Anybody know anything about Solar or Geothermal energy?

TN4994 wrote:Let us propose that Safehold is a relatively young planet and hasn't the vast oil fields of Mother Earth.
This would spur technology on a different path.

Not likely as we have textev that there is significant coal fields of Safehold, and I believe that we have textev of petroleum deposits as well.

Hydrogen is NOT safer to work with than propane it's LEL is 4% and it's UEL is 75% which means that it's an explosive mixture in almost any concentration in air. Secondly the activation energy for hydrogen combustion is very low it can ignite simply from the friction of a high pressure leak. Finally hydrogen will not liquefy under pressure at room temperature. Thus normal tank pressures are about 2400psi.

When compared to propane it's LEL is 2.1 % and it's UEL is 9.2% a total explosive range of only 7.1% as compared to 71%. It is harder to ignite propane and it liquifies at 130 psi at room temp.

By the way where do all of you think the electricity comes from to charge your electric cars? The vast majority comes from coal. The green movement is anti hydro, anti nuke, and now anti wind. I'm fine with some electric cars but we must build some new nuke plants. Also battery production is about the most environmentally nasty Industries out there.

I crunched the solar numbers from the beginning of the post. Industry standard conditions for photovoltaic cells are 1000w/m2 incident radiation at 41 degrees above the horizon and a direct solar path at equinox southern US average incident radiation between the tropics is 1366w/m2

At 100% efficiency 24/7. 314 GW of production would require 89 sq miles however current efficiencies for commercial cells range from 5-19% so let's just say 12% that takes it to 740 sq miles. But then you only get max power for about 6 hours a day (8 hours effective) on clear days which averages about 60% in the US. So to keep a reasonable reserve and keep the batteries charged you would need about 4900 sq miles of photovoltaics to replace 314 GW production.

According to DOE actual usage last year in the US was 570 GW or 4.7 x 10^15 watt hrs which means about 9000 sq miles (bigger than the state of New Jersey ) of solar panels with no safety factor at 8 hours effective and 60% sunny and zero loss in transmission storage or transformation which in real life is significant.

fleadermouse wrote:Hydrogen is NOT safer to work with than propane it's LEL is 4% and it's UEL is 75% which means that it's an explosive mixture in almost any concentration in air. Secondly the activation energy for hydrogen combustion is very low it can ignite simply from the friction of a high pressure leak. Finally hydrogen will not liquefy under pressure at room temperature. Thus normal tank pressures are about 2400psi.

As far as I can understand the techno-jargon, you're absolutely correct, except for one minor detail; propane is heavier than air and will concentrate to dangerous levels around your ankles. Hydrogen is lighter than air and will disperse above your head unless restricted by and impermeable barrier, like a roof without vents.

Castenea wrote:

Graydon wrote:Personal transportation is a fine thing; anybody with three kids doesn't want to take the subway with only one adult available for kid wrangling. People do live out in the country. Machine traction for agriculture is essential. It doesn't have to be powered by IC engines or fossil carbon, it's just that's what we happen to have, in large part because of the Great War and historical accidents around aircraft.

The historical ignorance is breath taking. Hit and miss one lung engines of under 30 HP were rapidly displacing all other engines out on farms from 1890 to 1910, well before the first world war.

Steam traction engines had two problems on many farms, obtaining fuel and obtaining water. There was barely enough thatch on a farm to fuel the engine, and getting it into the burn box took a lot of labor. Then there was the issue of getting water, as most steam engines were used on farms did not have condensers.

The hit and miss gasoline engines were lighter, faster to get operating, and cheaper to obtain and run. Gasoline powered tractors were lighter than steam tractors.

I pretty much agree with the critics of the IC engines about the issues they describe. But I am a bit more optimitic that those problems will be overcome. We are gradually working toward the hybrids and eventually the batteries for electric cars will be improved to the point where they will be more viable in cars and produced in sufficient volumne to bring the price down. Already we are starting to see price drop for batteries in such vehicles as the prius (sp).

Don

Weird Harold wrote:

Zakharra wrote: Isn't hydrogen, as a liquid or gas, even more volatile than gasoline? And don't hydrogen tanks leak the hydrogen over time?

Yes it is, and no it isn't.

If you don't ventilate hydrogen storage areas properly -- i.e. don't have roof vents for Hydrogen to escape through -- hydrogen can be very explosive.

However, if you have vents in the roof, so any loose hydrogen can escape containment, it never builds up to explosive concentrations

Hydrogen gets a bad rep because the Hindenburg blew up and they call fusion bombs "Hydrogen Bombs." It is actually safer to store and handle than propane, Methane, Butane, Natural Gas, gasoline or most other flammable vapors.

Hydrogen is much harder to store because hydrogen leaks through steel tanks - hydrocarbons don't. You lose about 20% per month from automotive hydrogen tanks (and yes, there are cars that run on hydrogen now).

The cryogenic storage or high pressure storage requirements are severe. This is beyond the capabilities of a 1900's tech level and stretches a 2000's tech level particularly for use by untrained personnel. Refueling fires are a significant hazard. Anyone who has worked with hydrogen in large quantities rapidly learns to treat it with respect.

AirTech wrote:Anyone who has worked with hydrogen in large quantities rapidly learns to treat it with respect.

Respect, yes.

The problem is that too many people who don't work with Hydrogen in any quantity fear Hydrogen far beyond what it deserves.

Where do small town boys in Safehold learn about women, then??? Without Sears and "Monkey Wards" I would have been clueless far longer!

Keith_w wrote:...

And later, you would have had the Sears-Roebuck catalog to provide A) ... B) toilet paper.

jgnfld wrote:Where do small town boys in Safehold learn about women, then??? Without Sears and "Monkey Wards" I would have been clueless far longer!

Keith_w wrote:...

And later, you would have had the Sears-Roebuck catalog to provide A) ... B) toilet paper.

Excellent point, I totally forgot about that, although I definitely used the same sort of textbook.

Keith_w wrote:Where do small town boys in Safehold learn about women, then??? Without Sears and "Monkey Wards" I would have been clueless far longer!

Keith_w wrote:...

And later, you would have had the Sears-Roebuck catalog to provide A) ... B) toilet paper.

jgnfld wrote:

Excellent point, I totally forgot about that, although I definitely used the same sort of textbook.

Must have been some way, as the race didn't die out before 1886, when Sears-Roebuck was founded.

fallsfromtrees wrote: quote="Keith_w" quote="jgnfld" Where do small town boys in Safehold learn about women, then??? Without Sears and "Monkey Wards" I would have been clueless far longer!

quote="Keith_w"...

And later, you would have had the Sears-Roebuck catalog to provide A) ... B) toilet paper. /quote
/quote

Excellent point, I totally forgot about that, although I definitely used the same sort of textbook. /quote

Must have been some way, as the race didn't die out before 1886, when Sears-Roebuck was founded.

I think that you are confusing reproduction with learning about women and, I suppose, for the gentler sex (ha-ha) about men. On the other hand I suppose that I am confusing anatomy with "understanding" women, which I have yet to do. I do recall in RAH's "Time Enough For Love" that one of the acquaintances' of Woody Smith's mother said that she had never seen her husband naked, and I wouldn't be surprised to find that that attitude was wide spread among the people of the Victorian age.