Thursday, November 11, 2010

Guest Blog by Cavan Stone: Where Does Our Energy Come From?

Today, the guest blogger is Cavan Stone, a graduate student in physics at Dartmouth. He studies Quantum Chaos, which examines the link between quantum mechanics and chaotic behavior. If you want, you can read one of his recent papers: this one on quantum chaos in a boson system.

Mr. Stone takes an active part in various energy discussions. I obtained his permission to use some of his recent remarks as a guest post on this blog.

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I think that going negative on this type of energy or that type of energy is not helpful. The truth is more like the following:

"I am for cheap electricity that does not harm our health or environment. I think nuclear is the best way of achieving that goal but in those instances where wind and solar are competitive, I'm for them. However, according to the DOE Wind Integration Report, wind can compose at most about 20% of our electricity market, or, by the governments own admission, a very optimistic 30%. (The government only does these projections through 2020.) Solar is even less than that in New England: just look at our weather.

These percentages can't really go up unless there is some radical technological breakthrough in energy storage technology. Right now, we still have to get around 80% from of our electricity from somewhere. According to the report, most of that will still be from fossil fuels. Fossil fuels benefit by avoiding payment for huge externalities that cause damage to our health and environment. I think it's clear that we need additional options to replace fossil fuels and the evidence supports nuclear as the best option for that 80%."

I know that this position does not play well to the cable news / extremist audience, but it plays extremely well to the internet and the John Stewart Daily Show Audience. And when it comes to extremists, either you have someone who'll refuse to listen or someone to whom you'll be preaching to the choir.

Cavan Stone
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Meredith comments:

Solar in New England is a little like solar in Germany. It isn't going to contribute that much (capacity factor around 10%) even with a big installed capacity.

To read about externalities for fossil, it is worth looking at the summary of the latest National Academy of Science report on Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use. Nuclear comes out very well.The difference between the best and the worst coal plants is huge.

People often look surprised when I say: "Well, there are really only three energy choices: nuclear, fossil and renewables. Renewables are great, but they can't do it alone. So we have to choose between nuclear and fossil for the rest." Somehow, in all the debates about Vermont's Energy Future and Shut Yankee Down and all that...people get the impression there are as many choices for electricity as there are for toothpaste.

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Many thanks to Cavan Stone for this post!

Beautiful image, from Wikimedia, of bunsen burner flames with different air feeds.

14 comments:

Jeff Schmidt said...

From the article:

"These percentages can't really go up unless there is some radical technological breakthrough in energy storage technology."

I've been wondering . . . I've heard that there are some companies working on energy storage by a number of systems:

* Arrays of many massive flywheels, magnetically suspended for almost zero friction-resistance to motion. These would be highly efficient (because, as long as you don't have too much loss to friction, you can very efficiently convert rotational kinetic energy to electrical energy), and could extremely quickly turn the mechanical kinetic energy back into electrical energy.

* Compressed gas systems which store the energy by compressing a non-flammable gas (like nitrogen, helium, etc), then are able to quickly output the energy through a decompression process.

* Pumped water storage - basically, pump a bunch of water up into a water tank or reservoir which is at a higher elevation, then you can reclaim the energy later by letting the water flow back down through hydroelectric turbines.

Would any of these technologies count as such a storage breakthrough? They are all, seemingly, much superior to chemical batteries. Or, is the storage capacity still too expensive with these types of ideas?

Meredith Angwin said...

Thank you for the comment, Jeff.

Briefly, my understanding is that there have not been any particular breakthrough on flywheels.

Compressed air storage. There's a local company, SustainX, that claims a breakthrough on compressed air energy storage.

http://www.sustainx.com/

I have looked at their website till my head spins. They claim isothermal compression. Okay. If you don't put in energy (or take it out) you get adiabatic compression. To have isothermal compression, you have to put energy in or out, and that takes energy (so to speak). Anyhow, people around here are excited by SustainX, and I hope it works. I hope they know how to make it work and I just don't understand it.

If you google regular compressed air energy storage, CAES, you will see that it is expensive and inefficient. It needs a breakthrough, IMHO.

Pumped water storage has been done. Howard Shaffer worked on a successful pumped water storage system many years ago. They have gone out of fashion because people consider them to be environmentally unacceptable, sort of like new big hydro projects are unacceptable.

Meredith Angwin said...

Hmm. SustainX has improved their website since my last visit, and they now talk about isothermal expansion and contraction as slow processes with heat exchange with the surroundings. This can work to give you isothermal processes. But can it give you power, moving so slowly? Pistons waste power because they move fast and not at equilibrium, but (at another level) that's the only reason we GET power from them.

Okay. I'm still scratching my head. I welcome explanations from readers!

By the way, I am aware that I may be overlooking something very big and clear, and that I may be making an idiot of myself in public. I truly hope to learn, though.

Jeff Schmidt said...

Meredith,

I'm no expert, but on the issue of 'moving slowly', it seems to me that you can have slow movement with a large amount of force/torque applied to something, and still transfer a lot of energy quickly.

