Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-l] Nuclear Reactors

At 08:11 -0400 04/08/2009, Rick Tarara wrote:

It is not a case of thinking up reasons 'why it won't work', but rather
trying to be realistic about what it is going to take TO make it work.

That too.

OK--'cleaner' coal, if you wish, but with one of the world's largest
supplies, coal (as clean as we can make it) is very likely to be part of our
near future (next century) energy supplies. With the inevitable phasing out
of oil and natural gas, the net environmental problems of coal can be
minimized.

Here's my take on the issue of transportable fuels.

In the final analysis the only part of the transportation sector that is sticky will be aviation. Any fuel for aircraft will need to have an energy density by volume and by weight that is comparable to current jet fuel. Failing that we will need a major change in the way we do air travel, and I don't contemplate that.

But it is possible to take the ground transportation sector completely off liquid (or gas) fuels, and provide ground transportation of people that can replace short-haul air ravel and thus mitigate the aircraft problem some. This will take some major improvements in battery technology, but mostly it requires some very innovative thinking, such as that being done by Shai Agassi (See the profile on him in Wired, at <http://www.wired.com/print/cars/futuretransport/magazine/16-09/ff_agassi>). Among other things, this innovative Israeli thinker envisions our small-vehicle fleet being completely electrified, with the capability to plug in to a recharger at virtually every normal parking spot, but also to have a network of shops that can, within 5 minute swap out a discharged or partly discharged battery, so you can be on your way without the charging delays inherent in battery use. His vision is that while the vehicles would be owned by the drivers, the batteries would not. Instead, for a suitable fee, batteries would be made available for the cars on demand, and changed whenever the envisioned trip was longer than the energy presently stored in the battery would provide for. This would mean that only those vehicles which were routinely used in areas where access to battery charging or swapping was either sparse or impractical or uneconomic would need a liquid fuel capability, and those vehicles could be hybrids. The details of his plan are both audacious and sensible, and, if he can make it work, could solve the personal vehicle issue definitively. More information on this plan is contained in the article in Wired referenced above.

Second, the railroads need to be electrified (this can be done incrementally, using most of the current locomotive fleet, which would require only modification to allow electricity to be drawn from overhead wires instead of the internal diesel-electric generator (which could be retained for emergency use as well as normal use on the non-electrified sections of rail). This would be used for long-haul freight traffic, and separate lines would be laid for high-speed passenger travel to replace short-haul air travel (say, 500 miles or less--at 200 mph, only air travel of distances greater than about 5-600 miles would take longer when airport time and transportation to and from the airports are included).

A robust freight rail system, coupled with ending the subsidies to truck freight companies for using roads, could replace long-haul freight presently done by trucks, and would provide an alternative to hauling coal from the mines to the power plants that now provides much of the railroads' revenue sources. Studies show that road damage varies with the cube of the vehicle weight, so a truck weighing 10 times that of a car will do 1000 times the damage to the roads, so getting the large vehicles off the roads will not only reduce traffic density but reduce the cost of maintaining those roads. Fewer roads will need to be built or expanded and they will last longer.

Electrifying the rails and the vehicle fleets will also remove a major source of air pollution. And, since electric motors are simpler and more rugged that internal combustion engines, maintenance costs will go down and vehicle lifetimes will go up, still further reducing the environmental drains by our transportation needs.

All of this will involve little if any change in our lifestyles and so should be able to be done rather seemlessly.

Together with some nuclear, coal can provide the high-density
power source that will be needed in _some_ locations. It too can be phased
out, but to do so that big IF about shipping power across country (say North
Dakota to New York) has to be solved, a national (international if you wish)
grid has to be designed and implemented--(that cost is almost never included
in 'renewables' estimates)--or we really would need to develop something
like Fusion power.

Whether we do anything about our energy sources or not, we need to overhaul the electric grid which is old and creaky and, as we have seen repeatedly, highly prone to large-scale failures. We need to have a grid that includes two-way communications between the providers and the users so that the electricity flow can be made as efficient as possible. It needs to be high-voltage DC to minimize line losses, and its control needs to be automated so that it can respond more quickly to changing conditions, and, if our storage system for handling varying load demands is to be in the batteries of our vehicle fleet, it must be capable of drawing on those batteries in an efficient manner without leaving the battery owners without the necessary energy in their cars when they need it. A group at the University of Delaware is presently working on a "smart grid" concept that will allow electric vehicles to serve and the storage system for the grid by drawing on the plugged in batteries on a second-by-second basis to smooth the load on the grid while never taking any connected battery below 80% charge (the more batteries connected, the less that will have to be drawn from any battery, so that if millions of batteries are connected no individual battery will have to be taken below 98 or 99%.

