Should we ban kerolox rockets

[MBobrik]

I know what Fischer Tropsch is, I went to college where I studied those things.

Yes, that particular technology does exist, but the viability of it (in terms of money, net energy gain and carbon footprint) depends heavily on every key of the whole production cycle and the actual way of usage.

First, in my post I merely pointed out that, fischer tropsch is able to produce an adequate kerosene substitute. I was not talking about efficiency yet.

Second, efficiency is a solvable problem. magnemoe above put even a concrete number - current technology would give us $120/barrel, which is not much higher than current oil prices. And I was talking about a hypothetical situation where all fossil fuels are completely banned, so competing with them would be a non-issue.

Yes, and that means it can not be base load power. It can be intermediate to peak load source.

We are talking past each other here. I was talking about producing synthetic kerosene for kerolox using rockets. It has per se no relation to power grid whatsoever. No base, intermediate or peak. It could happily dump out synthetic kerosene even completely disconnected from the grid. So why you are talking about grid load, like ... at all ?

Well yeah, if you use a crapload of copper to make 1 m thick rods as cables and you don't care about coronal discharge, you could transmit a lot more, but is that viable?

FIY

"HVDC requires less conductor per unit distance than an AC line, as there is no need to support three phases and there is no skin effect."

" Due to the space charge formed around the conductors, an HVDC system may have about half the loss per unit length of a high voltage AC system carrying the same amount of power."

Give me a few examples of such compounds.

Uh, ethanolamine ?

I'm talking about industrial processes, and you're sticking to semantics.

If it is chemically possible then it can be made even at industrial scale, methinks.

[NERVAfan]

Turning Sahara into a garden would require enormous amounts of energy (=lots of coal burned), and everything you do there lies against the powerful foot of nature. It's futile, just like it's futile to keep insides of a Venus surface probe at room temperature. Eventually, it will fail.

Sahara is something we can't battle even with GM plants, and even if we could, the consequences for the weather in Europe, western Asia and northern Africa could be disastrous.

So yeah... I'd leave that one alone.

Actually, I think turning (large parts of) the Sahara into farmland is quite viable as megaprojects go - it was apparently mostly grassland, with some lakes and stuff, up till ~7000 years ago. So it might not take much to push it back into that state.

It shouldn't mess with climate or ecology too much, as the climate/ecology of 7000 years ago wasn't much different from today.

Massive desalination and pumping water inland (by solar or nuclear power) would be the first step, basically a "Canals of Mars" setup. Making the soil better would probably be the hardest part.

[NERVAfan]

I made some quick calculations about solar at some point... If I get this right...

In 2008 the total global energy consumption was 143,851 TWh with electricity being 20,181 TWh a year.

A modern solar power plant that produce 165 GWh a year and can store this energy uses:

51 hectares of solar collectors.

About 200 hectares of total land usage.

28,500 tonnes of molten salt (60 percent sodium nitrate and 40 percent potassium nitrate).

870,000 cubic meters of water a year (or vaporised).

To fully supply the world with solar power, if all things stay the same, would require:

6,222,309 hectares of solar collectors.

24,401,212 hectares of total landusage.

2,477,172,727 tonnes of molten salts.

106,145,272,727 cubic meters of water a year (or vaporised).

Hmm... that doesn't seem right does it?

Well, if true... I stick by my original line of thinking, that providing a significant proportion of just the worlds electrical usage from solar power is a pipedream.

Actually that land use doesn't sound that bad for powering the entire world - 24.4 million hectares = 244,000 sq km is smaller than Nevada and only a tiny fraction of the world's land.

As for the water... does it have to be pure or fresh water? That amount would be nothing if you could use salt water. As for the molten salt... that might be an issue, I don't know what total world production of nitrates is like.

OTOH there are other ways to store energy eg pumping water uphill.

Perhaps someone else could provide some information of the additional effects of manufacturing, deploying and maintaning that many solar panels, the molten salts for storage and that much extra water vapor to the atmosphere.

The water vapor shouldn't make much difference, it's tiny in comparison to what evaporates from the ocean.

[MBobrik]

Actually that land use doesn't sound that bad for powering the entire world - 24.4 million hectares = 244,000 sq km is smaller than Nevada and only a tiny fraction of the world's land.

Look at his numbers. 165 GWh / year = cca 20 MW plant. There are already over 350 MW power plants that use the space and resources far more efficiently.

[AngelLestat]

You do ANYTHING and you generate waste heat

Waste heat is not the problem of global warming..

All the heat that human can produce is nothing compared to the sun heat we can trap in our atmosphere due extra Co2 levels.

