By Tuan Nguyen
Posting in Design
A "sub-critical" nuclear reactor design essentially allows for an off-switch.
Until this weekend, the nuclear industry was arguably in the midst of a resurgence.
As the terrifying memories of past disasters seemed to fade comfortably into the recesses of history books, many nations had started to explore nuclear energy as an greener alternative to fossil fuels. However, the 8.9 magnitude earthquake that struck Japan on Friday has set off a chain reaction of devastation that will likely lead to a widespread re-evaluation of planned facilities throughout the world.
And despite the outcome of Japan's efforts to prevent full-blown nuclear meltdown, the fallout over nuclear energy has already begun.
“This event may be a big dampener for our program,” Shreyans Kumar Jain, chairman of the Nuclear Power Corporation of India, told Bloomberg News. “We and the Department of Atomic Energy will definitely revisit the entire thing, including our new reactor plans, after we receive more information from Japan.”
In the U.S., it's still too soon to tell if the unfolding events on the other side of the Pacific has put into jeopardy President Obama's pledge to inject eight billion dollars into new nuclear construction projects. In an appearance on CBS's Face the Nation, Senator Joseph Lieberman suggested that America's nuclear energy ambitions will likely be put on hold, but cautioned against rushing to judgment.
“I think it calls on us here in the U.S., naturally, not to stop building nuclear power plants but to put the brakes on right now until we understand the ramifications of what’s happened in Japan,” Senatoron ’s “Face the Nation.”
But what rarely gets mentioned in these sorts of discussions are nuclear technologies under development that may someday lead to safer -- and possibly cleaner -- nuclear facilities.
For instance, the proposed pebble-bed nuclear reactor design encases enriched uranium fuel within tennis-ball-sized graphite spheres. Doing so allows the reactor to run at even higher temperatures temperatures (up to 1,600 °C) and cool down by way of a helium-gas coolant. A silicon carbide coating keeps the radioactive fission material of the spent fuel safely contained within the pebbles, even in the case of a core meltdown or when the coolant is lost.
South African power company Eskom had hoped to put into operation the world's first industrial pebble-bed nuclear reactor but abandoned the project as investors withdrew funding due to technical problems and soaring costs. China also has a prototype in the works.
To learn more about pebble-bed nuclear reactors, check out this very informative segment on 60 Minutes here. (Sorry, but I was unable to embed the video for you folks)
Another safe alternative involves swapping out uranium with a similar radioactive material known as Thorium. The naturally-occurring metal element has been researched as an alternative to uranium as early as the 1960’s right here in the U.S. at the Oak Ridge National Laboratory. The material alone can’t be used to sustain the chain reaction process known as nuclear fission, but can absorb slow neutrons to transform into U-233, an artificial version of uranium that is fissile.
Proponents of the technology often cite a whole host of reasons that makes thorium a more attractive fuel source than uranium. Some of the major advantages include:
- Thorium is a lighter than uranium and leaves behind less radioactive waste. Also, the waste would only remain radioactive for 500 years whereas Uranium byproducts have toxic properties that last upwards of 10,000 years.
- Unlike Uranium-fueled power plants, the thorium fission processes don't produce plutonium, a byproduct that has raised nuclear weapon proliferation concerns in the past.
- Most scientific estimates suggest that Thorium is three to four times more abundant than uranium.
But more importantly, the fact that thorium undergoes an entirely different fuel cycle lends itself to nuclear reactor designs that are also safer.
One such system, known as Accelerator Driven System, does away with uranium and plutonium altogether. Originally proposed by Nobel laureate Carlos Rubbia, ADS initiates the fission process by using a particle accelerator that shoots protons at a lead target to cause it to release neutrons as a way of kick-starting the thorium fuel cycle.
This kind of "sub-critical" reactor design, which differs from other reactors in that it requires neutrons from an outside source, essentially allows for an off-switch. Turn off the particle accelerator and the fission process is brought to a whimpering halt.
"If the particle beam is switched off, it is impossible for the fuel to enter a chain reaction and cause a meltdown, like that at Chernobyl," said Reza Hashemi-Nezhad, a physicist at the University of Sydney who is developing a prototype that may eventually be scaled up.
The CERN European Organisation for Nuclear Research estimates that an ADS reactor system would be at least three times cheaper than coal and 4.8 times cheaper than natural gas, due to the long life of the reactor.
Still, some environmental groups, while acknowledging the benefits of thorium-based nuclear technology, advocated steering clear of nukes altogether and instead focusing on further developing renewable energy technologies of the non-radioactive variety.
