Inertial Confinement Fusion

7 11 2008

Last week I discussed fusion power and how it may be the end all solution for our energy needs. I touched on the difficulties of using fusion power and some of the dangers associated with fusion power. I want to delve into those two particular areas a little deeper today, and I want to introduce an intermediate solution for our containment problem.

As with any nuclear reaction there is always concern about safety. Fusion power is unique in that in order to maintain the reaction, lots of energy is required. When there is a dip in power the system crashes. Unlike a fission reactor this crash results in immediate loss of fusion production, there is no chance for a runaway nuclear meltdown! The downside to most fusion reactions is the production of neutron radiation. Neutron radiation is easier to confine than gamma radiation but at a cost to the structure. After years of operation, fusion facilities would need to be shutdown and treated for the vast exposure to neutron radiation. Again it is a trade off in comparison to fission power. You trade years of stockpiled radiological waste with a building.

Well, if there are these problems confining fusion confinement, is it any good until we have the confinement solution? YES! Engineers and Scientist here and across the world have come up with in intermediate solution to full fusion confinement power. Extremely simplified, Inertial Confinement Fusion operates somewhat like your cars engine. A fusion fuel is heated, typically by a laser, until a fusion reaction occurs. The fuel is quickly consumed so the reaction does not take long. Without having to confine the reaction little energy is wasted on containment measures like plasmas and magnets. The heat generated by the reaction is still enough to boil water and create power. So like your gas engine, fuel goes in, it reacts and produces heat and work and then it is allowed to cool until the next reaction. Inertial confinement fusion could be used as the intermediate step between fully confined fusion power and our current technology. If you would like to know more, visit https://lasers.llnl.gov/. It is hard not to get excited about this technology. Almost in our grasp is the ability to generate completely clean energy far more effectively than current green technology (wind, solar, geothermal, etc.)!

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The Ultimate Solution

31 10 2008

This weeks discussion is going to focus on fusion power and why it can be the answer to the world’s energy needs. Fusion is a large topic that can’t really be explained and discussed in just one post, so be sure to check in next week to get the follow up.

First things first, what is the difference between fusion and fission (discussed earlier in a post about liquefied salt reactors)? In fission, an element, most often uranium, decays into two other elements. During this decay, lots of energy in the form of heat is produced. This energy is known as the binding energy. Take a look at the graph below (courtesy of http://www.lancs.ac.uk/ug/suttond1/), it relates elements and their binding energies. As discussed before, the heat that comes from a nuclear reaction is a dependant on the binding energy. The heat is used to drive steam turbines and produce electricity. The binding energy released is the difference of the binding energy of the reactants and products. Notice the difference in energy between uranium 238 (the reactant) and an element with 90 to 135 nucleons (common fission products). You see there is a difference of at most of 1 MeV. One fusion reaction is the production of He4 from deuterium and tritium (basically hydrogen with different numbers of neutrons). The graph indicates a difference 4 MeV! Now the actual deuterium and tritium reaction produces 3.5 MeVs but that is still four times the average fission reaction. This all traces back to getting a higher energy density and there is a lot of power associated with fusion. Think of the sun on a warm day. You feel hot because of fusion occurring 93000000 miles away. What are the evil by products of fusion power? Helium mostly. Whats bad about helium? It may make your voice go to a higher pitch, but that is about it. In fact, if people could choose a pollutant, you may want helium. Excess helium in our atmosphere is so light, it vents into space. Helium also is used for cooling superconductors. Suffice it to say, helium is not a bad deal for having such a powerful energy source.

I hope I’ve established that fusion power is a more effective, cleaner, and powerful energy source then our current champ fission power. So why hasn’t it been adopted across the board as a future energy source? There are lots of answers to that question, but one of the biggest problems is that of power consumption. Currently it takes more energy to contain the fusion reaction than the amount of power produced by the reaction. The picture at the top of my blog is a picture of one of the ways engineers are trying to contain the fusion reaction (it is a tokomak check it out: http://en.wikipedia.org/wiki/Tokamak) . Using powerful magnets and plasmas, scientists and engineers have been able to contain a fusion reaction but at the cost of large amounts of energy to power the magnets and plasmas. The goal now is to make a fusion plant capable of creating enough power to run itself and produce heat for power generation.

An experiment in France, called ITER, is currently being constructed to meet this goal. If successful it would be the first reactor capable of maintaining a fusion reaction and harnessing power created by it for a sustained amount of time.

Fusion power is great source of energy. It has many engineering challenges that have prohibited its use so far. Next week I’ll talk more on some of the cons to fusion power, a possible work around that may bypass the containment problem, and issue with fusion power buildings.





