First, take cars out of the 'energy needs' equation. They need a whole argument by themselves. After that, let's see where we stand.
I don't trust this generic argument because '40% of the US energy needs' is not specific enough. It's too easy to fudge.
Then, once we have a rough estimate after the cars have been removed we can work on increasing efficiency in other areas so that total number is reduced.
Thanks THT.
Sorry, but why remove the cars, if the big push is towards electrical/fuel cell vehicles?
That pushes them even more firmly *into* that power budget.
Really, try to have some vision.
(More to the point, one needs to have a coherent energy plan in mind... mine consists of pushing for electrical/fuel cell cars, electricity as the major transmission system, with hydrogen storage/fuel cell cogenerators for peak times. Eliminates 95% of the electrical grid problems we have, allows each energy generation technology to work at peak efficiency, and uses the existing infrastructure. Voila. )
And that '40% of the US energy needs' wasn't vague at all. Add up the amount of fuel used, coal burned, etc, etc, etc, and you have our energy budget. It's all energy. *HOW* we get it is the problem, and is precisely why all energy needs should be evaluated.
But, we've all got differing opinions, and none of us is in a position to do anything about it, so it's all pretty irrelevant.
And yes, I agree... the best thing we can do is *reduce* our &*($%@# energy use. Gulp, gulp, gulp.
where are our Icelandic AI members? if anybody knows geothermal, it's them.
the Danes have a square kilometer of offshore windmills, powering 8% of their country.
if anybody knows windmills, it's folks in the Low countries, Spaniards perhaps quixotically.
recently developed inline turbine generators for microhydro allow greater power efficiency with near zero environmental impact, sharing more in common with water mill factories and stream-wheels than dams
other renewable energy info from the US Gov can be found here
most exciting of all, (though still carrying the "fossil fuel" millstone), 60 Minutes II last night had a section with Dan Rather interviewing Dean Kamen of Segway fame . When the buzz on Kamen's then-unknown invention "Ginger" was circulating, many put their wishing hats on and predicted a Stirling Engine (runs on almost anything).
Quote:
The Stirling engine, named after its designer, Robert Stirling, a 19th Century Scottish minister, is a non-polluting device that plays heat against cold to create energy. It is a closed box with two chambers, one filled with gas. Once heated from the outside, with anything from burning wood chips to charcoal, the gas expands, creating pressure. That pressure drives a piston from the hot chamber into the cool chamber.
In Kamen's design, that mechanical power achieves two goals: It creates electrical power - 300 continuous watts ? enough to run a few electrical devices - and, as a bonus, creates enough heat to distill contaminated water, making it drinkable.
Rather and Kamen tested a prototype using water from the polluted Merrimack River near Kamen?s plant. Afterwards, Rather sampled some of the water.
Kamen put a simplified model onto the palm of his hand, an ice cube onto the other surface, and with that limited heat differential, you could actually see the piston move and a little wheel begin to rotate with power purely from the body heat plate and the icy plate. cool.
the critical portion of his actual prototype Stirling engine
'burning fuel' to heat the engine might cause pollution, sticking one end on geothermal wouldn't
Sorry, but why remove the cars, if the big push is towards electrical/fuel cell vehicles?
That pushes them even more firmly *into* that power budget.
Really, try to have some vision.
I was just talking about for the sake of our discussion. The car discussion is 20 threads on its own....
Quote:
Originally posted by Kickaha
And that '40% of the US energy needs' wasn't vague at all. Add up the amount of fuel used, coal burned, etc, etc, etc, and you have our energy budget. It's all energy. *HOW* we get it is the problem, and is precisely why all energy needs should be evaluated.
But who calculated our 'energy needs'? What did they include? That's what I'm saying. For the time being I think we should just concentrate on power sold to consumers, the same market at Nuclear Reactors. Start with that area and we'll get a huge portion of the problem.