According to a report on the Australian Broadcasting Corporation's website:
Australian Conservation Foundation president Ian Low says although thorium has advantages he says using thorium is like being run over by a diesel train rather than a steam train.
"It's true that the period of danger of radioactive waste from thorium reactors, if the design can be worked up and proven, would be hundreds of years rather than hundreds of thousands of years," he said.
"But we're still talking about very long lifetimes."
Mr Lowe says nuclear power is still a long way from becoming clean and green, even with thorium.
"If we spent as much as we spend every year on nuclear research on renewable energy, we wouldn't be talking about this issue," he said.
"We'd have had enough solar and wind and other forms of renewable energy to give us clean energy solutions for the entire future."
Video explaining thorium nuclear technology:
Related on SmartPlanet:
- China to develop a greener nuclear reactor
- France's latest green idea: underwater nuclear reactors
- Japanese nuclear plant damaged in earthquake, needs coolant
- Japan’s partial meltdowns and the future of nuclear power in the U.S.
Mar 13, 2011
Some science and politics are getting mixed up here and meltdown is far from the most important issue. With nuclear power, whether based upon Plutonium/Uranium or Thorium, we are creating a nuclear reaction and then putting in measures to control that reaction. If an accident occurs, without intervention, the results are largely unpredictable and entirely catastophic. It is impossible to engineer a totally fail safe nuclear reator. We must learn to decide what are acceptable risks. A fire in a spent fuel pond or around a containment vessel, a hydrogen explosion, a loss of cooling water, either in the reactor or the spent fuel ponds, all of which have happened, will result in a leak to the environment of dangerous radio-nuclides. Only those who ignore the evidence or use discredited data on dose rates say that the death toll from Chernobyl was any less than several thousands. Dr Chris Busby has stated that the death toll from Fukushima may be 400,000 over the next fifty years. Military and Civil uses of nuclear power are very different. The requirement for defence of the realm does override some of the safety considerations. The primary reason for using nuclear for the military is i) the length of time between refuelling and ii) the ability to work underwater without surfacing. When those imperatives do not apply, the military use other fuels. As for Throium, my firm belief is that, even if Thorium reactors were practical and economic, and even if the technical issues with running them could be resolved (fuel cycles are shorter in Th than U/Pu reactors), the fact that they don't generate Plutonium means that they will not be acceptable to many states, probably including the UK (although never stated publicly), which need Plutonium to build and maintain thermo-nuclear devices, such as Trident. If the UK cannot get Plutonium for Trident it will have to rely on other states, presumably the USA or maybe France to provide it. The civil and military uses of nuclear power cannot be divorced. It is practical to produce an atomic bomb just by using fissile uranium. The equipment to isolate fissile uranium from natural uranium is used to generate nuclear fuel. Nuclear fuel needs to be around 95% fissile uranium and weapons grade about 99.5% Plutonium is only necessary if you wish to produce a thermo-nuclear device, which uses a conventional nuclear chain reaction to seed nuclear fusion. These devices are much smaller than an atomic bomb and are used in missile systems such as Trident. If you are conserned about nuclear non-proliferation, the best way is not to have any nuclear power. A sound inspection regime (if that can ever be delivered) is always going to be second best.
No blame for Adm. Rickover (rip). The navy needed compact, high-power reactors, and the only way known to get them was to use highly-enriched Uranium or Plutonium for fuel. Why else would a nuclear powered sub or aircraft carrier not need refueling for decades? Also, the US Navy has an exemplary nuclear safety record, thanks in no small part to Adm. Rickover. Commercial power needs are different, and Thorium reactors should be part of the design because they do not encourage proliferation.
There may be massive amounts of lightning strikes around the world daily but what percentage of those are over the open ocean that covers over 70% of the planet? It would be difficult to collect those.
My original rerply, which shows up as #30 was terminated mid-stream by the automatic requirement to log in again. Sorry for the repeat. I thought #30 was lost with the need to sign in again.
