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re: wind and sun resources
23 dec 1997
greig ebeling wrote:
>the wind farms that you claim will be replacing fossil fuel plants.
>if they don't have energy storage systems, then what's going to happen
>when the weather is calm?
something else takes up the load, eg small-scale cogeneration?
who says windmills have to supply 100% of electrical grid power?
>calculate a price on electricity which is generated with wind,
>and stored in any of these schemes.
why store wind energy, if the wind fraction is small?
>i studied a semester of solar engineering as part of my 4th year in
>mech. engineering...
so it's no surprise that cos(45) = 0.71, ie a solar house with an
orientation error of 45 degrees still receives over 70% of the sun
of one with perfect orientation.
>>> in winter, in warm sunny sydney, in my passive solar plan house, i use
>>> gas heating for two months of the year (winter tends to be cold,
>>> cloudy and wet here). passive solar design saves me some money, and
>>> improves my lifestyle, so i'm all for it.
good... how cold and cloudy is sydney in winter? what is the average
outdoor temperature, and how much sun falls on a north-facing wall on
an average day?
>...very few people have the wherewithall to take advantage of passive
>solar designed houses.
it seems to me that most homeowners have the wherewithall to add on
an inexpensive sunspace to their existing houses in order to provide
some fraction of house heating, and to further add some inexpensive
thermal storage for more than one cloudy day, to raise that fraction.
>>> ...melbourne, adelaide and hobart to the south are not so lucky with
>>> weather, nor are more than half the population who cannot afford to
>>> have a north facing block, protected by hills from southerly busters.
who needs hills to block winds? that's nice, i guess, but not a
requirement for solar house heating. nor is "a north facing block,"
in the sense that many houses have 1 that faces the equator, within
45 degrees or so. mes design reasonably-priced cars to run uphill
as well as downhill, right? :-)
>>...what's wrong with large segments of the global population utilizing
>>solar thermal energy?
>
>it is too expensive.
some kinds are, eg pvs, but others are not. sunspaces can be
inexpensive, especially if they add floorspace to houses.
>...i am just trying to illustrate the limitations of passive solar
>design in reducing co2 emissions. it helps, yes. at a price, you bet.
>but it is not the answer. it's not even a small fraction of the answer.
perhaps there is no one answer.
"passive solar design" works well in some cases, eg in the southwest us,
but in colder cloudier places, sunspaces work better than direct gain, and
small fans can double efficiencies. and solar heating is glamorous, but
it seems like a small part of the picture--most of the work of making a
100% solar heated house consists in making it airtight and well-insulated.
>i am not against solar and wind energy.
you do seem to like it, but you also seem overly pessimistic.
>...many people are demanding less fossil fuels and less nuclear power,
>and demanding that solar and wind will replace them.
that is simplistic for now, no?
>it is my opinion that that they are too expensive and unreliable
>as energy sources, and therefore will not supply even a small
>fraction of our future energy needs.
i have a different opinion. it seems to me that "they" are different in
cost effectiveness, and "reliability" is a matter of weather statistics,
and heating is different from electrical power generation. and the sun
can provide a significant fraction of today's and tomorrow's house heating
needs at a reasonable cost.
nick
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