December 4th, 2006, 08:40 AM
As we are moving towards a peak-production of fossil fuels, I was wondering whether there will ever be a peak-production of nuclear fission energy. Is fission really an unlimited source of energy, as is often claimed by policy-makers, or does it also depend on a limited resource (uranium)? Or is this limited resource so abundent that we wont reach peak production within several centuries?
That's an interesting point to bring up. I really think that there is as much uranium as there was oil, maybe even more. And nuclear is more efficient than our ways of burning fossil fuels, so I think that the uranium supplies are going to last a while. At least as long as we need to finalize and perfect our wind and solar technology, as well as hydrogen and fuel cell technology. I think of nuclear as a transitional power source, a energy source that will bring us from dirty fossil fuels to clean renewable fuels.
I hope so :wink:
I found an article about the subject.
Here's their conclusion:
Looks like we don't have to worry about this one :wink: Because high-quality uranium is still very easy to find, and demand is still low, there hasn't been much exploration of uranium resources. But even high-quality sources are probably very abundant, and if they some day run out there are 'nearly infinite' sources (according to the article) at the sea-bottom and the upper earth crust. They're expensive to extract, but if we really need it we can always get them.In summary, the actual recoverable uranium supply is likely to be enough to last several hundred (up to 1000) years, even using standard reactors. With breeders, it is essentially infinite. Hundreds of thousands of years is certainly enough time to develop fusion power, or renewable sources that can meet all our power needs.
I think that's a bad way of looking at it. if you have a catastrophic failure in a coal burning power plant such as... oh, I don't know... the boiler explodes, what's the worst possible outcome? Now run the same scenario with a nuclear plant...That's an interesting point to bring up. I really think that there is as much uranium as there was oil, maybe even more. And nuclear is more efficient than our ways of burning fossil fuels, so I think that the uranium supplies are going to last a while. At least as long as we need to finalize and perfect our wind and solar technology, as well as hydrogen and fuel cell technology. I think of nuclear as a transitional power source, a energy source that will bring us from dirty fossil fuels to clean renewable fuels.
Yes, fission power is more efficient - in terms of cost of operation to power generated. However, the steam it generates still mills the old ass turbines invented in the 1800's, and power is still distributed over the cluster-f*k we call a 'power grid' (implement around the same time).
There's nothing efficient about nuclear power as far as you're concerned. In the end, you might save the power company a few pennies per kilowatt generated (and stuff a few extra pockets). Will you see the difference? heh...
Yes, fission power has its place. But it definitely isn't on the surface of this planet and/or as a stepping stone to other forms of energy generation.
To answer your question. Again, it all boils down to the cost.As we are moving towards a peak-production of fossil fuels, I was wondering whether there will ever be a peak-production of nuclear fission energy. Is fission really an unlimited source of energy, as is often claimed by policy-makers, or does it also depend on a limited resource (uranium)? Or is this limited resource so abundent that we wont reach peak production within several centuries?
As our refining process advance, our stockpiles will rise, prices will drop. Likewise, demand will soon follow, stockpiles will drop, prices will rise and so begins the next cycle... If this continues, I'm sure at some point we'll develop a refining process to re-process every known resource on the planet, and next processing cycle might be more cost efficient if done off-planet (ie: asteroid mining).
Though we know this number is finite, the time it will take us to reach this point is unknown. In other words; who cares. Our energy resources are very rarely chosen by their abundance.
Sorry to derail the topic, but seriously man. In my opinion, you're asking the wrong questions...
Tnx for the info Spirytus, but I don't think you need to charge in so roughly :wink: Most of us only have a layman's understanding of this subject, so yea we may be asking the wrong questions.
Actually I don't know how uranium ore is formed or deposited in the first place. Is this a process that leads to concentration of uranium ore in a few area's (like oil), or does every country have access to it? Will there ever be powerful 'uranium states' as there are oil states nowadays?
With modern reactor designs like pebble-bed reactors it is physically impossible for the reactor to melt down.Originally Posted by spirytus
He's just another person who over-exaggerates the risk and environment implications. Not only is nuclear waste disposed of properly (and with no environmental problems so far during the process), but nuclear meltdowns have been at an all time LOW since fission began being used.