Fusion power would make all our problems easier, but as has been pointed out, it has been 15 years away from practical use for the past 50 years, so I don't think we should hold out much hope for it, although I'm in favor of continuing research in it.

I can also imagine places where nuclear power would be practical and worth the risks, mostly in isolated areas where bringing in fuels is very expensive (like Antarctica, where, for a year or so we actually had a small operating reactor, but it was outlawed by the Antarctic Treaty which we ratified in the 60s, and so it was dismantled and removed). These would typically be small reactors (about which, thanks to Admiral Rickover, we know much less than we should), which would need refueling only rarely and could be largely automated since the demands on them would be fairly constant.

I find it difficult to imagine any scenario where coal would be the preferred energy source, unless the need existed in a very isolated location that happened to rest on a surface or near-surface source of high-grade coal.

My understanding is that liquefied or gasified coal, which are being loudly touted by some at the moment (the liquefied coal process was invented in Germany during World War II as a substitute for the petroleum they didn't have) is even worse than regular coal, with at CO2 emission rate considerably higher than when the same energy is obtained from non-liquefied coal--including, I presume, the energy and CO2 emission costs of producing it. So I cannot imagine using it as motor fuel, either. And it certainly isn't, as has been claimed, part of "clean coal."

There are several things to include in discussing using wind and solar for
the major fraction of energy needs:

1) As you phase out fossil fuels, you then move many energy demands from
'chemical' to electrical. Heating and transportation energy must now come
from the renewables. Biomass could only handle a fraction of the
transportation fuel needs--we just calculated (for our project) that 3% of
the energy needs in 2100 in the form of biodiessel (from soybeans) and
ethanol (from switchgrass) would require 150,000 square miles of land use.
If we can back off of oil soon enough, then perhaps some specialized
needs--big rig trucks and aviation might still draw from remaining petroleum
reserves. The big point here is that the electrical demand could triple
without oil and natural gas, and then if you want to eliminate coal, the
numbers become daunting.

I'm not a huge fan of biofuels. They may be necessary in some cases (aviation, for example, or large trucks or working vehicles--earth movers, etc.) but I think they re being overtouted now. And using food crops to produce biofuels is little short of criminal. The one area where they may find a beneficial use is in carbon sequestration, where algae may be able to be used to capture CO2 from coal burning. It's still new but may have some promise.

The extra load on electricity by converting the transportation and building sectors to electricity is something that we must be concerned about. I think that moving to larger dependence on electricity is basically sound, but we have to do a lot of coordinated planning (something we humans aren't very good at, unfortunately) in its implementation. A large increase in electricity demand is built into these goals, but a lot of it can be accommodated with aggressive efficiency standards. We don't need to use as much energy to heat or cool our homes and buildings as we do now, and we can take better advantage of our rooftops to provide at least part of our home-use electricity. Furthermore, these additional needs for electricity will take much of the sting out of power sales losses due to increased efficiency that are giving power company executives such grief at the moment.

And yes, we are going to have to rethink how we use a lot of our land. As I mentioned earlier, we need to make better use of our open parking lots. Covering them in solar PV panels would have multiple benefits, in addition to providing a great deal of the electricity we need. It would provide shaded/sheltered parking for those using the lots; it would provide local sources for the electricity to recharge car batteries while the owners are shopping; rainwater and snow falling on the panel surfaces can be captured and reused for local irrigation, thus reducing the erosion due to runoff from the non-absorptive surfaces that prevent rainwater and melting snow from percolating to the water table.

Wind parks can be built on agricultural land, but will use only about 20% of that land for the towers and access roads, so the impact on agriculture should be minimized. Soar PV and CST can be installed in desert areas without unduly impacting the habitats of the flora and fauna that normally reside there, if their installation is carefully designed. Offshore wind turbines can be larger than the onshore norms (most new European offshore wind installations are 5 MW and up, and these are become more common onshore as well--the largest designed so far are about 8 MW, but they are still being evaluated), and using larger turbines onshore can significantly reduce the land needed to provide the electricity they can provide. In addition, the larger turbines, being installed on 80-100 meter towers reach up into the more steady and higher speed winds aloft, increasing the performance factors of the installations. And Mark Jacobson's work at Stanford has shown that combining wind and solar installations with sufficient geographic diversity can provide a substantial fraction of the baseload power needed, reducing the need to have to wait for the availability of advance storage technologies in order to phase out many of the coal and nuclear plants we rely on today.