Thanks, hates idiots, I think there's one thing you may, or may not, be missing. With lightning farming there's not necessarily any storage problem at all. I only suggested storing power at the final usage site for local grid outages, which we have now leaving us with no electricity. As a resident of Houston, I'm all too familiar with this due to hurricanes and tropical storms. The beauty of lightning farming is that, due to the massive number of strikes 24 hours per day around the world
Thanks, Hates Idiots, I think there may, or may not, be one possibility folks are missing about lightning farming: One great advantage of lightning farming is the non-necessity of power storage. I only suggested storing power in capacitors at the final usage site in case of local grid loss due to storms etc physically damaging the local grid. Otherwise, I see no need for storage capacity at all. With a high capacity worldwide grid, electric power harnessed from lightning can be distrbuted worldwide. Due to the huge number of lightning strikes in many areas around the world 24 hours per day, every day of the year, and the ridiculous amount of energy in each of these strikes, it seems to me that the flow of electic power into the grid would be continuous, thereby releving any need for any storage. Again, a relatively small amount of storage at each final usage site might be a good idea, but I think not a real necessity. So, if what I'm suggesting makes any real world sense at all, we're left with a continuous, permanent, 100% non-poluting, never ending source of completely natural energy that can provide far more power to all people worldwide than the greatest energy hog in the U.S., the largest energy hog in the world. Think of what this would do to help bring the entire world up to "modern" standards of lifestyle and individual wealth and health.
http://www.npr.org/2011/03/16/134341220/midsize-solar-installations-grow-at-light-speed #22, 23, 24, I think that you'll find the above article relevant and interesting
The electric storage capability needed for your idea is what the solar industry has failed to deal with. If large-scale energy storage could be developed it could solve much of the worlds power needs between solar and harvesting lightning as you suggest. Going back to my dream car. If they can make the affordable lightweight storage capacity to drive an electric car on the longest night of the year in winter then they could scale it up for the bigger needs. No one has set that goal for the car industry. A 1 percent improvement in something is treated like a major milestone. No one is trying to make the leap.
LIGHTNING FARMING: I?ve been researching lightning. I?m not an electrical engineer but I have, and continue to have, a considerable amount of hands on industrial electrical experience for over 20 years. Researching the internet, I?ve found that the number of lightning strikes that reach the ground around the world every single day is astounding. The amount of electrical power from this huge number of strikes is near ridiculous. I?m thinking in terms of a worldwide electrical grid in order to bring very large amounts of power to all peoples of the world. One of the greatest acts of true democracy I can think of. If all industrialized nations are clearly out in front on this it will not only be a great boon to mankind, a great lifting from poverty, and a project that will make us all look (and actually be) a true friend of all the world. I think of the first three words of our constitution: ?We the PEOPLE?, and I think not only of us, but of ALL people. My basic proposition is: A very large number of lightning farms spread around the world everywhere there are large numbers of strikes, with very many tall radio/TV type towers with lightning rods, at each location. An extremely high capacity worldwide electrical grid. The ability to send to ground any power that?s in excess of the grid?s ability to handle to protect the grid. Upon delivery of the lightning?s static electricity to each final destination, collect and store a few days of excess power (in case of local grid outages due to storms, etc.). Store the energy in capacitors, not batteries. Discharge excess power to ground to protect the individual capacitors. Rectify the static electricity into standard AC currents for normal use with existing apparatus?. No other changes required. And all this power is 100% permanently free and totally non-polluting, as well as ending all people?s dependence on foreign oil, coal, natural gas, etc. Think of what it will do to the west?s position when we don?t need foreign oil ever again. Think what this will do to end poverty and provide tremendous opportunity to the world?s citizens. I urge a very serious, immediate and rapid study of such an idea with and by electrical engineers the world over. No politics or ideology, just engineering. If it?s feasible, let?s start building it tomorrow, not years or decades away. If we could gear up for World War II in about a year, the industrial world can do this rather quickly as well. All comments looked for and welcomed!!!
A reactor you can switch off and walk away from is just soooo attractive a proposition. One that needs a backup power supply to keep it from blowing up and poisoning a large area of the planet is a seriously bad idea. This time it was an earthquake and a tsunami that killed the backup power. Next time it could be a terrorist with little more than pair of pliers - or a few IEDs. Am I the only person thinking this through?
If they made a minimal solar installation mandatory on all new housing, say to charge batteries for exterior lighting, they could feed the excess power back to the grid. Add 20,000 homes a year in Florida and you just reduced the demand on central power stations on those hot sunny days when the AC is running in every building. I have to disagree on the drivers of the cost of Cape Wind. They were projecting the project costs in the billions before a single lawsuit was proposed. The majority of the projects cost increases have been driven by design changes driven by design flaws pointed out by critics. One example. They added millions to the cost of the project because the original proposal lacked simple navigation lights to mark the turbines for ships and planes as required by the Coast Guard and FAA.