Honestly I can't honestly think of a way to properly refute such...such....inane comments!
especially this one:
Wrong. The refining process hasn't improved very much within the last 10 or so years. Furthermore, as the population increases and more people start driving, more and more oil will be required. A simple change in a refining process can't produce more oil than what is there. Lets say we've used 50% of our oil so far. The next 50% will be used even faster than the last one. If there is 40% left, the next 30% will be used faster, and so on and so forth.
It's generally _impossible_ to improve a refining method to refine what isn't there. Furthermore, refining methods normally reduce cost and improve production slightly, it does *NOT* increase how much oil is remaining. We'll still run out.
That is such an idealistic claim not even *I* would make it. Asteroid mining would produce (at best) heavier elements like iron and such. There are no usable fuels in asteroids that I know of. SO what the deuce are you talking about?If this continues, I'm sure at some point we'll develop a refining process to re-process every known resource on the planet, and next processing cycle might be more cost efficient if done off-planet (ie: asteroid mining).
He's just another person who over-exaggerates the risk and environment implications... nuclear meltdowns have been at an all time LOW...
Simply because the cost of research/new-drilling-operations/prospecting didn't warrant it. As soon as it becomes economically feasible -- or in other words; profitable with limited risk to investment -- it will happened.The refining process hasn't improved very much within the last 10 or so years.
Look at the history of other resource such as gold. It hit many such 'peaks', until a new mining technique was developed, new deposits discovered, new refining methods implemented. I'm sure some bloke back in the 16th century stated that within 50 years all deposits of gold on earth will run dry. Likewise, I'm sure some poor schmuck believed it, and spent his fortune buying this stuff at a 'premium'.
Anyway, given the right incentive ( aka $$$), anything is possible.
Yes, fossil resources are finite -- as is every other resource on this planet (just as important).
Most of us here would generally agree that oil's importance on modern civilization is greatly exaggerated. We're told that existence without it is the end of the world as we know, forsaking oil means forsaking our sanctuary of comfort. The entire world is hooked on it like a junkie on coke - which makes this stuff even more easier to sell.
When we're told "fossil-fuel deposits will be depleted within 50 years" we cry out in unison "God noo!", added with more cries of "Someone please save us!" and in fine print: "At whatever the cost".
Exponential growth, exponential depletion? Nope, sorry. As demand will rise, so will the price. We'll never run out of oil for the same reason we will never travel faster than light. Supply vs demand."lets say we've used 50% of our oil so far. The next 50% will be used even faster than the last one. If there is 40% left, the next 30% will be used faster, and so on and so forth.
Given the fact that gasoline is still cheeper than drinking water we've got a ways to go yet before this even becomes a 'real' issue.
Who said we'll be bringing that stuff down to Earth? Smelting steel in space, is far superior to smelting this stuff here. Benefits include 0 g environment, vacuum smelting process, space-construction manufacturing. Get a quote from NASA for your 20x20m solid steel plate that you require for your mini-borg-cube you want shot into orbit... Also try the Russian space agency, I hear they give 20% discounts. If that doesn't work out, come back to me 8)That is such an idealistic claim not even *I* would make it. Asteroid mining would produce (at best) heavier elements like iron and such. There are no usable fuels in asteroids that I know of. SO what the deuce are you talking about?
Anyway, I'm just messing around... Trying to make my case; If it ever becomes profitable, it will be done.
Now that's interesting.With modern reactor designs like pebble-bed reactors it is physically impossible for the reactor to melt down.
I love Wiki, here's a link for anyone interested:
http://en.wikipedia.org/wiki/Pebble_bed_reactor
I'll do some more research on this subject, looks promising but it does have safety concerns associated.
It is also worth mentioning that no system in the history human engineering is failsafe. It's a human factor that will always remain prevalent in any system we design. Given x amount of time, the condition for failure will be met - no matter how remote the possibility. It's a calculated risk, just like anything else in our lives.
Problem with nuclear power is, it has to be perfect. You think this is?
