dioxide is
responsible for more than half of human-induced global warming
If much of the human effect which tends
to increase global warming comes from our use of energy, we need to
Who Needs Energy?
Everyone. Today the world uses a great
deal of energy and the usage is increasing dramatically in
In the early 1970s a fourfold increase
in the price of oil alerted the world to the need for more
efficient use of energy, and more diversity of supply.
In OECD* countries the response to
this, including greater use of electricity as a means of increasing
efficiency, led to a levelling off in demand for primary energy.
Between 1973 and 1985 primary energy demand in the OECD remained
unchanged despite an increase in gross domestic product (GDP) of
33%. Since 1985 energy use has been rising again.
Outside the OECD countries the picture
is different, and primary energy demand is increasing by about 50%
each decade. Overall, world energy demand is expected to increase
by more than 50% from 2005 to 2030.
Source: OECD/IEA World Energy
Any attempt to understand or forecast
global energy requirements must take account of population growth.
At the beginning of the twentieth century, world population was
about 1.5 billion. Today it is over seven billion and growing at
the rate of 90 million a year. By the year 2025 world population is
expected to reach 8 billion.
Rate of population increase
Rate of Increase per year
Over 90% of world population growth in the foreseeable future will be in the less developed countries, which already contain 75% of the world's people. United Nations projections show most of this growth taking place in urban areas.
Even with effective energy efficiency
programmes in developed countries there will be a global need for
much more energy if people in the less developed countries are to
improve their standards of living. A large part of this increase
will be in electricity.
World electricity demand is
forecast to double between 2002 and
2030. For instance, while the growth
in demand for primary energy in East Asia is around 5% per year,
that for electricity is 7-8% per year. In China, power generation
requirements are expected to almost double in 15 years, with much
of this being met by nuclear. China intends a fivefold increase in
nuclear power capacity by 2020 (from 2005 level).
The Increasing Role of Electricity
Electricity is the most widely used and
rapidly growing form of secondary energy supply. Its generation
accounts for about 40% of total primary energy supply. It offers
great flexibility of distribution and use, is relatively efficient,
very safe for the consumer, and environmentally benign in
Although overall energy intensity
(energy per unit of GDP) fell 25% worldwide 1971 to 1997,
electricity demand increased almost threefold over this period. The
share of electricity in total energy consumed will rise from 16% in
2002 to about 20% in 2030.
All energy conservation scenarios
assume the expanded use of electricity. The most important fuel for
generating electricity is coal which provides 40% of all
electricity generated. Uranium used in nuclear power stations today
provides 13.5% of the growing total.
Today 67% is from fossil fuels, which
give rise to substantial carbon dioxide emissions. In the OECD
countries nuclear power contributes about 23% of total
There is more electricity generated by
nuclear power today than from all sources worldwide about 40 years
ago (2560 billion kWh in 2009).
Electricity and Greenhouse Gases
Every form of energy conversion, such
as turning primary energy into electricity, has some environmental
In recent years attention has been
focused on the climate change effects of burning fossil fuels,
especially coal, due to the carbon dioxide which this releases into
Carbon dioxide contributes at least 60%
of the human-induced increase in the greenhouse effect. Electricity
generation is one of the major sources of this carbon dioxide,
giving rise to about 9.5 billion tonnes per year - 40% of it, or
about one quarter of the human-induced greenhouse increase.
Coal-fired electricity generation gives
rise to nearly twice as much carbon dioxide as natural gas per unit
of power, but hydro and nuclear do not directly contribute any. If
the amount of nuclear power were doubled, emissions from
electricity generation would drop by one quarter.
Conversely, there is scope for reducing
coal's carbon dioxide contribution to the greenhouse effect by
substituting natural gas or nuclear power, and by increasing the
efficiency of coal-fired generation itself, a process which is well
under way. Nuclear power is well suited to meeting the demand for
continuous, reliable electricity supply on a large scale (ie
base-load electricity), the major part of demand.
At the time of the oil shocks early in
the 1970s, France was heavily dependent on overseas supplies of
energy. Since then it has built 60 nuclear reactors in a major
programme. Nuclear power now provides 78% of its electricity, it
has become a major exporter of electricity (60 billion kWh per
year), and it now has a high level of energy independence. Moreover
the cost of electricity has declined markedly and per capita carbon
dioxide emissions are half those of its neighbours. Next door,
Italy is the only industrialized European country without its own
nuclear power generation, but it is also the world's main
electricity importer - mostly from France.
A 1,000 megawatt electrical (MWe)
coal-fired power station burning coal has a typical fuel
requirement of almost 3.2 million tonnes* of black coal a year.
*assumes coal yielding 24 MJ/kg and
plant operating at 80% capacity. Burning brown coal at 8.15 MJ/kg
would require 9.3 million tonnes of fuel.
A nuclear power reactor of the same
capacity, (after its initial fuel loading of uranium), has an
annual requirement of around 27 tonnes of fuel. Producing this
amount of uranium fuel requires the mining of 45-70,000 tonnes of
typical Australian uranium ore, or even less Canadian ore. This
yields about 200 tonnes of uranium oxide concentrate which is sold,
the rest stays at the mine, as tailings. The uranium oxide is
enriched to yield the 27 tonnes of actual fuel (see The Nuclear
Fuel Cycle in this series).
