>From the article: > Sovacool believes the mean of 66 gCO_2 e/kWh to be a reasonable > approximation.
[...] > The largest source of carbon emissions, accounting for 38 per cent of > the average total, is the "frontend" of the fuel cycle, which includes > mining and milling uranium ore, and the relatively energy-intensive > conversion and enrichment process, which boosts the level of > uranium-235 in the fuel to useable levels. Going to the original journal article on which this is based http://www.sciencedirect.com/science/article/pii/S0301421508001997 and noting, as I said, that CANDU reactors use *nonenriched* uranium, we find the gCO_2 e/kWh value for a CANDU to be: 15.41 Which compares rather favourably with "solar photovoltaic, at 32 gCO_2 e/kWh, and six times as much as onshore wind farms, at 10 gCO_2 e/kWh." The article goes on to single out the CANDU with the following comment: To give an idea about how much reactor design can influence lifecycle emissions, Boczar et al. (1998) comment that CANDU reactors are the most neutron efficient commercial reactors, achieving their efficiency through the use of heavy water for both coolant and moderator, and reliance on low-neutron-absorbing materials in the reactor core. CANDU reactors thus have the ability to utilize low-grade nuclear fuels and refuel while still producing power, minimizing equivalent carbon dioxide emissions. This could be why Andseta et al. (1998) conclude that CANDU reactors have relatively low emissions (15 g CO2e/kWh) compared to the average emissions from qualified studies as described by this work (66 g CO2e/kWh). Others, such as Storm van Leeuwen et al. (2007), contest these numbers and argue that the production of heavy water associated with CANDU reactors is very energy-intensive and can produce emissions more than a factor of one greater than the projection made by Andseta et al. [so 30 rather than 15, still better than photovoltaic -PV] -Pete On Tue, 26 Feb 2013, D & N wrote: > http://www.nature.com/climate/2008/0810/full/climate.2008.99.html > > > Nuclear energy: assessing the emissions > > *Kurt Kleiner reports on whether nuclear power deserves its reputation as a > low-carbon energy source. > * > > For decades nuclear power has been slated as being environmentally harmful. > But with climate change emerging as the world's top environmental problem, the > nuclear industry is now starting to enjoy a reputation as a green power > provider, capable of producing huge amounts of energy with little or no carbon > emissions^1 > <http://www.nature.com/climate/2008/0810/full/climate.2008.99.html#B1> . As a > result, the industry is gaining renewed support. In the United States, both > presidential candidates view nuclear power as part of the future energy mix. > The US government isn't alone in its support for an expansion of nuclear > facilities. Japan announced in August that it would spend $4 billion on green > technology, including nuclear plants. > > But despite the enthusiasm for nuclear energy's status as a low-carbon > technology, the greenhouse gas emissions of nuclear power are still being > debated. While it's understood that an operating nuclear power plant has > near-zero carbon emissions (the only outputs are heat and radioactive waste), > it's the other steps involved in the provision of nuclear energy that can > increase its carbon footprint. Nuclear plants have to be constructed, uranium > has to be mined, processed and transported, waste has to be stored, and > eventually the plant has to be decommissioned. All these actions produce > carbon emissions. > > Critics claim that other technologies would reduce anthropogenic carbon > emissions more drastically, and more cost effectively. "The fact is, there's > no such thing as a carbon-free lunch for any energy source," says Jim Riccio, > a nuclear policy analyst for Greenpeace in Washington DC. "You're better off > pursuing renewables like wind and solar if you want to get more bang for your > buck." The nuclear industry and many independent analysts respond that the > numbers show otherwise. Even taking the entire lifecycle of the plant into > account nuclear energy still ranks with other green technologies, like solar > panels and wind turbines, they say. > > > Life studies > > Evaluating the total carbon output of the nuclear industry involves > calculating those emissions and dividing them by the electricity produced over > the entire lifetime of the plant. Benjamin K. Sovacool, a research fellow at > the National University of Singapore, recently analyzed more than one hundred > lifecycle studies of nuclear plants around the world, his results published in > August in /Energy Policy/^2 > <http://www.nature.com/climate/2008/0810/full/climate.2008.99.html#B2> . From > the 19 most reliable assessments, Sovacool found that estimates of total > lifecycle carbon emissions ranged from 1.4 grammes of carbon dioxide > equivalent per kilowatt-hour (gCO_2 e/kWh) of electricity produced up to 288 > gCO_2 e/kWh. Sovacool believes the mean of 66 gCO_2 e/kWh to be a reasonable > approximation. > > "The fact is, there's no such thing as a carbon-free lunch for any energy > source." > > Jim Riccio > > The large variation in emissions estimated from the collection of studies > arises from the different methodologies used - those on the low end, says > Sovacool, tended