This is easy to see, just take the energy consumed by the world.. Convert all that into heat, and then compare that number with the extra heat trapped due co2 emmisions.

[shynung]

If it is chemically possible then it can be made even at industrial scale, methinks.

There's a difference between 'chemically possible' and 'can be mass produced at an industrial scale'. For example, it's relatively straightforward to produce the oxidizer O2F2; heat a large chemical reactor to 700 degrees C, and pour liquid oxygen and fluorine into it. However, approach any commercial chemical supply firms with orders for a few tons of the stuff, and one should expect most of them to reject it immediately. This is rational, because from a safety aspect, dioxygen difluoride is one nasty son-of-a-booster. From what I read, they explode seemingly at will, even when left alone.

Now, other products might be far more forgiving, but the industrial processes are much more complicated. Sure, it's possible to turn crops like corn or sugar cane into ethanol fuel; the Brazilians have been doing it for years. What's not so obvious is that they require several industries alive at once to turn that bushel of corn into a quantity of fuel. Even then, the product is relatively simple; ethanol has the formula C2H6O, while octane (the largest component in common gasoline fuels) is C8H18. The reason why gasoline (and oil-based fuels in general) are cheap today is the fact that it's already there, in the crude oil, just waiting to be separated via fractional distillation. Even without mentioning the relative simplicity of distilling crude oil compared to the farming, fermentation, and distillation typical of an ethanol fuel production cycle, crude-oil-based fuels already win hands down against ethanol in terms of price.

[MBobrik]

There's a difference between 'chemically possible' and 'can be mass produced at an industrial scale'. For example, it's relatively straightforward to produce the oxidizer O2F2;

True, I should be more specific. We are talking about something that plants do safely in their bodies at massive scale. So, methinks, it can be done at industrial scale too.

[Idobox]

Air is not like light, you don't need a fixed area. You can let a large volume blow through a small extracting apparatus.

When fossil fuels are banned there wont' be any CO2 producing power plants.

You still need to pump hundreds or thousands of tons of air through your system to extract tons of CO2. And that's expensive, both in term of energy and money.

Even if fossil fuel power plants are closed, you could still have biomass power plants and use the CO2 for algae farms. Also, cement and steel production are two of the largest CO2 emission sources, and will keep existing for a long time.

But the first step we have to do is to cut our energy consumption. Stop driving cars, use good insulation, live in dense cities and you have solved 70% of the problem. Plant trees every where you can, and you have a massive and cheap carbon sink. Stop eating meat, especially beef, and you're almost there.

Then, you can start thinking of how to produce the electricity you need.

Trying large scale capture of CO2 before you have done all that is waste of resources, because you would have a larger impact for less cost with any of those.

[shynung]

True, I should be more specific. We are talking about something that plants do safely in their bodies at massive scale. So, methinks, it can be done at industrial scale too.

Why not use the plants themselves? Farm them in massive amounts, then process the biomass harvest into fuel. Why bother with inventing the industrial processes when one can make something else make it for him?

Now we're back at the ethanol biofuel business model. It's possible, but it would be much more expensive per joule of energy produced. How much would you think it will impact the human population as a whole, facing drastically-increased energy cost in comparison to today's crude-oil fuels?

Of course, somewhere, someone will respond by suggesting to use nuclear sources. How much sociopolitical obstacles remain for that option in an energy-scarce future, I have little idea, but judging from today's society, it wouldn't change much different.

[sal_vager]

Why not use the plants themselves?

People might want to eat those, or grow edible stuff on the same land.

[shynung]

People might want to eat those, or grow edible stuff on the same land.

Now we run into the classic 'Food vs Fuel' problem. This would have solidified the position of the crude oil industry, since it needs less space than energy crops for the same net energy output.

[MBobrik]

You still need to pump hundreds or thousands of tons of air through your system to extract tons of CO2. And that's expensive, both in term of energy and money.

Why not use the plants themselves? Farm them in massive amounts, then process the biomass harvest into fuel. Why bother with inventing the industrial processes when one can make something else make it for him?

The reason is that plant efficiency really sucks. 2-4 %

- - - Updated - - -

Now we run into the classic 'Food vs Fuel' problem. This would have solidified the position of the crude oil industry, since it needs less space than energy crops for the same net energy output.

Or nuclear. Or solar in desert areas. Or wind turbines.

[shynung]

The reason is that plant efficiency really sucks. 2-4 %

So? If there is no substitute that proves more profitable than regular old farming, it would still be the prime method.

Or nuclear. Or solar in desert areas. Or wind turbines.

