Does corn Ethanol need to die?

[Megaton]

Also, and I hate to double post, but this is something I really want clarified: evidently there is plenty of oil below a certain depth that could provide enough fuel for generations, but it would cost too much to build the rigs to get at it. How is that possible when you consider the economics of scale, because if there's really that much oil it seems like building the rig would be less and less expensive over time and actually help out the economy a TON. I know I must be missing something there. >_>

 

[cignus_pfaccari]

Note one technical inaccuracy - nuclear energy does not produce greenhouse gasses, but it does produce waste heat that gets dumped into the environment. Nuclear plants are normally situated on rivers or large bodies of water precisely so they can dump heat into that water.

Pity they can't use all that excess heat for *something*, though my understanding is that the released water isn't quite at bath temperature when it's released into a river.

On broad average, the Earth's surface gets about 250 watts per square meter (this takes into account the fact that it is dark at night, that you don't get much in the early morning and late evening, and so on, but ignores clouds). Peak solar energy on a clear day on a surface perpendicular to the sun's light at sea level (like at the equator at an equinox) is about 1000 watts per square meter.

The more recent stuff is apparently not using photovoltaics, but instead using mirrors to concentrate sunlight to boil water* to run a turbine. It's possible to store that heat (via something like liquid sodium) and even out the electricity supply over the day/night cycle and account for cloudiness.

* - It's kind of ironic that we use nuclear power and other such highly advanced technologies to, well, boil water. I vaguely remember reading something about a direct current thing with nuclear power, but it was a long time ago and in a GURPS book.

Brad

 

[freyar]

Sorry, I'm a physicist,

I've wondered if that might be true based on your clear explanations of things in a number of these threads. You are a brave, brave person to clear things up in public like this. Despite sharing your profession, I usually just get too frustrated after a while to keep up the public explanations.

Ending threadjack now...

 

[Ranger REG]

Like Hawaii in climate, yes. But not like Hawaii in size. Hawaii just isn't big enough to be the nation's energy breadbasket.

Who says about helping the mainland?

 

[Umbran]

... evidently there is plenty of oil below a certain depth that could provide enough fuel for generations, but it would cost too much to build the rigs to get at it.

As I understand the state of things, it isn't that simple. The issues aren't just depth. Most oil isn't sitting in pressurized pools just waiting to come gushing out like in the cartoons - the oil is often impregnated into the surrounding rock, and you need to inject steam or detergents at high pressure to coax it out. Or the reservoir is under the deep ocean, so that you can't build a stable rig on a solid base. Or you have to drill sideways for a couple miles to reach the stuff.

And, even after we've done everything we currently know how to do, and an oil field is "dry", there's actually a whole bunch of petroleum still impregnated in that rock, but we don't know how to get it out economically.

For my sensibilities, "enough fuel for generations" isn't good enough. That kind of verbiage is the gateway to complacency. "We don't have to worry, because we have enough for generations," is really easy to say. But it may take generations to develop alternate energy sources, and if you ignore the problem it'll just ocme to bite that later generation on the butt. And, really, a "generation" is what, 20 years? That still puts us at running out of available fossil petroleum before the end of the century.

 

[Umbran]

Who says about helping the mainland?

As if the ethanol would be good for something other than getting drunk if you weren't getting metals and machinery from across the oceans?

 

[Umbran]

Pity they can't use all that excess heat for *something*, though my understanding is that the released water isn't quite at bath temperature when it's released into a river.

Yes. Hot enough to damage aquatic ecology in the long run, but not hot enough to do a lot of useful work.

The more recent stuff is apparently not using photovoltaics, but instead using mirrors to concentrate sunlight to boil water* to run a turbine.

Solar towers are in no way new. As I understand it, the best recent stuff is in photovoltaics - increases in efficiency tide with simpler, cheaper, and less ecologically damaging production methods. Still nowhere near the point where you could roof your house with them, and have it be energy independent, but stepping forward.

 

[Jdvn1]

Deleted because I think there's no reason to get into semantics when I think they don't affect the issue.

 

[Jdvn1]

Like Hawaii in climate, yes. But not like Hawaii in size. Hawaii just isn't big enough to be the nation's energy breadbasket.

Some day we'll have agricultural towers just for growing food!

Not enough land? Build up!

 

[Ranger REG]

As if the ethanol would be good for something other than getting drunk if you weren't getting metals and machinery from across the oceans?

Well, if we can't look to the east side of the Pacific, look to the west side.