Exploring Hydrocarbon Depletion
Page added on April 3, 2013
With fusion energy research about to reach a pivotal goal, many of us remain in the dark about this important energy source and its implications. What is it? How does it work? Why do we need to know? Where will the opportunities lie? When will it be mainstream and have economic impact? Who are Canada’s leaders in fusion research? What research has been done in Canada? What can Alberta and Canada do to be better prepared?
To answer these questions, we talked with Dr. Allan Offenberger, Professor Emeritus of Electrical and Computer Engineering at the University of Alberta and co-chair of the Alberta/Canada Fusion Energy Program. Dr. Offenberger headed up Alberta’s fusion research program prior to his academic retirement in 1995.
What is fusion?
Nuclear fusion occurs when positively charged ions of hydrogen or its isotopes have sufficient energy to overcome Coulomb repulsion, (Coulomb repulsion is the opposing force between two positively charged or two negatively charged ions). Fusion occurs when this resistant force is overcome, momentarily combining (fusing the particles) then splitting into two new products – e.g., deuterium and tritium which then produce a neutron and helium. In the pro-cess, large amounts of energy are re-leased due to the change in mass. This process is defined by Einstein’s equation E=MC2.
Dr. Allan Offenberger
Fusion is very different from fission. In fission, energy is produced as a result of splitting apart heavy uranium atoms to release nuclear energy, the products of which are radioactive. Since the products of fusion, unlike fission, are not directly radioactive, waste or handling and storage issues are much reduced. Fusion is the process that powers our sun and all stars in the universe.
Our sun contains massive amounts of hydrogen, the fuel of fusion. The hydrogen ions within the sun’s mass exist in high temperature conditions that yield a huge steady flow of energy even with a slow fusion reaction rate. This energy flow is of such magnitude that it powers the entire solar system.
All the elements of the periodic table and all life and matter that exist in nature is created from the process of fusion of lighter particles. Not only do we get energy from the sun’s fusion, all the building blocks of life itself are created as a result of fusion processes. Photosynthesis and renewable energy in the form of solar and wind are also derived from fusion.
Why has mankind grappled with producing fusion on Earth?
Since the fuels of fusion can provide virtually unlimited clean energy, mankind has been motivated to capture this prodigious energy. Fusion is an ideal energy source for our planet, created from the reaction of naturally sustainable and universally available fuel. The question that man grapples with is – why, with an abundance of fuel on earth, can we not produce fusion energy as in the sun?
The primary answer is that, on earth, we cannot assemble the massive amount of slow burning fuel as in the sun and so we must devise schemes to work with small amounts of fuel and rapid burning. While replicating conditions for fusion on earth is not easy, remarkable progress has been made over the past few decades. The conditions required for fusion power generation are twofold:
1. Heat the fuel to extraordinary temperatures of one hundred million degrees to enable a fusion event to take place; and
2. Provide sufficient confinement to prevent escape of the high temperature fuel in order to achieve more energy output than is expended in heating the fuel to ignition.
High temperature is critical for hydrogen nuclei to overcome Coulomb repulsion and enable particles to fuse and ultimately transforming into neutrons and helium atoms. Confinement is essential since the high temperature and further reactions would be quenched by particles escaping to surrounding material surfaces.
For controlled fusion, initial and continuing experimental efforts have utilized magnetic confinement as one of the mainline approaches. Magnetic fusion energy (MFE) research from the 1950’s to the present has led to the world’s largest international fusion project – ITER, which is based in France.
An alternative approach to magnetic confinement, the inertial fusion energy approach (IFE) began after the laser was invented in 1960. The inertial scheme is based on using laser or particle beams to irradiate a small fuel pellet and heat the fuel to ignition temperature inducing fuel burn before the pellet can disassemble under the very high temperatures that is generated. Theoretical calculations and subsequent experimental work determined that lasers could be used to produce the tremendous fusion temperatures required; the remaining issue is to achieve adequate confinement.
The stimulating science associated with lasers plus prospects for generating clean energy from fusion has attracted the attention of bright scientists worldwide. Over the past 30 years, with the financial support of defence and academic research programs in the U.S. and elsewhere, IFE science and technology have made remarkable progress. In particular, Lawrence Liver-more National Laboratory has now built a low repetition rate, high energy laser system called NIF (for National Ignition Facility) that should achieve fuel ignition. With success at NIF, scientists are on the verge of seeing proof-of-principal demonstration of energy gain from IFE.
How will a fusion reactor work?