to leave parts of the lifecycle out of their analyses, while > those on the high end often made unrealistic assumptions about the amount of > energy used in some parts of the lifecycle. The largest source of carbon > emissions, accounting for 38 per cent of the average total, is the "frontend" > of the fuel cycle, which includes mining and milling uranium ore, and the > relatively energy-intensive conversion and enrichment process, which boosts > the level of uranium-235 in the fuel to useable levels. Construction (12 per > cent), operation (17 per cent largely because of backup generators using > fossil fuels during downtime), fuel processing and waste disposal (14 per > cent) and decommissioning (18 per cent) make up the total mean emissions. > > According to Sovacool's analysis, nuclear power, at 66 gCO_2 e/kWh emissions > is well below scrubbed coal-fired plants, which emit 960 gCO_2 e/kWh, and > natural gas-fired plants, at 443 gCO_2 e/kWh. However, nuclear emits twice as > much carbon as solar photovoltaic, at 32 gCO_2 e/kWh, and six times as much as > onshore wind farms, at 10 gCO_2 e/kWh. "A number in the 60s puts it well below > natural gas, oil, coal and even clean-coal technologies. On the other hand, > things like energy efficiency, and some of the cheaper renewables are a factor > of six better. So for every dollar you spend on nuclear, you could have saved > five or six times as much carbon with efficiency, or wind farms," Sovacool > says. Add to that the high costs and long lead times for building a nuclear > plant about $3 billion for a 1,000 megawatt plant, with planning, licensing > and construction times of about 10 years and nuclear power is even less > appealing. > > http://wiki.answers.com/Q/What_is_the_carbon_footprint_of_nuclear_energy > > Natalia > > On 24/02/2013 8:29 PM, Ray Harrell wrote: > > How about farming? The Pol Pot alternative? > > > > REH > > > > -----Original Message----- > > From: [email protected] > > [mailto:[email protected]] On Behalf Of michael gurstein > > Sent: Sunday, February 24, 2013 9:18 PM > > To: 'RE-DESIGNING WORK, INCOME DISTRIBUTION, EDUCATION' > > Subject: Re: [Futurework] Washington State nuclear waste leak > > > > Carbon based energy sources? > > > > M > > > > -----Original Message----- > > From: [email protected] > > [mailto:[email protected]] On Behalf Of D & N > > Sent: Monday, February 25, 2013 12:05 AM > > To: [email protected] > > Subject: Re: [Futurework] Washington State nuclear waste leak > > > > To what? > > > > N. > > > > On 24/02/2013 12:52 PM, michael gurstein wrote: > > > I'm not sure... depending on how you strike your frame of reference, > > > nuclear would seem to possibly be the least worst least risk > > alternative... > > > M > > > > > > -----Original Message----- > > > From: [email protected] > > > [mailto:[email protected]] On Behalf Of D & N > > > Sent: Sunday, February 24, 2013 7:02 PM > > > To: RE-DESIGNING WORK, INCOME DISTRIBUTION, EDUCATION > > > Subject: Re: [Futurework] Washington State nuclear waste leak > > > > > > This has been suggested, from time to time, by those who cannot hazard > > > a guess as to potential for harm. The real message is--don't create it > > > at > > all. > > > Natalia > > > > > > On 24/02/2013 9:45 AM, michael gurstein wrote: > > > > One thing I've always wondered is why no one seems to have suggested > > > > just sending it off into space? > > > > > > > > M > > > > > > > > -----Original Message----- > > > > From: [email protected] > > > > [mailto:[email protected]] On Behalf Of Keith > > > > Hudson > > > > Sent: Sunday, February 24, 2013 1:43 PM > > > > To: RE-DESIGNING WORK, INCOME DISTRIBUTION, EDUCATION; pete > > > > Subject: Re: [Futurework] Washington State nuclear waste leak > > > > > > > > At 09:12 24/02/2013, Pete wrote: > > > > > > > > > (PV) I disagree, in as much as problems at Hanford do not reflect > > > > > anything about the current state of nuclear technology. > > > > > Hanford is not a commercial power station, it is a federal research > > > > > establishment and part of the weapons infrastructure The closest > > > > > Canadian equivalent would be Chalk River, but there is really no > > > > > equivalent as we made no attempt to refine isotopes for weapons in > > > > > Canada. > > > > (KH) Our equivalent in the UK is Sellafield with scores of waste > > > > tanks (some > > > > leaky) contaning radioactive liquids of long half-life that should > > > > have been sequestered decades ago. One of the reasons why a solution > > > > has not yet been found is the poor quailty of scientists and > > > > engineers attracted to a career in nuclear projects. Whereas, 70 > > > > years ago, it took dozens of the world's most brilliant physicists to > > > > construct the nuclear bomb, today, most UK universities (201 out of > > > > 203) eschew teaching nuclear engineering because they can't attract > > > > students of any calibre. Our Nuclear Inspectorate has been under > > strength. > > > > > (PV) But Chalk River was a reasearch institute active during the > > > > > early years of exploring nuclear energy, and it also has great > > > > > warehouses full of hazardous materials. > > > > > > > > > > We have learned much from the activities in these projects, and no > > > > > one today would consider storing nuclear wastes as liquids in tanks, > > > > > certainly not