Quote:
Originally posted by Kickaha
But, we've all got differing opinions, and none of us is in a position to do anything about it, so it's all pretty irrelevant.
That's true of everything we discuss here.
I'd like to see a breakdown of the different types of powerplants in the country and their locations. Coal burning, giant dams, nuclear, whatever. Then decide the dirtiest (coal) and work out a method to replace them. In some areas, solar would help. Along the coasts, other methods could be used. In some areas coal might be the only solution, but it should be a last resort. And even in that case they could be cleaned up.
I was just talking about for the sake of our discussion. The car discussion is 20 threads on its own....
I think cars need to be removed is because they aren't going to be driving around with solar panels on them. The solar panels that will supposedly be covering a tremendous amount of land area causing all this environmental damage will be powering homes and businesses, not cars.
Solar -> electricity -> H2 generation -> fuel cell car.
Or...
Solar -> electricity -> electric car.
Take your pick.
Either way, solar becomes a viable source for automobiles.
Bring on the damned H2 economy already, will ya? Use the electrical grid for large-scale transmission and H2 for onboard storage, and voila. Distributable, cogeneration, long-term storage... all within one nice framework with few problems.
What the hell is the 'new' reactor technology that doesn't leave waste and can't overheat? Crap. I read about it in the mid 80's, but it was probably shelved so we could use more oil.
Either way, solar becomes a viable source for automobiles.
I'm just saying replace one piece at a time. If we can move away from coal burning plants and produce excess green electricity, cars that can tap into the power grid will become more prevalent.
Pebble reactors use hundreds of thousands of tennis ball sized graphite balls filled with thousands of uranium fuel pellets.
We had one of these in Germany (look for THTR Hamm), which was based on Thorium and Uranium as fuel and contained >600.000 graphite balls. It's coolant was Helium, a secondary cooling system relied on liquid Sodium.
It was constructed in the early 80s and was powered on in '86. Almost immediately, one of the balls got caught somewhere and burst, triggering an emergency shutdown. In the following years, it became evident that the graphite balls were susceptible to wear and broke about 1000 times faster than anticipated, leading to radioactive graphite dust accumulating and eventually a much higher emission of radioactivity as planned. One day, the sodium leaked, catching fire immediately but luckily far enough from the core, so no major radioative spill resulted.
With horror, scientists discovered in the following three years that in case of a severe emergency, the graphite dust could catch fire, eventually explode and destroy the whole building (a fortified containment was deemed unnecessary at planning time, since it was a "secure" reactor type) leading to a *massive* contamination and fallout (Chernobyl, anyone?).
So, it was mothballed in '89 and finally dismantled in '91.
Personally, I have a hard time believing anyone come up with something as demented as superhot graphite and liquid sodium for cooling from the beginning...
Right. Sorry, this guy was tentatively pro-nuclear at *BEST*. He helped write some of the most stringent medical and environmental risk guidelines on the planet, at that time.
He just happened to have both eyes open, and look at actual facts instead of pie-in-the-sky wishing.
I have no wish to insult your good professor. I am sure that he is a man of intelligence and integrity, as most scientists involved in the nuclear industry are. However, as a scientist writing safety guidelines for the nuclear industry, it would seem that he was in fact involved in the industry and I would presume, based on his writing the guidelines, that he felt that, if the industry followed the guidelines, it was more or less safe. I have found those involved in this industry frequently pass on pro-nuclear propaganda ? well-meaning pro-nuclear propaganda ? that downplays the benefits and puts forward speculative risks of green energy sources. One of the mantras of the nuclear lobby ? you can see it on virtually every one of their websites - is that all forms of energy production have environmental impacts. This is true, but it downplays the different nature of the impacts.
Quote:
All we did was run the numbers through a weather model and voila... unexpected, rather *large* climatalogical change from a supposedly 1--% benign energy source. *NO* energy source is 100% impact free, was the lesson. That's all.
[?]