Hydrogen Fuel Cell Technology for Automobiles

24 10 2008

I attended a presentation several years ago by an employee of the renewable energy lab in Boulder. One of his slides indicated that nearly two thirds of our fossil fuel energy was expended for transportation. We are feeling that fact right now with gas prices just coming off three and four dollars a gallon. My colleagues in combustion have told me that for every gallon of gasoline burned, twenty pounds of carbon dioxide is emitted. Obviously, American’s reliance on private transportation can’t be broken. Our infrastructure is setup for private automobile use and the independence of setting your own schedule. We can’t just drop the car to solve the two problems of pollution generated and fossil fuels consumed.

A solution to this problem has been known for years. In fact preproduction models have driven across the United States to raise awareness. Hydrogen fuel cell vehicles are an admirable and sustainable solution to dependence on fossil fueled vehicles. Let me start off with a little explanation of how fuel cells work and why they are an excellent solution. I’ll finish with the problems and reasons that they haven’t been adopted in large scale.

Using the stored chemical energy in hydrogen and oxygen, fuel cells present the chemicals (in this case hydrogen and oxygen) to an electrolyte. The electrode is where the the chemical reaction takes place. An electrolyte separates electrodes and serves as a barrier. This barrier will only allow certain chemical species through. In the case of hydrogen, positive ions are produced by the electrode, labeled as the anode in the picture below, and flow towards the electrolyte, labeled as the PEM (proton exchange membrane) in the picture below, which allows only the positive hydrogen atoms through and not the by product electrons. These electrons are then used to generate current (as discussed in the first blog post). So, the two fuels, hydrogen and oxygen undergo a chemical process that releases electrons to be used for power. As everyone knows, when you combine oxygen and hydrogen they make water. So now we have a energy storage device, much like a battery, that produces power and extremely pure water.

Hydrogen fuel cell cars are currently twice as efficient as similarly sized vehicles with predictions of further enhancement.1 Hydrogen as fuel also has very good merits. According to nations watchdog on fuel economy2, “The United States currently uses 20 million barrels of oil a day at a cost of 2 billion dollars. Half of this oil is imported”. Hydrogen can be produced from many sources. It is the most abundant element in the universe3! Oxygen comprises approximately 30% of our atmosphere. Needless to say, hydrogen fuel cell fuels are abundant and the only emission produced is water. The combination is a future solution that enables American’s to continue our private automobile lifestyles with a positive influence to the environment.

With all of this great science behind it, why haven’t fuel cells be widely adopted? The answer is in our present ability to harness hydrogen. While collecting hydrogen is not impossible, the current processes used are energy intensive. Gains by zero emission vehicles are destroyed by the power required to produce the fuel. Hydrogen itself is also a very volatile element (remember the Hindenburg4?). The space shuttle uses liquid hydrogen and oxygen for the main engines. All chemists know what a the positive hydrogen ion is, a strong acid! Oxygen is also one of the most corrosive elements known to many of the materials currently used in automobiles.

Hydrogen fuel cells are a great technology. They satisfy all of the requirements of a future energy source and adapt well to our current infrastructure. Problems exist and many of them are nontrivial. Engineers and scientists need to work together to solve these problems, but once solved our major dependence on foreign oil and environmental impact will be greatly helped.

1http://www.fueleconomy.gov/feg/fuelcell.shtml

2http://www.fueleconomy.gov/feg/fcv_benefits.shtml

3http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/971113i.html

4http://en.wikipedia.org/wiki/Hindenburg_disaster





Unrelated but cool. The Pioneer Effect.

21 10 2008

In 1972 NASA began the process of sending two satellites on a one way journey out of our solar system. The launch of Pioneer 10 and 11 allowed mankind to glimpse some of the outer gas giants as we never had seen them before. A famous plate is caried on both spacecraft depciting mankind in the event the satellites are ever intercepted by intiligent life. Despite being launched in 1972 and 1973 the Pioneer spacecraft continued communication with earth until 2003 at a distance of 7.5 billion miles away from earth. Despite the lack of communication scientists and engineers have been keeping a keen on on the spacecraft for good reason. These two objects have travelled further than any man, woman, or child, will for the foresable future. Things have started to get interesting though. For some reason, not explainable by physics as we know now, the spacecraft are slowing down. They aren’t leaving our solar system as fast as they were mathematically predicted to. Now there is a slew of hypothesis for why Pioneer 10 and 11 continue to slow down, but the scientific community cannot agree one answer. The Pioneer Effect is important because it reminds us of how insignificant we really are. We can barely huck a small object out of our solar system (it has taken us over 30 years to get it there too!). As a race, humans make advancements every day. We may marvel at our wonders but we should always keep in mind there is so much more to learn and understand.





