solar self consumption device.....

QrizB

Reed_Richards said:

Petriix said:
I'm fairly certain that all immediate electricity demand in the UK is met by gas power stations with a round trip efficiency of around 60%. It's objectively better for the planet for you to export the surplus and burn gas to heat your water at 80% efficiency. 

I disagree.  Whilst this may be true at times of peak ("Immediate") demand, the time when you have spare solar power is not when there is peak demand, most likely gas power stations are off or in idle mode.

Looking at http://www.gridwatch.templar.co.uk/ it seems as though the UK has been running at least 5GW of CCGTs continuously (or at least, with very few exceptions) for the past year, and at least 10GW in daylight hours for the past fortnight.

Unless your domestic generation works best in the dark it's likely that any exported power will displace gas generation.

Reed_Richards

That's fascinating @QrizB but I am surprised to see how much demand there is in the middle of the night and how small the early evening peak in demand is relative to the rest of the day.  Also the solar contribution is not reported well quantified.    

JKenH

nologo said:

I am considering  solar for my large south east facing roof, I know Im not going to save the planet on my own but every little helps.

I have mains gas heating, & a large hot water tank with two immersion heaters installed.(economy 7 style) 

As fits are low my main objective is self consumption, so to this end a solar diverter to hot water is a good start, someone working from home three days a week(office/ computer) is also useful, but I think I recall  device that could divert excess  to another device ( resistance heater/oil filled rad) but cant for the life of me remember what its called, can any body help?  also any other ways to self consume?   we have delay timers on our dishwasher & washing machine so thats another idea 

TIA. nologo

I have one of these - an insulated low wattage boiler. 

https://www.scottsofstow.co.uk/neostar-perma-therm-water-boiler-and-dispenser/

At 680 watts it is useful on cloudier days (aka the British summer) when using a kettle would draw from the grid and for someone working from home there is always hot water on tap for a quick cuppa. The main benefit, it being insulated, is to time shift your kettle usage to periods of cheap or free electricity (solar). Having a built in timer, I find it particularly useful to heat a boiler full on my Octopus Go Faster tariff which ends at 6.30 am, just before I get up.

I also use a couple of  ASHPs (aircon units) to heat the house using solar power and they have had a lot of use this month. They are incredibly efficient.