Side note; If we compiled a list of "famous last words", I wonder how many instances of "impossible" we'd find? 8)
Just keeping you on your toes :wink: nothing wrong with a good debate...Tnx for the info Spirytus, but I don't think you need to charge in so roughly Wink Most of us only have a layman's understanding of this subject, so yea we may be asking the wrong questions.
Actually I don't know how uranium ore is formed or deposited in the first place. Is this a process that leads to concentration of uranium ore in a few area's (like oil), or does every country have access to it? Will there ever be powerful 'uranium states' as there are oil states nowadays?
Here's a quick quote (yep - wiki http://en.wikipedia.org/wiki/Uranium )
Interesting read.Uranium is distributed worldwide. The world's largest single uranium deposit is located at the Olympic Dam Mine in South Australia.
Australia has the world's largest uranium reserves — 40 percent of the planet's known supply....
In spite of Australia's huge reserves, Canada remains the largest exporter of uranium ore [what's that aboot eh?], with mines located in the Athabasca Basin in northern Saskatchewan. Cameco, the world’s largest, low-cost uranium producer accounting for 18% of the world’s uranium production, operates three mines in the area.
Which brings me to the last link of the night:
http://www.albinoblacksheep.com/flash/end.php
WTF ?
I would much rather live next to a properly designed nuclear power plant than next to a coal power plant. Coal plants send far more radioactive waste into the air than nuclear plants - in addition to all the chemically toxic smog that they spew. If you consider nuclear plants dangerously unsafe, you should be really outraged about coal plants.
Saying that we shouldn't use nuclear power because of Chernobyl is akin saying that we shouldn't drive cars because the Chevrolet Corvair was an unsafe car.
According to the laws of physics was we understand them, it is physically impossible for a pebble-bed reactor to melt down.It is also worth mentioning that no system in the history human engineering is failsafe. It's a human factor that will always remain prevalent in any system we design. Given x amount of time, the condition for failure will be met - no matter how remote the possibility.
Are there possible dangers associated with a pebble bed reactor? Of course. A steam valve could get struck closed and someone could be killed in a steam explosion. The plant could catch fire. A truck hauling radioactive waste away from the plant might crash. Someone might trip and break their neck walking through the plant's parking lot. But there are no systems anywhere that are perfectly safe. To put it in persective, if you live next to a nuclear plant you are about 40000 times more likely to be killed in a car crash than by radiation from the plant.
Why would nuclear power have to be perfect? We already use coal plants that aren't perfect, so why are you suddenly insisting that nuclear plants be perfect?Problem with nuclear power is, it has to be perfect. You think this is?
Suppose a nuclear reactor provides safe, clean energy to a city for 10 year. In the 11th year there's a fire at the plant and some radioactive material escapes into the atmosphere, which increases the odds of getting cancer for every person living in the city by 0.00003%. Perfect? No. Acceptable? Hell yes.
Here's a flaw in your reasoning: Coal isn't perfect, lets not use it. Fire isn't perfect, lets not use it. Solar energy isn't perfect, lets not use it.
So basically we have to sit around with nothing until we manage to make something perfect? How can we do that when we have nothing?
Wow...blatant ignorance of nuclear reactors...chernobyl was one of the earlier reactors that had a serious design flaw. In case you were smart enough to research the incident, only one other reactor that i know of exists with the same design today. And it's due to be upgraded.Rolling Eyes hypothetical question; would you feel comfortable raising your family within 100 miles of chernobyl given the chance?
So much for your hypothetical situation. And, psst, I live within 100 miles of a nuclear reactor. You fail.
Right...it's been profitable ever since oil refining started. The cheaper it is to refine the oil, the less cash monies spent on getting it. The COST of research, drilling operations, etc, is already inanely high. Many oil wells are too small to drill to be even profitable, and because of this they AREN'T drilled at all.Simply because the cost of research/new-drilling-operations/prospecting didn't warrant it. As soon as it becomes economically feasible -- or in other words; profitable with limited risk to investment -- it will happened.