Yup, it could... except that in those cases the heat is being absorbed by the structure, then released just as in the case of the ground. In a panel it's being *removed* to make other energy forms. Sorry, non-argument.
We were investigating using it for *large-scale* power production, to actually eliminate using fossil and other sources that are known to be destructive. In large-scale systems, you need efficiencies of scale, hence looking for the best places to locate these panels. The SW wins, hands down. Unfortunately, it screws the Midwest.
The model that you discussed in class is an example of the speculation I am talking about. I looked a bit more into this on the web and, while solar does have some environmental consequences, heat loss was not a big concern. First of all, solar panels only convert a fairly small portion of the sun?s energy into electricity. Most of the energy remains as heat. The solar panels heat up during the day and release the heat at night, like other surfaces. Second, to the extent that some potential heat is lost through conversion, this loss is not permanent. Heat is released again in electrical applications. While the heat is transported to other areas, this is only a problem ? if at all (due to the small amount of heat loss) ? under the model of digging up huge portions of the southwest to send power elsewhere. This model need not and will not be implemented.
Further, even if we were to dig up huge tracts of the southwest to install massive solar fields ? which we are not ? I suspect that the model showing definite environmental impacts on the midwest is speculative at best. Even under the advanced weather modelling studying whole-earth effects of global warming ? which have been developed only very recently - scientist still are uncertain about impacts on specific areas. I am dubious about the model in your university course a decade ago (no insult to you or the professor intended).
The real impact of the ?panel over the south-west model? rather would be on local flora and fauna. Some people think that the desert is dead and that we can do what we want there. This is, of course, false. You simply cannot convert the U.S. southwest into one big solar field. But this is not going to happen and does not need to happen.
There are also environmental impacts of the manufacturing of solar panels themselves, but these ? while of concern ? are essentially even when compared to manufacturing of the components of other power sources and are minimal when compared with overall manufacturing activity. Recycling can minimize the effects in any case
Quote:
Figure it out for yourself... calculate the square meters it would take to produce 40% of the US energy needs, then look for places where it can be used *most* effectively (remember, northern latitudes require more m^2 of land and panels..., cloudy days decrease effectiveness, populated areas are problematic (although roofs are good - one of his suggestions)) The data is out there. Use it.
I looked more into this. The figure I saw in one study was that in order to produce solar powered electricity equivalent to 20% of the total energy demanded in the United States, which is 7.5x(10 to the power 12)kWh per year, the total area of panels needed would be 7.5 x 10(to the power 12)kWh / 263 kWh/m2 = 28.6 x 109m2, which is which is equivalent to 11,050 mi2, an area comparable to the state of Massachusetts. (This is based only on current efficiencies of solar cells ? not expected advances). While this is a large area, Massachusetts is a pretty small state, relatively speaking. I.e. we need not talking about digging up the whole Southwest. And while it is not the 40% you talked about, keep in mind we are talking about total energy, not just current electrical production. Twenty-percent of total energy would be pretty good and is quite a bit more than is produced by all current nuclear plants.
Further, these panels do not have to be located all in one area. In fact, it would be a bad idea to do this. You noted that your study sought ?efficiencies of scale?. This is the wrong approach. As many theorists have now realized, power generation actually has inefficiencies of scale in many cases, due to power loss over large transmission distances. Interconnected micro-generation ? where energy is produced as close as possible to where it will be used - is recognized the way of the future. Solar power is remarkably flexible and does not have particular inefficiencies in small scale applications. It is ideal for micro-generation.
The panels would be dotted throughout rooftops throughout the nation and on some land as well, but not in the huge concentrations in any one area to cause the speculative environmental problem talked about by the professor. Some would be located in the northeast as well and while solar energy does not work as efficiently here as in the southwest, the example I linked you to earlier shows that it still works well enough to be viable even with current solar technologies. The example is producing one megawatt of power in the northeast. (The total U.S. generating electrical generating capacity in 2000 was 604,514 megawatts). There must be 100,000 or more such big industrial and commercial rooftops in the industrial northeast (never mind in areas that are even better for solar production). Even just using these northeast rooftops would represent a big step forward.
