Thanks all for your replies, still trying to take it all.

share your doubts to know the true  energy transfers  Perhaps also missing is any account of all the gadgets that are consuming your energy just to get to the point of "spilling over" back to source  or does some of it  leak next door  first ? ?However you quantify it  Volta amps Kirchoff : Could a better starting point be if units of energy ( joules)  were used   Akin maybe to Fusion power research  Vital breakthrough is energy out is greater than energy in . (Still not there ) .  Perhaps the simple approach of measured  energy in vs energy out would be much clearer if applied over and above the mystic solar claims ?  ciao Ms O 

Anne Otis said:

Vital breakthrough is energy out is greater than energy in . (Still not there )

If only! But then the Universe would have boiled over millennia ago. Are you serious?

In relation to nuclear fusion, energy break-even, i.e  more out than we put in was achieved a couple of years ago, and not just in a run-away explosion, but also in terms of heat out of a controlled plasma higher than the energy put in to restrain it from burning out of the containment fields. Some US papers describe this as self-ignition which sounds much sexier, but is a bit misleading. Even so this is a long way from commercial break-even, where the electricity sold pays for the machine, and a 'long' run is seconds or minutes, not the  years of controlled operation that would be needed in a real power station. Equally things in this arena seem to jump a factor of ten per decade more or less, so it may not be as far away as it looked.

Mike.

mapj1 said:

In relation to nuclear fusion, energy break-even, i.e  more out than we put in was achieved a couple of years ago

Hm, I might just accept more usable energy out than we put in.

I must say that I admire TPTB for investing in such very long-term work, which may in fact never be feasible.

A question on inverter voltage level to raise above grid voltage. Does the level of voltage increase with amount of energy generated? I am thinking this may be the case because for example to export voltage level at meter needs to be higher than grid at meter. 

Does the level of voltage increase with amount of energy generated?

The over-voltage is in proportion to the current being pushed back ' the wrong way' into the mains at that time. So the rise, (or reverse voltage drop if you like) on the line in the street is in proportion to power being exported  to grid at the instant of measurement, rather than total generated power at that instant some of which may be used locally, (or indeed the total generated energy, which of course steadily increases the longer it has been running - a voltage rise that did that would be both non-physical and very awkward ;-) 

(but in a battery to talk about total energy and not just power is exactly right,  as the state of charge does depend on current in and out and time)

I may appear to be splitting hairs about definitions, and I am sure I know what you meant,  but it is important to be very clear what we mean by flows of energy to and from where ,and the power with which it happens. There is already a lot of misleading bumf out there that is in many cases well meaning but wrong,  and in other cases clearly intended to spread confusion and separate the weak from their savings and I have no desire to add to the confusion.

Mike,

Does the level of voltage increase with amount of energy generated?

The over-voltage is in proportion to the current being pushed back ' the wrong way' into the mains at that time. So the rise, (or reverse voltage drop if you like) on the line in the street is in proportion to power being exported  to grid at the instant of measurement, rather than total generated power at that instant some of which may be used locally, (or indeed the total generated energy, which of course steadily increases the longer it has been running - a voltage rise that did that would be both non-physical and very awkward ;-) 

(but in a battery to talk about total energy and not just power is exactly right,  as the state of charge does depend on current in and out and time)

I may appear to be splitting hairs about definitions, and I am sure I know what you meant,  but it is important to be very clear what we mean by flows of energy to and from where ,and the power with which it happens. There is already a lot of misleading bumf out there that is in many cases well meaning but wrong,  and in other cases clearly intended to spread confusion and separate the weak from their savings and I have no desire to add to the confusion.

Mike,