Monthly Archives: March 2007

Future of Fusion

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It is my belief that the next major source of energy for Earth’s population will be terrestrial fusion energy. I believe that the type of reactor that will become a mainstream source of energy initially will be the spherical tokamak.

A spherical tokamak is a tokamak with a very short aspect ratio. That is to say the height to width ratio is high relative to conventional tokamaks. The ITER reactor being built is not a spherical tokamak, it is a more conventional design and I believe this is a serious mistake. The confinement qualities improve as the aspect ratio of the plasma becomes more circular and thus a short aspect ratio spherical design can provide more fusion for the same magnetic field strength.

There is more operating experience with conventional tokamaks and I believe this is why a conventional design was chosen for ITER. I believe ITER will be completely obsolete by the time it comes online. By that time I expect that the Chinese and perhaps other countries will already have electricity producing reactors in service. It’s too little too late.

While we’ve all been dicking around over where ITER would be build, the Chinese started construction of a superconductive tokamak reactor in February of 2006 and it saw first plasma in September of 2006. Prior to this reactor no superconductive tokamak reactors had been built.

The significance of a superconductive reactor is that the coils that produce the magnetic fields are superconductive and thus create no heat from their operation. Because of this they can operate for indefinite periods. Existing research reactors use copper coils to generate the magnetic field and they overheat with more than a minute of operation so sustained operation is not possible.

ITER was to be the first superconductive tokamak test reactor to allow testing in a steady state operation. The Chinese realize the urgency of the world energy situation and built a superconductive test reactor in seven months instead of waiting the scheduled twelve years for ITER to come online.

I believe the Chinese will rapidly complete the material research that needs to be done and go on to build a full-power prototype in short order. They will work out any glitches in the prototype and then go on to produce commercial power producing reactors on a feverish scale. Meanwhile, contracts for materials for ITER will not even have been bid out yet.

The Chinese will discover reactors with a shorter aspect ratio perform better and so their design will quickly evolve into a spherical design.

It is often stated that the fuel for hydrogen fusion reactors will be so cheap that it is essentially free because deuterium constitutes one of two thousand hydrogen atoms in seawater. There is a small rub however and that is that current tokamaks can not reach the necessary temperature and pressures for deuterium-deuterium fusion to take place efficiently and so a 50-50% mix of deuterium and tritium is used.

Tritium occurs naturally as the result of cosmic ray bombardment in the upper atmosphere but at extremely small concentrations insufficient for commercial exploitation. Instead, tritium is usually bread from lithium which makes lithium a necessary fertile material from which to breed the fuel for fusion reactors.

Lithium exists in the earths crust in concentrations of only 20 parts per billion, and in seawater it is even more scarce having a concentration of only about .17 parts per billion. Presently, the price of lithium is around $27 / 100 grams, trivial considering the amount of energy that can ultimately be obtained from that 100 grams, but as the number of fusion reactors escalates, so will the demand for and price of lithium.

The tokamak design is tremendously expensive and complex. This design requires the fuel be heated to a temperature in which the average kinetic energy is favorable for a D-T reaction to occur. The problem with a thermal approach is that the nuclei all have different energies and many nuclei will either be not energetic enough or too energetic for a reaction to occur. Thus a thermal approach is inefficient.

Some potential nuclear fusion fuel cycles create neutrons, D-D and D-T are among these, and the bombardment of reactor components by these neutrons results in neutron activation rendering them radioactive. They are not nearly as hot as spent fuel, but they still represent a disposal issue.

Other fusion fuel cycles create no neutrons, boron and hydrogen nuclei create only charged products, no neutrons, and thus result in no neutron activation or embriddlement of reactor components.

However, the energy levels requires to achieve hydrogen-boron fusion are beyond those that are obtainable in tokamak reactors at present.

There are alternatives to the tokamak that have the potential for sustaining the necessary temperatures and pressures. One of these is a device called a levitated dipole reactor. The earth generates a dipole magnetic field which contains a plasma at extremely high temperatures with no problem. A recent reactor design involves magnetically levitating a superconductive magnet to provide a similar dipole field. It is believed that this reactor design may be capable of reaching the temperatures necessary for hydrogen-boron fusion.