Coal-fired power stations worldwide
consume over 4500 million tonnes of coal each year to make 40% of
the electricity. This compares with about 70,000 tonnes of natural
uranium (82,000 t of oxide concentrate from the mines) providing
the fuel for the nuclear power stations which make 13.5% of the
world's electricity. Coal-fired power needs about 20,000
times as much fuel from mines for each kilowatt-hour.
Much of the coal is used in the country
in which it is mined, though often it has to be transported long
distances, which requires considerable energy (and results in
further greenhouse gas emissions).
By comparison, very little uranium is
required to do the same job. The 1000 MWe nuclear power station
requiring 27 tonnes of fresh fuel per year means an average of
about 74 kg per day, which would fit in the back of a car. An
equivalent sized coal-fired station needs some 8600 tonnes of black
coal to be delivered every day, or rather more brown coal
Emissions of carbon dioxide from
burning fossil fuels are about 28 billion tonnes a year worldwide,
of which around 38% comes from coal, 21% from gas and 41% from
Each year the 1000 MWe coal-fired
power station produces about 7 million tonnes of carbon dioxide,
perhaps 200,000 tonnes of sulphur dioxide (depending on the
particular coal) and typically about 200,000 tonnes of solids,
mostly fly ash. The ash contains several hundred tonnes of toxic
heavy metals including arsenic, cadmium, lead, vanadium and mercury
which remain toxic forever. If brown coal is used the carbon
dioxide figure is about 9 million tonnes.
Methods exist for removing
sulphur dioxide and nitrous oxide although the cost is high. Fly
ash is generally captured and dumped in landfill. However there is
no economically feasible way to remove or reduce carbon dioxide
from the burning of coal. None of these emissions occur at a
nuclear power station, where virtually all wastes are contained in
the 27 tonnes or so of used fuel, and are therefore not released to
The combustion of coal may also release
radioactive heavy metals (including uranium and thorium) contained
in it, though these are mostly retained in the ash. The use of
natural gas releases radioactive radon. The amount of radioactivity
released is negligible relative to the natural background radiation
levels, but is often greater than that from nuclear power
If the electricity produced worldwide
by nuclear reactors were generated instead by burning coal, an
additional 2600 million tonnes of carbon dioxide would be released
into the atmosphere each year. This can be compared with the target
of a 5% reduction (600 million tonnes per year) in carbon dioxide
emissions by the year 2010, as agreed in 1997 at Kyoto just for the
Every 22 tonnes of uranium used avoids
the emission of one million tonnes of carbon dioxide, relative to
coal. When the electricity comes from coal, every kilowatt hour of
it results in about a kilogram of carbon dioxide being emitted.
Borosilicate glass from the first waste
vitrification plant in UK in the 1960s. This block contains
material chemically identical to high-level waste from
reprocessing. A piece this size would contain the total high-level
waste arising from nuclear electricity generation for one person
throughout a normal lifetime.
The total amount of used fuel resulting
from operation of all the world's commercial nuclear power stations
is about 12,000 tonnes per year. About two thirds of this is
treated as waste, while the rest is reprocessed to recover useful
fuel material. The reprocessing of used fuel results in only about
3% of it being high-level radioactive waste (which is then
incorporated into glass), with the balance being recycled as fresh
Handling, storage and treatment of
these radioactive wastes has been undertaken in many countries for
several decades without incident. Nuclear power is the only
energy-producing industry which takes full responsibility for all
its wastes and costs this into the product.
The used nuclear fuel elements - or the
separated high level wastes - are stored for up to 50 years to
allow for the decay of most of the radioactivity and heat (to about
0.1% of what it was when removed from the reactor) before final
disposal. Today the waste disposal issue is not a technical problem
but one of public and political acceptance.
The Role of Renewables
Renewable energy sources for
electricity are diverse, from solar, tidal and wave energy to
hydro, geothermal and biomass-based power generation. Apart from
hydro power in the few places where it is very plentiful, none of
these is suitable, intrinsically or economically, for large-scale
base-load power generation.
Because of their diffuse nature (making
them difficult to harness efficiently) and their intermittent
availability (giving rise to the need for storage or back-up from
other sources), their role in meeting electricity demand on any
significant scale will always be limited. A 20% contribution to
grid supply is the maximum conceivable for non-hydro sources, and
about half of this is likely. Renewables have most appeal where
demand can accommodate small-scale, intermittent supply of
All of the various means of generating
electricity have a role to play in meeting the rapidly increasing
demand for this form of energy. Fossil fuels, particularly coal and
gas, will remain important. Since reliability is the most important
attribute of electricity supply, the role of non-hydro renewables
Nuclear electricity is one part of the
solution of the energy equation for today and tomorrow,
particularly in the light of concerns about carbon dioxide
emissions. Without nuclear power the world would have to rely
almost entirely on fossil fuels, especially coal, to meet demand
for base-load electricity production. This has significant
environmental, and particularly greenhouse gas, implications.
Nuclear power plants do not emit any
carbon dioxide, nor any sulphur dioxide or nitrogen oxides. Their
wastes end up as solids and, though requiring careful handling, are
very much less than the wastes from burning coal and are easily
Whenever new electricity generating
capacity is required, or old fossil-fuelled plants need to be
replaced, it is therefore sensible to consider nuclear as a serious
option. Nuclear electricity has accumulated over 14,000
reactor-years of operating experience.
The continued and expanded use of
nuclear power is one among a range of measures which will
effectively limit future global carbon dioxide emissions. Some 50
countries have chosen nuclear power as part of their energy mix.
They have over 430 power station reactors in operation and more