re: wind and sun resources
30 dec 1997
todd flach wrote:
>>david hatunen wrote:
>>>...trying to use random and varied rooftops for solar generation would
>>>involve interconnections and interfaces that would cost more than the
>>>solar units themeselves.
it seems we've now destroyed that myth.
>all electricity generated by rooftops covered by pv's would be used in the
>same building on which they are installed.
probably true, if the owners have finite bank accounts and reasonably
large electrical loads.
>these pv's need not be connected to the grid.
true, although that seems like a good idea, given the pvs.
>the would be connected "directly" to the few appliances which
>could use them, and perhaps, some battery storage. you still need connection
>to the grid to aquire the necessary "baseload" electricity...
why overcomplicate things? a few backwards lamp dimmers would be a lot
cheaper and simpler, and probably wouldn't make the meter go backwards
if they only supplied a small part of the load in a cost-effective system
(elevator motors in office buildings have long sourced grid power when
the elevators descend, with no utility fanfare, cries of fried linemen,
interconnection agreements, net metering tarrifs, and so on.)
this is sort of like solar house heating. a sunspace that only supplies a
small part of a house heating load just makes the furnace run less, as if
the house were in a warmer climate. thermal storage doesn't add much to
system performance, if the sunspace heat will almost always be used.
>...down south... the winter season is short and mild, and passive solar
>heating is a burden in the summertime.
passive solar house heating can work wonderfully down south, with lots
of sun and mild outdoor temperatures. why should anyone in texas burn
gas for house heating? a sunspace shaded and vented in summertime can
keep sun out of house windows and keep the house cooler in summertime
than it would have been without the sunspace...
>>and why bother with this electrical molehill when it's such a small
>>fraction of home energy use, vs heating and cooling with oil or gas,
>>and the electrical use can be easily halved with compact fluorescents
>>and so on, and the cost/kwh is falling under deregulation?
>your comments on using super-efficient electrical appliances are
>absolutely relevant in any situation of power source. here again,
>though, the higher initial investment has to be weighed against
>the present value of lower long-term power costs.
it's interesting to calculate the cost of saving vs generating a watt,
for small and large systems. someone here posted a part of a report that
estimated how much electrical energy could be saved by conservation, vs
new generation, for the same capital cost in millions. conservation won.
in the small, would you a) unplug 5 60 watt 1000 hour 55 cent 865 lumen
incandescents (300 watts, 4,325 lumens) and replace them with a sears
hardware fixture costing $9.99, including 2 40 watt 20,000 hour 2250 lumen
4' fluorescents (80 watts, 4,500 lumens), or b) buy enough pvs to make
220wx8h per day, including installation, batteries and inverters, or
c) put 1 or 2 $929 honda generators in your basement to supply 1,500 or
3,000 watts of electrical power in the winter, along with 25k or 50k btu/h
of house heat, while burning 0.23 or 0.46 gallons of gasoline per hour or
d) add a 32' wide x 12' deep x 16' tall plastic film lean-to sunspace
with 384 ft^2 of two-story floorspace (including a hot tub? :-) made from
$500 worth of standard commercial greenhouse components to the south side
of your house to collect 31 kw (106k btu/h) of peak solar house heat?