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Renewables
#51
(10-17-2014, 09:12 PM)Cray Wrote:
(10-16-2014, 10:50 PM)Fsci123 Wrote: I'm skeptical... But if they succeeded...

This announcement is atypical of Skunk Works. Normally they have a working prototype to show off by the time they announce their results.

Frankly, I'm willing to bet they've come down with a common fusion researcher syndrome, Robertbussarditis. This is a condition where your back-of-the-envelope calculations indicate you'll achieve miracles in a short period because your idea is the greatest ever.

So, I'm responding to this like I am to eCat: I'll check back in a year and see how things are going.

Regarding fusion in small (as in smaller than a ten-storey building) units, it looks to me (I have a science degree but I'm no engineer) that DPF (dense plasma focus) fusion shows more promise than any of the Polywell variants. It looks as if the units might be as small as a large domestic fridge and cost maybe $50k, to start - of course, if production ramps up they will get cheaper and may get smaller.

Advantages include; much nearer to a working prototype, next to no neutrons (a different reaction is used) and perhaps of most interest to members and guests here, a reasonably easy route to making a fusion rocket out of it.

Of course, the resultant availability of 500km/sec torchships brings its own set of problems...
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#52
(01-13-2015, 12:38 PM)tmazanec1 Wrote: The Limits to Growth predicted a peak and collapse of industrial civilization around 2030 if trends then being followed continued. They have continued, but we haven't reached the drop-off point yet. It did project that, by about now, it would be too late to prevent this collapse, however. I purchased TLTG when it came out in the Seventies, and even had a version of their World Model on my Apple ][+, so I remember this quite well. They may or may not be correct, but we can't tell from the fact that industrial civilization is still tootling along in 2015.

The predictions of TLTG do follow the data of the last few decades quite closely, except for two minor discrepancies; population has not grown quite as fast as they predicted, and pollution is somewhat less drastic than envisaged. The birth rate in almost every country outside Africa is now hovering somewhere around replacement levels, so population growth is less than predicted; also pollution has declined in the First World to almost negligible levels, thanks to environmental laws. But the depletion of resources (especially fossil fuels) continues to follow the predictions.

What is controversial is the 'overshoot and collapse' model. showing that both will start to happen in the 2030s. Since there is no sign of an overshoot and collapse happening yet, most people disregard the possibility. Even in TLTG most of the growth signs are still positive for the period around 2015, except for the projected increase in pollution, which really hasn't happened (except for the increase of CO2, which is a separate issue).

Overshoot and collapse is a concept found in ecology, and has plenty of evidence to back it up there; but the population of a species in the wild does not rely on technology in the way human populations do. Already our species has developed numerous technologies to address the resources issue, such as recycling, renewable energy and shale oil, which have contributed to the recent collapse of oil prices in the last year. Unfortunately, the same environmental concerns that have resulted in a reduction in pollution levels in the West are also inhibiting the adoption of nuclear power technology, which could be a much better solution to the power shortage than fracking.

But the main lesson of TLTG remains true; as the world becomes increasingly wealthy it will use resources at an increasingly rapid rate. This rate of increase is reduced by the fact that population has not grown quite as quickly as predicted, but the path to a wealthy global economy is likely pass through a period in this century when increased demand meets falling resources, and new strategies will be needed to address this.

Better recycling, increasing adoption of renewable energy sources, and (hopefully) fusion power should address the main problems of falling resources; to ensure (for instance) that there is enough fresh water to replenish aquifers and reverse salinification of soils will require a lot of energy, and currently we don't have a good strategy in place to source that energy.
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#53
The issue of carbon dioxide pollution is a separate one, although TLTG does not really address it as one. CO2 is a result of fossil fuel use, so its production will decline as fossil fuels run out; however as shale oil exploitation technology increases, we might see an extension of the fossil fuel era (there is a metric fuckload of kerogen down there). I tend to think of CO2 as being a temporary problem, as developments in biotechnology and artificial photosynthesis will actually require this gas to be present in the air, changing the pollutant to a valuable resource. In fact, given sufficiently advanced technology, almost any pollutant can be repurposed as a resource, even nuclear waste.

But these sort of projected, hypothetical technologies depend on the continuation of our technological society. At OA we assume for the purposes of the scenario that technology will continue to advance, into realms we can barely glimpse at the moment. Some of the technologies that may result should help us get through the 'overshoot and collapse' scenario, but only if they are available when they are needed - this is not guaranteed by any means.
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#54
(01-13-2015, 06:59 PM)iancampbell Wrote: Regarding fusion in small (as in smaller than a ten-storey building) units, it looks to me (I have a science degree but I'm no engineer) that DPF (dense plasma focus) fusion shows more promise than any of the Polywell variants. It looks as if the units might be as small as a large domestic fridge and cost maybe $50k, to start - of course, if production ramps up they will get cheaper and may get smaller.