@riverat1, well said, good points. The best solution to the distribution of power generation probably resides somewhere in between 'one per country' and 'one per household', as economies of scale come into play, especially when it comes to maintenance. My feeling is that the cost of PV cells is still too high, so far. It may not be possible to get high efficiency, low cost of production, environmentally sound PV cells. I would love to be proved wrong, though. It's sad that projects like Cape Wind here in Mass. had their costs driven up by lawsuits, to the point that the electricity produced now will not be competitive with coal/gas generated power. We need to make the best use of the best technologies, and we need to work together to find and implement them.
@steve, I wasn't proposing building one giant solar cell array, just pointing out that the total area of solar cells needed isn't that outrageous a number. Personally I think a widely distributed system of many separate panels will be more robust in general than a large concentrated array for photovoltaic solar energy. Those smaller widely distributed (like on roof tops) arrays won't require all that much in the way of newly built facility and transmission. Also, just to head off other potential objections, I'm not proposing that all of our power be derived from photovoltaic either. Wind, solar thermal and other technologies again improve the robustness of the electrical system.
A small, efficient and affordable solar panel is the goal. When I can drive an affordable Prius on a sunny day using just a solar panel built into the roof than solar will be considered mature. To do this conversion rates need to be north of 80 percent. I also want to drive that Prius all night at 50 mph during the winter. Then the power storage technology will be considered mature. Once those 2 goals are met you will change the planet. When a solar charged power cell in a car can operate that car overnight in the cold on the longest night of the year, we will have technology that will allow a small solar power plant to provide power to a small town in Colorado on that same night. Until then we need to look for alternate energy sources to bridge the gap while the technology catches up. The sad part is, no one in the solar or automotive industries have publicly set those goals. Forgetting the energy storage issue, in the past 5 years the solar industry has been content with seeing a 5 percent improvement in the conversion rate of modern panels. At that rate of technological improvement I will not consider solar power to be mature for almost 60 years. They need to think small then scale up. How do we bridge the gap until the tech catches up?
@riverat1, two other major issues are the cost of building such a facility, and transmission. Not saying I hate the concept, just pointing out that these are significant engineering issues that must be overcome. PVs have a limited life (under 20 years), and up to 7 years to get to 100% ROI. The greater the concentration of generation, and the longer the average distance from generation to use, the greater the cost of the copper cables required. (Also a significant security risk, with a single point of failure, or close to it). One of the neatest combinations I've seen recently was a PV/solar heat duo, http://www.smartplanet.com/technology/video/new-spin-on-solar-hot-water-and-electricity-in-one-system/6195151/ , this seems to reduce the quantity of solar cells required by concentrating the solar energy, and then removing the excess heat (which would otherwise destroy the PV cells in short order) and then using that heat to generate yet more usable energy. Is even this technology cost-effective without subsidies? I don't know, but I like it.
#8, This statement is true only if every photon reaching earth, and every puff of wind were efficiently (with at least an 80% conversion rate) captured and utilized. Don't be ridiculous. Far more solar energy strikes the Earth in one day than the human race uses in a whole year. The Total Solar Irradiance at the Earth's surface is about 1,361 Watts/sq. meter. I've seen a calculation that at current efficiencies it would take a photovoltaic array less than 50x50 miles to provide all of the electricity for the world. The issue is storing it for use when the Sun isn't shining.
Interesting discussion. The current crisis drives this conversation. What if the plant had not been built on a sea shore where vulnerable to tsunami damage? What if, no other changes necessary, it had a gravity feed from a reservoir of coolant a bit uphill from the reactors? All the possible new types/styles of reactor are not built, on the ground, and operating. Perhaps a levee around all current plants built where vulnerable to flood might make more sense in the short run than shutting down large numbers of reactors with no plausible substitute for lost capacity.
@janitorman requiring no fuel. No power company. No oil company. No coal sales. Where is the return for the government? No fuel tax. No power tax. No oil tax. No coal tax. That is not a good thing for the politician Oh! Wait a minute! I can see clearly now, the fog is gone. After they get 80% of the homes and businesses converted to solar or wind or geo they can come in and install a couple of meters and charge you a tax on everything you are using including drying the laundry outside, you are using solar and wind power for that. Roy No one's Life, Liberty or pursuit of Happiness can be guaranteed while Congress is in session.