2) The population (U.S.) is going to continue to increase. Can we hold the
population down to say 450 million by 2100? That will take some aggressive
work in immigration policy. If the country keeps adding a million or more
immigrants a year, immigrants with traditionally higher fertility rates than
the 'native' population, and generally more religious attitudes against
birth control, 450 million would be a very low estimate. So lets assume at
least a 50% increase in population.

The best way I know of to bring immigration to the US under control (both legal and illegal) is to do those things necessary to help the nations that are presently providing most of our immigrants to improve the lot of their citizens so that the incentive for them to emigrate to survive is reduced. Almost all of our current population growth is immigration-driven. If we can reduce that, we can control, and even start to reduce, our population. However, this probably won't happen before our population reaches the 450 million level, which makes is even more important that we be prepared to handle that population increase, and having adequate energy to serve their needs is one of the things we need to do. Of course if we continue to rely on petroleum and coal to provide that energy, I suspect that the problem will be much less because many of those people will be dying off before they can get to our shores. Anyone thinking that is a good solution will surely find a warm welcome at the Adolph Eichmann Club.

3) Efficiency and conservation can certainly lower energy needs. 25%
proves difficult (for my classes) to fully quantify, but that should be
possible and maybe a bit better. However, with the population growth it
means the overall energy demand will increase and with the reduction or
elimination of most 'chemical' energy sources, the demand for electricity
rises sharply.

Most of the EU now uses about half our per capita energy, and they are claiming that they can reduce that by an additional 25-40% with further efficiency efforts. Since their living standards are certainly comparable to ours, I suspect that we should not have too much trouble increasing our efficiency in energy use by 50%. Much of that can come from the building and residential sector, which are presently woefully inefficient. Several of us on this list have been able to reduce our electricity use significantly by just being more careful about turning off unneeded lights and replacing incandescent lights with CFLs, as well as some obvious things like only running the clothes washer or dishwasher when you have a full load, and eliminating extra rinse cycles when possible.

Smaller cars and more reliance on public transportation will help control the electricty use in the transportation sector. I know that we are addicted to large vehicles, supposedly on the specious argument that they are safer, but I think we can convince the public that, by reducing the overall size of the cars in our fleet that we can improve safety, especially if we can get most of the large trucks off the road. And an intelligently designed and attractively priced public transportation system will help in that area as well. On my last several trips overseas, I have been greatly impressed with the ease and low cost of the public transportation systems in most European and Japanese cities. My wife and I will be moving to the Dc area this summer and in anticipation of not needing a second car because of the excellent bus and subway system there, when my car was totalled in an accident (no injuries) we decided not to replace it. Even living in an area with absolutely rotten public transportation, we have not been unduly inconvenienced by having only one car, and we have saved quite a bit by not having to support two cars.

I don't think that arguing that "we can never change American love for cars, so forget public transportation," is valid at all. the same thing used to be said about smoking, but look what has happened in about 30 years--interestingly, about the same span of time we have to make significant inroads into our GHG emissions if we want to prevent catastrophic change. I know cars are not cigarettes, and that the change won't be easy, but it can be done if we go about it right.

4) So what's a 'reasonable' estimate of yearly energy demand in 2100? We
work with 20,000 TWh or a power demand of 2.3 TW.
What do such huge numbers really mean? IF--you wanted to run the country on
wind (assuming you had a grid and had generators spread so that you could
guarantee the 25% availability at all times (according the Hugh), then using
1.5MW generators (pretty much the standard although bigger ones are
available) you need over 6 MILLION wind generators. In a more realistic
system, without any fossil fuel, you might split up the demand, but you
can't get much more than 3% from Hydro (and the environmentalists want to
dynamite all the dams anyway), maybe 3% from geothermal, might push 10-12%
from biomass, but then you have to split the rest--over 80% between wind and
solar. Without coal and nuclear--this is huge.