Nuclear, yes. Solar or wind, I doubt it. The latter two takes a long time to get their return on investment.

[MBobrik]

So? If there is no substitute that proves more profitable than regular old farming, it would still be the prime method.

If there isn't any more efficient substitute. However the bar is set very low with natural photosynthesis efficiency and inefficiencies of planting and harvesting on top of that.

[Bill Phil]

Isn't coal primarily stored solar-energy from millions of years ago, fossilized dead trees? So technically it's solar power... Technically.

[xenomorph555]

Isn't coal primarily stored solar-energy from millions of years ago, fossilized dead trees? So technically it's solar power... Technically.

If you go back far enough, all energy is transmuted nuclear energy.

[K^2]

Do you know what the short term looks like for example in Germany ?

Germany is an edge case. Most pollution is produced by China and US. EU follows with notable gap.

Politics is a huge factor, but even with the right policy, we cannot switch everyone over in just a few years.

From what I see, EROEI of photovoltaics is 6.9 which is comparable to oil from tar sands.

Sounds about right. Now consider that life time of a panel is about 20 years. So that is 3 years before it pays for itself. And this figure is for optimal illumination, which is rarely the case. In a cloudy region and with no sun tracking, you easily roll over a decade.

Look, if it was easy, it would have been done already. We are on the right path with solar. But we need an intermediate solution as well.

[magnemoe]

You still need to pump hundreds or thousands of tons of air through your system to extract tons of CO2. And that's expensive, both in term of energy and money.

Even if fossil fuel power plants are closed, you could still have biomass power plants and use the CO2 for algae farms. Also, cement and steel production are two of the largest CO2 emission sources, and will keep existing for a long time.

But the first step we have to do is to cut our energy consumption. Stop driving cars, use good insulation, live in dense cities and you have solved 70% of the problem. Plant trees every where you can, and you have a massive and cheap carbon sink. Stop eating meat, especially beef, and you're almost there.

Then, you can start thinking of how to produce the electricity you need.

Trying large scale capture of CO2 before you have done all that is waste of resources, because you would have a larger impact for less cost with any of those.

CO2 cleaning is done on industrial scale already, its not hard its just uneconomical. if you burn natural gas and clean the co2 this uses 1/3 of the energy produced by the gas.

This require that you use injection so it cost almost nothing to store the co2 in the gas field, downside is that you have to run the generator in the area of the well so you probably lose the waste heat to.

And yes this process is used on some gas wells as the gas contains to much co2 initially.

Cement and steal can be imported from other countries and don't affect our co2 budget. Yes its how politicians think, no its its not uncommon or illogical, anybody who has prepared for an major exam know the crystal clear focus it generates, only the short term result as in the grades count, anything else is irrelevant, use any exploit possible.

See no need to cut the energy consume, rater open up for more nuclear plants large scale, use special rules to solve not in my backyard issues fast.

Simply asking the green to eat one holy cow as an sacrifice to show how important global warming is and in the same time solve 70% of the problem.

And yes your idea is unpopular. Think I would be elected with an landslide before you no both of us will lose over the professionals why don't care about imported cement but cares about nimby

[magnemoe]

Sounds about right. Now consider that life time of a panel is about 20 years. So that is 3 years before it pays for itself. And this figure is for optimal illumination, which is rarely the case. In a cloudy region and with no sun tracking, you easily roll over a decade.

Look, if it was easy, it would have been done already. We are on the right path with solar. But we need an intermediate solution as well.

Note that solar is pretty much perfect for counter AC use, who use lots of power in hot areas with lots of sun. No sun and the AC drains less power.

Outside of sunny areas solar has no place outside of distributed supply for off the grind systems.

[NERVAfan]

Now we run into the classic 'Food vs Fuel' problem. This would have solidified the position of the crude oil industry, since it needs less space than energy crops for the same net energy output.

This is why you need cellulosic biofuels. Grain crops throw away most of the plant (stem/leaves), if that could be converted to biofuel... (it can, but it's not industrial-scale yet, IIRC).

[K^2]

This is why you need cellulosic biofuels. Grain crops throw away most of the plant (stem/leaves), if that could be converted to biofuel... (it can, but it's not industrial-scale yet, IIRC).

Yeah. Dedicated biofuel farming is stupid, since we are throwing more fuel into harvest than you'd get out of biofuel from the same land. But if we start utilizing biproducts of farming we already do as biofuel, we can significantly cut amount of fuels we put into farming. And that's a significant chunk of our CO2 emissions, at least in the States. (Note that even if we don't turn cellulose into biofuel, it still contributes to CO2 footprint as it decomposes.)

