permaculture

[jedd <jedd@progsoc.org>]

On Sun, 17 Jun 2007, Kenneth Benway wrote:
> To whoever changed the topic name I would suggest that maybe next time
> you consider using a more empowering title like "Feasible Power
> Solutions" which has a more positive intonation than "Infeasible power
> fantasies". 

 That would be me, Ken.

 It was hard to feel empowered by an infeasible suggestion that
 Florida (in the USA, yes?) goes completely solar for all its
 power needs.

 Perhaps if  I was part of the 0.0027% of the population of the planet
 who lived in Florida I may feel differently. I can but idly speculate.

> 8. Geothermal technologies that leverage ground water temperatures with
> respect to stabilizing ambient air temperatures to a desired level.

 Here's the first of the caveats we've been waiting for, and that I was
 intimating earlier with my solar will be a component reference,
 prompting the 'infeasible' response to the '100% solar' claim.

 Solar has obvious flaws - it relies upon the sun, being the biggest
 one - that preclude it from being a contender for 'sole provider'.

 Most green power gen techs have similar limitations, which is
 why they're far more compelling when treated as components of
 a whole system or power provisioning.  By whole I mean integration,
 not what you might mean by whole [1].  <oooh, I feel dizzy>

 The large scale plants Robyn was mentioning came up on this or
 one of the other permy lists several weeks ago, after the Beeb did
 a report [2] on a new solar thermal plant on the Iberian peninsular.
 (Yes, yes, the yanks had one some years ago that has since been
 steadfastly ignored by everyone in power <npi> over there, and yes,
 it's conceptually a scale-up of the old portable parabolic kettle.)

 The Beeb suggests this is a 11MW plant currently, but will upgrade
 to produce around 1.1GW.  The WP article Robyn cited [3] hints at
 the same plant being 50MW.  I'm not sure which of those sites
 I distrust more .. but in any case, the conversion rates at the dish,
 so to speak, compare favourably to PVC's .. despite constant 'new
 advances' that promise to bring PVC's up from their 15%-ish (?)
 efficiencies Real Soon Now.

 Segue - happily, here in .au [4] they're building a hybrid system.
 Lots of mirrors focussing sunlight onto a relatively small area of
 PVCs, that promises to be pretty interesting.  It sounds like this
 could also be adapted to urban environments relatively safely - not
 as good as rooftop gardens, but more attractive than GSM towers.

 Unhappily, however, they fall into the same trap as the Andalusian
 crew when insisting there are zero greenhouse emissions.

 If we (by which I mean the anti-stupidity lobby) insist that the
 nucular [5] proponents include the whole cost of a fission-nuclear
 power plant - from build through fuel acquisition through to
 decommissioning -  then green techs should be calculated with this in
 mind also.  The embodied energy in a PVC is typically considered to
 take around 5 years to pay itself back, on an energy in / energy out
 basis.  Depends on utilisation, of course, but averages are handy
 things to work with, and the point is that PVC's require significant
 energy & resources to produce, and we shouldn't be seen to be
 discounting them.

 Looking at the concrete tower near Sevilla ... that's a seriously
 expensive (in resources rather than euros) structure, and it should
 be factored in before making claims of it being a power source with
 zero greenhouse emissions.  Slipping the words 'while running' is a
 tad sly, and I don't think does us any favours.

> 3. relates to emerging technologies such as "room temperature
> superconductors" which I would certainly like to know more about.

 If you're looking to acquire wealth, and this is in no sense
 financial advice being offered here, prime real estate 10+ metres
 above current sea levels, and mobs doing research into room temp
 superconductors are the two places to throw your money, IMHO.

 I rabbit on about superconductors periodically, and I'm sure you are
 already familiar with the technology per se, but the effects of the
 discovery or invention of one that runs at room temperature would
 be enormous.  Partly in high tech (computer & comms systems) but
 ultimately in power generation and transfer.  Think a submarine
 cabling system, a la the extant fiber optic comms network around
 the planet, but for transferring power.  Make it the backbone of a
 global wind, tidal, wave, solar network.  Nice!

 Actually, at some point the cost of providing a satisfactory insulate
 and of maintaining a low temperature, along with the average temps
 at bottom of the sea being around 4C, makes 'room temperature'
 somewhat of a misnomer compared to what's really required, but
 the term is used to distinguish the fantasy from the current reality
 of warmest superconductivity (around -120C).

> With regard to the second remark the answer is storage batteries.

 I'd suggest you revisit this plan.

 Storage batteries are expensive (as above - resources, as well as
 raw currency), messy, dangerous, high maintenance, inefficient.

 Have you considered how this would scale to the 'whole of Florida'
 plan you're formulating?  It may be, like the real estate needed to
 produce 100% of energy needs from solar, a case of simple math <sic>,
 but I'd humbly suggest you start doing the simple math earlier rather
 than later.

 As of about a decade ago (I've not heard of any challenges to this
 since) received wisdom was that the most efficient way we had of
 storing energy was to pump water up a hill.  This obviously was
 predicated on providing large scale and long term energy storage,
 but that's exactly what you're talking about here.

> As I mentioned earlier it can become difficult to find these valuable
> nuggets of pertinent information when searching this list. 

 Minimising and inlining quoted material makes this easier, albeit for
 everyone else.  Other people's laziness just makes it harder for
 those who know what they're doing.  An eternal truth, alas.

 Jedd.


 [1]  https://lists.ibiblio.org/sympa/arc/permaculture/2007-June/027465.html
 [2]  http://news.bbc.co.uk/2/hi/science/nature/6616651.stm
 [3]  http://en.wikipedia.org/wiki/Solar_thermal_energy
 [4]  http://www.solarsystems.com.au/documents/SolarSystemsMediaRelease.pdf
 [5]  http://www.slate.com/id/2071155/