How this applies to gas compression, I imagine that if you have a very large volume of air that is compressed, that large amount of air can push very strongly against some sort of turbine or piston, spinning/moving that turbine/piston with low speed but high torque/force, maybe, and that torque/force could be used, to spin a generator quite quickly, perhaps?

Again, I don't know for sure, but I do know, at least, that a large mass, moving slowly, can still represent a lot of energy. Think of a large big-rig truck, fully loaded with whatever - 20 tons, say, of cargo, moving 3 miles per hour - it's not moving quickly, but I wouldn't want to be standing in front of it.

Jeff Schmidt said...

Sorry for so many posts, but just had another thought

Has anyone ever tried doing 'vaccuum energy storage'? What I mean is, compressed air energy storage basically exploits a difference in pressure between the atmosphere, and the air tank, right?

Well, instead of compressing air, could you pump air out of a tank until it reaches almost a vaccuum state, using the energy you want to 'store', then later reclaim that energy by allowing atmospheric pressure to re-enter the tank, blowing past turbines or driving a piston, or something on the way in?

Anonymous said...

Note that improved storage technology also benefits nuclear power, and does so at lower storage requirements than weather-harvested sources.

Oh, and Jeff, the maximum pressure differential you can get with vacuum is one atmosphere. You can do a lot better than that with compression. My job involves vessels at 65 atmospheres and more, and they are run-of-the-mill.

Joffan

Jeff Schmidt said...

@Joffan,

Yeah, now that you mention it, that makes sense - you can get a lot more 'energy density' compressing gas to 65 or more atmospheres, than you can with vacuum with a difference of one atmo, so I suppose that means 'cheaper' storage in less space. That's probably why no one is trying vacuum storage.

ExpiPi137 said...

Per Lawrence Livermore

https://www.llnl.gov/str/JulAug05/pdfs/07_05.4.pdf

Another radical technological breakthrough could come from control over nuclear isomer states. I must stress however that the research into this is very much high risk - high gain and some very famous scientists have doubted its possible. However, its not unheard of for famous scientists to eat crow.

ExpiPi137 said...

While isomers of Hafnium proved to be difficult to induce energy transfer. There have been minor breakthroughs in inducing energy release in isomers of Thorium-229. Which just so happens to be a waste product of the Liquid Salt Thorium Reactor. Right now they are getting the thorium from decay of the government's stockpile of U-233, but if the research into Thorium isomers pays dividends, there is going to be a huge demand for Thorium-229 far exceeding the present supply. What would otherwise be the reactor's trash would suddenly become treasure.

Ron Mylar said...

The guest blogger is Cavan Stone, a graduate student in physics at Dartmouth. And also it takes an active part in various energy discussions.

Anonymous said...

There are other options. The best option is conservation. If you don't waste it then you don't have to generate it. As for storing energy there are other options: Use hydro as backing storage for wind and solar. Instead of storing power you can control the demand. The largest users of electricity are home heating and cooling and the fridge not of which needs to be on every seconds. Turn them off or down to match supply. One good option for the future are pluggable hybrids since they can provide a storage option.

ExpiPi137 said...

The government wind integration study, I (Cavan Stone = ExpiPi137) am referencing,

http://www.nrel.gov/wind/systemsintegration/news/2010/803.html

already factors natural gas and hydro in its estimate of 20-30%.

Conservation as in accomplishing more using less energy can contribute significantly. Plugin hybrids as well have potential to help us cut down our oil consumption.

However, as someone who has faith in the peer review scientific process, I have to conclude that man made climate change is occurring and that if we wish to prevent it rapid action is required.

That being said, when we evaluate these options there is a factor that is commonly ignored and that is how soon can something be brought online into the system. To integrate both plugin hybrids and the "smart appliances" you mentioned requires building sensors and adapting our transmission system to have more awareness of where energy is going.

There is definitely a contribution these technologies can make but in terms of cutting our carbon emissions as soon as possible, building nuclear power plants appears to be our best option. From a technical standpoint, we have all the scientific, engineering, and business know-how and infrastructure to integrate these plants into the electrical grid starting now.

Even from a political stand-point, long considered nuclear's weakness, the majority of opposition to these plants comes from those who believe in climate change and also those profess most about believing in science. I think the case can be strongly made to the opposition to look at the science and weigh the potential for nuclear to rapidly cut our carbon emissions versus a health and environmental impact that science can demonstrate to be significantly less compared to activities popularly considered to be benign.

Engineer-Poet said...

Going back to SustainX, the only way to achieve isothermal compression and expansion of air is to have it in intimate contact with a heat-transfer medium.

Water is a very good heat-transfer medium.  Note that their description of the technology is almost all about hydraulics.

Regardless of what's used for storage, it's hard to deny that storage works just as well for time-shifting constant nuclear output to peak hours as it does for smoothing spiky wind-farm profiles.  It's a great thing to have no matter what else is on your grid.

Meredith Angwin said...

Thanks, Engineer-Poet. I hope SustainX succeeds. It would be an important breakthrough and a local firm! I appreciate everyone who has helped me understand their technology.