The means of generating power from Inertial Fusion is similar to that of an internal combustion engine – fuel pellets injected into a target chamber at a rate of about 600/min while laser beams are fired to ignite the fuel within the chamber. The fusion power plant would include a pellet factory; an injection system to deliver pellets to the centre of a chamber, a laser system to ignite the fuel pellets, and a circulating lithium blanket in the chamber to absorb the energy of the neutrons emerging from the fusion reaction. In addition to removing the heat to an external loop, the lithium is needed to produce tritium as part of the fuel cycle (deuterium-tritium reactions having the lowest temperature required for fusion; tritium is not found in nature due to its short decay lifetime). The captured energy would be used to heat water to create steam and generate electricity.
In effect, fusion fuel replaces coal, natural gas or fission fuel in a power plant; the electric generating infrastructure remains basically the same. The system is inherently safe with the ability to shut down instantaneously if a pellet is not injected or the lasers are not fired. The amount of tritium in the system is limited (and used to make the fuel pellets) and is not an evacuation hazard outside the power plant. The residual decay heat in the system is low and does not require external cooling or other intervention on shutdown.
What is the potential timeframe for implementation?
Once ignition is achieved at NIF, the world’s expectation for fusion will change dramatically. The next step will be to demonstrate an operating inertial fusion system at a power plant repeti-tion rate which is the rate of several hundred pellet/laser shots per minute. Commercialization would follow this prototype demonstration phase. LLNL has developed a plan (called LIFE for “laser inertial fusion energy”) with in-put from the electrical utilities to imple-ment inertial fusion energy; it envisages 10 years to a prototype demonstration (following ignition) and 20 years to commercialization.
What will be the international impact?
A transformative change is coming and the economic impact will be profound. With fusion we will finally have sustainable, clean energy for electricity generation that will benefit every country in the world. Environmental concerns will be addressed. Geopolitics associated with energy supplies will vanish because the fuels of fusion (deuterium and lithium) are found everywhere – on land and in the oceans. The amount of fuel to be acquired and transported is very small compared to alternatives. The fuel required to run a fusion power plant for a year can be delivered in the back of a pick-up truck; in comparison, a coal-fired plant burns approximately 26,000 train-car loads of coal to produce the same output power of one gigawatt of energy.
Electricity is becoming a more important currency for both stationary and mobile transport applications. Our homes, industry, consumer products and, increasingly cars, are being powered by electricity, driving the demand for more power generation.
It is anticipated that coal-fired electrical power plants will be nearly phased out by mid-century in the U.S. and alternative clean energy sources will be the norm. In other places in the world such as India and China, massive new power generation is required. Fusion provides an ideal source for generating base load electricity. Worth noting is that China has included fusion as one of the five priorities in their 2020 vision planning.
As a measure of the economic impact, with worldwide projected demand of 40,000 new electric power plants needed in this century, the required investment will exceed $100 trillion in to-day’s dollars.
Do you foresee oil becoming a stranded asset or will the demand for oil continue for a period of time?
Oil is a valuable resource and it will continue to be used in many products. Oil is important for pharmaceuticals, lubricants, plastics and many other chemical products. In the future, carbon will play an important role in electronics and composite materials. Burning carbon is not the best way to use this resource but high energy density transportable fuel will be required for some time even after fusion is realized. In the long run, increased stationary and mobile applications of electric energy will force Canada to adjust to a future less dependent on fossil fuels. Changing our current economic model is inevitable.
What commercial applications have arisen from fusion research?
The impact of fusion research and development is pervasive. A new state of matter, called plasma, results at high temperatures; its importance to fusion research has had a major impact on plasma physics. Producing, understanding and controlling this state has resulted in many scientific and industrial spin-offs. A few examples include materials processing, plasma etching (used to fabricate integrated circuits), plasma assisted chemical vapour deposition (to produce highly purified and performing solid materials) and ion implantation (important for microelectronic fabrication). Plasma phenomena affect the earth’s magnetosphere, the magnetic field surrounding the Earth that blocks the sun’s particles which affect electricity grids and communications. Super-computers were initially used for plasma and fusion calculations. Accelerators, pulse power and astrophysics are other areas that are impacted.
First generation high-energy lasers for fusion energy research were developed using very large flash lamps for optical pumping. The Livermore laser facility was designed around this older technology. Today, the technology has changed dramatically. New all-solid-state lasers are much smaller, more reliable, more efficient and have many more application areas – medicine, communications, scanners, entertainment, metrology, materials processing in cutting, welding, annealing, and more.
