Monthly Archives: April 2007

Chinese Sustainable Energy Program

China, with it’s billion and a half citizens, faces a huge challenge. For them, it’s not just a matter of maintaining the status quo, it’s a matter of having a huge population desiring to enjoy a modern lifestyle.

They intend to attain that for their citizens by quadrupling the gross national product and doubling energy consumption by 2050 over what it was in 2000. They are presently depending upon coal to generate 75% of their electricity. Their target is to reduce that to 38% by 2050. Presently electricity demand is increasing 15% per year and coal fired plants are the fastest way for them to meet that demand. Chana is installing more than one 1000 MW coal fired plant per week at present.

The pollution generated takes a huge toll on not only the health of Chinese citizens, but also on food production. The haze generated by burning all of that coal reduces net sunlight at ground level by more than 1%, with an attendant reduction in food crops. Presently, there is more than 250 GW of coal fired generating capacity under construction or in the pipeline. Already, over 40% of China’s rail capacity is dedicated to hauling coal, pollution aside this trend can not continue indefinitely.

China is planning on transitioning towards renewable sources, small scale hydro, biomass, wind, and solar among them. China also tends to make use of nuclear fission and in addition is aggressively pursuing a fusion research path aimed at bringing fusion online commercially.

To gain an understanding of just how aggressively the Chinese are pursing fusion power, consider this. The rest of the world is contributing to the twelve year construction of what was to be the worlds first superconducting tokamak fusion reactor, ITER, to allow sustained operating at commercial power levels so material issues such as how the diverter would function long term and engineering issues like heat load and neutron embriddlement could be worked out. The US contribution to this project over a 12-year period amounts to less than what we spend on imported oil in two days.

By contrast, the Chinese started construction of a superconducting fusion test reactor in February of 2006, it say first plasma in September of 2006. I’m going to lay odds that they will have fusion power online commercially before ITER is fully constructed.

China intends to build an additional 30 nuclear fission reactors for power production over the next fifteen years and by 2050, China intends to have a total of around 150GW of nuclear capacity online. This equates to about 150 nuclear fission plants if a gigawatt design is used, presently domestic plants are of a 300 MW and 600 MW size.

The Chinese are also having great success with wind power. While electricity produced by coal fired plants is averaging around 8¢/KWh, electricity produced by wind is averaging about 4.5¢/KWh. As one might expect, that is making wind power look like a very attractive investment, however, it can not be scaled up presently as fast as coal can and consequently coal still leads new power production. I suspect though that the economics of wind power will drive a rapid acceleration in the rate of wind power production.

China is also exploring advanced high temperature nuclear fission reactor technology. Conventional boiling water reactors or pressurized steam reactors operate at low temperatures with resulting poor thermal conversion efficiency. However, South Africa has produced and is operating gas cooled pebble bed reactors which can operate at far higher temperatures with an attendant improvement in efficiency.

China has demonstrated the inherent safety of a 10 MW pebble bed reactors by shutting off cooling while the reactor was operating at full power and demonstrating it’s ability withstand that without damage or radiation release. Pebble bed reactors use fuel pellets about the size of billiard balls that contain fuel inside of a graphite ball, and in some designs that is in an outer casing of silicon carbide. In my opinion the latter is a much better design because silicon carbide is not reactive with oxygen so even if the containment vessel cracks a silicon carbide encased fuel pellet will not allow radioactive materials to escape where a graphite pellet could potentially burn in that situation.

Pebble bed reactors are safe and thermally efficient, however, they are not efficient in their overall use of fuel because their operation is inherently one-pass meaning less than 1% of the uranium fuels potential can be extracted. The spent fuel is difficult to extract from used pebbles and so at present no reprocessing technology exists and the fuel can not be reprocessed.

Those are some of the things happening in China. I think it’s worth while viewing how other countries are addressing their energy needs and environmental concerns. For the time being China’s dependence upon coal is catastrophic for the environment but they are working on transitioning from coal which I see as a positive step.

Rig Zone

Even though in my opinion burning hydrocarbons for energy is the antithesis of a sustainable economy, I’ve added RigZone.com to the sidebar so those of you who wish to keep track of what the oil companies are doing have that resource readily available.

If you take a look at it on a daily basis, you won’t miss on the oil field discoveries. If you dig around a bit, the field development tab is a good place to look, you can look at the specifics, how much oil they find, how development is going on a particular field, the estimated production life of that field, etc.