$50,000 and smaller than a fridge? What's the estimated power output on a thing like that? Like with most things fusion sounds too good to be true. I don't have the expertise to judge whether or not DPF is promising (I've read a few articles and seen a few videos) but I'm skeptical on the grounds that we've been chasing this dream for the better part of a century and we're still not beyond lab prototypes. I'm not dismissing fusion power itself but if anything it's shown itself to be entirely non-trivial, so much so that I tend to rule it out in discussions of future energy production in the mid-future (decades).
OA Wish list:
  1. DNI
  2. Internal medical system
  3. A dormbot, because domestic chores suck!
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#55
(01-13-2015, 08:55 PM)stevebowers Wrote: But the main lesson of TLTG remains true; as the world becomes increasingly wealthy it will use resources at an increasingly rapid rate. This rate of increase is reduced by the fact that population has not grown quite as quickly as predicted, but the path to a wealthy global economy is likely pass through a period in this century when increased demand meets falling resources, and new strategies will be needed to address this.

Better recycling, increasing adoption of renewable energy sources, and (hopefully) fusion power should address the main problems of falling resources; to ensure (for instance) that there is enough fresh water to replenish aquifers and reverse salinification of soils will require a lot of energy, and currently we don't have a good strategy in place to source that energy.

I've read proposals for nuclear powered desalination that could be economically viable in certain nations. In any case in recent years I've come round to the notion that the future isn't going to be the bright, rich, energy fuelled world we thought it would be (that's yesterday's future) but isn't necessarily going to be a dystopic wasteland either. For the most part it seems that fossil fuels will run out, or at least continue to get very expensive (recent market bounce notwithstanding) but hopefully the world is on track for installing a decent level of non-fossil fueled energy infrastructure before then.

Solar PV in the last decade has seen installation rates that are almost exponential. Wind, hydro and other sources are also seeing a rise. In the western world new regulations are in place that enforce higher energy efficiencies on buildings and products (so much so that energy efficiency is something you see advertised on products) and we may be seeing the beginning of electrification of all ground transport.

When I think of the future at the moment I tend to see a world of:

- Expensive but clean energy
- High efficiency environments
- Lots of automation
- A fair amount of lifestyle changes to deal with the first point
- More equality between countries
- Less equality within countries
- More gadgetty gadgets
OA Wish list:
  1. DNI
  2. Internal medical system
  3. A dormbot, because domestic chores suck!
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#56
(01-13-2015, 09:49 PM)Rynn Wrote:
(01-13-2015, 06:59 PM)iancampbell Wrote: Regarding fusion in small (as in smaller than a ten-storey building) units, it looks to me (I have a science degree but I'm no engineer) that DPF (dense plasma focus) fusion shows more promise than any of the Polywell variants. It looks as if the units might be as small as a large domestic fridge and cost maybe $50k, to start - of course, if production ramps up they will get cheaper and may get smaller.

$50,000 and smaller than a fridge? What's the estimated power output on a thing like that? Like with most things fusion sounds too good to be true. I don't have the expertise to judge whether or not DPF is promising (I've read a few articles and seen a few videos) but I'm skeptical on the grounds that we've been chasing this dream for the better part of a century and we're still not beyond lab prototypes. I'm not dismissing fusion power itself but if anything it's shown itself to be entirely non-trivial, so much so that I tend to rule it out in discussions of future energy production in the mid-future (decades).

Estimated power output at that size is 5MW or thereabouts. And I am not at all sure whether the stated size is just for the reaction chamber without all the ancillary stuff - it probably is.

One more thing about DPF is that the proposed reaction (proton/B11) puts out most of its energy in fast alpha particles - which is a very good thing, because it means non-thermal methods of energy extraction can be used giving very good efficiency.

And one more thing - if one wants to be purist about it, proton/B11 should probably be described as fission. Smile
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#57
You know this talk of collapse reminds me of San Marino. When mason Marinus built small church in the hills the Roman Empire still stood, weak but still standing both east and west.
Centuries past, kingdoms fell and empires collapsed but that tiny republic survived it all. Who knows, may be some sort of collapse is coming and maybe some Marinus is building proverbial church as we type.
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