What are the carbon emissions created by nuclear power stations?

Answer 1

Nuclear energy has a significant carbon cost of mining uranium fuel. This carbon cost is usually exported to another nation's mines. The actual carbon cost can be reduced by cutting safety in extremely poor countries, which leads to greater worker mortality but doesn't show up in the carbon budget.

The best nuclear ores are all mined. The true carbon cost of additional nuclear energy must be measured in the carbon cost of mining additional ores, not in the current average carbon cost of mining.

The carbon cost of the threat of terrorism incidents at nuclear plants is hard to calculate. Are we invading other countries because terrorist organizations will strike domestic nuclear power plants first? Also, would one successful terrorist incident instantly double the carbon cost of protecting all nuclear power plants?

We don't know how to measure the carbon cost of protecting people from nuclear waste for thousands of years. For example, the current U.S. policy on nuclear waste at the Hanford Military Reservation, which is in the floodplain of the Columbia River, is to leave the waste in place underground until it leaks into the river and is gone, or until a river flood overruns the area. This method of neglect produces a very small carbon footprint.

The decommissioning of reactors has a high carbon footprint. The carbon cost of decommissioning can be amortized over more years of electricity production by extending a nuclear plant's lifetime. However, old nuclear plants tend to have more radioactive leaks, and may have a slightly higher risk of a disaster.

The Ukraine has an issue where authorities have encased the disastrous Chernobyl reactor in a concrete casing and have abandoned the nearby city and region. Nuclear radiation has helped destroy the casing, and a new concrete tomb is planned. The entire region of Chernobyl is now threatened by fuel buildup on the forest floor. A forest fire would pump huge amounts of radiation into the air, which would cross national boundaries. Again, this storage problem's carbon footprint is low, simply because in case of a fire much of the isotope radiation would blow into some other country.

What we find is that the carbon footprint involved in generating nuclear energy and nuclear safety efforts are inextricably linked. The carbon costs in keeping people extremely safe from radiation would be enormous. Nuclear energy would be a net carbon sinkhole, where it would be more practical just to burn fossil fuels for electricity. If, however, many public health and safety shortcuts are taken by a government, especially by exporting safety problems or ignoring the mining and nuclear waste problems, nuclear energy has a much lower carbon footprint than just burning fossil fuels.

A:Early studies of the carbon footprint of nuclear power seem not to have included the construction, decommissioning, and waste disposal, which are always included in a total carbon footprint. Waste disposal is a particularly difficult area to deal with because no one know how it will be done, so no one knows what figures to use for carbon footprints. So estimates from studies dated 1998 to 2003 at the carbon footprint were all in the range of 11-13 grams of CO2 equivalent per kilowatt hour (g. CO2e/kWh). Four studies in 2004 and 2005, two of which agreed with the earlier estimates, produced an average figure of 43.5 CO2e/kWh. Five studies in 2006 produced an average of 84 CO2e/kWh. And three studies in 2007 produced an average of 93 g. CO2e/kWh for nuclear power. Since the earlier studies were clearly not addressing the total carbon footprint, and the later ones were, we can probably use a figure of 85 g. CO2e/kWh. An article by Benjamin Sovacool arrives at 65 g. CO2e/kWh, averaging the early and late numbers, but the earlier numbers are clearly wrong, despite the fact that they are much quoted.

To put this into context, the following are average estimates of total greenhouse gasses by production type with numbers of grams of CO2e/kWh:

1000 - coal

900 - oil

750 - open cycle natural gas

580 - closed cycle natural gas

(closed cycle natural gas combined with co-generation might bring this down to 400 g. CO2e/kWh)

500 coal plant burning 50% coal with 50% miscanthus

110 - old solar photovoltaics

95 - biomass from miscanthus

85 - nuclear

40 - concentrated solar thermal with thermal storage

35 - new solar photovoltaics

25 - biomass from gasification of wood chips (used to fuel conventional natural gas turbines)

21 - wind

15 - hydroelectricity

<10 - geothermal doublet

These numbers come mostly from the Wikipedia article cited below. The figure for nuclear is extracted from the Sovacool article cited by using only studies dated after 2004. The figures for solar come from current solar literature as solar technology has changed a lot in the last ten years. The figures for biomass come from the UK Parliamentary Office of Science and Technology.