Peak Oil

In spite of everything I’ve presented here there are people who still want to buy into the peak oil scam. I’m not sure how much I should try to convince people otherwise because while there isn’t a peak oil situation immediately looming, at least not in the sense that we’ve used up half of all the worlds oil reserves, there is the problem of damage to our environment, and that is real and threatening and the right reason for transitioning to alternatives to oil.

I’m sure that James Howard Kunstler is a far more persuasive author than I am, and he’s also motivated to sell books. So what chance do I have of competing?

Those of you who really want to know the truth, it’s out there if you dig for it. One place I like to look is http://www.rigzone.com/. It is geared towards the oil industry and consequently not high in entertainment value like Kunstler’s book, however, it contains real data, the new oil field discoveries, the technological developments, the economics involved. There are other sites like it but that one makes everything available to anyone who cares to go and take a look.

On the other hand, if you just want to be entertained, read Kunstler’s book. Really, I’m not sure it’s a bad thing for the public to believe a peak oil crises is upon us, because if that actually provides the motivation to get us to move onto something environmentally less damaging then it’s not a bad thing.

My only gripe with the peak oil scam, besides the fact that it is a scam, is that by creating a perceived shortage it’s driving the price of oil up and sucking money out of the economy that could be used to invest in alternatives. It’s also causing major problems for many people economically forcing people to choose between heating and eating while the oil companies rake in 35 billion a quarter in profits. And it’s causing many Americans to look the other way while we conduct a war in the middle east because they believe it’s securing oil. In reality, it’s cut the production in Iraq considerably driving the cost of oil up which of coarse is what the multinationals had intended in the first place.

All of this isn’t to say that cheap oil is not getting scarce. There is plenty of oil left but it’s not the low sulfur light crude under so much pressure that all you have to do is poke a hole in the ground and it comes gushing out. There is plenty of deep oil, the kind you have to drill down 20,000+ feet and through granite or basaltic capstone to get to. There is plenty of oil shale and tar sands, which yield thick bitumen that has to be cracked into lighter molecules in order to be commercially useful and that increases refinery costs. There is about as much heavy oil in California as there is Venezuela. There is much oil off the Gulf of Mexico yet to be tapped but much of it is in deep water and requires deep drilling to get to. There are regions off the Pacific coast believed to have oil but they haven’t been allowed to even be explored let alone tapped.

I’d much rather see us move to clean renewable resources than tap all of these and spew more filth into the atmosphere and environment in general. I’d rather see it happen though because it’s the right thing to do for our planet and not because oil companies thought they could boost their profits by creating a perceived shortage.

Nuclear Fuel Shortage?

This article concerning a nuclear fuel shortage, on MIT’s website, leaves me shaking my head and wonder what they up to. There has to be an agenda behind this besides a genuine concern over having enough fuel for reactors because if we really had a fuel shortage we wouldn’t be creating a national waste repository that is intended to store nuclear waste for 20,000 years.

Some background is necessary regarding the entire nuclear fuel cycle. We mine natural uranium ore, the uranium once extracted from that ore contains proximately .72% U-235, and 99.27% U-238, and .0055% U-234.

In a uranium fueled nuclear fission reactor, the isotope U-235 is the fuel because it can be caused to fission, that is break into lighter elements, by absorbing a slow (thermal) neutron, and in turn also give off neutrons when that happens, which are then absorbed by another U-235 atom, continuing the chain. The resulting daughter elements are slightly lighter than the original uranium element and that mass difference is converted into energy.

U-238 isn’t completely inert however. It absorbs neutrons becoming U-239, decays to Np-239 through beta emission (emits an electron, one of the neutrons becomes a proton), and then Np-239 decays into Pu-239, again through beta decay. Pu-239, like U-235 is fissionable with thermal neutrons.

Thus in a reactor fueled with U-235 and U-238, a percentage of the U-238 atoms will absorb neutrons and become Pu-239 adding to the fissionable fuel inventory in the reactor.

However, notice that U-238 does not emit neutrons during it’s conversion to Pu-239. A light-water moderated reactor can not sustain a nuclear chain reaction with a natural isotopic mix. It is possible to sustain a nuclear fission chain reaction using natural uranium if graphite or heavy water is used as a moderator. Heavy water is expensive in the quantities required and graphite is a fire hazard as was demonstrated in Chernobyl.

To get around this problem uranium is enriched, isotopes are separated using gas diffusion, centrifugal, or laser isotopic enrichment methods so that fuel containing 2.5%-5% U-235 and 95-97.5% U-238 results.

