Martin Brown wrote in message ...
In message , PrisNo6
writes snip

Thanks, Martin. Your informed comments gave me many insights into an
area I do not know much about.

Despite what the ILE in the UK says there is no reason why FCO
luminaires for LPS lamps cannot be manufactured. They are used for
street lighting in mainland Europe. And then you do get energy savings.

My own impression in the U.S. is that politically the only way that
light-pollution reduction could be "sold" to the non-astronomy public
is on the grounds of increased energy efficiency. This assumes that
the life-time replacement and electricty costs of FCO-LPS lamps for
highway lighting is less than life-time costs of new lamps as existing
ones wear out.