Sunday, May 08, 2005

nuclear errata

Engineer Poet has pointed out that I may be too pessimistic about the ability of nuclear power to fill the liquid fuel gap, which in turn led me to realize I had made an error in previous posts:
“One of them is you would have to build 10,000 of the largest power plants that are feasible by engineering standards in order to replace the 10 terrawatts of fossil fuel we're burning today.” - Professor David Goodstein

I calculated the proportionate energy cost as being composed only of oil, when I should have taken all fossil fuels into account. In other words, using David Goodstein’s numbers, 4651 nuclear plants worldwide would equal the energy contained in the oil we burn. The remainder would fill the gap for coal and natural gas.

However, in addition to that, E.P. points out that much of the energy content of oil burned in cars is simply wasted, such that it is not necessary to build the “energy equivalent” in nuclear power plants to receive the same benefit in output, should we use efficient batteries.
“An average power of 183.5 GW isn't huge compared to other energy usage. The summer electric generation capacity of the USA in 2002 was over 900 gigawatts, roughly 5 times as much as the average output of all gasoline and diesel powered transport.”

One still must consider energy losses as electricity is transported across the grid, stored in the batteries, and the energy cost associated in constructing and maintaining a trunk full of batteries for every car. I don’t know how that stacks up to petrol engine efficiencies.

Oil is only part of the depletion picture, and hybrids are trickling in to the installed base of vehicles slowly, with insufficient battery life to be used without fuel. Complex industrial requirements aside, every little bit helps when talking about the coming wave of depletion. Food for thought.

16 Comments:

At 7:32 AM, May 09, 2005, Blogger odograph said...

I suppose we could calculate what it would take to charge a fleet of the just-retired GM eletric cars. It would probably represent a good approximate demand.

 
At 1:11 PM, May 09, 2005, Blogger Engineer-Poet said...

If you are looking for data on electric demand, I can refer you to no better site than AC Propulsion; they are closely associated with EPRI and have a heap of white papers on the impact of electric vehicles on the grid.

One of the scenarios they've investigated is the use of electric vehicles for grid regulation, selling services back to the grid.  Enough such vehicles plugged in and you could absorb almost any shock, even major power lines going down without warning.  This could be a major contributor to national security - and I'll put $100 down that the energy bill moving through Congress does zero to encourage the plug-in hybrids which could make this happen.

 
At 1:31 PM, May 09, 2005, Blogger Engineer-Poet said...

NB:  I am not familiar with Goodstein's paper, but it appears likely based on his numbers that he is contrasting the input of the world's fossil-fuel consumption to the output of 10,000 nuclear-electric plants.

This is only a legitimate comparison if one is looking at energy used to produce electricity.  If the energy product is industrial process heat (e.g. low-pressure steam), a conventional nuclear plant could supply almost its full electric output AND two times as much energy again as steam.  If you build a plant just for process heat, you won't have any losses in the conversion to electricity; you can cut the number of plants by roughly a factor of 3.

Too many of these facile analyses are done without an adequate check for confounding factors; this makes them not unlike comparisons of apples and grapefruit.

 
At 4:19 PM, May 09, 2005, Anonymous And assorted wingnut said...

It'd be really interesting in seeing what these numbers are in data which aren't eight years old.

And what about things like the 25 million million gallons of things like pure (B100) biodiesel- which doesn't really fit into any of the categories, but which had fifty times the market share by 2003 that it did in 1999?

Are those of us who are making the move to 'greener' fuels contributing anything at all to the equation, or are we just deluding ourselves because, in spite of all our best intentions, it's too little too late?

 
At 7:01 PM, May 09, 2005, Blogger monkeygrinder said...

Wingnut: The graph is old, best I could do on short notice, but the percentage breakdown has changed hardly at all in the intervening years.

As for biodiesel, it is great in terms of recycling things already produced. I endorse it wholeheartedly in those terms.