Energy Economics – An Opinion

10 10 2008

It is going to be hard to ignore the effect of the current economic situation when it comes to future energy solutions. With the world in a financial panic and the United States on the brink of recession, one may ask does  progressive action on the energy front really matter? My answer to this is yes. I think that an energy revolution can spur the United States and the world out of this economic depression. The United States suffered through many years of financial turmoil after the great depression of 1929 until one event surged the US out of depression.  World War Two saturated our workforce with new jobs and factories employeed millions to meet the needs of a warfighting nation. We could respond to this economic crisis the same way. Instead of responding the a military threat, we would be responding to the energy threat. Instead of tanks, planes, and bombs, we would have research, testing, and implementation. We should attack energy problems with the same spirit and gusto that we had when responding to threat posed by an entire world at war. The United States could revolutionize and emerge not only as a superpower (again), but as the world leader in sustainable and clean energy. So in this economic downturn, remember there can be good in all of this. Be like me and hope for an energy revolution that will avert this economic quagmire we are currently in!





The Wright Brothers would be worried.

3 10 2008

Just about the time finals starting wrapping up this semester I want you to think about something for me. I am sure many of you will be traveling over the long winter break to places long and far. Air travel will allow you to quickly and, well, somewhat conveniently arrive at your destination. Remember that if you travel around December 17th, you will be flying on the 105th anniversary of powered flight (courtesy of the Wright Brothers).

So why bring this up in the Future Energy Technology weblob? Because we are celebrating 105 years of powered flight; and power and energy go hand in hand. Unlike other modes of transportation, like cars, trains, and buses, there has been no production of an aircraft that runs on anything but combustible hydrocarbons. To be fair, the Air Force has tested a B-52 using bio fuels, but bio fuels are not a sustainable future energy solution (something I’ll touch on later). We have had hydrogen powered cars drive around the country, trains that have been nuclear powered, and most unusually a bus that ran on nothing but the inertia from a large mass wheel, but commercial planes still require good old JP-8.

For my own personal interest and future career goals, I keep an eye out on the latest technology trends in the aerospace industry. In my research, I have yet to find any attempt to convert commercial aviation to renewable energy (besides the Air Forces biofuel B-52). It surprises me that the industry that leads the way in innovation and technology hasn’t thought of a new way to fuel their aircraft!

What are we going to do about this? I have no idea. My hope is to raise awareness of the issue. The United States has some the best scientists and engineers in the world and we need to look to them to come up with a solution that will keep us flying for years to come.

So how will the candidates get around without gas?

John McCains Beoing 737

John McCain's Beoing 737

Barack Obamas Boeing 757

Barack Obama's Boeing 757





A response and thank you.

26 09 2008

The goal of this blog is to inform readers of realistic solutions for energy for the future of the United States and the world. What’s important to remember is our energy is primarily carbon based. I showed last week that the energy density (how much power we get per pound of material) of these carbon materials is far lower than other available materials. As a race, we need to strive to efficiently produce power. It is the only way that we will continue to enjoy the lifestyles we currently enjoy. I’ve loved the comments back and wanted to touch on a few of them before continuing on with future energy ideas.

There was some concern about some of my comments with regard to solar power. I want to reiterate that I like AVA Solar’s approach to introducing low cost solar power to the energy market. The glass based panels are an excellent way to reduce the cost of power from the sun. With that being said, I do NOT think that making solar power a primary mainstay of our energy infrastructure is a good idea. Solar panels are very sensitive to environmental effects (temperature, moisture, incident angle, etc.) and when it is cloudy or dark a method is still needed to store the energy collected. Building a massive array of batteries to keep the power is not only terribly expensive but environmentally threatening. Can you imagine the mining required to produce enough nickel for such a task? That is why I believe solar to be a niche solution. The implementation of an all or primarily solar based power system would require radical transformation of the current power grid and complex storage techniques. Remember, we are striving for energy density, and solar power does not satisfy that requirement despite not being carbon based.

I was expecting a much stronger response to my post on the Liquid Fluoride Thorium Reactor (LFTR). Nuclear power has garnered an incredibly bad image and I was convinced many slanderous remarks would be made! The United States Navy has proven nuclear power can be safe and effective. All of the current aircraft carriers and submarines have nuclear reactors that allow them to have impressive performance characteristics. The Navy has had only two instances where nuclear power may be responsible for the loss of human life. I say “may” because the two boats in question were submarines and investigation of the wrecks is quite difficult given their current positions. Nuclear power from fission will always yield a radioactive by product. I realize there are concerns of what to do with this material. I think better solutions are available but as shown, the energy density compared to coal just can’t be beat.

One reader has broached the topic of fuel cells a few times. Let me just say I can’t wait to address fuel cells, particularly hydrogen fuel cells. I don’t want to spoil a blog so I’ll be brief and say I do indeed want to touch on fuel cells and give the public and idea of why they are so great, why they haven’t been implemented, and why one day the word battery may become obsolete.

I want to thank the readers of Future Energy Technology weblog. I hope that you have found points to agree and disagree with my views. I believe it to be incredibly important to have an open and intelligent dialog on what will be the biggest challenge of the next 30 years. Please check back next week for another post!