Kickaha, I respect your posts and I thank you for them. Actually, I note that in your other posts you are remarkably pro-solar and have some of the same ideas that I do about applications. In any case, my purpose in this thread is not to argue that solar would have no negative impacts. Despite what I have written above, I do not think that solar is a panacea. My real purpose is to argue that, whatever the difficulties of going toward other green energy sources, staying with nuclear is far worse. I just have not seen any hard data or arguments that overcome my concerns about the safety of plants (small risk in any one plant ? I know ? but catastrophic impact when it happens), the disposal of waste, or the use of the waste for making weapons. I think that we are largely just looking away from these problems and benefiting from electricity now whose huge costs will be felt later -and keep in mind that even the current costs of nuclear generation are huge. I think that nuclear should be phased out.
We had one of these in Germany (look for THTR Hamm), which was based on Thorium and Uranium as fuel and contained >600.000 graphite balls. It's coolant was Helium, a secondary cooling system relied on liquid Sodium.
The sodium cooled the helium? Or is was used in place of the helium.
Quote:
Almost immediately, one of the balls got caught somewhere and burst, triggering an emergency shutdown. In the following years, it became evident that the graphite balls were susceptible to wear and broke about 1000 times faster than anticipated, leading to radioactive graphite dust accumulating and eventually a much higher emission of radioactivity as planned. One day, the sodium leaked, catching fire immediately but luckily far enough from the core, so no major radioative spill resulted.
With horror, scientists discovered in the following three years that in case of a severe emergency, the graphite dust could catch fire, eventually explode and destroy the whole building (a fortified containment was deemed unnecessary at planning time, since it was a "secure" reactor type) leading to a *massive* contamination and fallout (Chernobyl, anyone?).
Granted. But such as it is with technology. Initial designs can break the first few times around, but get better with each successive revision. It doesn't look to be a physics problem, rather, a design flaw, so I think it can be fixed. If the South Africans build their modular pebble bed reactor in the next few years, we'll see if it works out. Their design rotates pebbles in and out of the core, identifies and discards the broken spheres, uses an all helium coolant system (with water cooling the helium elsewhere in the work cycle) and hopefully uses a different pebble design.
Quote:
Personally, I have a hard time believing anyone come up with something as demented as superhot graphite and liquid sodium for cooling from the beginning...
There will be stranger things to come. Molten lead coolant. Liquified uranium as fuel.
Where is some good information about the NG car conversion program in Canada?
Thanks.
Hello Bunge
I am afraid that I don't know of a particular source for this, but if you did a Google search I am sure that you will find something.
I know that natural gas power for cars does exist in Canada. It was in the news a fair bit a few years ago and I am fairly sure that it is still being used, especially in fleet vehicles (taxis, postal vehicles etc.). It caused some excitement when it came out, because it was cheaper and cleaner burning than gasoline. I think that it is considered less attractive now, as the price of natural gas has increased greatly in this country.
Natural gas for vehicles is not a big interest of mine, as it is, in the end, still a fossil fuel, cleaner though it may be. I am more excited about hydrogen-powered or hydrogen-cell-powered vehicles (using hydrogen from green electrical production). I think that this has real possibilities, although I have become impatient with the slow progress in actual implementation. The cost of the switch over to such new technologies will be large, but in my view, well worthwhile. Also, consider how much we are spending each year in supporting and subsidizing non-green technologies: inexplicable.
Comments
Originally posted by Wrong Robust
not at all, and I hope it stays that way, my point being that subtle jabs at one side of the political spectrum is totally unnecessary, and pointless.
I guess I hadn't seen it....
Originally posted by bunge
First, take cars out of the 'energy needs' equation. They need a whole argument by themselves. After that, let's see where we stand.