When natural uranium is enriched, typically 15% of the natural uranium becomes enriched uranium at 3.5% U-235, and 85% becomes deplented uranium with .3% U-235. So only 29.2% of the U-235 present in the original ore ever gets into the reactor and about 17% of the U-238. More than 80% of the energy potential of the ore has been eliminated before it ever makes it into the reactor.

During the reactors operation, approximately 1% of the U-238 is turned into Pu-239 and a percentage of that is then fissioned along with U-235 fuel. But at some point the ratio of fissionable isotopes drops too far and waste products that absorb neutrons but do not fission and supply neutrons increases to the point where a chain reaction can no longer be sustained and the reactor must be refueled.

At that point when the spent fuel is removed from the reactor and placed in waste ponds, only 4-5% of the U-238 present in the original fuel (1% or so of what was in the original ore) was used and much of the Pu-239 bred from that is still unused as well as a percentage of the original U-235. Between than .75% and 1% of the natural uranium’s energy potential has been utilized in a one-pass fuel cycle.

MIT is saying we have a fuel shortage because we are presently mining uranium at a rate of only about 65% of the rate that we’re using it in reactors. In the United States, reactors are only using it in a 1-pass fuel cycle and thus more than 99% of the energy potential of that fuel is being wasted.

In addition to that we have huge stockpiles of Pu-239 that have accumulated as part of the weapons programs in the United States and Russia and this also could be used to fuel reactors. It is more problematic however because it is relatively easy to build a bomb from Pu-239, but not from reactor grade uranium which is only enriched to a maximum of around 5% and more typically 2.5-3.5%.

The problem that shuts down the reaction isn’t just a lack of fissionable U-235 and Pu-239, it is the build-up of other actinides, elements heavier than uranium, which absorb thermal neutrons but do not fission and provide additional neutrons as well as some fission products that are neutron absorbers which poison the reaction by absorbing too many neutrons. Fission products also create mechanical problems.

If we reprocess the spent fuel, remove the U-235 and Pu-239, and re-use those in MOX fuel (mixed metal oxides, U-235 and Pu-239), and do this to the greatest extend that we can, we can extract around 2% of the uraniums fuel potential.

Just moving from a single pass to a multi-pass fuel cycle would reduce the amount of uranium that we would need to mine to less than that which is currently being mined. There really isn’t a shortage of uranium, it’s just less expensive to mine fresh ore than to reprocess waste.

We should reprocess, because by doing so not only do we reduce the amount of uranium that needs to be mined, but we reduce the long-lived radioactive wastes by a similar amount.

However, there is a way that we can extract 60-70% of the uraniums fuel potential (with current isotopic separation efficiency) and eliminate most of the long-lived radioactive waste.

In the spent fuel there are two radioactive components. Actinides which includes uranium and all elements that are heavier, and fission products, the daughter products of the fission products. The fission products are highly unstable and decade to stable isotopes in a relatively short time frame. By the time 300 years have passed, they will have decayed to the point where there radioactivity is no higher than the natural ore that was originally mined and are considered safe for disposal at that point.

It is the actinides that are problematic because they have much longer half-lives and it will require in excess of 20,000 years for them to decay to the point where radioactivity is no greater than the original ore.

Of all the actinides produced, only the isotopes U-235 (present in the original uranium fuel), U-233 (bred from thorium, and Pu-239 and Pu-241 are fissionable with thermal neutrons. But all of the actinides are fissionable with fast neutrons. Burning these requires the use of fast-flux nuclear reactors. Early fast-flux reactors had some inherent safety issues because reaction rates could vary rapidly.

However, generation IV reactors have been developed which have inherent stability features. For example, fuel designs that have negative temperature – reactivity coefficients such that as the temperature increases the reaction rate automatically decreases. There are numerous schemes for accomplishing this.

In general fast-flux reactors use either a liquid metal (typically sodium or lead), a liquid salt, or a gas coolant operating at greater temperatures than a boiling water or pressurized water reactor would operate at. This higher temperature translates into higher efficiency. Also, the liquid metal cooled reactors operate at close to atmospheric pressure so there are less plumbing problems.

By using these reactors, 60-70% of the energy content of the uranium ore can be extracted. This can be improved further as separation efficiency improves. Right now however, we have an excess of weapons plutonium stockpiled that can be blended with natural uranium rather than enriching it, and that is providing for a portion of our fuel needs and is the reason we do not have to mine more.

The cost of uranium is a trivial portion of the total cost of producing electricity. If it were to increase by 100x, it would still only account for approximately .7¢/KWh and a 100x cost increase would increase the supply tremendously.

