@grahamf They are not interested in small installations and they take advantage of the fact that there can be enough generation to still make it attractive.

There is another factor which I think smells somewhat.

My contract is with EDP, but when Solar PV came along they split off the entire distribution business to a new company, E-REDES and all questions of import/ export have to go through them even though there is no contractual connection.

I have a fight with them currently after a very unlikely bill in February and with a meter check tomorrow.

Posted by: @davidalgarve

↑

There is another factor which I think smells somewhat.

My contract is with EDP, but when Solar PV came along they split off the entire distribution business to a new company, E-REDES and all questions of import/ export have to go through them even though there is no contractual connection.

I have a fight with them currently after a very unlikely bill in February and with a meter check tomorrow.

Same here, you buy (or sell) electricity from/to one company (an electricity retailer), but its another company (the distribution network operator) that has to agree to solar/battery connection.  However the regs oblige the DNO to agree to connections up to a certain amperage and oblige the larger retailers to pay for exported electricity (albeit at a lot less than 12p/kWh). 

This seems to be a case where the UK got it right.  Better not let certain sectors of the UK media know, it will spoil their fun.

@davidalgarve very frustrating, but I get the impression that you may be making some progress?

@grahamf

Posted by: @grahamf

↑

very frustrating, but I get the impression that you may be making some progress?

Not really.

E-REDES did a very rudimentary meter check which proved nothing.

With help from MelPump I have obtained heat pump consumption from MelCloud  over the exact period in question, (2,020kWh) and similarly extracted a figure from my heat pump Shelly EM3 (1,900kWh). It seems that I can't expect any better accuracy from either.

However, whichever I use of these takes me nearer to the billed figure of 2,554kWh and MelPump suggest that the greater consumption could be down to: a) colder and longer winter and b) the poor pipework mods to change the buffer tank to a volumiser, which resulted in a reduced available flow rate. (Almost wish I had never started on the buffer tank exercise!)

So I have more or less given up on this battle and dreading the new 2 month bill expected any time soon.

We are now on MelPump Summer settings and more solar being produced, so I am starting to plan doing the pipework improvements. I will have to use Plex again and I intensely dislike their sharp elbows, but there is not much copper availability here now. I am rooting through my parts boxes to find any larger radius screwed brass fittings.

Unfortunately, I have to have a hip replacement operation so don't know how all that will fit in!

@grahamf On the initial question of when to heat the DHW, I am trying an alternative approach with MelPump switching on at 15:00; 6Deg hysteresis and ending at 17:00, aimed at taking advantage of fully charged batteries.

However, I am not convinced because it still draws 6kW which my 4kW solar cannot provide so I am paying at peak rates for part of the consumption. Also, it is only just giving reasonable water temperature for 7:00am showers