I don't trust this generic argument because '40% of the US energy needs' is not specific enough. It's too easy to fudge.
Then, once we have a rough estimate after the cars have been removed we can work on increasing efficiency in other areas so that total number is reduced.
Thanks THT.
Sorry, but why remove the cars, if the big push is towards electrical/fuel cell vehicles?
That pushes them even more firmly *into* that power budget.
Really, try to have some vision.
(More to the point, one needs to have a coherent energy plan in mind... mine consists of pushing for electrical/fuel cell cars, electricity as the major transmission system, with hydrogen storage/fuel cell cogenerators for peak times. Eliminates 95% of the electrical grid problems we have, allows each energy generation technology to work at peak efficiency, and uses the existing infrastructure. Voila.
And that '40% of the US energy needs' wasn't vague at all. Add up the amount of fuel used, coal burned, etc, etc, etc, and you have our energy budget. It's all energy. *HOW* we get it is the problem, and is precisely why all energy needs should be evaluated.
But, we've all got differing opinions, and none of us is in a position to do anything about it, so it's all pretty irrelevant.
And yes, I agree... the best thing we can do is *reduce* our &*($%@# energy use. Gulp, gulp, gulp.
the Danes have a square kilometer of offshore windmills, powering 8% of their country.
if anybody knows windmills, it's folks in the Low countries, Spaniards perhaps quixotically.
recently developed inline turbine generators for microhydro allow greater power efficiency with near zero environmental impact, sharing more in common with water mill factories and stream-wheels than dams
other renewable energy info from the US Gov can be found here
most exciting of all, (though still carrying the "fossil fuel" millstone), 60 Minutes II last night had a section with Dan Rather interviewing Dean Kamen of Segway fame . When the buzz on Kamen's then-unknown invention "Ginger" was circulating, many put their wishing hats on and predicted a Stirling Engine (runs on almost anything).
The Stirling engine, named after its designer, Robert Stirling, a 19th Century Scottish minister, is a non-polluting device that plays heat against cold to create energy. It is a closed box with two chambers, one filled with gas. Once heated from the outside, with anything from burning wood chips to charcoal, the gas expands, creating pressure. That pressure drives a piston from the hot chamber into the cool chamber.
In Kamen's design, that mechanical power achieves two goals: It creates electrical power - 300 continuous watts ? enough to run a few electrical devices - and, as a bonus, creates enough heat to distill contaminated water, making it drinkable.
Rather and Kamen tested a prototype using water from the polluted Merrimack River near Kamen?s plant. Afterwards, Rather sampled some of the water.
Kamen put a simplified model onto the palm of his hand, an ice cube onto the other surface, and with that limited heat differential, you could actually see the piston move and a little wheel begin to rotate with power purely from the body heat plate and the icy plate. cool.
the critical portion of his actual prototype Stirling engine
'burning fuel' to heat the engine might cause pollution, sticking one end on geothermal wouldn't
Originally posted by Kickaha
Sorry, but why remove the cars, if the big push is towards electrical/fuel cell vehicles?
That pushes them even more firmly *into* that power budget.
Really, try to have some vision.
I was just talking about for the sake of our discussion. The car discussion is 20 threads on its own....
Originally posted by Kickaha
And that '40% of the US energy needs' wasn't vague at all. Add up the amount of fuel used, coal burned, etc, etc, etc, and you have our energy budget. It's all energy. *HOW* we get it is the problem, and is precisely why all energy needs should be evaluated.
But who calculated our 'energy needs'? What did they include? That's what I'm saying. For the time being I think we should just concentrate on power sold to consumers, the same market at Nuclear Reactors. Start with that area and we'll get a huge portion of the problem.
Originally posted by Kickaha
But, we've all got differing opinions, and none of us is in a position to do anything about it, so it's all pretty irrelevant.
That's true of everything we discuss here.