...must...resist...urge...to ad-hom....GRR...Look at the history of other resource such as gold. It hit many such 'peaks', until a new mining technique was developed, new deposits discovered, new refining methods implemented.
Resources such as gold are even less common today than they were years ago. What new mining technique? What new deposits? New deposits were being discovered ALL THE TIME throughout history. Hell, people discover new deposits today simply by tripping on a gold nugget.
As for new refining methods...are you insane? The refining methods mean little or nothing for gold, only how much impurities are tossed out (which, by the way, ends up making the original product even smaller). Refining doesn't make MORE, it makes LESS impurities, more of a by-product, and less of the original product.
Also, glancing at wiki, the refining process hasn't changed in over 50 years. Whee.
And a loser is you: Gold is still fairly abundant today. Although major mines haven't been located for a few years.I'm sure some bloke back in the 16th century stated that within 50 years all deposits of gold on earth will run dry. Likewise, I'm sure some poor schmuck believed it, and spent his fortune buying this stuff at a 'premium'.
in antiquity, the stuff was pretty much LYING ON THE GROUND. Now days people normally have to dig fairly deep, unless they find it in rivers that wash it to the surface.Gold in antiquity was relatively easy to obtain geologically; however, 75% of all gold ever produced has been extracted since 1910.[2] It has been estimated that all the gold in the world that has ever been refined would form a single cube 20 m (66 ft) on a side (8000 m³).
People have offered millions of dollars for someone to prove evolution possible. Thus far those creationists have rejected all evidence, I guess it isn't possible to prove someone that hard-headed wrong with the prospect of cash after all.Anyway, given the right incentive ( aka $$$), anything is possible.
And refining processes don't increase the supply. Woo-hoo!Yes, fossil resources are finite -- as is every other resource on this planet (just as important).
Oil is the reason you have a computer, oil is how you drive, oil is how your bike is made, oil is how your chair is made, oil is basically the foundation of every factory, service, energy production, everything known to man.Most of us here would generally agree that oil's importance on modern civilization is greatly exaggerated.
It isn't exaggerated, it's a frightening UNDERSTATEMENT.
Wrong. Everything uses it. Factories, the people that build the factories, the people that make the stuff that builds the factories, and so on and so forth. Without oil, the process becomes MUCH harder, sometimes impossible, and takes fifty times as long. The world is quite literally hooked on how fast and easy it makes everything. Once it "runs out," most of the economy will go belly up, since most of it depends 100% on oil.We're told that existence without it is the end of the world as we know, forsaking oil means forsaking our sanctuary of comfort. The entire world is hooked on it like a junkie on coke - which makes this stuff even more easier to sell.
This isn't some trickery, this is a cold hard fact.
I highly doubt within 50 years. Oil will just become continually scarce, and thus cost more to mine, so prices will rise, demand will rise, etc. Unfortunately, however, you just described the mindless publics reaction. I, on the other hand, don't care.When we're told "fossil-fuel deposits will be depleted within 50 years" we cry out in unison "God noo!", added with more cries of "Someone please save us!" and in fine print: "At whatever the cost".
Er...what the fuck? What. The. Fuck? Are you BEGGING me to flame you? In any closed system, entropy, and in this case Exponential depletion, will be a reality. You said yourself oil is finite, so how can exponential depletion not be true? Your logic is about as rational as a retarded child running after a ball into the street while the street light is green during rush our!Exponential growth, exponential depletion? Nope, sorry. As demand will rise, so will the price. We'll never run out of oil for the same reason we will never travel faster than light. Supply vs demand.
What. The. Fuck.?! I don't know what world you live in, but if cars ran on drinking water we'd be sitting freaking pretty. Unless I misunderstood the term "drinking water," and you mean something more utterly stupid like that $5 a gallon purified bullshit that nobody buys.Given the fact that gasoline is still cheeper than drinking water we've got a ways to go yet before this even becomes a 'real' issue.
Except...I get it for $2 a gallon, and gas prices are $2.50+. Woot!
