SEG - safe for now?

[Drellingore]

Is there any reason to believe that the current SEG system is likely to get changed/discontinued any time soon?

I haven't watched news since April 2021, so I'm a bit out of a loop. I've done a bit of online searching, and can't find any clear and imminent threats, but I thought I'd check with you fine folks. 

[Dillsue]

I cant see electricity suppliers not wanting to buy excess renewable generation so I'd be surprised if SEG or a similar system wasnt in place for a good while. If youre making a decision to install kit based on receiving payments its probably prudent to also consider the same project without payments.

[SteamyTea]

1 hour ago, Dillsue said:

cant see electricity suppliers not wanting to buy excess renewable generation

Not from large suppliers that offer reliability and flexibility, but small domestic suppliers are probable a pain to them.

As well as that, domestic suppliers are often trying thier hardest to not export.

 

The idea of SEG, FiTs and previous schemes (ask @DamonHD what he has) was to help start an industry, not reward purchasers.

 

The UK is currently trying some very complicated and difficult schemes (just look at what Octopus are doing) to understand. This is mainly because we are trying to shoehorn a distributed generation system onto a centralised generation system, and the easy way to do that is to cut usage, not increase generation.

Edited January 6, 2023 by SteamyTea

[Kelvin]

 I wouldn’t make any decisions on renewables based on SEG or any other scheme the Government sees fit to come up with. My plan is still to consume as much as we can generate/store. Any payments for excess will just be a variable benefit. 

[Drellingore]

On 06/01/2023 at 12:24, Kelvin said:

My plan is still to consume as much as we can generate/store. Any payments for excess will just be a variable benefit. 

 

Yep, same here. We need a 22kWp system to cover our own usage in deepest, darkest winter, which means we'll have huge excesses in the summer. Maybe I just need to find more high-demand hobbies... Get myself a kiln or something!

[ProDave]

Self use is king.

 

Since i installed my PV, I have exported 334kWh.  If I had been paid for that at 5p  I would have been paid £16.70  Even some of the more realistic rates like 15p would only have earned me £50.1

 

I will let someone else calculate how long it would take to repay the "MCS premium"  to enable me to claim that pittance.

[Radian]

15 minutes ago, ProDave said:

I will let someone else calculate how long it would take to repay the "MCS premium"  to enable me to claim that pittance.

 

Sure, but the other side of the coin is what happens in the future, if distributed generation gets the rewards it deserves when the serious move towards decentralised generation begins. 

[Marvin]

1 hour ago, Drellingore said:

 

Yep, same here. We need a 22kWp system to cover our own usage in deepest, darkest winter, which means we'll have huge excesses in the summer. Maybe I just need to find more high-demand hobbies... Get myself a kiln or something!

Hi @Drellingore

 

Er... just checking...  Our 5.12kW system produces about 200kWh for the whole of December, so I 'm just wondering if you've taken into account the reduction in energy over the winter peroid.  

 

Here is our PV's energy production over the last year in months using a 5.12kW system

 

Month kWh Jan 204 Feb 294 Mar 601 Apr 744 May 818 Jun 902 Jul 816 Aug 770 Sep 536 Oct 362 Nov 296 Dec 171

Good luck   M

[SteamyTea]

2 minutes ago, Marvin said:

Our 5.12kW system produces about 200kWh for the whole of December

That is about half my usage, and if I had a heat pump, it would cover it all.

 

Trouble is, I would have to cover my neighbours roofs in PV to supply just me.

 

Should have jumped on the 'Roof for Rent' scheme and that 200 kWh would have earned me around £120.

[Drellingore]

25 minutes ago, Marvin said:

I 'm just wondering if you've taken into account the reduction in energy over the winter peroid

 

Thanks for the data! Yep, this works out perfectly. Our average daily consumption is 22kWh (we have two electric cars, family of four). If we extrapolate your generation to our size array, we get:

 

(171kWh * (22kWp/5.12kWp)) / 31 days == 23.7kWh

 

[jack]

1 hour ago, Drellingore said:

We need a 22kWp system to cover our own usage ...

 

Is there any particular reason to specifically target "covering our own usage"? I get why it's a target conceptually, but it's actually pretty arbitrary - there's no logical reason to assume that this is the optimal target when you take costs into account.

 

I assume you're going for batteries too. Have you modelled how changing battery and array capacity changes the numbers? Is it possible that a smaller array with more battery capacity allows better usage?