I'd like to see a breakdown of the different types of powerplants in the country and their locations. Coal burning, giant dams, nuclear, whatever. Then decide the dirtiest (coal) and work out a method to replace them. In some areas, solar would help. Along the coasts, other methods could be used. In some areas coal might be the only solution, but it should be a last resort. And even in that case they could be cleaned up.
Originally posted by bunge
I was just talking about for the sake of our discussion. The car discussion is 20 threads on its own....
I think cars need to be removed is because they aren't going to be driving around with solar panels on them. The solar panels that will supposedly be covering a tremendous amount of land area causing all this environmental damage will be powering homes and businesses, not cars.
Solar -> electricity -> H2 generation -> fuel cell car.
Or...
Solar -> electricity -> electric car.
Take your pick.
Either way, solar becomes a viable source for automobiles.
Bring on the damned H2 economy already, will ya? Use the electrical grid for large-scale transmission and H2 for onboard storage, and voila. Distributable, cogeneration, long-term storage... all within one nice framework with few problems.
Originally posted by bunge
What the hell is the 'new' reactor technology that doesn't leave waste and can't overheat? Crap. I read about it in the mid 80's, but it was probably shelved so we could use more oil.
Maybe they're referring to fusion?
Originally posted by Outsider
Maybe they're referring to fusion?
No, it was a new style of nuclear reactor. I believe Scott and THT posted about it.
Originally posted by Kickaha
Either way, solar becomes a viable source for automobiles.
I'm just saying replace one piece at a time. If we can move away from coal burning plants and produce excess green electricity, cars that can tap into the power grid will become more prevalent.
Originally posted by THT
Pebble reactors use hundreds of thousands of tennis ball sized graphite balls filled with thousands of uranium fuel pellets.
We had one of these in Germany (look for THTR Hamm), which was based on Thorium and Uranium as fuel and contained >600.000 graphite balls. It's coolant was Helium, a secondary cooling system relied on liquid Sodium.
It was constructed in the early 80s and was powered on in '86. Almost immediately, one of the balls got caught somewhere and burst, triggering an emergency shutdown. In the following years, it became evident that the graphite balls were susceptible to wear and broke about 1000 times faster than anticipated, leading to radioactive graphite dust accumulating and eventually a much higher emission of radioactivity as planned. One day, the sodium leaked, catching fire immediately but luckily far enough from the core, so no major radioative spill resulted.
With horror, scientists discovered in the following three years that in case of a severe emergency, the graphite dust could catch fire, eventually explode and destroy the whole building (a fortified containment was deemed unnecessary at planning time, since it was a "secure" reactor type) leading to a *massive* contamination and fallout (Chernobyl, anyone?).
So, it was mothballed in '89 and finally dismantled in '91.
Oh, yes - the Uranium is weapons-grade too.
This is how it ended
Personally, I have a hard time believing anyone come up with something as demented as superhot graphite and liquid sodium for cooling from the beginning...
Originally posted by Kickaha
*SNORT*
Right. Sorry, this guy was tentatively pro-nuclear at *BEST*. He helped write some of the most stringent medical and environmental risk guidelines on the planet, at that time.
He just happened to have both eyes open, and look at actual facts instead of pie-in-the-sky wishing.
I have no wish to insult your good professor. I am sure that he is a man of intelligence and integrity, as most scientists involved in the nuclear industry are. However, as a scientist writing safety guidelines for the nuclear industry, it would seem that he was in fact involved in the industry and I would presume, based on his writing the guidelines, that he felt that, if the industry followed the guidelines, it was more or less safe. I have found those involved in this industry frequently pass on pro-nuclear propaganda ? well-meaning pro-nuclear propaganda ? that downplays the benefits and puts forward speculative risks of green energy sources. One of the mantras of the nuclear lobby ? you can see it on virtually every one of their websites - is that all forms of energy production have environmental impacts. This is true, but it downplays the different nature of the impacts.
