Nuclear power won't fix the energy problem

[mheslep]

I think you are missing the economic point here. These "some commuters", even if they represent only a small portion of the total market, will have a great impact on the marginal price elasticity of demand. The only way the economic problem is solved is through diversification, and it doesn't take a lot to make a large impact.

Commuters are not a small portion, they are the majority share of transportation fuel use.

And given that half the cars on U.S. roads are driven 25 miles a day or less, a plug-in with even a 20-mile-range battery could reduce petroleum fuel consumption by about 60%

www.calcars.org/epri-driving-solution-1012885_PHEV.pdf
Im skeptical of that figure, 60% must refer to transportation fuel use only (65% of the total). Even so, 30-40% relief from oil would change the energy situation dramatically in net importing countries.

 

[Dale]

Commuters are not a small portion, they are the majority share of transportation fuel use.

I thought so, but it wasn't worth arguing the point, since even a small portion will have a relatively large impact on the economics of petroleum.

 

[Astronuc]

So, what is sillier than piping water 1000 miles to keep the fountains at Disneyland flowing? Well, desalination, of course… Desalination uses even more energy than piping water from Northern to Southern California, 4,000 kWh/Acre-foot (3.24 Wh/liter). This is because desalination either uses reverse-osmosis filtration, essentially filtering ocean water by pumping water, at high pressure, through a membrane, or distillation, where water is evaporated and condensed. Both of these methods require a lot of energy for pumping and/or heating the water.[continued]

http://www.triplepundit.com/pages/as...he--002579.php


A little later in the article:

But innovative solutions are under development. A new concept desalination plant utilizes ocean breezes and cold ocean water. It does this by piping cold ocean water through pipes. The water is then sprayed on a screen where some of it is picked up by the breeze in the form of humidity. The humid air then passes over the cooled pipes, where the water condenses and is collected, salt free.

I'm not sure about that, since the fog rolling in over San Francisco and Golden Gate bridge contains - sea salt! And why use cold water - perhaps it's less saline.

If evaporation (and condensation) were used with solar thermal energy as the source, then it would make sense. And perhaps using process heat from nuclear plants would make sense too.

I heard recently that some California tomato farmers have simply walked away from their fields, leaving the plants to whither, since it costs too much to produce the tomatoes (water and fuel costs).

There have also been power cycles based on thermal differentials between ocean surface and deep (cold water).

Nuclear can play a role, but it is not a solution by itself. Part of the solution is conservation and efficiency. Nuclear suffers from the inherent limitations of the efficiency of the Rankine cycle (~34-37% efficiency). Higher temperatures can be used in some advanced designs, but there are materials degradation issues that challenge the economics, reliability and safety.

 

[Ivan Seeking]

I think you are missing the economic point here. These "some commuters", even if they represent only a small portion of the total market, will have a great impact on the marginal price elasticity of demand. The only way the economic problem is solved is through diversification, and it doesn't take a lot to make a large impact.

In a static market, it appears that you would be correct, but you are not considering the increasing demand beyond what we have today. And that was part of my point in posting the references to the need for clean water. The grid is already in trouble, and we already have huge additional demands coming online.

That has only become true in the last few months.

This has been true for as as long as I can remember. Do you remember the gas shortages of the 70s?

 

[Ivan Seeking]

We've been through all this.
https://www.physicsforums.com/showpost.php?p=1584293&postcount=12
Electric hybrid plug in vehicles are indeed very close; half a dozen models will come out in the next two years. They will be using Li Ion batteries. They have the energy density and the lifecycle. Nobody is proposing to use old tech lead acid batteries for electric cars. Edison tried and failed to make that work early in the last century. Li Ion has 5 to 8x the energy density of lead acid.

We have been through that. The Tesla has probably $50,000 worth of batteries.

 

[Dale]

This has been true for as as long as I can remember. Do you remember the gas shortages of the 70s?

I'm going to call "BS" here. Unless you were in a coma between the gas shortages of the 70's and now, then you are well aware that petroleum has been unbeatably cheap for most of that time.

I know you are not intentionally being dishonest here, but your bias is clouding your rationality. Algae biodiesel is a great idea and I applaud your pursuit of it and wish you much success. You have every reason to be biased in favor of algae biodiesel, but it is very myopic to say that other technologies do not also have their value in solving the overall economic problem. You seek for a replacement to petroleum, while I would prefer a diversification of our energy sources. Any investor knows the value of diversification, surely you do too.

