On 13 Dec 2003 05:49:28 GMT, athol wrote:

Have they yet manufactured a PV cell that produces more electrical
energy during its economic life than the gross energy required to make
the cell in the first place? Last time I checked, they were close but
hadn't broken even.

It is open to debate but I think so
http://www.homepower.com/files/pvpayback.pdf
http://www.titansolar.com/pvfaq.html

Of course these people are enthusiasts.

One does not question the energy cost of a dry cell battery, yet is
has sufficient utility to be worthwhile using one, even when the
financial cost is measured in GBP/kWhr.

Man's use of energy historically had nothing to do with efficiency, so
that industrialists were quite happy to trade burning coal to produce
1/4% of its heat as motive steam power against employing manual
labour. From that point increasing efficiency gained a competitive
edge.

At the moment this has balanced out at a trade of fossil heat versus
electrical power of from 3:1 to 2:1 depending on capital spend, there
is no reason to suppose it will stay that way.


Economic life of wind turbines was similar last time I checked - the
energy required to make the parts, assemble and install the whole
thing and maintain it through its lifespan was more than the amount of
electrical energy produced...

Again I doubt this, though I was surprised to see their working life
put at around 20 years. Of course the whole drive for these is highly
dependant of the renewable obligation payment levied on fossil fuels.

AJH