Yeah...sure..."benefits". Guess how much steel you'd have to smelt before it becomes profitable to even dream of coming back? Guess how large your ship would have to be, in order to HAUL that much? Fuel requirements, distance, etc, is off the charts. And you, sir, are off your rocker. It's LESS than profitable. So much so it's largely INSANE. Any shipment from space back to earth tends to drain money, not replace it.Who said we'll be bringing that stuff down to Earth? Smelting steel in space, is far superior to smelting this stuff here. Benefits include 0 g environment, vacuum smelting process, space-construction manufacturing. Get a quote from NASA for your 20x20m solid steel plate that you require for your mini-borg-cube you want shot into orbit... Also try the Russian space agency, I hear they give 20% discounts. If that doesn't work out, come back to me Cool
The only way that's feasible? If we were to live out in space. Woo.
sure it'll be profitable. If we make an engine that runs on nuclear fission capable of breaking earths gravity, going a lot of miles to the asteroid belt, "mining" the crap, going back to the moon, refining it, sending it to earth, and making a profit.Anyway, I'm just messing around... Trying to make my case; If it ever becomes profitable, it will be done.
That's about as likely to happen as I am to give birth to twin rino's that breathe fire.
I have following perspecive to tell about that we should look at all the avalilable resorces .
The critical question is "When is the date of the maximum daily amount of world oil production--the peak?" After that oil will be an irreversibly declining resource facing an increasing demand which cannot be met. The world passed its peak of rate of oil discoveries in the 1960s, but there is a lag time from discovery to full production. Although estimates differ slightly, it seems clear that the peak of world oil production will be reached at least by 2020, and possibly within the next decade (Campbell 1997; Campbell & Laherrere 1998; Ivanhoe 1995).
One statistic points up the need to think about alternative energy sources; the world now uses about 26 billion barrels of oil a year, and in new field discoveries we are finding less than 5.5 billion barrels annually. The world is going out of the oil business. With the many good things which oil now does for us, what will happen when we no longer have it? What are the possible alternatives to oil? Can any one of them or all combined really fill the gap left by the depletion of oil?
Alternative energy sources can be divided into nonrenewable and renewable.
Alternative Energy Sources
Nonrenewable
Renewable
Oil sands, heavy oil
Wood/other biomass
Coal
Hydropower
Shale oil
Solar energy
Gas hydrates
Wind energy
Nuclear fission
Wave energy
Geothermal
Tidal power
Fusion
Ocean thermal energy conversion
Need For Careful Analysis
There is much casual popular thought that energy sources are easily interchangeable, with little examination of the facts. For example, who mentions energy density? Solar energy is a very low-density energy, whereas gasoline is a high-density energy form. There is also the need to determine how available these alternative energy sources are under varying conditions. Wind and solar energies are intermittent and undependable.
We here briefly examine these alternative energy sources as to their advantages and limitations, and their potential to individually or collectively replace oil. We consider those alternatives closest to conventional oil (from wells), and then expand our alternative energy horizons.
Oil Sands/Heavy Oil
This oil exists in huge quantities (trillions of barrels) particularly in Alberta, Canada and Venezuela. This is true oil but in deposits which take special treatment to recover the oil. The oil sands must be mined, and then processed in various ways. Heavy oil deposits can be injected with hot water or steam. Because of these processes, the net energy recovery is considerably less than from conventional drilled wells. At present about 500,000 barrels a day is recovered from the Athabasca oil sands of Alberta. To increase this 10-fold to 5 million barrels a day would be a very large task, with severe environmental limitations. This must be put in the perspective of the 72 million barrels of oil the world now consumes daily. Other similar oil deposits have the same problems of scale and net energy recovery. In total, oil sands and heavy oil can replace conventional oil only to a small degree.
Coal
Coal is a very large energy source, but it must be mined, it is not nearly so easy to handle and transport as is oil, and it has much less energy density. For use in producing electricity in power plants (burned under boilers), it can replace oil. But converting it to a liquid fuel that might be used in motor vehicles is expensive, and doing this on a scale that could significantly replace oil in vehicle use becomes an impossibly large mining project. Coal can replace oil in some uses, but not in most. Although considerable progress has been made, coal production and burning still have environmental problems, which are of major concern. Adding to the greenhouse effect is one.