 

[Ivan Seeking]

Commuters are not a small portion, they are the majority share of transportation fuel use.


www.calcars.org/epri-driving-solution-1012885_PHEV.pdf
Im skeptical of that figure, 60% must refer to transportation fuel use only (65% of the total). Even so, 30-40% relief from oil would change the energy situation dramatically in net importing countries.

Hmmm, sure enough, if we only consider gasoline consumption, we only get about 4 gallons per household per day. So if we look at typical commutes [edit: avergage commutes, not the same], people are only using a fairly small amount of energy. However, I still see some problems. That average does not imply that people who drive great distances can use stored electric energy. So while the people who drive only a few miles to work can use it, the people who cannot are not reflected by the average number.It may be that the majority of gasonline is used by a fairly small percentage of the commuters, in which case we may see little impact on demand. Next, we buy crude, from which we get, gasoline, diesel, heating oil, kerosine, etc. So, ironically, the amount of crude required is not reduced by simply reducing the demand for gasoline. Of course I guess we could just go into the refining business and sell gasoline to Mexico or Canada, if we didn't have a generally increasing demand beyond the gains.

 

[Ivan Seeking]

I'm going to call "BS" here. Unless you were in a coma between the gas shortages of the 70's and now, then you are well aware that petroleum has been unbeatably cheap for most of that time.

Oh please, this has been the holy grail of battery technology for decades. You are simply unaware.

Don't you think there is motive for a $2 laptop battery? It is the same problem. Think about it. Using our best state-of-the-art, it cost typically $100 to power your laptop with a battery. How does that compare to the energy requirement of a car? Also, my laptop batteries start getting weak within a year of use.

The Tesla essentially uses laptop batteries.

 

[Ivan Seeking]

If I seem biased, it is only because I think it the problem is critical and that there are no simple solutions. We can certainly do things to help lessen the pain, but we have been hearing promises for decades that have never panned out - the same ones that we are hearing today. And the oil problem is not new; even when the price was low, anyone paying attention knew that the situation would eventually become critical. And this was all true long before I ever heard of the algae option.

What has changed is that after decades of failed promises, I realized that there were no substitutes for oil. In fact it was personally devestating to come to this realization. Until algae came along, I had all but lost hope.

 

[Ivan Seeking]

[A little later in the article:
I'm not sure about that, since the fog rolling in over San Francisco and Golden Gate bridge contains - sea salt! And why use cold water - perhaps it's less saline.

Yes, I considered including that, but it is just another promise. I think the systems going online will be standard RO. Also, in California, they are planning to treat waste water, and then use it for human consumption.

Given that we find water shortages or dwindling supplies in many areas of the US, we can expect large additional demands on the grid to help provide clean water to population centers.

Nuclear can play a role, but it is not a solution by itself. Part of the solution is conservation and efficiency. Nuclear suffers from the inherent limitations of the efficiency of the Rankine cycle (~34-37% efficiency). Higher temperatures can be used in some advanced designs, but there are materials degradation issues that challenge the economics, reliability and safety.

With the technology that we have today, nuclear energy cannot replace oil. That is a simple fact. And what annoys me greatly is that by making nuclear an issue within the context of the oil problem, as McCain has done, we are only chasing our tails.

 

[Dale]

With the technology that we have today, nuclear energy cannot replace oil.

It doesn't need to replace oil! Have you completely missed my point?

What we need is diversification, alternatives, options, choices, ... not a replacement.

 

[Ivan Seeking]

We are discussing our options, and we have few. There is only one that even promises to replace the energy obtained from oil and that can be used for transportation at an affordable price.

Diesel cost about $5 a gallon now. This affects everything from the price of food, to the price of widgets from China.

Nuclear power can't put food on your table. That requires diesel fuel, and lots of it.

 

[Ivan Seeking]

Something else to remember is that to whatever limited extent we can reduce gasoline usage [or slow the increase in demand] this will not have a significant effect on the price of fuel. That is determined by global markets. So the benefit that we can hope for is that individuals reduce the economic pain of the price of fuel directly. But this will not help reduce the price of food or steel.

 

[mheslep]

We have been through that. The Tesla has probably $50,000 worth of batteries.

