Thursday, September 30, 2010

A Thorium Grand Plan

There is properly speaking no Thorium Grand Plan, but an ongoing discussion of a thorium grand plan has continued on the Energy from Thorium Discussion pages for about two and a half years. The "Thorium Grand Plan" discussion was initially inspired by A Solar Grand Plan, an article that appeared in the January 2008 Scientific American. Anyone interested in post-carbon energy planning should read the Grand Solar plan along with the 720 comments that followed . The Grand Solar Plan itself turned out to be something of a fiasco, as an examination of the comments would reveal.

In order for any solar energy scheme to work on a 24 hour a day basis, there would have to be a massive amount of overnight energy storage. The Grand Solar Plan suggested that air could be compressed and stored for night time recovery in caverns, and then recovered to drive turbines to generate electricity. "Dan M. " commented,
COMPRESSED AIR STORAGE
When I read the proposal concerning the use of compressed air for energy storage, I spent a bit of time double checking my understanding. The reason for this was that I remembered that underground storage of compressed air typically needed relatively large spaces to work quickly and efficiently. I looked up a couple of sources (1)(2), and found information that was consistent with what I recalled.

The first think I wish to point out is the high temperature of the compressed air calculated in the first reference. In a salt cavern, this is acceptable, because the volume of the gas is large, the thermal contact is only at the walls of the cavern, and salt, IIRC, is a decent insulator.

Now, contrast that to storage in a porous formation. Most porosity that I've observed is fairly small grain porosity. One way to think of it is to think of sandstone as sand that has been subjected to significant pressure so that it is pressed together to form a rock. Think of the size of the grains of the sand and you get a feel for the size of the pore spaces in a typical sandstone

Given this, what happens when hot air is put in contact with the sand. Even at 70 bar (the storage density mentioned in the first reference), the density of the air is still in the 0.01 g/cc range. Contrast that to the sandstone matrix density of 2.65 g/cc, or the limestone matrix density of 2.71 g/cc. It is true that, gram per gram, the heat capacity of the air is higher, but it's only about 25% higher than limestone, so the relative masses of the air and the matrix rock (e.g. limestone, sandstone, & dolomite) is about 1 to 800 or so. Given this, the heat capacity of the rock per cm of rock/stored air is about 500x that of the air. Thus, the compressed air will lose a significant amount of its energy heating the rock⬦particularly with typical grain sizes.

If you look at my first two references, you will see specific mention of the limited availability of suitable locations for downhole compressed air storage. The quick calculation I gave indicates one of the reasons for this.

The second problem with typical formations is the speed at which the gas can be withdrawn. If you look at the DOE's discussion of natural gas storage(3), you'll see a reference to the advantage of caverns for quick retrieval. The permeability of the formation has a tremendous influence on the speed at which the natural gas can be withdrawn. Obviously, the permeability of a cavern is near infinite. Other formations have lower permeability. If it is low enough, the oil and gas in the rock cannot be accessed. Even when it is suitably high, the process takes a matter of years in most cases of oil and gas wells.

Obviously, storage of natural gas for the winter season uses formations with better permeability than this. Still, it would be quite acceptable to have a natural gas reservoir that would take 60 days to draw down. That would not be acceptable for compressed air. It is true that the air will flow faster, but there would still be energy lost as the hot air travels through the narrow pore spaces.

So, if one is to propose compressed air for the storage of massive amounts of energy (say in the range of 100-200 billion kWh), one needs to determine energy loss for the technique in available formations, as well as the total of available formations. Nothing I've seen about this technique indicates that the US has sufficient available suitable formations to handle this.

(1) http://www.doc.ic.ac.uk/~matti/ise2grp/energystorage_report/node7.html
(2) http://www.greenhouse.gov.au/renewable/aest/pubs/aest-review.pdf
(3) http://tonto.eia.doe.gov/ftproot/natgas/storagebasics.pdf
"Dan M's" is right, compressed air energy storage has many practical problems, that are unlikely to be completely resolved. The compressed air energy solution so highly touted three years ago, has over the last couple of years largely slipped out of the energy discussion.