 

Where are you going to put the array? 22 kW is physically huge. For comparison, we have 8.5 kW and this is what it looks like on the (flat) roof of our house. For reference, the house footprint is roughly 160 m²:

 

 

I assume have three phase? If not, you'll struggle to get approval to connect an array that big to the grid.

 

Apologies if you've already worked through all of these questions, but 22 kW is the largest domestic array I've ever heard of!

[Marvin]

17 minutes ago, Drellingore said:

 

Thanks for the data! Yep, this works out perfectly. Our average daily consumption is 22kWh (we have two electric cars, family of four). If we extrapolate your generation to our size array, we get:

 

(171kWh * (22kWp/5.12kWp)) / 31 days == 23.7kWh

 

Sounds good.

 

As @jack just said...

 

Have you considered the distribution network operator (DNO) requirement for such a large system? it look like about 100amps. 

 

 

 

[Marvin]

Hi @Drellingore

 

Daily results for our 5.12kW system this January:

 

Date	energy
01/01/2023	1.36
02/01/2023	12.24
03/01/2023	0.45
04/01/2023	1.07
05/01/2023	3.00
06/01/2023	2.52
07/01/2023	3.00
08/01/2023	1.54
09/01/2023	8.42
10/01/2023	0.22
11/01/2023	4.33
12/01/2023	0.00
13/01/2023	12.31
14/01/2023	2.17
15/01/2023	7.52
16/01/2023	6.63
17/01/2023	2.62
18/01/2023	11.80
19/01/2023	14.16

 

So as @jack points out: its not a constant flow of energy.

 

We looked at off grid and keeping our lifestyle... ho ho!  Forget it without massive storage. If we covered all the roof both sides, the front and back garden and everything there would still be inadequate panel surface to supply what we require in the winter.  

 

I am with @Radian and wait for decentralised generation and more importantly decentralised storage. 

I also agree with @ProDave philosophy about self use being king.

[tuftythesquirrel]

27 minutes ago, jack said:

For comparison, we have 8.5 kW and this is what it looks like on the (flat) roof of our house.

Sorry, have you got a better picture?

[jack]

17 minutes ago, tuftythesquirrel said:

Sorry, have you got a better picture?

 

No, sorry. That's just a grab from Google maps. Bing is no better.

 

I really just posted it to roughly show that an 8.5 kW array takes up more than 50% of a large flat roof.

 

29 minutes ago, Marvin said:

I am with @Radian and wait for decentralised generation and more importantly decentralised storage.

 

We're tantalisingly close to having vehicle batteries form part of the grid. Our EV has only a 38 kWh battery, but that's nearly three times the capacity of the Tesla Powerwall 2. I know you wouldn't use it in the same way, but when EV batteries eventually come with two or even three times that as standard, that's a lot of energy on tap.

 

My main concern is complexity. We have PV, an EV, an immersion diverter, an ASHP doing DHW and heating, FiTs, and a cheap overnight rate. The complexity involved with optimising that lot is already bewildering. What happens when we move to a more complex situation where you have all that lot, plus batteries, plus vehicle to grid, plus variable half-hour pricing both in and out?

[tuftythesquirrel]

1 minute ago, jack said:

No, sorry. That's just a grab from Google maps. Bing is no better.

 

I really just posted it to roughly show that an 8.5 kW array takes up more than 50% of a large flat roof.

Sorry, thought you had splashed out on a drone😁

[jack]

Just now, tuftythesquirrel said:

Sorry, thought you had splashed out on a drone😁

 

Ha, no, but my neighbour is a cameraman and has a massive drone he uses for work. Might ask him to get some shots next time he has it out in the garden.

[SteamyTea]

42 minutes ago, Marvin said:

12/01/2023 0.00

What happen?

[Drellingore]

1 hour ago, jack said:

Is there any particular reason to specifically target "covering our own usage"?

 

Nah, not really. It's an emotional starting point. We don't want to be off-grid, but we'd like to not need it. We've got a 3 acre field next door to try and provide as much permaculture food security too. Part of the rationale is to do my best to leave something to the kids and descendants that will be a 'safety net' of sorts - so they don't need to pay for rent, electricity, very basic foods, etcetera.

