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Yes, that is one of my favourite source books. One particularly depressing statistic in there is that the solar power available for Europe will not be sufficient to support the population, so (assuming this source will supply a significant fraction of Europe's needs) much of the power will need to come from North Africa or elsewhere, and once again political factors become paramount. Europe could become dependent on North Africa, a situation which once existed at the height of the Roman Empire.
(09-20-2014, 06:28 AM)FrodoGoofball Wrote: [ -> ]Of course, there's also fusion. Unfortunately, there have been multiple setbacks in recent years, but the work I've seen lately suggests that neither laser ignition, which has consistently failed to sustain a reaction long enough to even come close to break even, nor "cold" fusion, which consistently produces inconsistent results, are completely "dead" as possible sources of future energy.

A CBS News report suggests that scientists are realizing we don't understand nuclear reactions as well as we thought we did.

I don't know what will happen in our real future, but in OA we assume that hot fusion becomes available for power generation in about 2058 c.e., coincidentally a little more than forty years from now (c.f. the old adage fusion is always 40 years away)
Quote:The paradox of fusion energy is that it is always 40 years away, and has been for some 60 years.

Note that in OA cold fusion doesn't work, or at the very least it only provides power at a deficit. Some very odd nuclear reactions could be possible given nanoscale manipulation of elements, but the energy given off will be transient and feeble compared to the energy achieved in a chain reaction or hot fusion reactor.
But given fusion, even David Makay is optimistic.
Here is his chapter on Deuterium Fusion
Quote:Deuterium fusion

If we imagine that scientists and engineers crack the problem of getting
the DD reaction going, we have some very good news. There’s 33 g of
deuterium in every ton of water, and the energy that would be released
from fusing just one gram of deuterium is a mind-boggling 100 000 kWh.
Bearing in mind that the mass of the oceans is 230 million tons per person,
we can deduce that there’s enough deuterium to supply every person in
a ten-fold increased world population with a power of 30 000 kWh per
day (that’s more than 100 times the average American consumption) for 1
million years

That is without considering the vast resources in the Solar System's Gas Giants, and the atmosphere of the Sun (Paul Birch noted that Sun Mining would be the most profitable source of fuel, thanks in part to the Sun's abundant energy). The fusion in the Sun gives off a billion times more energy than this planet can ever intercept, so a space-based civilisation should have ample power - but of course that is the entire premise of OA, and to get there we have to get through the energy bottleneck of the next century.

Note that every new colony in an extrasolar system faces a similar bottleneck - there is ample energy in almost every solar system, but to access it you have to expend a lot of energy to build the infrastructure.
After skimming the book that was linked to a few thoughts:

a) Toward the end the author basically seems to be saying that in order to make renewables work with anything like current tech, some lifestyle changes would also need to be made (changes in transport design away from cars for example) which seems reasonable (ignoring the 'people problems' that have already been mentioned as perhaps the single biggest bottleneck.

b) With (a) in mind - what about the impact of improved insulation and efficiency? Smart grids are being developed now, even if a global grid seems a good ways away and improvements in insulation tech and perhaps changes in building designs that can make better use of passive solar could be phased in over time. IIRC there was a suggest that just painting roofs white or in lighter colors could help with cooling costs (meaning energy used) in many areas. Computer controlled systems for lights, water usage, etc. might also increase efficiency demand and help reduce the overall amount of energy required.

c) While it's not a renewable per se (but H2 is rather common), hydrogen fuels might also play a role in the future. Various experimental programs are out there, including using fuel cells on buses (which would seem to have fewer of the issues associated with alternative fuels than cars do and have better performance as detailed in the linked book). It also appears that some work has been done on trains in this area. If H2 fuels could be phased in, they could reduce or replace the segment of the energy equation for transport. For that matter, I've seen at least one (old) proposal for H2 fueled jet aircraft many years ago. So might impact the air transport segment as well.

Finally re evening out power from renewables - would it be possible to 'store' energy via hydrogen fuel cells to act in this capacity?

(09-20-2014, 07:04 PM)stevebowers Wrote: [ -> ]Note that every new colony in an extrasolar system faces a similar bottleneck - there is ample energy in almost every solar system, but to access it you have to expend a lot of energy to build the infrastructure.

Well, yes and no. While it's true that all the energy infrastructure must be built and that requires energy, it's also likely that:

a) if you have the wherewithal to build a starship in the first place, you have quite a bit of energy available onboard to power the initial construction.

b) Your construction systems can themselves be both automated and solar powered. Given that in OA such systems are also probably self-replicating and totally automated, the 'bottleneck' becomes one of locating optimal starting points, deploying the construction units, and then waiting for them to do their thing. If you've already got the wherewithal to sit in a ship for the years or decades it took to get there, sitting for a few more months or years isn't likely that much of an issue.

For that matter, with the kind of tech involved, it might make more sense to send the robots ahead and have them start building before the ship arrives. That way, your initial colony infrastructure is all built when you get there. No bottlenecks required.

Particularly in the early part of the scenario, a colony ship would arrive with only minimal energy to spare - almost all of the fuel would be expended, and much of the mass of the ship would be discarded. In a system where the volatiles are in the outer reaches and the power sources are in the inner system, the colonists would need to rearrange resources on a significant scale before achieving sustainable growth. This stage would also be faced by any robots that prepare the system beforehand, so they will need to be well-programmed and adaptable.