One exciting medical application involves using ultra-short pulse, high power lasers – developed for plasma/fusion research – to accelerate protons to deliver precise doses of energy to destroy cancer cells. Accelerating pencil beams of protons to penetrate more or less deeply into tissue depends only on the proton energy; this ensures that only cancer cells and not surrounding tissue are targeted.
The use of high power lasers to create sun-like conditions in the laboratory has an important application in astrophysics research aimed at understanding the origins of our solar system, physical processes in stars and the connectedness of the very small to the very large.
And these are but a few examples of the impact of fusion research.
What important contributions resulted from the University of Alberta research?
The University of Alberta research program over the years has resulted in several pioneering contributions. This includes developments in high power laser systems; plasma production and heating using lasers; laser/plasma inter-actions, especially instabilities induced by high intensity laser radiation; laser scattering measurements and instrumentation techniques to name a few. The U of A graduate and postdoctoral level training of scientists has been a key aspect of its contribution to lasers, plasmas and fusion research.
In the first decade, the U of A focus was on developing high power CO2 lasers to study energy coupling (particularly instabilities resulting in poor coupling). Over the course of an extensive experimental research program, we learned that long wavelength lasers were ideal for studying the basic physics of energy coupling but were not ideal for fusion energy applications. This knowledge led to a new program developing short wavelength KrF lasers for fusion related research requiring all new approaches in designing, building and operating short pulse, high energy systems. The world’s first pulse compressed KrF laser system was developed and operated at the U of A using a sophisticated combination of optical beam multiplexing and stimulated scattering. This facility was subsequently used for many experimental studies that demonstrated efficient target absorption without severe side effects for short wavelength laser radiation. In the course of this research many innovations were introduced in laser techniques, instrumentation and materials science.
Unfortunately, Canadian funding was not available to scale up the research program and so KrF laser operations were eventually terminated. The scaling up called for a major expansion of facilities, requiring national program funding. In fact, a fusion energy pro-gram was proposed for Canada (initially administered by NRC then AECL) and I was a member of the national advisory committees for both agencies. Three sub-programs were proposed: magnetic confinement, inertial confinement and fusion fuels. Quebec came forward to sponsor the magnetic fusion component and Ontario the fusion fuels component; both programs received matched funding from the federal government. Sadly, both programs were terminated in the 1990’s. Alberta was expected to lead the inertial fusion program (it was the largest laser fusion research pro-gram in Canada). Unfortunately, Alberta chose not to co-fund this proposal, and as a result, the third recommended component did not materialize, even though it was recognized that many spin-off benefits would accompany such a program.
The world of science and technology does not stand still and so Canada has been largely on the sidelines in fusion research and development since then.
What has Canada and Alberta’s involvement been in fusion research since?
Canada is the only major developed country in the world not involved in a national program of fusion research at an internationally-competitive level. This has long-term implications for Canada in energy, environment and economy. How can we prepare? It would be prudent to invest some of our current wealth from carbon fuels in alternative energies such as fusion to prepare for the future. Given that the rest of the world is moving aggressively towards a non-carbon future and we seem to be going in the opposite direction, Canada and Alberta must change their mindset.
At present, fusion-related research in Canada is to be found in small academic science programs, the type of research that is done as part of doctoral dissertations in universities. This is the nature of ongoing laser fusion research at the U of A and magnetic fusion re-search at the University of Saskatchewan, with current activity limited by funding.
What should Canada be doing?
Canada does not have a national energy strategy; it is set at the provincial level (each emphasizing one of hydro, nuclear, coal, or other forms of energy). Alberta could take the national leadership in fusion by building on the excellent international research relationships that have been established over the years. Getting Canada back in the game by joining the research and development efforts and collaborating with international research centres will leverage past investments elsewhere and enable research niches to be identified. Inevitably, Canada will want to be involved as the applications and their economic opportunities arise.
The U.S. is taking a proactive role. The U.S. Secretary of Energy advised LLNL researchers not to wait for ignition but to start planning how to move the technology to a power demonstration phase. This directive resulted in LIFE – Laser Inertial Fusion Energy – planning at LLNL. Conceptual designs for the scaling of single-shot fusion experiments at NIF to a repetitive power device in the U.S. are already highly advanced. This planning has engaged the participation of U.S. utilities representing 75 per cent of the electrical generation capacity (this ensures the suitability of LIFE for utility application). U.S. vendors who will need to scale up operations to accommodate implementation have also become involved. The LIFE group projects a commercial power demonstration unit in approximately 10 years following ignition.