In a later comment, "Dan M" stated,
I think that the foundation of our disagreement is that I don't think that we now know the best path, or the true cost of various paths.
"ShermanDorn" pointed to the last statement and announced,
Bingo. I'm not an historian of science and technology, but I had to brush up on that literature for a class I was teaching this semester, and this article strikes me as one of those arguments for massive infrastructure development based on fragile assumptions. Invest in renewables, absolutely! Commit billions on a specific strategy, no way!
To their credit, plan authors, Ken Zweibel, James Mason and Vasilis Fthenakis, stuck around and offered defenses of their assertions. "DanM" noted their professionalism and commented,
I appreciate your willingness to enter the dialog concerning your proposal with the general public. I also appreciate your willingness to take counter proposals and perceived difficulties as good faith arguments by those who also want to see a solution to the problem of greenhouse gasses as well as the geopolitical difficulties inherent in the transfer of large amounts of money to unstable and unelected governments. . . .

OK, so let me go on to discussing my position/y'alls responses. It appears to me that you have come to the conclusions that the only way to significantly reduce and eventually eliminate the reliance on oil and coal is to convert to solar power. I see that there are a number of possible solutions that are not simply niche players. They include:

1) Wind
2) Sequestering
3) Solar
4) Nuclear Fusion
5) Nuclear Fission . . .

As for nuclear power, the anti-nuclear movement has succeeded in adding tremendous costs to nuclear power in the US. The fact that other countries are planning/building nuclear power plants without the massive (in terms of the total cost/price) subsidies that are given to wind power and solar power throughout the world indicates that nuclear power is more than cost competitive with wind and solar on a level playing field.

So, in conclusion, I think that there are a number of things we can do to cut greenhouse gas emissions. The most cost effective immediate thing we can do is choose nuclear power as a replacement for proposed coal plants. Subsidized wind comes next in cost effectiveness. Solar power is one of a number of definate maybes for a long term solution. I think we should explore all of these, without choosing one prematurely.
Once again "Dan M" put his finger on a major problem, the existence of competing alternative solutions that cannot and should not be ruled out from further consideration. Unfortunately the discussion was breaking down at this point, because the plan authors chose to engage in a broad, demagogic, and highly irrational attack on nuclear power, repeatedly mentioning the word "Chernobyl" as if the very word were an argument.

The word "Chernobyl," coming from plan authors was enough to signify the end of serious dialogue on the Solar Grand Plan, and that plan authors were unwilling to allow a dispassionate discussion of the relative merits of solar and nuclear oriented plans to take place. My assessments of the relative costs and difficulties of solar and nuclear power, assessments that has been repeatedly supported by similar assessments on Brave New Climate, and Masterresources, indicate that the cost of the GSP would be several times higher than the cost of a full scale nuclear deployment.

Shortly after the publication of the Grand Solar Plan, the then 58 member of the Energy from Thorium community embarked on an ambitious project to create a Grand Thorium Plan.
Klaus Allmendinge suggested,
Seeing the popularity of the SciAm Solar Grand Plan article in the blogosphere, I think it is high time that Kirk and others on this forum launch a "Thorium Grand Plan" article in SciAm.
Apparently SciAm is widely read in political circles as well. It would provide a good forum to introduce the concepts shown on this site.
As regards the SGP, I think it is so full of holes, it sinks before a first penny is spent. Just the infrastructure requirements (DC-AC, AC-DC inverters, bus bars and such) to interconnect that large an array would probably exceed the cost of the solar cells themselves, no matter how cheap. Add to that the real cost of the compressed air storage and its additional energy requirements (read natural gas), and there should be no question. I read the entire discussion on the SciAm web-site.
This was the launching point of the Thorium Grand Plan in Late January 2008. At present there are 547 comments on the TGP topic. In addition, many of my posts on Nuclear Green are intended to contribute toward the development of a Thorium Grand Plan. Despite this significant amount of work, a Thorium Grand Plan has yet to emerge. Indeed there are questions about the necessity of such a plan for the near future.