Here's Robert Freitas' strategy for robotic reproduction; maybe we should fold something like this into the Neumann article. It is a long and complex business, but (it seems) by no means impossible.
I would disagree on several fronts:

a) For interstellar travel in any kind of 'reasonable' time frame to work at all you are talking about fielding energies hundreds to tens of thousands of times the output of our entire civilization. The more so if you are actually going to do an actual colonization mission. The amount of fuel required to power the ship as a type of space colony in its own right (rather than a propelled vessel) would be minimal in comparison - even if you wanted enough to run it for years or decades just on internal sources.

b) Using mag-braking as Zubrin has suggested a colony ship could slow down with essentially zero fuel expenditure (except for the last bit of the trip). This takes longer with the slower ships early in the timeline, but they are slower anyway, so I'm not sure it makes that much difference. Regardless, use of magbraking should greatly reduce the amount of fuel required for decel and thus free up a margin for use for energy when the ship arrives.

c) It isn't correct as a blanket statement to say that the power is in the inner system while the volatiles are in the outer. The Earth is in the inner system and gets plenty of solar energy and has plenty of volatiles. In addition, if you have a fusion drive and a colony ship, then you can just go to the outer system and extract fusion fuel from the volatiles there - no need to bother with the inner system for that - although you may (or may not) need to send mining expeditions around for raw materials (depends on the composition of the bodies in the outer system).

Conversely, you could put the ship in orbit in the inner system and use solar energy and then send out mining expeditions to volatiles sources in the outer system if your energy tech is more slanted that way.

d) Unless your colony is of minimal mass, it will have various secondary craft that could be sent out to extract resources from different locations in the system as well as the experience of industrial scale resource extraction in the solar system - as such the miners should have a good idea of where to find what. Possibly precursor probes would have already surveyed the system thoroughly and located useful concentrations of resources before the expedition ever arrives - the entire notion of colonists simply arriving in a new solar system with no idea of what they will find and no preparation owes more to the colonization of the Americas and the American West (and a heavy dose of romanticism) than any realistic assessment of how an interstellar capable civilization (even an early one) would go about colonizing a new solar system.

To provide a point of comparison - imagine what would happen if a new continent suddenly appeared in the middle of one of the oceans and our civilization decided to set up colonies there. We certainly wouldn't do it the way the first English or Spanish colonials did it. We would use satellites, recon flights, both manned and drones, and the experience of decades to a century of resource location techniques as part of the process. At least that level of tech is likely to be employed with a colony.

e) In OA we presume that nanotech and neumann technology come along fairly early in the timeline, along with advanced robotics in various forms. By the time of the ND, neumanns could apparently replicate on timescales of a year or less. Far faster than what Freitas describes (I agree it might be interesting to use his article as a resource to inform an updated Neumann article - but we also need to take into account tech that he doesn't in this paper and that we already include in the setting) and therefore able to accomplish far more than what he describes here. We also make mention of some issues with self-rep tech that is too long unsupervised in OA, and that also would need to be taken into consideration - but that also makes a place for adventures and stories of various sorts.

The upshot of all this is that I would argue that by the time we have the means to launch interstellar colonies, we also will have the means to bypass the sort of bottlenecks described here - as well as take an approach to colonization that is quite different from that normally depicted in SF, which itself is based on ideas of colonization that are centuries out of date.

My 2c worth,

Some of the colony ships were sent out in the Interplanetary Age, with relatively basic nanotech and relatively low powered ships; some of the earliest First Federation missions would have been very similar in capability, since they were launched by a civilisation still on the road to recovery. I note that Freitas' favoured target would be a moon of a gas giant, where the best mix of volatiles and metals might be found, and energy is quite abundant in the magnetic field. But such a location might be dangerous for colonists. Maybe a good strategy would be to send an advance party of robots to the gas giant moons, which could then send secondary missions to establish more habitable locations. Unless, of course, the colonists were accustomed to colonise gas giants themselves.

Most, but not all, of the colonies in the later eras would be established by expeditions with much better technology, and would have more chance of rapid success.
Nuclear energy, fission and fusion, is just like GMOs, victim of ignorance. Anyone willing to read a little can see that most fears are unfounded, yet the scare mongering of certain people continues to win over the reason.
For example Germany had little to no reason to quit nuclear power. Yet it did and now it has to burn more coal than ever. It's even worse in Austria, not only did they waste billions constructing and then never opening perfectly fine plant, for last twenty years they protest against plant in Czech Republic, produce horror documentaries about it and sometimes block border, yet they still use energy it delivers to the grid.
One of the more interesting ideas Freitas has is that a self-repping robot swarm might not find all the elements it needs, but could use fusion to create some of the rarer elements - I don't think we've ever considered the earliest colony missions as having that kind of small-scale fusion capability, although they all have fusion or catalysed fusion drives. Even the beam-propelled craft would need a fusion drive to decelerate to orbital speed. Certainly later colony missions could use fusion/transmutation to fill the gaps in the resource table, but I don't think this technology would be available for the earliest interstellar colonists.
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