Dave Liquorice wrote:

I do wonder how "green", cradle to grave, a complex SMPSU is compared
to a simple linear supply. The SMPSU might be more effcient in use
but will that energy saving be more than the extra energy it took to
make?


Big linear supplies are less efficient to manufacture as they require
more materials. Only the transformer and case/heatsink are recyclable.
They also mess up the 50Hz supply waveform. Linear wallwarts for low
power have better power factors as they are inherently more resistive
and inductive (lousy regulation)even when feeding a capacitative load.
Low power SMPSUs are now produced in such volume that the processes are
ultra efficient, leading to less to recycle. Just look at the selling
prices.