Yet elements of a plan do exist. There is a clear LFTR deployment plan for the United States, or more accurately some alternative deployment plans. The basic outline of the deployment plan is to build small ~100 to 250 kWe LFTRs in factories, transport them in several sections to home locations for final set up. Recycle coal fired power plants when possible. House the LFTRs underground if physically and economically feasible. Start the LFTRs with U-235 from American Bomb stockpiles, or with Reactor Grade Plutonium from the "spent nuclear fuel" from Light Water Reactors. Make efficient use of the heat produced by the MSRs/LFTRs. This includes using top, middle and bottom work cycles. For example, using the top heat (up to 1200 C) for industrial process purposes, using the rejected heat from the top cycle for electricity generation, and then using the rejected heat from electrical generation for desalinization or for district heating or cooling. MSRs/LFTRs do not have to be reserved for base load electrical production. If the capital costs can be made low enough, and the MSR/LFTR operations made sufficiently efficient, they do not have to be confined to base load generation. MSRs/LFTRs can operate on an intermediate, load following basis, say for 16 hours a day. During those periods of time when electricity demand drops, the intermediate load reactors can switch to hot salt production. The hot salt can be stored, and then used to provide electricity through dedicated, low cost, thermal air or gas turbines, during periods of peak demand. Alternatively the intermediate load LFTR can be shut down using the LFTRs negative coefficient of reactivity. This would put the LFTR on reserve standby, from which status it can be quickly brought back to electrical production, should the situation demand it.

The incomplete thorium Grand Plan has identified the existence of sufficient accessible global thorium resources to keep a high energy thorium based economy going for millions of years. Thus the thorium based economy is sustainable. In addition, the LFTR answers all of traditional environmentalists objections to nuclear energy. It is safe, it does not produce long lived actinides, the most feared component of nuclear waste, and depending on its design, the LFTR will produce a tiny amount of nuclear waste, than will be dangerous for at most 300 years. Yet it is entirely possible that with the LFTR there will be no nuclear waste at all, and that everything that comes out of the LFTR as "spent fuel products" will be recyclable. The LFTR would not be a proliferation tool of choice, without proliferation resisting modifications, and such modifications are possible if desired. Large scale production of LFTRs will reduce nuclear costs. LFTRs potentially have much higher levels of thermal efficiency than light water reactors, and therefore will need less water if water cooled. If the availability of coolant water is an issue, LFTRs can be air cooled. Terrorist threats can be prevented by housing LFTRs in inaccessible underground chambers that cannot be attacked by aircraft.

In addition the LFTR will be environmentally friendly, and will have a small physical footprint as well as require far less material to build. The LFTR Energy Returned on Energy Invested (ERoEI) will be easily several hundred times greater than that of a conventional Light Water Reactor. In addition to these benefits the LFTR would be an effective tool for fighting Anthropogenic Global Warming. The LFTR can fill a number of gaps in all current energy plans. For example its can serve as a reliable electrical generation backup, and fulfilling part time generation roles, without disastrous cost penalties. The LFTR can serve as a useful source of industrial heat. LFTRs can be used to power commercial ships at sea at a lower cost than conventional reactors can. LFTRs can provide low cost, stand alone electrical generation for isolated communities, and with their superior safety, can be safely housed in urban areas. If distributive generation and grid models are viewed as desirable, small LFTRs can be available to provide local electrical services. On the other hand, by clustering LFTRs, they will be capable of powering the entire grid.

There are several obstacles to LFTR acceptance. In 1972, Oak Ridge National Laboratory identified the development tasks, that would be required to build a LFTR prototype. The cost today of completing that plan might be as little as $2 to $3 billion dollars. Development of a commercial LFTR prototype might cost $5 to $10 billion dollars. Development of a highly efficient closed cycle CO2 orHelium turbine would probably cost a few more billion dollars. This sounds like a lot, but the development cost of the Boeing 787 Dreamliner and the Airbus 380 fell in a similar cost range.

The views of the Energy from Thorium community continue to evolve. Recent thinking has focused on the development of uranium fueled Molten Salt Reactors (UMSR) as either a first step toward the LFTR, or as an alternative goal. The advantage of the UMSR would be that most of its technology has already been tested. Thus UMSR development costs would be far lower that for the LFTR, and its development will require far less time. The UMSR would compete with LWRs and potentially could cost considerably less. Some former LFTR advocates now are arguing that were the UMSR to emerge, LFTR design and production can be deferred for a considerable period of time.