 

1 hour ago, jack said:

I assume you're going for batteries too

 

Yep. I'm just at the start of figuring everything out, but I was figuring a few powerwalls or equivalents. Annoyingly we've got 112kWh of storage in the two cars, but neither does V2H

 

1 hour ago, jack said:

Where are you going to put the array?

 

It's a 22m long barn with a south-facing roof - that's also ignoring the other building, which is on a north/south alignment.

 

1 hour ago, jack said:

I assume have three phase?

 

Yeah, there's already a three phase supply to the property. I'll need to figure out what goes on what phases, and all that jazz. I'm just at the beginning, really.

 

1 hour ago, jack said:

22 kW is the largest domestic array I've ever heard of!

 

Yeah, we might have to register as a power plant (I can't remember what the technical term is).

 

1 hour ago, Marvin said:

Have you considered the distribution network operator (DNO) requirement for such a large system?

 

It's something we'll need to think about, for sure.

 

24 minutes ago, jack said:

My main concern is complexity.

 

Agreed. Asking on a Tesla forum, others have done similarly complex systems, and unfortunately there's no decent book on the subject.

[Marvin]

35 minutes ago, SteamyTea said:

What happen?

very cloudy

[Roger440]

1 hour ago, Drellingore said:

 

Nah, not really. It's an emotional starting point. We don't want to be off-grid, but we'd like to not need it. We've got a 3 acre field next door to try and provide as much permaculture food security too. Part of the rationale is to do my best to leave something to the kids and descendants that will be a 'safety net' of sorts - so they don't need to pay for rent, electricity, very basic foods, etcetera.

 

 

Yep. I'm just at the start of figuring everything out, but I was figuring a few powerwalls or equivalents. Annoyingly we've got 112kWh of storage in the two cars, but neither does V2H

 

 

It's a 22m long barn with a south-facing roof - that's also ignoring the other building, which is on a north/south alignment.

 

 

Yeah, there's already a three phase supply to the property. I'll need to figure out what goes on what phases, and all that jazz. I'm just at the beginning, really.

 

 

Yeah, we might have to register as a power plant (I can't remember what the technical term is).

 

 

It's something we'll need to think about, for sure.

 

 

Agreed. Asking on a Tesla forum, others have done similarly complex systems, and unfortunately there's no decent book on the subject.

 

If you have aa field, are you not better of ground mounting the panels much nearer vertical and getting the best possible winter production and sacrificing peak summer performance when you cant hope to use it all?

[Drellingore]

6 minutes ago, Roger440 said:

If you have aa field, are you not better of ground mounting the panels much nearer vertical and getting the best possible winter production and sacrificing peak summer performance when you cant hope to use it all?

 

It's in an AONB, who will likely object to that. As would the wife

[Roger440]

2 hours ago, jack said:

 

No, sorry. That's just a grab from Google maps. Bing is no better.

 

I really just posted it to roughly show that an 8.5 kW array takes up more than 50% of a large flat roof.

 

 

We're tantalisingly close to having vehicle batteries form part of the grid. Our EV has only a 38 kWh battery, but that's nearly three times the capacity of the Tesla Powerwall 2. I know you wouldn't use it in the same way, but when EV batteries eventually come with two or even three times that as standard, that's a lot of energy on tap.

 

My main concern is complexity. We have PV, an EV, an immersion diverter, an ASHP doing DHW and heating, FiTs, and a cheap overnight rate. The complexity involved with optimising that lot is already bewildering. What happens when we move to a more complex situation where you have all that lot, plus batteries, plus vehicle to grid, plus variable half-hour pricing both in and out?

 

What would happen is it would be a disaster. Many people would have long periods with non functioing equipment, that they cant possibly hope to understand.

 

The reality is we wont get to that point as there simply isnt the ability, nor funding, to do this at scale.

 

Dont forget, the majority of the population havent worked out when or if you need to open a window in your house. To the point a child died.

 

Given that the level of complexity you describe, is beyond my ability to understand, and i understyand much more than the man on the clapham omnibus, i will resist it for as long as possible, because out in the real world, there is simply no support if you dont understand it yourself

 

 

[Roger440]

8 minutes ago, Drellingore said:

 

It's in an AONB, who will likely object to that. As would the wife

 

Shame. Can you not put them on the side of the barn?

[Drellingore]

1 minute ago, Roger440 said:

Shame. Can you not put them on the side of the barn?

 

Nah, the barn is almost all roof. The walls are only a couple of meters tall, if that.