I'm not so sure I agree with the recent spike in the environmental community's enthusiasm behind nuclear energy as a "renewable" option. Besides the obvious danger (we thought 9/11 was bad...imagine if we did that to ourselves with a Chernobyl or Three Mile Island?) the common fact that most folks forget is where to store the incredibly toxic spent fuel rods after they burn up. Ask Nevada and they'll tell you they're already sick of becoming the dumping ground the nation's nuclear facilities. If we can't agree on a place to put these things, why are thinking of building power plants that will produce more of them?

Go solar. Its clean, efficient, and dropping in cost.

Regarding Japhet's comment, no US reactor is built like Chernobyl. Chernobyl was a graphite moderated, water cooled reactor with a positive void co-efficient of reactivity. It had no containment building and many of the safety systems taken for granted in US reactors were degraded or missing in the Soviet design. A Chenobyl accident cannot by the Laws of Physics happen at any US light water reactor, and the RBMK design is forbidden in any western reactor. As far as TMI goes, that accident PROVED that when the worst does happen, the US design protects public health and safety. Not a single person, not a single animal, not even a mouse was physically harmed by the accident at TMI. Additionally, post-TMI modifications under NUREG-0737, Reg. Guide 1.97, etc., have served to enhance the already robust protection that existed prior to TMI. As far as spent fuel rods go, they can be reprocessed and consumed in fast neutron reactors or Carlo Rubbia Energy Amplifiers, making the issue of long term geological repository a moot point. As to Japhet's question, "If we can't agree on a place to put these things, why are thinking of building power plants that will produce more of them?", perhaps he needs to consider the millions of tons of mercury, NOx, SOx, and COx discharged by the coal fired plants that supply 52% of US electricity before he begins to decry nuclear power. We contain all our own waste and that waste can be reprocessed and re-used for the next generation of nuclear reactors; not so with coal plants which by the way release more radioactivity in the form of uranium, thorium and radium than a nuclear power plant. Yes, Mr. Japhet, you get more radiation dose from a coal plant than a nuke plant. Again and again and again you eco-greenies demonstrate your overwhelming ignorance of the facts.

Unless we make further improvements in solar energy technology, it's not going to be enough to meet the world's energy needs, especially if the entire world fully industrializes and begins consuming energy like the most developed regions do. Whether nuclear is eco-friendly or not, the fossil fuels are going to run out, and unless other sources (solar, geo-thermal, winds, tidal) undergo some massive revolutionary breakthrough which makes them all sufficiently efficient and sufficiently dispersable (ie, able to be used anywhere in the world to generate enough power for the region they service) to replace fossil fuels and nuclear energy, they're not going to be able to meet our needs.

Nuclear energy will never be perfectly safe, but unless we're willing to go back to the middle ages, we're not going to have much choice in the end, but to go back to it.

Wind and solar energy are too diffuse to use on any grand scale. Their capacity factors are equally dismal around 20 to 30% compared to nuclear's 90+%. No wind - no wind power. No sunlight - no solar power. Read Robert L. Bradley Jr.'s article "Renewable Energy: Not Cheap, Not 'Green'" at:

http://www.cato.org/pub_display.php?pub_id=1139&full=1

and consider the facts at the Nuclear Energy Institute.

http://www.nei.org/index.asp?catnum=2&catid=262

Comparative Measures of Power Plant Efficiency

Economic Efficiency is the most important measure of efficiency because it measures how a plant uses scarce resources and what the value of those resources is. Economic Efficiency is measured using production cost. Production cost is the cost of operating the plant—including fuel, labor, materials, and services—to produce one kilowatt-hour (kWh) of electricity. Nuclear power has the lowest production cost of the major sources of electricity, with production cost of 1.72 cents/kWh. Coal has a cost of 1.8 cents/kWh, natural gas 5.77 cents/kWh, and petroleum 5.53 cents/kWh. Hydro has a production cost of 0.5 cents/kWh. Data is not readily available for wind and solar but some data indicates production cost is around 1.2 cents/kWh for wind and 2.1 cents/kWh for solar.