from power plants, which shouldn't produce such > > > > > material. > > > > > > > > > > Canadian heavy water reactors, which I might remind you, can run > > > > > quite happily on what is considered the spent fuel of a US light > > > > > water reactor, typically run on unenriched uranium, which requires > > > > > no exotic processing to prepare, and when spent, in a CANDU reactor, > > > > > it is really quite spent, and can be prepared as a solid waste block > > > > > encapsulated in glass, and stored underground in the same mines from > > > > > which it was extracted, nested in gravel beds in the Canadian > > > > > Shield, where there is zero risk of groundwater contamination nor > > > > > exposure via earthquakes or whathaveyou. > > > > (KH) I didn't know the above, but the point is taken -- apart from > > > > "zero" > > > > risk. > > > > > > > > > (PV) I don't have any really strong opinions about the adoption of > > > > > nuclear energy one way or the other, but most criticisms I hear of > > > > > the industry just aren't up to speed with the current state of the > > > > > technology. Pointing at 60 year old mistakes as a reason to dismiss > > > > > the current technology makes no sense. > > > > (KH) One 60 year-old mistake is that no insurance corp has yet agreed > > > > to cover nuclear reactors. Another fact of the last 60 years is that > > > > no civil engineering firm that has been all too eager to design and > > > > build a reactor has yet agreed to run them and to supply electricity > > > > at the price stated on the tin (that is, the low price that > > > > politicians keep on telling us is the real price) -- or indeed to run > > > > them at all. What's more -- considerably more -- is that the cost of > > > > sequestering radioactive wastes year after year, or rather century > > > > after > > > century, has never yet been estimated and published. > > > > (Even glassified blocks, buried at very deep level has to be > > > > inspected regularly so that its safety for hundreds of generations of > > > > humans is > > > > assured.) The long and the short of both of the above facts is that > > > > nuclear power has had to be subsidised before, during, and after > > > > construction. We've never been given the true costs of > > > > nuclear-generated > > > electricity. > > > > Keith > > > > > > > > > > > > > > > > > > > > > -Pete > > > > > > > > > > On Sun, 24 Feb 2013, Keith Hudson wrote: > > > > > > > > > > > It was good to read this because I think it comes just at the right > > > > > > time to permanently affect new build in the advanced countries. The > > > > > > news of these leaks comes on top of the realization of universal > > > > > > shale gas and ought > > > > > now to > > > > > > finally stop the bleatings (and false propaganda) of the wannabe > > > > > > power > > > > > station > > > > > > constructors (who, be it noted, are not the slightest bit > > > > > > interested in running them once built). > > > > > > > > > > > > Keith. > > > > > > > > > > > > > > > > > > At 21:56 23/02/2013, Natalia wrote: > > > > > > > Most of you have probably read this by now. Given what this news > > > > > > > reveals, how can more new builds of such plants be justified? > > > > > > > > > > > > > > > > > > > http://www.cbsnews.com/8301-201_162-57570857/wash-state-governor-6-u > > > > > n > > > > > d > > > > > erground-nuclear-tanks-leaking/ > > > > > > > Natalia > > > > > > > _______________________________________________ > > > > > > > Futurework mailing list > > > > > > > [email protected] > > > > > > > https://lists.uwaterloo.ca/mailman/listinfo/futurework > > > > > > _______________________________________________ > > > > > > Futurework mailing list > > > > > > [email protected] > > > > > > https://lists.uwaterloo.ca/mailman/listinfo/futurework > > > > > > > > > > > > > > > > > _______________________________________________ > > > > > Futurework mailing list > > > > > [email protected] > > > > > https://lists.uwaterloo.ca/mailman/listinfo/futurework > > > > _______________________________________________ > > > > Futurework mailing list > > > > [email protected] > > > > https://lists.uwaterloo.ca/mailman/listinfo/futurework > > > > > > > > _______________________________________________ > > > > Futurework mailing list > > > > [email protected] > > > > https://lists.uwaterloo.ca/mailman/listinfo/futurework > > > > > > > _______________________________________________ > > > Futurework mailing list > > > [email protected] > > > https://lists.uwaterloo.ca/mailman/listinfo/futurework > > > > > > _______________________________________________ > > > Futurework mailing list > > > [email protected] > > > https://lists.uwaterloo.ca/mailman/listinfo/futurework > > > > > _______________________________________________ > > Futurework mailing list > > [email protected] > > https://lists.uwaterloo.ca/mailman/listinfo/futurework > > > > _______________________________________________ > > Futurework mailing list > > [email protected] > > https://lists.uwaterloo.ca/mailman/listinfo/futurework > > > > _______________________________________________ > > Futurework mailing list > > [email protected] > > https://lists.uwaterloo.ca/mailman/listinfo/futurework > > > > _______________________________________________ Futurework mailing list [email protected] https://lists.uwaterloo.ca/mailman/listinfo/futurework