Another design is one that was invented by Robert Bussard. Basically, this design is based upon the fusor concept but replaces the physical grids with electron clouds held in place magnetically theoretically allowing it to achieve power levels that are viable for commercial power production. Unfortunately, a full-scale reactor of this design has yet to be built, and with Robert Bussard being 78 years old, of ill-health, and without others championing this design, it is likely that it never will be.

Ultimately, one of these designs may replace the Tokamak but I believe the Tokamak reactors will be the first to go online commercially. In large part I believe this is because they are sufficiently capital intensive that existing energy companies can feel secure that they still can have a lock on the energy market.

Long term however, I believe these other designs and perhaps some we haven’t even though of will take their place owing to their ability to operate on aneutronic fuels.

Either way, lithium will become the limiting factor for tokamak reactors and boron for aneutronic reactors based upon proton-boron fusion.

Another option is He3, which is exceedingly rare on earth but less rare on the moon. However, using that fuel source would require a substantial industrial presence on the moon and a substantial space transport system presently not in place.

So overall I think fusion will be a considerable improvement over burning hydrocarbons both in terms of environmental impact and availability, however I don’t believe it’s going to approach free by any means, both because ultimately the demand for lithium will drive the price up and because the reactors will be capital intensive to build even if they are relatively inexpensive to operate.

This if coarse is not to discount exploiting the natural fusion reactor in the sky, however, the density of solar power is problematic for many applications and earthbound exploitation is limited by available land.

Category: Future

I Wish I Had All The Answers

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I wish I had all the answers to the worlds problems but I don’t. There are some things I know we’ve got to do if we are going to survive on this planet let alone thrive and find happiness and meaning in our lives.

Some of the things we must do, we must forgive each other. As the old saying goes, “An eye for an eye and a tooth for a tooth just leaves us with a lot of toothless blind people.”

We need to find a way to live within our means, this is a lesson I’m learning the hard way in my personal life as my own personal means have shrank considerably. But on a planetary basis, we’re running into this as well, we can only extract so much raw materials and create so much waste before we starve to death while drowning in our waste.

This means we need to recycle everything. The nutrients we extract from the soil, we need to get them back into the soil.

We need to stop depending upon one-way chemical reactions between atmosphere and minerals for our energy needs and shiftp towards energy sources which can be sustained indefinitely.

Even though I have elaborated that I think there are enough hydrocarbons that they could provide for our energy needs for a long time, we’re altering our atmosphere in undesirable ways and we do considerable environmental damage extracting hydrocarbons.

Tar sands are being mined in Alberta Canada, oil (heavy crude) extracted, cracked, and then sold to the United States. It takes a ton of sand to extract a barrel of oil, they extract it in huge open pit mines. This results in a huge amount of toxic trailings. The tar sands are largely below forested land. They have to clear all the trees to get at it.

We’ve got tar sands in the United States as well, huge quantities, but it is deeper and not readily accessed via open pit mining so here companies are experimenting with in situ methods of extraction. These involve heating in some way in order to lower the viscosity enough for the oil to be pumped.

We also have oil shale and extracting the oil from it has it’s own environmental consequences.

We have huge quantities of coal, and it can be processed into liquid fuel, again with environmental consequences.

Bottom line is that extracting hydrocarbons will get increasingly difficult and increasingly destructive to the environment, and burning them is always destructive to the environment, so we need to move on to something else.

We need to find a way to get along, these wars, not only do they inflict tremendous human suffering, but they waste tremendous resources and prevent the international coordination that we need. Today, pollution is no longer a local problem it is global, the same is true of resource exhaustion.

We need to find a way to stop producing crap we don’t need. Our existing economic system would collapse if we did this, there needs to be a way to modify or replace it with something that is efficient for the production and distribution of what we need but doesn’t involve marketing a lot of useless crap and producing that useless crap.

We need to find a way to love each other even with our differences, and respect our differences and accept them. Only if we can start thinking on terms of what is best for the planet as a whole can we make the right decisions for our planet.