I start to get concerned when people suggest replacing 20% or more of our liquid fuel supply with bio-fuels.

The acreage it would take to do this would be immense, and food production has been running shortfalls lately. So the tradeoff would be, feed people, or drive?

One of which is the green position.

 
At 7:10 PM, May 09, 2005, Blogger monkeygrinder said...

EP:
On confounding factors -

More important then screwing things up the first time is the willingness to fix it the second time.

For example, the nuiclear future you describe is rosy and thrifty.

Our current nuclear reality is a heaping pile of shit.

So it seems like the smartest minds out there can be confounded by energy, especially when we are talking about nuclear, being one of the most complicated industrial processes we have in the world.

There is less that can go wrong with a wind turbine. KISS.

And it is with some sadness that I note current plans for new nuclear infrastructure in the U.S. involve off the shelf designs from ten and twenty years ago.

Fourth generation pebble bed reactor designs are considered too risky to invest in.

 
At 8:05 PM, May 09, 2005, Anonymous an assorted wingnut said...

So, how far do we follow King Lud? Do we figuratively fling nos sabots into the equivalent of those automated weaving machines— and is there even a contemporary equivalent (crashing our hard driver, or pinging our servers a million times with fragmented 8k data packets doesn't seem quite the same, is it)?

And c'mon. Just like me, you'd be lost on a farm.

Salim aleikum and stay cross-threaded, my brother. :-)

 
At 8:07 PM, May 09, 2005, Anonymous an assorted wingnut said...

OK, that's weird. It doesn't like me italicizing 'nos sabots.' Freakish.

Salim aleikum and stay cross-threaded, my brother. :-)

 
At 9:17 PM, May 09, 2005, Blogger monkeygrinder said...

I'd suggest soylent green, but there are people afoot who might take me seriously. (We needn't be the luddites, we can just eat them.)

I'd be lost on a farm but I wouldn't mind living next to farmers. I'll cultivate beer trees.

Looking at the amount of oil left in say, 2030, using ASPO numbers (see sidebar link) we'll (the globe) have plenty of oil to continue industrial farming and food transportation from now until then - if we wish. Less gadding about in hummers, of course.

If everybody shares.

The "prisoners dilemma" may come into play at some point.

 
At 9:34 PM, May 09, 2005, Blogger WHT said...

Getting it right to an order of magnitude is good enough for engineering. The guy sounds more like a poet.

 
At 10:19 PM, May 09, 2005, Blogger Engineer-Poet said...

Oh, there is most certainly less to go wrong with a wind turbine.  There is also less that a wind turbine can do; you can have a nuclear economy without fossil backups, but you need some serious advances in unrelated technologies to be able to say that about wind.

Are you so taken aback by my refutation of Goodstein's numbers that you have nothing to say regarding e.g. AC Propulsion?

 
At 11:02 PM, May 09, 2005, Blogger Engineer-Poet said...

I almost forgot:  Pebble-bed reactors are certainly too risky if the global market is 50; limited sales don't justify much effort to improve upon the installed base.  But if the global market is 10,000 units of 100 MW each?  You can make some serious dough with a better product at that volume.

I'm sure the money people are waiting until they can be sure the political obstacles are out of the way.

 
At 11:08 PM, May 09, 2005, Blogger monkeygrinder said...

EP:
I don't have any problem with your refution of Goodsteins numbers in terms of petrol engines in cars. On the other hand, for another example gas turbine power production plants are a lot more efficient. So there is a wide variety of analysis to be made, and then aggregated.

I would point out again that there are efficiency problems with using batteries as well, and also power lost in transit on the grid.

I'm still not satisfied that battery technology is sufficient to do better in the here and now. The AC Propulsion site is great. However, I notice the prices for the battery pack ranged from 5k to 50k. I'm guessing the 50k option is the one used to drive from LA to Vegas.

