[Marxism] "Major Discovery" From MIT Primed to Unleash Solar Revolution
II
Les Schaffer schaffer at optonline.net
Fri Aug 1 13:56:44 MDT 2008
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David Walters, et al.:
for what its worth, i am currently consulting on a concentrating solar
power system (CSP) design ... but CSP simply delivers high temperature
steam to run a turbine to produce electricity to do XXXX. How CSP would
relate to this new electrolysis is unclear, no? you claim the
breakthrough is in storage. but storage is only needed if you want to
make some fraction of electric users fully dependent on solar.
otherwise its simply another source of power. and if you store, you
have
to reconvert and transmit later, and we know our transmission
infrastructure is creaky. now a global transmission system, powering
the
shadow while while the other side sunbathes, that would be something,
eh?
but lets grant this breakthrough storage scheme and see what kind of
area is needed so that solar could fill the tank, so to speak. how many
square meters of sunny area would be needed, in the US for example, to
power itself, assuming you *could store* and re-transmit through the
remaining say 16 hours of dawn, dusk, and night?
well, whats our latest power usage, averaged over 24 hours? from
wikipedia:
http://en.wikipedia.org/wiki/Energy_use_in_the_United_States
i get about 1,000,000 MW for the electric production rate in 2006.
(nameplate capacity)
so, lets say we can collect solar energy at 100% efficiency over a
third
of the day and store for the other two thirds of the day. then we need
3,000,000 MW of instantaneous production.
3,000,000 MW / (1.4 kW / m^2) = 3,000,000 / .0014 (m^2) =
2,142,857,143
(m^2) = 825 sq miles (= 530,000 acres)
this sets the *scale* for solar-electric production without revolution
in the way we live. that is 825 square miles of the earth's brightest
surface blanketed with solar collectors, connected to electrolysis or
energy storage of your choice and re-transmitted now or later.
interesting number. not quite as fearsome as i first guessed, but
plenty
big... everything 100% efficient, nothing but the best for us .... ;-)
you can play with the numbers. you want to promise us some clean/safe
nuclear, take some fraction of 824. want to keep burning coal but at a
reduced rate? reduce it some more. and so forth. want to reduce
electric
consumption by half? want to leave the others forms of production and
just eliminate coal-fired, thats 400 sq miles then. you think we can
collect for 12 hours of the day in New Mexico?: 500 sq miles. etc etc
etc ...
for the quibblers amongst us: when i say that 825 sq miles sets the
scale for solar-electric production, it means its an order of magnitude
estimate. if the wikipedia #s are wrong or misleading, the point is to
set the gross scale at which one would need area for solar power
collection at the 1.4 kW/m^2 intensity. if you come up with 325 sq
miles
or 1600 sq miles, its only incidental.
andy pollack: did this answer your question, or do we need more details
on collectors and efficiencies and all that? can someone like the
railroad man make an estimate of the cost (materials, labor,
environmental) to produce say 100 square miles of x% efficient
collectors?
by the ways:
1. someone pointed out on a blog that the water usage for this new
conversion scheme would be large.
2. the wikipedia #s give us (potential) electric production as of two
years ago, not total energy use.
3. that wikipedia article above states there is about 400 MW of solar
electric generation in the US in 2006. i don't know if that is daily
average or what. but that requires about 0.1 sq miles of existing
collector surface area. so we have at least three orders of magnitude
to go.
4. Rhode Island has 1545 sq miles. so half of Rhode Island.
to sum up, storage of solar energy is a piece of the puzzle, but only a
piece, and not the most important piece. to keep things as they are
(consumption-wise), supply must equal demand. in power this is true.
storage is a detail. so the MIT claim is hype, though the prof has come
up with an interesting and potentially useful technology.
Les
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