Solar panel

[Jason L]

Afternoon, 

 

I am planning on having solar panels on the front of my house, which is south-west facing.

It looks like 9 panels giving 2.7Kw system, the house is 108sq.m gross internal and its just for me to live in and i work from home.

Wil that be enough to cover my daytime needs, and if so do you think the will be much left over to warrant looking at a battery system to go with it ?

here is the floor plans

Ta J 

 

2010-BC-SK01 rev G proposed plans and elevations.pdf

[ProDave]

I self use 95% of what our 4kWp panels generate.  the 2 keys to maximum self usage are use the big appliances (WM, tumble dryer and dishwasher) one at a time close to mid day, and fit an immersion heater dump controller to sump surplus power to the immersion heater.

 

I would only fit battery storage if I had more than 4kW of panels personally.

[SteamyTea]

44 minutes ago, Jason L said:

Wil that be enough to cover my daytime needs

What are your daily needs?

45 minutes ago, Jason L said:

if so do you think the will be much left over to warrant looking at a battery system to go with it

See previous answer.

But heating up a tank of water is a lot less capital expenditure.

[Jason L]

9 minutes ago, ProDave said:

I self use 95% of what our 4kWp panels generate.  the 2 keys to maximum self usage are use the big appliances (WM, tumble dryer and dishwasher) one at a time close to mid day, and fit an immersion heater dump controller to sump surplus power to the immersion heater.

 

I would only fit battery storage if I had more than 4kW of panels personally.

Cheers, so it sounds like it wont have any left over then.   im not having an immersion heater, but thats good advice to plan on when to use the big appliances ta.

[Jason L]

1 minute ago, SteamyTea said:

What are your daily needs?

See previous answer.

But heating up a tank of water is a lot less capital expenditure.

To sit here with a couple of computers on and the kettle boiling often !  occasional washing machine and dish washer etc.

I am planning on having a MVHR system installed.

[ProDave]

4 minutes ago, Jason L said:

Cheers, so it sounds like it wont have any left over then.   im not having an immersion heater, but thats good advice to plan on when to use the big appliances ta.

I reckon the immersion heater takes about 1/3 of what I generate.  It is a handy place to dump spare generation to avoid it being exported.  Even when the big appliances are on, there are gaps in their usage when power still goes to the immersion.

 

Are you saying you don't have / will not have a hot water tank?

[SteamyTea]

1 minute ago, Jason L said:

To sit here with a couple of computers on and the kettle boiling often !  occasional washing machine and dish washer etc.

I am planning on having a MVHR system installed.

Well the washing machine will probably peak at 2kW, kettle at 2.8kW.

Computers can be anything from a few watts (mine used 8W) to 300W for an old Apple Desktop.

 

So realistically your PV will not cover your peak loads.  It is a rare day they produce peak power in the scheme of things.

What they can do is reduce the amount you import while those heavy loads are on.  When those loads are off, you need to divert the power to something else.  This is why water heating is useful.

 

Don't get Power (kW) mixed up with energy (kWh)

[Jason L]

1 minute ago, ProDave said:

I reckon the immersion heater takes about 1/3 of what I generate.  It is a handy place to dump spare generation to avoid it being exported.  Even when the big appliances are on, there are gaps in their usage when power still goes to the immersion.

 

Are you saying you don't have / will not have a hot water tank?

Thank you,  no,  at the moment I'm planning on a little gas combi boiler,  i wont get through a lot of hot water,  but i have just decided to look into the possibility of an ASHP, in which case there would be a tank.   

[Dave Jones]

battery / powerwall may be a better option than solar. It allows you to timeshift your grid demand to cheap rate so you allways pay cheap rate whatever time of day it is.

[Jason L]

4 minutes ago, SteamyTea said:

Well the washing machine will probably peak at 2kW, kettle at 2.8kW.

Computers can be anything from a few watts (mine used 8W) to 300W for an old Apple Desktop.

 

So realistically your PV will not cover your peak loads.  It is a rare day they produce peak power in the scheme of things.

What they can do is reduce the amount you import while those heavy loads are on.  When those loads are off, you need to divert the power to something else.  This is why water heating is useful.

 

Don't get Power (kW) mixed up with energy (kWh)

wow so they would just cover the kettle then when i put that on ?     looks like i wont have to worry about wasting any then. !

cheers

J

 

[Jason L]

1 minute ago, Dave Jones said:

battery / powerwall may be a better option than solar. It allows you to timeshift your grid demand to cheap rate so you allways pay cheap rate whatever time of day it is.

i have never heard of that  ill take a look ta

[SteamyTea]

1 minute ago, Jason L said:

wow so they would just cover the kettle then when i put that on

Only at a certain time on a very sunny day.

 

You only have a kettle on for a minuted or two, the panels will be generating something all during the daylight hours.

So you will still be loosing a lot to the grid.

[Jason L]

1 minute ago, SteamyTea said:

Only at a certain time on a very sunny day.

 

You only have a kettle on for a minuted or two, the panels will be generating something all during the daylight hours.

So you will still be loosing a lot to the grid.

Is that correct that the grid is start up the pay back scheme again for what i give back to the grid ?

[SteamyTea]

Just now, Jason L said:

Is that correct that the grid is start up the pay back scheme again for what i give back to the grid ?

There is already a way to sell back to the grid, but you have to have an MCS installation.  This, at the moment, makes it not really worth while.

[ProDave]

It's called the "smart export Payment"

 

You get paid about 5p per unit exported, you have to have an MCS install to claim it (££££) and you must have a smart meter.

 

If I had been eligible, I would have earned just over £5 per year for the small amount I export.  I wonder how long that would take to pay the extra for am MCS install?

[Dave Jones]

there is no RHI for solar anymore

[jamieled]

12 minutes ago, Dave Jones said:

there is no RHI for solar anymore

There never was for solar PV.

[markharro]

Has anyone heard of this website that seems to offer some very low priced (used) panels? - https://www.secondsol.com/en 

[Nickfromwales]

On 12/11/2020 at 16:51, Dave Jones said:

there is no RHI for solar anymore

It was called the Feed In Tariff ?

 

On 12/11/2020 at 17:04, jamieled said:

There never was for solar PV.

You could have thrown him a bone ?

[Nickfromwales]

On 12/11/2020 at 15:43, Dave Jones said:

battery / powerwall may be a better option than solar. It allows you to timeshift your grid demand to cheap rate so you allways pay cheap rate whatever time of day it is.

Nope!!
The saving of load shifting via batteries is NOT an economical choice at all. The difference in cost of electricity vs what you’ll spend on a decent sized ( 9.6kw ) battery system, and if A/C retrofit then add 15% losses for conversions to / from D/C > A/C make it worse again. Then factor in having the drive the arse off the system JUST to make it sensible to own, plus some systems have a limited throughput so you’ll wipe the warranty out early ( Powerwall for one ) and then the fact that the batteries will be out of warranty in 10 years or less and then deal at 13 years...........

List goes on.
Also you can’t empty or charge the battery quickly, so imagine having a soprano singer with huge lungs to store loads of oooomph for belting a tube out, but then only a tiny drinking straw for a windpipe, and you get an idea.
 

EG; a 6kw hob would still see you pull from the grid if connected to the same sized, fully charged battery system. 
 

Too many probs unless you spend 5 figures on a multi BMS / multi battery trio of parallel stacks. Then you’ll need the batteries to last 30 years to get your money back as you’ll be into the big name German stuff then, with matching big budget. 
?