This places the carbon footprint of nuclear as 400% to 1600% of wind, hydro, solar, but about 15% of natural gas, and 8.5% of coal. Bear in mind that some estimates for the nuclear are much higher.

A:There is no direct release of carbon dioxide from the fissioning of uranium to make electricity. A:What must be recognized to make a proper accounting of the true carbon footprint is indeed, as stated above, the building of the plant. However that must be amortized over the life of the plant. If you do not amortize that input you cannot make an honest declaration. Furthermore, you must also consider same with regard to "eco-friendly" devices like windmills and solar panels; which in the case of the latter, has a fairly high carbon footprint with regard to plant building and manufacturing; But as with nuclear power, solar panel carbon footprint can be amortized lower over time. When considering only the raw materials and manufacturing/processing of both solar and nuclear raw material you find that the nuclear fuel's carbon footprint ends with delivery to the nuclear plant and renders an immediate carbon-free high BTU output which quickly surpasses the BTU inputs required in all the processing operations prior to the fuels use, while the solar panel, once installed, has to operate a significant amount time before its BTU output can match the inputs required for production let alone achieve the significantly high BTU input:output ratio that is found in nuclear energy. Without this consideration all other assertions are specious.

Finally, the carbon footprint spent fuel disposal or reprocessing still does not change the BTU ratio significantly.

Answer 2

There is a lot of disagreement on this.

An article in Nature Reports called "Nuclear energy: assessing the emissions," dated 24, Sept., 2008 says that estimates vary from 1.4 gCO2e/kWh to 288 gCO2e/kWh, with an average of 66 gCO2e/kWh.

If we take the average estimate, then nuclear power releases a good deal more carbon dioxide than wind or even the older photo voltaics (PV) use in the studies, and about 16% of the emissions of natural gas. The highest estimate puts it at 60% that of combined cycle natural gas (the most efficient form of natural gas use).

Having seen some of the calculations I am inclined to believe the emissions of the nuclear industry may be 40% of those of natural gas.

The unit of measure, gCO2e/kWh, means "the equivalent of grams of CO2 per kilowatt hour." The reason for the need of equivalents is that some emissions are worse than others. Methane is about 37 times as powerful as CO2 for global warming. Nitrogen trifluoride, which was once used for the manufacture of PVs is about 17000 times as powerful as CO2.

Another aside, newer PVs have only a fraction of the carbon emissions that the old ones had. And the old ones are not making any more as they are used.

Answer 3

This is a little more complicated than it looks, because there are many technologies, and many levels of efficiency.

Carbon footprints are rated according to the total greenhouse gas cost during the lifetime of the object. Different greenhouse gasses have different effects, so the solar footprint has to be rated on a basis that is uniform. The basis is carbon dioxide, or CO2. Also, the benefit has to be standardized, and it is easy to understand power delivery in terms of kilowatt hours. Carbon footprints can be conveniently rated in grams CO2 equivalentper kilowatt hour (g CO2e/kWh).

Most efficient, and the lowest carbon footprint of just about any technology, is solar thermal. It seems to have a carbon footprint of 5 to 10 g CO2e/kWh.

Newer solar photovoltaic (PV) technologies are rated between 23.6 and about 40 g CO2e/kWh.

Concentrated solar thermal, which is especially interesting because the energy is stored as heat to be converted into hot water later, is rated as about 40 to 45 g CO2e/kWh.

Old PVs are rated at about 105 g CO2e/kWh.

By way of comparison, hydro and wind are rated at about 12 to 20 g CO2e/kWh. Nuclear is rated at about 65 to 180 g CO2e/kWh. Combined cycle natural gas is 455 g

CO2e/kWh. Oil is about 900 g CO2e/kWh, and coal 1000 g CO2e/kWh.

Answer 4

Nuclear fission does not give off carbon, carbon monoxide or carbon dioxide. The only carbon footprint would come from the vehicles and machinery use to pull the uranium out of the earth.

Answer 5

I found the website K1 Project very helpful. They had several articles underneath their Learn/Energy tab which should answer any questions about nuclear fusion.

Answer 6

None. Carbon can be produced by complex nuclear fusion processes, but so far no-one has managed to do so. That's a task we have to leave to the natural workings of stars!