"Li-ion batteries are not as durable as NiMH and NiCd designs, and can be extremely dangerous if mistreated. At a typical 100% charge level (notebook battery, full most of the time) at 25 degrees Celsius, Li-ion batteries irreversibly lose approximately 20% capacity per year from the time they are manufactured, even when unused. (6% at 0 °C, 20% at 25 °C, 35% at 40 °C. When stored at 40% charge level, these figures are reduced to 2%, 4%, 15% at 0, 25 and 40 degrees Celsius respectively.) Every (deep) discharge cycle decreases their capacity. The degradation is sloped such that 100 cycles leave the battery with about 75% to 85% of the original. When used in notebook computers or cellular phones, this rate of deterioration means that after three to five years the battery will have capacities too low to be still usable."

Sound about right? How much energy goes into battery manufacture?

 
At 7:03 AM, May 10, 2005, Blogger Engineer-Poet said...

On the other hand, for another example gas turbine power production plants are a lot more efficient. So there is a wide variety of analysis to be made, and then aggregated.

Indeed.  I've been pushing IGCC for a while, because it's both more efficient than atmospheric powdered-coal boilers (due to the combined-cycle system) and can be cleaned up to an extreme degree (due to the separate handling of the fuel gas).

I would point out again that there are efficiency problems with using batteries as well, and also power lost in transit on the grid.

The grid as a whole is about 93% efficient.  I can't tell you anything about batteries qua batteries, in part because every chemistry has different characteristics.

I'm still not satisfied that battery technology is sufficient to do better in the here and now.

Especially not the cobalt-oxide based Li-ion, but the lithium-iron phosphate chemistry and nanoparticle stuff coming out of Altair Nanomaterials and Toshiba looks like they're rewriting the book on all that.  Cycle lifetimes are going way up, power density is going way up, and the need for scarce elements seems set to disappear.

One Prius+ conversion has already used Valence Technology LiFePO4 batteries; this was expensive, but the basic materials cost appears to be very low; there is nowhere to go but down.

 
At 10:49 PM, May 10, 2005, Blogger monkeygrinder said...

Well, we for sure have a car based infrastructure in America.

I think we should take a more European approach, and invest in trains for the next little while, that is my bias.

I see a big shakeout coming; cars must get smaller and smaller to the point where they won't fit the average americans mental preconception of car, SUV's may literally be against the law in a few years lest they crumple up the next gen of light mobiles.

As for the batteries on the way, sounds good. I'll be watching.

We go to war with the infrastructure we have, not the infrastructure we'd like to have.

 
At 7:57 AM, May 12, 2005, Blogger Engineer-Poet said...

"Well, we for sure have a car based infrastructure in America.... We go to war with the infrastructure we have, not the infrastructure we'd like to have."

I found that interesting, juxtaposed with this:

"I think we should take a more European approach, and invest in trains for the next little while, that is my bias."

The difficulty with trains is that most American cities are too spread out to use them for intra-urban transport, and adding rights-of-way would be extremely expensive.  Trains appear to compete best with short- and medium-haul air transport.  Jet fuel accounts for about 7.5% of petroleum consumption, so there are inroads to be made there - but not the huge dent which can be made by cutting into motor gasoline (45%) and diesel (distillate fuel oil, ~20%).

"cars must get smaller and smaller to the point where they won't fit the average americans mental preconception of car"

This is not going to happen.  The DC ESX3 was a full-sized car able to get 72 MPG; even if the commercial version only got 50 MPG while burning fuel a GO-HEV version might achieve an effective 200 MPG.  With that kind of economy you don't need to shrink cars to skateboards, and people aren't going to do it absent the need.

"SUV's may literally be against the law in a few years lest they crumple up the next gen of light mobiles."

I'd like to see most of the current crop banned from the roads until they are retrofitted with bumpers which actually meet other cars on theirs, not at the top of the trunk lid or the door/window junction.  There is no excuse for this dangerous "feature".  If the retrofits make these vehicles so ugly that nobody wants to be seen in one, it can only improve the situation.

 

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