Operational Efficiency measures how efficiently a plant’s capacity to produce electricity is utilized. Operational Efficiency is measured using a measure called capacity factor. Capacity factor is the ratio of the total electricity that a plant produced during a year compared to the total potential electricity that would have been produced if the plant operated at 100 percent power during every hour of the year. It is essentially the percentage of electricity that a plant produced compared to the electricity that it could have produced operating constantly at peak output. Nuclear plants typically have the highest capacity factor of any generating source with capacity factors of about 90 percent. Fossil fueled plants have lower capacity factors; coal typically has around a 70 percent capacity factor, natural gas plants of different types can vary from 14 percent to 50 percent capacity factors. Many renewables have low capacity factors. Wind and solar generation typically average around 25 percent capacity factors.

Energy Efficiency measures the amount of energy in the raw fuel needed to produce a specified amount of electricity. These fuels include natural gas, coal, oil, and uranium for nuclear energy. Energy Efficiency is measured using a measure called the heat rate. The heat rate is the amount of energy (Btu) in the fuel needed to produce one kilowatt-hour (kWh) of electricity. The lower the heat rate the more energy efficient a plant is. Plants that use a steam cycle such as coal, nuclear energy, and some natural gas plants tend to have heat rates of around 10,000 Btu/kWh. Some natural gas plants using the combined cycle technology have heat rates of around 7,500 Btu/kWh. Heat rate is not applicable for wind and solar plants, since they do not use fuel in the traditional sense of the word.

To those who believe that hydro-electric power is a CO2 emissions-free source of green energy, consider the following article, "Hydroelectric power's dirty secret revealed", in the New Scientist magazine. Only nuclear energy is truly CO2 emissions free. (BTW, given the low capacity factors and diffuse nature of solar and wind, their contribution to green house gas reduction will always be minimal.)

NewScientist.com
24 February 2005
Duncan Graham-Rowe
http://www.newscientist.com/article.ns?id=dn7046

Contrary to popular belief, hydroelectric power can seriously damage the climate. Proposed changes to the way countries' climate budgets are calculated aim to take greenhouse gas emissions from hydropower reservoirs into account, but some experts worry that they will not go far enough.

The green image of hydro power as a benign alternative to fossil fuels is false, says Éric Duchemin, a consultant for the Intergovernmental Panel on Climate Change (IPCC). "Everyone thinks hydro is very clean, but this is not the case," he says.

Hydroelectric dams produce significant amounts of carbon dioxide and methane, and in some cases produce more of these greenhouse gases than power plants running on fossil fuels. Carbon emissions vary from dam to dam, says Philip Fearnside from Brazil's National Institute for Research in the Amazon in Manaus. "But we do know that there are enough emissions to worry about."

In a study to be published in Mitigation and Adaptation Strategies for Global Change, Fearnside estimates that in 1990 the greenhouse effect of emissions from the Curuá-Una dam in Pará, Brazil, was more than three-and-a-half times what would have been produced by generating the same amount of electricity from oil.

This is because large amounts of carbon tied up in trees and other plants are released when the reservoir is initially flooded and the plants rot. Then after this first pulse of decay, plant matter settling on the reservoir's bottom decomposes without oxygen, resulting in a build-up of dissolved methane. This is released into the atmosphere when water passes through the dam's turbines.

"Drawdown" regions

Seasonal changes in water depth mean there is a continuous supply of decaying material. In the dry season plants colonise the banks of the reservoir only to be engulfed when the water level rises. For shallow-shelving reservoirs these "drawdown" regions can account for several thousand square kilometres.

In effect man-made reservoirs convert carbon dioxide in the atmosphere into methane. This is significant because methane's effect on global warming is 21 times stronger than carbon dioxide's.

Claiming that hydro projects are net producers of greenhouse gases is not new (New Scientist print edition, 3 June 2000) but the issue now appears to be climbing up the political agenda. In the next round of IPCC discussions in 2006, the proposed National Greenhouse Gas Inventory Programme, which calculates each country's carbon budget, will include emissions from artificially flooded regions.

But these guidelines will only take account of the first 10 years of a dam's operation and only include surface emissions. Methane production will go unchecked because climate scientists cannot agree on how significant this is; it will also vary between dams. But if Fearnside gets his way these full emissions would be included.

With the proposed IPCC guidelines, tropical countries that rely heavily on hydroelectricity, such as Brazil, could see their national greenhouse emissions inventories increased by as much as 7% (see map). Colder countries are less affected, he says, because cold conditions will be less favourable for producing greenhouse gases.

Despite a decade of research documenting the carbon emissions from man-made reservoirs, hydroelectric power still has an undeserved reputation for mitigating global warming. "I think it is important these emissions are counted," says Fearnside.