Solar and wind are niche power sources if you happen to live in areas with lots of sun and or wind. I happen to live in a place with limited amounts of both so neither is worth large-scale use to us. Safe and efficient nuclear, efficient meaning low waste, must be a part of the solution until solar collection and electric power storage, from both wind and solar, become more efficient to replace nuclear. By all accounts those goals are decades away so nuclear is the only non-global warming solution to fill the gap if the global warming crowd are successful in shutting off the worlds oil. To cling to the dogma of solar and wind are the only solutions shows how out of touch you are with the state of technology for both.
Such arguments tend to use facts selectively, ignoring such things as: - Geothermal power - Wave, tidal, and ocean current power - Energy efficiency (we use energy very wastefully today) If we utilized all our renewable options, we would have plenty of power. Thorium reactors do appear to be worth further research, especially the self-regulating LFTR concept. Uranium and plutonium reactors, however, should be eliminated as quickly as possible - they are simply not worth the tremendous risks they present.
Great google-talk.... the full video is worth watching. Another great google-talk is http://www.google.com/url? sa=t&source=video&cd=1&ved=0CDYQtwIwAA&url=http%3A%2F% 2Fwww.youtube.com%2Fwatch%3Fv%3DFhL5VO2NStU&ei=otZ- TZzlI8Gutwf_lYXwCA&usg=AFQjCNENnHIpnRraoFqYHVmr9Cbh6nR 1Qw&sig2=-dO2W3tH3unJnAWwXRzsxQ or, do a google-video search for "Should Google go Nuclear" the first result is what you want (or second, they're both the same). Why worry about fission and thorium when we already have fusion with boron?
janitorman: You don't seem to have a technical grasp on the problem at all! Solar energy isn't that much of a solution because even if you could capture 100% of the energy of the sun's rays (scientifically impossible, since any form of energy conversion creates losses), there's just not that much wattage of power per square foot of sunshine! That's why the solar power "farms" you may have seen out in the desert have huge arrays of panels taking up a LARGE amount of space, and even then, they all have to be turned and tilted to follow the sun for the most efficient results. Even after constructing all of that, those plants don't output anywhere NEAR as much electricity as a nuclear plant can. A lot of progress has been made with wind generation lately, but it, too, has a lot of limitations. There's not always a consistent wind blowing in the places that need electricity, and you incur BIG losses if you have to move that power down miles and miles of wire to get it from a wind farm to the customer.
@janitorman, solar power is great if you have the right place to put it. The reality is, you need a fairly sunny environment to generate solar power and, as important, you need a way to efficiently store that power for night and the literal rainy day. Solar power is still not cost effective as yet. I believe we will get there in time, but right now, without the tax credits and the like solar would pretty much be dead for the individual homes. Consider a power generating company. Unless they also own the raw fuel source they have a good incentive to switch to alternate sources. If it made economic sense for them to install a power system on every house they would do it. They would own the power generator, or lease it out (tax and liability issues determine some things) and collect a check as usual. Sadly, it does not yet make sense for them. In some cases it works for small private companies that don't have obligations to states, cities and unions that they must deal with. There are companies that now do what i mentioned above, provided you have a large enough electric bill to make it worth their while. As for the use of wind, again that requires the appropriate situation. It is even harder to find a local where it is practical and then you need to have the cooperation of your neighbors since the wind generators tend to make noise, not to mention in a small enough lot your tower might be shading their solar panels. :-)
Thank Hyman Rickover. Back in time when there was discussion of using thorium reactors, Rickover decided he wanted the fissile material for bombs. As a result, plutonium reactors were built.
There are a number of designs, some from as early as the 1960's, which are inherently far safer than most plants currently in operation. Several of these offer an effectively unlimited safety period in case of loss of coolant or loss of power to operate the system. Most notably, the Integral Fast Reactor, which requires no power and no human intervention to prevent a core meltdown. This is a design that has been built and tested by shutting off the water and seeing what happened! It safely stabilized, as designed. And this is only 1 design. All we need know are governments willing to build them and require their power companies to implement them regardless of any increase in cost (and in at least 1 design, the cost is actually less than current designs).
Mr. Lowe is as typically misinformed as most anti-nuclear luddites. The design of thorium reactors has been proven and in use by Canada for decades, he exaggerates the half-lives of radioactive waste materials by a magnitude, and fails to realize that the money spent on alternative energy sources far exceeds (by a factor of 20x) what has been spent on nuclear research in the past 50 years. He states, ?We?d have had enough solar and wind and other forms of renewable energy to give us clean energy solutions for the entire future.? This statement is true only if every photon reaching earth, and every puff of wind were efficiently (with at least an 80% conversion rate) captured and utilized. Our best efforts to date can only harness a minute fraction of that energy, and very inefficiently, to boot...no more that 5-17% of what little energy is captured results in usable power, depending on the technology used.