We have enough raw energy in the sun, the wind, and geothermal to each meet our entire electrical energy needs indefinitely into the future (assuming that we are able to keep our population within enough bound that we don't have to cover the entire land area of the earth with standing people). If we plan wisely (as noted, not one of humanity's strong points) we can meet our energy demands with an intelligent mix of those three without having to resort to coal or nuclear power in any significant way. A combination of distributed and concentrated energy sources, a nationwide smart grid, and a public transportation system that is at least as well subsidized as our roads are today, and buildings that are constructed with energy efficiency forefront in the builders' minds should do it, and except for cleaner air and some spread-out energy farms, we shouldn't see much difference in how our country looks in 2050 than it does today. And Lester Bown, in his "Plan B, 3.0" has detailed suggestions as to how we can help the rest of the world get there, too, and ithout breaking the bank along the way.

5) Effective use of solar (and to a lesser extent wind) will most likely
require storage techniques--maybe electrolysis to hydrogen--to assure an
'energy on demand' network. Whatever the storage and distribution system,
it will cost some big bucks. We've estimated about $5 trillion for a
hydrogen capable pipeline distribution system.

Storage is possible, as I've outlined above. Hydrogen is iffy at best, and really only reasonable in the very long term. We would need as much infrastructure for hydrogen as we now have for gasoline, and it would need to be safer, since hydrogen is even more dangerous than gasoline. Since hydrogen is not a source of energy, but only a way to store it and move it around, we'd still need the means to produce it in the quantities needed. I think there are more practical ways to handle the storage problem, and at much less cost than hydrogen would be.

6) Cost estimates have to account for the likely shorter lifetimes of wind
generators and some forms of solar (PV panels) compared to fossil/nuclear
plants (about 75 years) and dams (100 years or more). We don't have enough
experience to know the replacement rate for large wind generators, but it is
likely to be at least twice that of current plants--this increases the cost
above those normally estimated for the switch to renewables. Again, such
estimates are just to be somewhat realistic about the task--not to dismiss
it.

That's true, but the installation cost of those items is already less per kW than either a coal or nuclear plant. At present their expected lifetime is about 30-40 years, about the same as a nuclear plant (without extension) and about half to 2/3 of the lifetime of a coal plant. Furthermore, they only need to be replaced incrementally--that is when an individual unit actually fails, so the replacement costs are spread out over a longer period of time. And as the capital costs of wind and solar installations decrease, their expected lifetimes increase, so I am optimistic that this will not be a great problem. However, we have replaced systems in our society with more expensive ones on several occasions, seeing the increase expense worth it for the increase convenience, so either way, I think we'll handle this problem.

**********************
To repeat what we do in my energy class--a MODEL of energy distribution for
100 years in the future (one that still uses coal and nuclear but is heavy
on wind and solar) costs out at $30-50 trillion--capital costs-- and uses
about half a million square miles (much for biomass) of land. What these
numbers say, to me, is that this is not a 10 year, 20 year, or barely a 50
year project. To be affordable, the transition must be stretched over a
century time frame. However, clearly we need to start now (we are starting
now) and will have to ramp up the transitions, but thinking we can eliminate
the fossil fuels in a couple decades is, IMO, delusional.

I would guess that the estimated costs are probably a bit high, but not excessive, considering that our GDP over that same period will be of that same magnitude each year. In other words, we are talking about costs on the order of 1-2% of our GDP. And actually doing this work will in itself contribute to our GDP so we may actually see lower costs per GDP than that.

Eliminating all fossil fuels in twenty years is not realistic (short of a major program on the order of WW II). But stopping their growth within the next few years (less than 10) is possible and reducing our emissions by 90-100% by 2050 is well within reason (See Makhijani's book, "Carbon-Fee and Nuclear Free," that I referenced in an earlier post). Hopefully, by that time also, our world population growth will have leveled out or nearly so (at something around 9-9.5 billion) and we can start working to bringing it down to a sustainable level (probably about half that).

Hugh
--
Hugh Haskell
mailto:hugh@ieer.org
mailto:hhaskell@mindspring,.com

So-called "global warming" is just a secret ploy by wacko tree-huggers to make America energy independent, clean our air and water, improve the fuel efficiency of our vehicles, kick-start 21st-century industries, and make our cities safer. Don't let them get away with it!!

Chip Giller, Founder, Grist.org