All we did was run the numbers through a weather model and voila... unexpected, rather *large* climatalogical change from a supposedly 1--% benign energy source. *NO* energy source is 100% impact free, was the lesson. That's all.
[?]
Yup, it could... except that in those cases the heat is being absorbed by the structure, then released just as in the case of the ground. In a panel it's being *removed* to make other energy forms. Sorry, non-argument.
We were investigating using it for *large-scale* power production, to actually eliminate using fossil and other sources that are known to be destructive. In large-scale systems, you need efficiencies of scale, hence looking for the best places to locate these panels. The SW wins, hands down. Unfortunately, it screws the Midwest.
The model that you discussed in class is an example of the speculation I am talking about. I looked a bit more into this on the web and, while solar does have some environmental consequences, heat loss was not a big concern. First of all, solar panels only convert a fairly small portion of the sun?s energy into electricity. Most of the energy remains as heat. The solar panels heat up during the day and release the heat at night, like other surfaces. Second, to the extent that some potential heat is lost through conversion, this loss is not permanent. Heat is released again in electrical applications. While the heat is transported to other areas, this is only a problem ? if at all (due to the small amount of heat loss) ? under the model of digging up huge portions of the southwest to send power elsewhere. This model need not and will not be implemented.
Further, even if we were to dig up huge tracts of the southwest to install massive solar fields ? which we are not ? I suspect that the model showing definite environmental impacts on the midwest is speculative at best. Even under the advanced weather modelling studying whole-earth effects of global warming ? which have been developed only very recently - scientist still are uncertain about impacts on specific areas. I am dubious about the model in your university course a decade ago (no insult to you or the professor intended).
The real impact of the ?panel over the south-west model? rather would be on local flora and fauna. Some people think that the desert is dead and that we can do what we want there. This is, of course, false. You simply cannot convert the U.S. southwest into one big solar field. But this is not going to happen and does not need to happen.
There are also environmental impacts of the manufacturing of solar panels themselves, but these ? while of concern ? are essentially even when compared to manufacturing of the components of other power sources and are minimal when compared with overall manufacturing activity. Recycling can minimize the effects in any case
Figure it out for yourself... calculate the square meters it would take to produce 40% of the US energy needs, then look for places where it can be used *most* effectively (remember, northern latitudes require more m^2 of land and panels..., cloudy days decrease effectiveness, populated areas are problematic (although roofs are good - one of his suggestions)) The data is out there. Use it.
I looked more into this. The figure I saw in one study was that in order to produce solar powered electricity equivalent to 20% of the total energy demanded in the United States, which is 7.5x(10 to the power 12)kWh per year, the total area of panels needed would be 7.5 x 10(to the power 12)kWh / 263 kWh/m2 = 28.6 x 109m2, which is which is equivalent to 11,050 mi2, an area comparable to the state of Massachusetts. (This is based only on current efficiencies of solar cells ? not expected advances). While this is a large area, Massachusetts is a pretty small state, relatively speaking. I.e. we need not talking about digging up the whole Southwest. And while it is not the 40% you talked about, keep in mind we are talking about total energy, not just current electrical production. Twenty-percent of total energy would be pretty good and is quite a bit more than is produced by all current nuclear plants.
Further, these panels do not have to be located all in one area. In fact, it would be a bad idea to do this. You noted that your study sought ?efficiencies of scale?. This is the wrong approach. As many theorists have now realized, power generation actually has inefficiencies of scale in many cases, due to power loss over large transmission distances. Interconnected micro-generation ? where energy is produced as close as possible to where it will be used - is recognized the way of the future. Solar power is remarkably flexible and does not have particular inefficiencies in small scale applications. It is ideal for micro-generation.