Shale Oil
The production of oil from oil shale has been attempted at various times for nearly 100 years. So far, no venture has proved successful. One problem is that there is no oil in oil shale. It is a material called kerogen. The shale has to be mined, transported, heated to about 900 degrees F, and have hydrogen added to the kerogen to make it flow. The shale pops like popcorn when heated so the resulting volume of shale after the kerogen is taken out is larger than when it was first mined. The disposal problem is large. Net energy recovery would be low at best. It also takes several barrels of water to produce one barrel of oil. The largest shale oil deposits in the world are in the Colorado Plateau, a markedly water poor region. So far shale oil is, as the saying goes: "The fuel of the future and always will be." Fleay (1995) states: "Shale oil is like a mirage that retreats as it is approached." Shale oil will not replace oil.
Gas Hydrates
These are very large deposits of natural gas which are in a solid substance composed of water molecules forming a rigid lattice of cages. Most of the cages contain a molecule of natural gas, chiefly methane. They exist as relatively thin zones interbedded with other sediments, and are known from two distinct areas--Arctic regions and at the edge of the continental shelves where there are cold bottom temperatures. So far recovery has defied Japanese and Russian engineers, and the likelihood that this energy form can be economically recovered seems remote.
Nuclear Fission
The end product of nuclear fission is electricity. How to use electricity to efficiently replace oil (gasoline, diesel, kerosene) in the more than 600 million vehicles worldwide has not yet been satisfactorily solved. There are severe limitations of the storage batteries involved. For example, a gallon of gasoline weighing about 8 pounds has the same energy as one ton of conventional lead-acid storage batteries. Fifteen gallons of gasoline in a car's tank is equal to 15 tons of storage batteries. Even if much improved storage batteries were devised, they cannot compete with gasoline or diesel fuel in energy density. Also, storage batteries become almost useless in very cold weather, storage capacity is limited, and batteries need to be replaced after a few years use, at large cost. There is no battery pack which can effectively move heavy farm machinery over miles of Midwest fields, and no electric battery system seems even remotely able to propel a Boeing 747 14 hours nonstop at 600 miles an hour from New York to Capetown (now the longest scheduled plane flight). Just the considerable additional weight to any vehicle using batteries is a severe handicap in itself. In mobile machinery, electricity is not a good replacement for oil, which is the limitation many alternative sources have where electricity is the end product.
Geothermal Energy
This is heat from the Earth. In a few places in the world there is steam or very hot water close enough to the surface so that the resource can be reached economically with a drill. The steam or hot water flashed to steam, can turn a turbine, turning a generator producing electricity. At best, because of the scarcity of such sites, geothermal energy can be only a minor contributor to world energy supplies, and the end product is electricity, the limitations of which have already been described.
Hydroelectric Power
Originally thought of as a clean, non-polluting, environmentally friendly source of energy, experience is proving otherwise. Valuable lowlands, which are usually the best farmland, are flooded. Wildlife is displaced. Where anadromous fish runs are involved as in the Columbia River system with its 30 dams, the effect on fish has been disastrous. Also, hydroelectric power, if reservoirs are involved, as is the case of most such facilities, is not a renewable energy source. All reservoirs eventually fill with sediment, which means hydroelectric power is not truly renewable. Some reservoirs have already filled, and many others are filling faster than expected. We are enjoying the best part of the life of huge dams. In a few hundred years Glen Canyon Dam and Hoover Dam will be concrete waterfalls. And, again, the end product is electricity, not a good oil replacement.
Solar Energy
This is a favorite source of future energy for many people, comforted by the thought that it is unlimited. But, quite the contrary is true. The Sun will exist for a long time, but at any given place on the Earth's surface the amount of sunlight received is limited--only so much is received. And at night, or with overcast skies, or in high latitudes where winter days are short and for months there may be no daylight at all, the sunlight received is very limited at times. Direct conversion of sunlight to electricity by solar cells is a promising field, but the amount of electricity that can be generated by that method is not great compared with demand. The conversion efficiency is low, about 12 percent with present technology.