Why are we discussing this issue at all, as Ian Lowe says, we HAVE the ability to convert completely to renewable energy such as solar and wind. Here's why: someone won't make MONEY off of it once it's built! You'll have your OWN power source right at your house, requiring no fuel. No power company. No oil company. No coal sales. Eight billion on nuclear, Mr. O'bama? Why not 8 billion on home solar and wind. That would pretty much provide all the power we'd need for the foreseeable future... for FREE, no fuel costs!
The problem is they need to pin down the technology to do it as safely as possible. The goal should be a design like the mentioned quantum nucleonic reactor where the reactors static state is harmless. To rely on artificial mechanical cooling of any kind when static makes all current reactor designs inherently unsafe. If the unit requires cooling when offline, not producing power, you are wasting energy heating something you are not using. Artificial cooling when offline reduces the overall efficiency of the system because you are using power generated by another source when you are putting out no power. To clear it up for people, I am not talking perpetual motion here. What I am saying is the system would run only as long as the fuel lasts, but the only outside power used by an efficient design should be at startup, shutdown and to support 24/7 monitoring even when not generating power.
If all the money wasted on nuclear power generation had been put into broadcast power from space ( Issac Asimov wrote that we had the technology to do it in 1990 ) we wouldn't be worrying about meltdowns or what to do with the most toxic waste in existence!
@FuzzyIce: Actually, the gasoline in your car's tank is more hazardous due to fire than explosion - it is extremely unlikely that a car's gas tank could explode, despite what the movies tell us. The air/fuel mixture inside the tank is too rich to burn, much less explode. (Similarly, the mixture inside a diesel fuel tank is far too lean.)
@ pauc 1: I agree one hundred percent. Gasoline is a powerful explosive and we commute daily in our cars carrying a 'potential bomb' in our cars. Technology is all about finding solutions for diminishing the risks of artificial devices made by man to produce us some good. Unlike the reactor that melted in Chernobyl, the Japanese cores are contained by steel envelopes that have more strength than concrete. And up to this point, they had stopped the reactions so going to the 'Syndrome of China' scenario is very hard, unless another big quake hit them again. We can't give up technology just because of the risks... Bigger risk is do nothing and wait for human kind to return burning logs for heat.
The hysterical response to anything containing the word "nuclear" in the name has hindered/prevented process improvements because there was no potential for sales or profits. We need to find a way to change the name. The medical community changed "Nuclear Magnetic Resonance" to "Magnetic Resonance Imaging" because of the hype effect.
The Air Force had been working on quantum nucleonic reactors for Predator drones. This obtains energy by using X-rays to encourage particles in the nuclei of radioactive hafnium-178 to jump down several energy levels, liberating energy in the form of gamma rays. If successful, the concept would have given the world a portable power source that would be scalable. With reactors ranging in size from a microwave oven to a cargo box trailer it could be used to power a drone or the cooling system of a a full sized nuclear reactor. As far as safety goes, the unit has an off switch. Turn off the x-rays and the gamma rays disappear. No heavy cooling needed. There were rumors of test flights of a quantum powered Predator drone out of Wright Patterson in Ohio, but the Air Force never confirmed or denied the rumors.
You bring up an excellent point. I would ask you to do a Google for "lightning". Choose the Wikepedia article. There you'll find a map of the world showing where the most frequent strikes take place. There appear to me to be a great many over land, and given the power of each average strike I get the firm impression that those are far more than enough.
I don't think storage is any problem at all. As I mentioned, ALL the storage would take place at the end user's end. If every user of electricity had their own capacitor on site (such as in their basement) then there's no need for any massive storage capacity anywhere. Store only what you personally need (with a decent fudge factor for grid outages, etc.).
Sorry but solar and wind are still too expensive to be a realistic replacement for coal. In addition to this they can not provide for the base power demands without a storage technology. Again existing storage technologies are too expensive. I would love to see solar and wind solve our energy problems but the current and near project state of the technology makes them poor choice for the answer. I have been waiting 40 year to see them become affordable and it hasn't. I hope it will not take another 40 year for to actually happens. In the mean time we need to develop the thorium nuclear cycle which offers, as I see it the best chance of beating out coal. It is a demonstrated technology and $8 billion should be easily enough to bring the technology to commercial viability. If you have researched this topic carefully you need to!!!