The panels would be dotted throughout rooftops throughout the nation and on some land as well, but not in the huge concentrations in any one area to cause the speculative environmental problem talked about by the professor. Some would be located in the northeast as well and while solar energy does not work as efficiently here as in the southwest, the example I linked you to earlier shows that it still works well enough to be viable even with current solar technologies. The example is producing one megawatt of power in the northeast. (The total U.S. generating electrical generating capacity in 2000 was 604,514 megawatts). There must be 100,000 or more such big industrial and commercial rooftops in the industrial northeast (never mind in areas that are even better for solar production). Even just using these northeast rooftops would represent a big step forward.
Kickaha, I respect your posts and I thank you for them. Actually, I note that in your other posts you are remarkably pro-solar and have some of the same ideas that I do about applications. In any case, my purpose in this thread is not to argue that solar would have no negative impacts. Despite what I have written above, I do not think that solar is a panacea. My real purpose is to argue that, whatever the difficulties of going toward other green energy sources, staying with nuclear is far worse. I just have not seen any hard data or arguments that overcome my concerns about the safety of plants (small risk in any one plant ? I know ? but catastrophic impact when it happens), the disposal of waste, or the use of the waste for making weapons. I think that we are largely just looking away from these problems and benefiting from electricity now whose huge costs will be felt later -and keep in mind that even the current costs of nuclear generation are huge. I think that nuclear should be phased out.
Where is some good information about the NG car conversion program in Canada?
Thanks.
Originally posted by Smircle
We had one of these in Germany (look for THTR Hamm), which was based on Thorium and Uranium as fuel and contained >600.000 graphite balls. It's coolant was Helium, a secondary cooling system relied on liquid Sodium.
The sodium cooled the helium? Or is was used in place of the helium.
Almost immediately, one of the balls got caught somewhere and burst, triggering an emergency shutdown. In the following years, it became evident that the graphite balls were susceptible to wear and broke about 1000 times faster than anticipated, leading to radioactive graphite dust accumulating and eventually a much higher emission of radioactivity as planned. One day, the sodium leaked, catching fire immediately but luckily far enough from the core, so no major radioative spill resulted.
With horror, scientists discovered in the following three years that in case of a severe emergency, the graphite dust could catch fire, eventually explode and destroy the whole building (a fortified containment was deemed unnecessary at planning time, since it was a "secure" reactor type) leading to a *massive* contamination and fallout (Chernobyl, anyone?).
Granted. But such as it is with technology. Initial designs can break the first few times around, but get better with each successive revision. It doesn't look to be a physics problem, rather, a design flaw, so I think it can be fixed. If the South Africans build their modular pebble bed reactor in the next few years, we'll see if it works out. Their design rotates pebbles in and out of the core, identifies and discards the broken spheres, uses an all helium coolant system (with water cooling the helium elsewhere in the work cycle) and hopefully uses a different pebble design.
Personally, I have a hard time believing anyone come up with something as demented as superhot graphite and liquid sodium for cooling from the beginning...
There will be stranger things to come. Molten lead coolant. Liquified uranium as fuel.
Originally posted by bunge
Chinney,
Where is some good information about the NG car conversion program in Canada?
Thanks.
Hello Bunge
I am afraid that I don't know of a particular source for this, but if you did a Google search I am sure that you will find something.
I know that natural gas power for cars does exist in Canada. It was in the news a fair bit a few years ago and I am fairly sure that it is still being used, especially in fleet vehicles (taxis, postal vehicles etc.). It caused some excitement when it came out, because it was cheaper and cleaner burning than gasoline. I think that it is considered less attractive now, as the price of natural gas has increased greatly in this country.
Natural gas for vehicles is not a big interest of mine, as it is, in the end, still a fossil fuel, cleaner though it may be. I am more excited about hydrogen-powered or hydrogen-cell-powered vehicles (using hydrogen from green electrical production). I think that this has real possibilities, although I have become impatient with the slow progress in actual implementation. The cost of the switch over to such new technologies will be large, but in my view, well worthwhile. Also, consider how much we are spending each year in supporting and subsidizing non-green technologies: inexplicable.