Re: on energy conservation....


"abelard" <abelard3@xxxxxxxxxxx> wrote in message
news:rj6v23p2s00op9d0orhu459he3q30pkg8f@xxxxxxxxxx
On Wed, 25 Apr 2007 19:15:32 +0200, abelard <abelard3@xxxxxxxxxxx>
wrote:


continuation
http://www.spiegel.de/international/world/0,1518,476231-4,00.html
"....The south-facing glass side of the structure captures the winter
sun, but during the summer the sun is high enough in the sky so that
the rooms don't heat up.

The building, a so-called positive energy house, actually produces
more energy than its residents need -- it's essentially a tiny power
plant. The solar panels on the roof produced almost 9,000
kilowatt-hours of electricity in the first year. Subtract the
structure's own power usage along with heating costs and there's still
a surplus of around 2,000 kilowatt-hours left over. The monthly
expenditures of ?100 for electricity and heat are more than offset by
the ?400 in revenue the solar panels bring in.

Except that ignores the cost of buying the solar units. In Germany they
typically assume that solar units produce the energy equivalent of 900 hours
at peak output, so 9000 kWh of electricity implies a capacity of 10kW, which
would run to a cost of around ?40,000 including roof strengthening,
installation and inverters. The tariff in Germany for solar powered
electricity is just under 50 cents per kWh, so the extra 2,000 kWh will
bring in ?1,000 per year not ?400 per month. ?1000 per year doesn't really
pay for a ?40,000 investment with a 25 year life.

In the real world we would only get 7 cents per kWh for electricity, so this
domestic generation is only feasible with massive tariff subsidies at
present. But watch out for thin film technology.


.

Relevant Pages

  • Re: on energy conservation....
    ... sun, but during the summer the sun is high enough in the sky so that ... The building, a so-called positive energy house, actually produces ... The solar panels on the roof produced almost 9,000 ... kilowatt-hours of electricity in the first year. ...
    (uk.politics.misc)
  • Re: Are libraries dying?
    ... KWH for electricity. ... Roof top solar PV is not economical. ... except in places where electricity is ridiculously overpriced. ... Not a big monster 15 KW panel system that costs $30,000. ...
    (rec.arts.sf.written)
  • Re: Destroy this argument....
    ... The sun is not available 24 hours. ... Electricity is a relatively "local" use item. ... capability for solar almost equal to the base load, ... a solar one and a backup conventional ...
    (sci.energy)
  • Re: Also I tried to be open-minded, I tried splitting H2O tonight with 12V 120 amps,
    ... Was it an efficient investment of the electrical energy? ... yes - when one considers that not all electricity is ... Solar electricity from photovoltaic sources is intermittent and direct ... A metric ton of hydrogen has the same heating value as; ...
    (sci.energy.hydrogen)
  • Re: Electric Car? How about a Compressed Air Car?
    ... photovoltaic power generating system is used to turn the electric ... that excess solar power could be used to directly charge ... Generating H2 with the excess energy ... hydrogen gas is converted into electricity through a fuel cell. ...
    (rec.aviation.piloting)