A uranium shortage doesn’t exist and won’t limit nuclear power production. Intelligent use of uranium could reduce the fuel consumption to less than 2% of that which is presently required to generate a given amount of electricity. Thorium can be used as a fuel and there is 3x as much thorium in the Earth’s crust as there is uranium, and what’s more uranium produces more long-lived actinides than does thorium for the amount of energy produced.

What is the motivation behind MIT’s announcement of an impending uranium shortage?

Heat Pump Dryers

The Japanese have had microwave clothes dryers for some time. These use microwaves to heat the wet clothes rather than hot air and by doing so they save approximately 35% in energy consumption. They switch to resistive heating for about the last 10% of the cycle to prevent problems with metal objects. For reasons I am not familiar with these are not available in the United States.

Heat pump dryers are now available in the United States, and these save approximately 65% of the energy consumed by an ordinary dryer. Dryers generally represent around 6% of a households energy consumption, and if you have teenage kids even more. In addition to directly consuming 6% of a households energy budget, dryers also contribute to energy required for heating and/or air conditioning because the air they exhaust to the outside hot came from the inside, and that air will be replaced by cold or hot air from the outside requiring additional energy for heating or cooling the house.

Heat pump dryers cost about $300 more than a conventional resistive heating dryer. Over a ten year lifespan, they will save approximately $1000 in electricity costs assuming the average cost of 8¢/KWh and average household laundry. The savings will be even greater where the rates are higher or if your household has a higher than average amount of laundry. This is before you factor in heating and air conditioning savings which are even greater.

A heat pump dryer is also more convenient to install, requiring only a drain like a washer and no external vent. In addition a heat pump dryer requires only a standard 120 volt outlet, not the larger 240 volt 30 or 40 amp circuit of a resistive heating dryer.

Instead of heating air, blowing it over clothes, and then exhausting the hot air outdoors and taking fresh air from indoors, a heat pump dryer heats air, passes it over clothes, dehumidifies the air, and passes it over clothes again and again. No air is exhausted outdoors, and liquid water from the dehumidified air is simply drained. Heat energy is not wasted.

Not including the savings in heating and cooling, if everyone switched to heat pump clothes dryers it would save 445 billion KWh of electricity every year, 35 billion dollars in electricity costs each year nation wide. Because our trade deficit, and economic woes, are in large part the result of the energy we import, this would be a very good thing for our domestic economy. Surplus electricity could be used by electric vehicles, or we could burn less natural gas for power generation and instead liquify it and use it to power our vehicles instead of imported oil.

It would reduce the average load on the power grid by 50 megawatts, about 1/10th the output of a medium sized nuclear reactor, but it would reduce the peak load by more than this because most people don’t do clothes at 4AM.

Anything we can do to save energy consumption will allow a larger portion of our energy needs to be satisfied by renewable and environmentally benign sources and less carbon dioxide will be generated as a result.

Don’t get me wrong, I actually like warm weather. It’s the species dying off, cities underwater, desertification of farmland and forest, things that really bothers me. Unfortunately they seem to be an intrinsic part of global warming. A great deal of global warming would be happening without our contribution. We should not accelerate or intensify it further by altering our atmosphere.

Even better than a dryer when weather permits is a clothes line. 100% renewable (solar) powered, no electricity consumption.

Heat Pump dryers are available in Japan and Europe from multiple vendors but like microwave dryers they are not widely available in the United States. One company that does produce a number of heat-pump consumer appliances is Nyle Special Products, and I’ve included a link on the side bar. If anyone knows of other suppliers that make household heat pump dryers available in the United States, please contact me and I will add them.

Trains

This BBC article regarding a new French train speed record got me to thinking about our own railroads. When I was young, other countries citizens were reading about the state of the art developments in our country. Allowing our national railroad infrastructure to deteriorate is a major mistake. Other countries have developed their railroads, electrified them, made them functional for transporting people and goods.

Electrified railways can be powered by any energy source. With the exception of some urban light rail systems, our railways are not electrified. Instead, we depend upon diesel fueled locomotives to move our trains. 59% of our oil is imported from other countries. This is extremely damaging to our economy and national security. Burning producing, refining, and burning hydrocarbons is damaging to the global environment.

As the price of oil continues to increase, there will come a point when electrification starts to look like a good option. Problem is, when that time comes, resources to do so will be scarce because all of the money has been spent importing oil or prosecuting wars over the stuff.

Like fusion energy, this is an investment in our future that we should be making now. We need to know we can still move produce from the farms to our cities when diesel for trucks and existing trains runs out.