Public knowledge and public acceptance are also obstacles to the emergence of the LFTR. In fact the Molten Salt Reactor technology was virtually unknown to the public as recently as 4 years ago. Members of the EfT community undertook a public education mission, using all forms of social media including blogs, comments on blogs and internet new outlets, public lectures, You Tube videos, an open science forum, an online document archive, Facebook pages, and Twitter pages. The LFTR message is beginning to reach technically sophisticated young people, as well as mature adults, and it is beginning to penetrate into the mainstream media. Thus the LFTR advocacy community can look with pride at its accomplishments. TheEnergy from Thorium Discussion Forum is considered a model for other Internet based Open Science Forums. And the EfT Document Archive is a valuable resource, for anyone who wants to study advanced forums of nuclear energy using internet resources.
Thus the use of Social Media by the EfT community has made its message far better known. The growth of the EFT core community to nearly 800 members from less than 40 a little more than 3 years ago, does not fully represent the spread of its message, Today hundreds of thousands and perhaps millions of people have read about the LFTR in the main stream media, and have encountered the concept through social media. LFTR advocacy has taken on a life of its own outside the EfT community. Thus the EFT community, despite its small beginnings, has so far seen major success.

A third barrier to LFTR success, is public confusion about energy. A clear majority of the public believes that energy problem can in part or completely be solved by renewables and efficiency. Yet renewable costs are high, and solutions to problems related to the intermittency of renewable resources threaten to push the cost of renewable resources far beyond any realistic threshold. Economist have long raised questions about the effect of energy efficiency on energy consumption, and the assumption that energy demand can be lowered by increasing efficiency is at best still open for debate. In addition the assumptions about how rapidly efficiency can move forward seem very unrealistic. Despite these problems with the conventional wisdom on energy, the public, in large, seems to still accept it without questioning. Once the log jam created by the public's energy illusions is broken progress towards a rapid realization of LFTR potential can and should be made.

A fourth barrier to LFTR progress is the problems posed by the nuclear regulatory system. The Nuclear Regulatory Commission is poorly prepared to handle technologically advanced nuclear systems, and the NRC methods of operations are totally inconsistent with the transformation of the American energy system from fossil fuels to nuclear generated electricity. The NRC will require a revolutionary transformation if the full potential of the LFTR can be realized.

One final barrier would be capital and industrial organization The LFTR would be a very large risk for any investor. Its total development investment, required before any revenue would be coming in, would probably be somewhere between $10 and $15 billion. An even larger investment would be required to design and build the factories and the field deployment systems required to facilitate a massive global LFTR deployment. Investors willing to take these risks, and the skilled human resources required to create this new industry must be found.

Despite these and other barriers, LFTR advocates are confident that their very ambitious goals can be accomplished. They have yet to create a comprehensive plan, yet they have created many elements of such a plan. Given the size of the task they have undertaken, and their success to date, they cannot be said to be doing badly.

4 comments:

LarryD said...

Put me down in the UMSR-as-a-first-step camp. This step can be justified as solution to the SNF disposal issue alone, if need be. And it reduces the risk of the next step, which is almost always a preferable strategy. Break a risky project down into less risky sub-projects. Works on the cost/investment side too. Revenue from USMR can help fund LFTR R&D, at least.

Recovery of thorium from rare earth mine tailings is something that needs to be started, also. I know I'm stating the obvious here, but but if we're trying to develop a plan, it needs to be explicitly stated.

Kirk Sorensen said...

Hi Charles, I continue to work actively on the TGP, putting numbers and data around ideas. I am moving closer to something that I feel like the larger thorium group can adjust/augment/rip-apart/improve before public discussion. But the broad outlines are in this talk I gave at TEAC2:

http://energyfromthorium.com/2010/03/29/kirk-sorensen-teac2-talk/

Charles Barton said...

I know you have been working on something. I do not think that progress on our grand plan has ended, rather the plan seems to be evolving. i hope to offer a discussion of reverse engineering as a planning tool in a few days.

The North Coast said...

$15 Billion to develop the LFTR and, oh, another $50B to $100B to manufacture and deploy, for a total of about $115B?

That is chump change compared to the $1.4 Trillion we have spent on the "stealth" housing bailout in the form of guarantees for house loans and price supports.

Electric rate payers are either going to have to pay for rapidly escalating coal and gas prices over the next couple of decades, or to transition to a new and hopefully more advanced energy regime. Which will it be? Rapidly increasing prices for polluting and remorselessly depleting fossil fuels, or for a form of energy that can extend the fuel cycle thousands of years and steeply reduce carbon emissions, while providing us with all the energy we will ever need?

The thing we must get make the public see, and FEEL, is the cost in money and lifestyle sacrifices that will be required with the current fossil fuel regime, and how much more it will cost in just a very short time.

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