[Starman4308]

Yeah. Dedicated biofuel farming is stupid, since we are throwing more fuel into harvest than you'd get out of biofuel from the same land. But if we start utilizing biproducts of farming we already do as biofuel, we can significantly cut amount of fuels we put into farming. And that's a significant chunk of our CO2 emissions, at least in the States. (Note that even if we don't turn cellulose into biofuel, it still contributes to CO2 footprint as it decomposes.)

Not necessarily. You'll just regrow those same stems next year, so the CO2 released by decay gets absorbed into the next year's crop.

Cellulosic biofuels are probably in the end a good idea, I'm just concerned that it might cause a net flux of nutrients from farms to the processing plants. An ideal process would let you extract the phosphorous, nitrogen, and other useful things and return it as fertilizer.

[Idobox]

CO2 cleaning is done on industrial scale already, its not hard its just uneconomical. if you burn natural gas and clean the co2 this uses 1/3 of the energy produced by the gas.

This require that you use injection so it cost almost nothing to store the co2 in the gas field, downside is that you have to run the generator in the area of the well so you probably lose the waste heat to.

And yes this process is used on some gas wells as the gas contains to much co2 initially.

Cement and steal can be imported from other countries and don't affect our co2 budget. Yes its how politicians think, no its its not uncommon or illogical, anybody who has prepared for an major exam know the crystal clear focus it generates, only the short term result as in the grades count, anything else is irrelevant, use any exploit possible.

CO2 capture makes sense where there is a lot of it, in the exhaust of some factories or power plants. So, we agree on that point.

Now, buying cement or steel from other countries is going to be very expensive. Also, if your politicians play that game, they won't either try capturing CO2, which would increase tax and energy costs, when they could just hope other countries will be greener.

[K^2]

Not necessarily. You'll just regrow those same stems next year, so the CO2 released by decay gets absorbed into the next year's crop.

You are double counting. The whole point here is to capture excess of CO2.

[78stonewobble]

Actually that land use doesn't sound that bad for powering the entire world - 24.4 million hectares = 244,000 sq km is smaller than Nevada and only a tiny fraction of the world's land.

As for the water... does it have to be pure or fresh water? That amount would be nothing if you could use salt water. As for the molten salt... that might be an issue, I don't know what total world production of nitrates is like.

OTOH there are other ways to store energy eg pumping water uphill.

The water vapor shouldn't make much difference, it's tiny in comparison to what evaporates from the ocean.

Well I'm no expert.

24 mio hectares is about the size of the entire United Kingdom and this is just for the electrical production. If you want the heat too, I certainly would coming from Denmark, it's about 7x times these numbers, using this method.

I pulled the numbers from this and related articles (50 MW plant):

http://en.wikipedia.org/wiki/Andasol_Solar_Power_Station

It's in Spain, so somewhat more efficient than putting a plant in ie. the UK or Denmark.

Presumably fresh water IS best, since it would be less corrosive to piping and so on, but whether it's necessary I don't know.

The molten salts, are supposedly produced in the same ways as fertilizer (afaik) and if calculated that right (quite a bit ago), diverting the entire worlds fertilizer production to a project like this would get enough salts produced in 20-30 years. However that would presumably leave alot of people starving, which offcourse is another way of solving the entire problem, but if we only use 5 percent of the global production of fertilizer, it would take hundreds of years to produce enough. Again feel free to check my math, because I sure as hell isn't sure of it.

Pumping water uphill does seem like a better solution, but it is highly dependent on geography and can be dangerous, since dams can and do collapse. If the geography isn't there... It becomes a mega project by itself.

Yeah, the water vapor is tiny compaired to what evaporates from the ocean, but it is replacing co2 production and there, supposedly, water vapor is a much more capable greenhouse gas. So a plant like this would be adding to global warming, but whether it's alot or nothing, is beyond me, at this very early hour.

The reason I picked this plant is because it was both plant AND storage (well 7.5 hours worth of storage).

I'm still interested in knowing the enviromental cost of producing that many photo voltaic panels on such a scale, deploying them and maintaning them indefinately. If anyone has any ideas...

While I do think a project like this could be possible, it is a mega project and there are other difficulties. Supplying the entire world from one megaproject in ie. Sahara (or perhaps 2-5 places world wide)... Would be awesome, but think of the cooperation needed and the infrastructure and how many contries would be entirely dependent on the goodwill of other countries, because they could cut the cables at any point. Think about how we need to scale it up often, to accomodate the parts of the world that want to live like we do (and who can blame them for wanting to?).

Edited December 22, 2014 by 78stonewobble