Solar energy in quantity requires huge installations. It has been estimated that an area of 60 square miles in relatively clear central Oregon would have to be covered with solar cells in order to meet the present electric needs of that State. About 10% of the cells have to be replaced each year. But the big problem is how to store significant amounts of electricity when the Sun is not available to produce it. That problem remains unsolved. The statement that "solar energy will not make next century's electricity" is probably right. And the end product is electricity--a very limited replacement for oil.
Wind Energy
This energy source is similar to solar in that it is not dependable. Also, it is noisy, and the visual effects are not usually regarded as pleasing. The best inland windfarm sites tend to be where air funnels through passes in the hills that are also commonly flyways for birds. The bird kills have caused the Audubon Society to file suit in some areas to prevent wind energy installations. Wind can produce some electricity and be a small help in the total energy demand. But the end product is electricity, no significant replacement for oil.
Wave Energy
All sorts of installations have been tried to obtain energy from this source, but with inconsequential results. Piston arrangements moved up and down by waves, which in turn move turbines, have been tried in The Netherlands, but the project was abandoned. Waves are not dependable, and in any event the end product is electricity, and producing it in significant quantities from waves seems a remote prospect.
Tidal Power
It takes a high tide and a special configuration of the coastline, a narrow estuary that can be dammed, to be a tidal power site of value. Only about nine sites have been identified in the world. Two are in use and generate some electricity. Damming estuaries would have considerable environmental impact. The Bay of Fundy in eastern Canada has long been considered for a tidal power site, but developing it would have a negative effect on the fisheries and other sea-related economic enterprises. It would also disturb the habits of millions of birds, which use the Bay of Fundy area as part of their migration routes. Summary: Very few sites, ecologically damaging, not a significant power source. And, the end product is electricity.
Ocean Thermal energy Conversion (OTEC)
Within about 25 degrees each side of the equator the surface of the ocean is warm, and the depths are cold to the extent that there is a modest temperature differential. This can be a source of energy. Use a low boiling point fluid such as ammonia that at normal atmospheric temperature of 70 degrees Fahrenheit is a gas. Pump colder water from the deep ocean to condense the ammonia, and then let it warm up and turn to gas. The resulting gas pressure can move a turbine to turn a generator. But the plant would have to be huge and anchored in the deep open ocean subject to storms and corrosion, and the amount of water that has to be moved is enormous, as the efficiency is very low. OTEC does not appear to have much potential as a significant energy source, and the end product is electricity.
Wood And Other Biomass
Wood has long been used as a fuel, now to the extent that large areas are being deforested resulting in massive erosion in such places as the foothills of the Himalayas, and the mountains of Haiti. Wood can be converted to a liquid fuel but the net energy recovery is low, and there is not enough wood available to be able to convert it to a liquid fuel in any significant quantities.
Other biomass fuel sources have been tried. Crops such as corn are converted to alcohol. In the case of corn to ethanol, it is energy negative. It takes 71% more energy to produce ethanol than is obtained from the ethanol. Also, using grain such as corn for fuel precludes it from being used as food for humans or livestock. It is also hard on the land. In United States corn production, soil erodes some 20-times faster than soil is formed. Ethanol has less energy per volume than does gasoline, so more gasoline has to be purchased to make up the difference. Also, ethanol is not environmentally friendly, as advocates would like to believe. Pimentel (1998) states: "Ethanol produces less carbon monoxide than gasoline, but it produces just as much nitrous oxides as gasoline. In addition, ethanol adds aldehydes and alcohol to the atmosphere, all of which are carcinogenic. When all air pollutants associated with the entire ethanol system are measured, ethanol production is found to contribute to major air pollution problems." With a lower energy density than gasoline, and adding the petroleum energy used to plow, plant, cultivate, and transport the corn for ethanol production, ethanol does not save gasoline nor does it's use reduce atmospheric pollution.
A comprehensive study of converting biomass to liquid fuels by Giampietro and others (1997) concludes: "Large-scale biofuel production is not an alternative to the current use of oil, and is not even an advisable option to cover a significant fraction of it."