Each of us, we’re all connected more than we realize with each other and with every other living thing on this planet, and even perhaps with the things we don’t ordinary think of as living.

Category: Future

Energy Planet – Renewable Energy Directory

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Someone sent e-mail mentioning Energy Planet’s Renewable Energy Directory and I thought it was worth a mention here. It’s got a listing of a quite a few suppliers of things like solar panels, storage batteries, wind and tide energy, pretty comprehensive actually.

Category: Future

Healthy Oceans, Lakes, Rivers, and Streams

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The health of natural bodies of water and the entire planets ecosystem is threatened by excessive nutrients entering the oceans and other natural bodies of water. In this article, I discuss one of the sources of those nutrients, fertilizer runoff. In future posts, I will discuss other sources, human and animal wastes, and industrial sources.

Anyone who has lived in Washington has seen the changes to our beaches. Beaches had sand, upon which you could walk, sit, or play. You could wade into the water and see through it down to a depth of several feet. Now the beach is littered with seaweed and the waters are murky brown-green with algae.

An increase in available nutrients, primarily nitrogen and phosphorous has created the increase in algae and other plant materials in the Puget Sound and Pacific Ocean. The sources of these nutrients are fertilizer run-off, human and animal waste, and industrial pollutants.

We could ignore aesthetics, but algae blooms near the surface block light from getting down to any deeper waters, depriving the deeper waters of oxygen. Fish and other life die off leaving huge dead zones. Anaerobic bacteria that make their living by metabolizing sulfur compounds thrive in the absence of oxygen and create hydrogen sulfide as a waste product. Hydrogen sulfide is highly toxic and smells like a fart. Some former mass extinctions may have resulted from anaerobic bacteria creating so much hydrogen sulfide that it killed most land land species as well as ocean life.

You can see more is at stake than simple aesthetics, death by global fart if this isn’t addressed, a mass extinction including the human race. To prevent mass extinction by global fart we need to do two things, stop fertilizer runoff and improve sewage treatment sufficiently that substantial amounts of nitrogen, phosphorous, and other nutrients, are not discharged from treatment facilities.

Fertilizer runoff comes from residential and agricultural sources. Fertilizing your lawn then watering it excessively carries nutrients off into storm drains which drain untreated into lakes and streams. Is a green lawn is really worth mass global extinction by fart? Help your grass grow healthy using aeration, a mulching lawn mower and allowing your grass to grow slightly taller.

Only water enough to soak down several inches. Grass roots do not grow deeper than this so additional water only leaches nutrients from the soil, including any fertilizer you added, down the storm drains off to your local stream. If you use a mulching mower so all nutrients consumed by growing grass are returned to the soil, and water properly so that minerals aren’t leached from your soil, you should not need fertilizers.

The practices that allow a grass lawn to grow green without causing runoff also apply to food agriculture. Get onto Google Maps and view an agricultural region such as central Washington state, you will see these big circles, rows and rows of huge circles. These are agricultural fields in which a sprinkler system that consists of a central hub with a long pipe which has a series of wheels supporting it out from the central hub, and has sprinklers mounted on it. It irrigates the land by spraying water as the pipe makes a complete 360 degree turn through the field around the central hub.

This method of irrigation is simple, cheap, and extremely wasteful. Instead of going into the soil where needed, water is sprayed on top. Much is lost to evaporation as the spray travels through the air before it even gets to the crop. Usually, these are just run on timers and take no consideration of the amount of moisture already in the soil and how much the plants actually need.

Over watering causes the water to go past the roots, leaching minerals from the soil as it does, down past the top soil into the clay below and eventually into the ground water where it caries the minerals leached from the soil with it, or it runs off the top into nearby streams. Minerals leached from the soil require replacement by artificial fertilizers.

This type of watering should be replaced by controlled drip irrigation where water is placed directly into the soil and monitored at the depth of the roots so only enough water is provided as needed. This practice eliminates water waste and eliminates mineral leaching. The system is more expensive initially but saves the farmer the expense of unnecessary fertilizer and water. More importantly, it prevents nutrients from entering natural bodies of water.

We need to take these steps to preserve our biosphere which provides us with sustenance.

Category: Future