The battery cost for plugins is still an issue as I mentioned above, though one can't use the Tesla for cost comparisons; it is a 250HP exotic limited production sports car. A realistic price point at the moment for batteries appears to be about $1k/kWhr:

How much you'll pay for one remains an open question, and one answered by the price of the lithium ion batteries. "They're over $1,000 a kilowatt hour," Tom Turrentine, director of the Plug-in Hybrid Electric Vehicle Research Center at UC-Davis, told Wired.com. "The Volt battery is 16 kilowatt hours. That's $16,000 just for the battery."

http://blog.wired.com/cars/2008/06/bob-lutz-drives.html
Keep in mind also that all electric cars may do without many things found in current ICE cars including the transmission, clutch, flywheel, axles, differentials, driveshaft, universal joints, starter, and alternator.

 

[mheslep]

I have no clue, but I'm amazed by that figure. So I googled a bit and I found this:
...
and:

http://www.fao.org/docrep/w7241e/w7241e05.htm#1.2.1 photosynthetic efficiency
)

Yes as I said max possible (theoretical) efficiency derived from the chemical equation:
CO2 + 10 photons + H2O = CH2O + 1/2O2. (450kJ captured / 1700 kJ light)/mole
which gives 25% efficiency. Unfortunately much of solar radiation is not in usable wavelengths by existing plants, which cuts it down to 11%. Again that's existing plants, and perhaps some engineered organism might be produced in the future that can use more UV and IR.
More text from the FAO link:

Furthermore, fixation of one CO2 molecule during photosynthesis, necessitates a quantum requirement of ten (or more), which results in a maximum utilization of only 25% of the PAR absorbed by the photosynthetic system. On the basis of these limitations, the theoretical maximum efficiency of solar energy conversion is approximately 11%. In practice, however, the magnitude of photosynthetic efficiency observed in the field, is further decreased by factors such as poor absorption of sunlight due to its reflection, respiration requirements of photosynthesis and the need for optimal solar radiation levels. The net result being an overall photosynthetic efficiency of between 3 and 6% of total solar radiation.

Adding a factor of about 1/3 for the Rankine cycle (steam cycle), we obtain finally of the order of 1 - 2 % solar efficiency. (1/2 is very optimistic, it is only reached in combined gas turbine - steam cycle plants

Well another reason to skip a heat cycle and go straight from solar PVs to batteries and 90% eff. motors.

 

[Ivan Seeking]

The battery cost for plugins is still an issue as I mentioned above, though one can't use the Tesla for cost comparisons; it is a 250HP exotic limited production sports car. A realistic price point at the moment for batteries appears to be about $1k/kWhr:

1 KWHr is 3413 BTUs, say at 80% efficiency for charging, and 80% efficiency at the point of use, but we will be generous and say 90% and 90%. So that leaves us with 2765 BTUs of energy storage for $1000.

We get 125,000 BTUs from a gallon of gasoline at about 25% efficiency, or 31,250 BTUs of output energy.

So it would take $11,000 worth of batteries to get the energy storage and output of one gallon of gasoline.

 

[Ivan Seeking]

Well another reason to skip a heat cycle and go straight from solar PVs to batteries and 90% eff. motors.

We don't have the batteries at anything close to an affordable price. You want to bet everything on a technology that has stumped the experts for decades, and just hope that it comes along, this time?

 

[mheslep]

We don't have the batteries at anything close to an affordable price. You want to bet everything on a technology that has stumped the experts for decades, and just hope that it comes along, this time?

"You want to bet everything"? Not me, nor do I see anyone else seriously 'betting everything' on hybrids; current budgets are moving things along nicely. Please take a look at how battery technology has progressed in the last few years before making pronouncements. You should well no someone could point to the 70's/80's Aquatic Species Report and say the same thing.

 

[mheslep]

1 KWHr is 3413 BTUs, say at 80% efficiency for charging, and 80% efficiency at the point of use, but we will be generous and say 90% and 90%. So that leaves us with 2765 BTUs of energy storage for $1000.

We get 125,000 BTUs from a gallon of gasoline at about 25% efficiency, or 31,250 BTUs of output energy.

So it would take $11,000 worth of batteries to get the energy storage and output of one gallon of gasoline.

Charging efficiency is not relevant for sizing the battery, only to the overall energy usage cycle. Even in the $11k / 1 gallon-equivalent scenario you've drawn we have a usable commuter vehicle - that's more than enough in a 50 mpg equivalent plugin hybrid to go to work/school and back. And that's now with just released technology, in low production numbers. Another 40% improvement or so in energy density/$ looks plausible. As we discussed elsewhere converting that 1 gallon of fuel would have a large impact on US fuel usage, displacing it with electric use.