Fusion
Fusion involves the fusion of either of two hydrogen isotopes, deuterium or tritium. Deuterium exists in great quantities in ordinary water, and from that perspective fusion is theoretically an almost infinitely renewable energy resource. This is the holy grail of ultimate energy. Fusion is the energy that powers the Sun, and that is the problem. The temperature of the Sun ranges from about 10,000 degrees Celsius on its surface to an estimated 15 to 18 million degrees in the interior where fusion takes place. Containing such a temperature on Earth in a sustainable way and harnessing the heat to somehow produce power has so far escaped the very best scientific talent. However, even if commercial fusion were accomplished, the end product again is likely to be electricity, and not a replacement for oil.
Hydrogen And Fuel Cells
Questions are sometimes raised as to using these for fuel sources. Neither is a primary energy source. Hydrogen must be obtained by using some other energy source. Usually it is obtained by the electrolysis of water, or by breaking down natural gas (methane CH4). Hydrogen is highly explosive, and to be contained and carried in significantly usable amounts it has to be compressed to hundreds of pounds per square inch. Hydrogen is not easy to handle, and it is not a replacement for pouring 10 gallons of gasoline into an automobile tank.
Fuel cells have to be fueled, most use hydrogen or some derivative of oil. Fuel cells are not a source of energy in themselves.
Summary
Oil is a unique energy source that has no complete replacement in all its varied end uses. The British scientist Sir Crispin Tickell concludes, "...we have done remarkably little to reduce our dependence on a fuel [oil] which is a limited resource, and for which there is no comprehensive substitute in prospect." [Italics mine]
Coming to realize that oil is finite, any and all suggestions of means to replace oil are welcomed. Cheerful myths are enthusiastically embraced. These include: that there are two trillion barrels of economically recoverable oil in the Colorado Plateau oil shales; that dams and their reservoirs are a source of indefinitely renewable energy and that they are environmentally benign; that solar, wind, geothermal, and hydro-electric power can supply the electrical needs, from the Arctic to the tropics, of the Earth's nearly six billion people (likely to become at least 10 billion in the next fifty years); that coal, oil from oil sands, and biofuels can replace the 72 million barrels of oil the world now uses daily; and that somehow electricity produced from various alternative energy sources can readily provide the great mobility which oil now gives to the more than 600 million vehicles worldwide. Regrettably, none of these cheerful myths appear to be valid.
The mega-myth is the popular public placebo that "The scientists will think of something." The energy spectrum from burning wood to fusion that fuels the Sun is now well known. If there is some major exotic energy source beyond what has been listed, we have no evidence of it. What we know now is apparently what we have.
The reality appears to be that the world is rapidly running out of a resource that in many ways is irreplaceable. The result will be a great change in economies, social structures, and lifestyles. We have been living on a great fossil fuel inheritance accumulated during more than 500 million years. We will soon exhaust this capital, and we will have to go to work to try to live on current energy income. It will not be a simple easy transition.
In a remarkably perceptive book written in 1952, The Next Million Years, Charles Galton Darwin described historic changes in the human condition, calling them "revolutions." He wrote that there is one more revolution clearly in sight:
"The fifth revolution will come when we have spent the stores of coal and oil that have been accumulating in the earth during hundreds of millions of years...it is obvious that there will be a very great difference in ways of life..."
Life will go on, but in a different paradigm. Oil will be sorely missed.
That's pretty misleading; I don't know of any serious proposals to use lead-acid batteries in electric cars. Modern lithium-ion batteries have an energy density of around 700 kj/kg, which means you would "only" need about three tons of them to equal a 15 gallon tank of gas. Still not great, but you overstate the problem by a factor of 5.
And I'd like to add...That's pretty misleading; I don't know of any serious proposals to use lead-acid batteries in electric cars. Modern lithium-ion batteries have an energy density of around 700 kj/kg, which means you would "only" need about three tons of them to equal a 15 gallon tank of gas. Still not great, but you overstate the problem by a factor of 5.
Petrol engines are only about 30% efficient, electric motors are around 85-90%. Now factor that in and you start to see why electric cars are more of a reality than your 'raw energy output' figures suggest.
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