Circular reasoning (Rolfe's solar energy system)

[Bam Bam]

Although his last comment when I asked why they were being obstructive was probably nearest the mark. "Because they can." Apparently they have a certain number of working days to respond, and that takes us into July. I can't make any waves because apparently he shouldn't have made the system live at all prior to the G99 being issued, or at the very least limited the inverter to 3.5 kwh. However he didn't, and we're on a "don't ask don't tell" basis here.

Our export tariff with Octopus took about 6 weeks to get sorted last year and we already had the DNO agreement sorted out in advance!

Sounds like your installer has got lucky in the past and hoped he would again.

It might just take someone to complete some checks and update the system but there is nothing particularly in it for the DNOs and it takes up their staff time so I expect they tend to take that long. To be fair I wouldn't expect them to pay staff to sit around waiting for new requests to come in, and solar has probably become more and more popular over time.

Perhaps you will be able to get some of the stages done in parallel though and catch up a bit - we had to wait for the MCS paperwork before we could apply for the export tariff and you'll have to wait for the DNO anyway.

 

[Rolfe]

OK, I don't even know what MCS or DNO are.

 

[Bam Bam]

OK, I don't even know what MCS or DNO are.

Sorry!

DNO is the District Network Operator. They are responsible for making the last mile of the grid work.

MCS is the microgeneration certification scheme. Your installer will be registered, but they will have to do some official paperwork and the utility will probably ask to see this before approving you for export.

Basically there are several stages of bureaucracy to go through, which takes time. To avoid people doing dodgy installs etc.

 

[Rolfe]

Thanks.

 

[Alb]

DNO stands for Distribution Network Operator and their scope is way more than the last mile of the grid. Easiest to go to the website of your local DNO if you want a deeper understanding:

General information

We power communities to thrive today and create a net zero world for tomorrow while delivering a safe, resilient and responsive network for all our customers.

www.ssen.co.uk

 

[Rolfe]

Thank you.

All is going according to plan here. Sun splitting the sky, just a bit of high, broken cirrus cloud. Car has been charging pretty steadily at over 4 kWh since 9.30, when I saw the system beginning to export and plugged it in. 17 kWh delivered already. I was up on the village green all morning manning a charity stall at our gala day, watching developments on my phone with interest.

The car thinks it will be done by 4.30, which of course it won't be, because solar output starts to tail off a bit after three in the afternoon due to the angle of the roof. But if it doesn't get all the way to 100% and balanced today, it can finish in the morning. Then I will have filled the car from sunshine. Very satisfying.

 

[Archev]

Thank you.

All is going according to plan here. Sun splitting the sky, just a bit of high, broken cirrus cloud. Car has been charging pretty steadily at over 4 kwh since 9.30, when I saw the system beginning to export and plugged it in. 17 kwh delivered already. I was up on the village green all morning manning a charity stall at our gala day, watching developments on my phone with interest.

The car thinks it will be done by 4.30, which of course it won't be, because solar output starts to tail off a bit after three in the afternoon due to the angle of the roof. But if it doesn't get all the way to 100% and balanced today, it can finish in the morning. Then I will have filled the car from sunshine. Very satisfying.

Aye ye cannae wring petroleum out of them cirruses.
All sounds idyllic over there. I’m in glorious Tyndrum where the sun is about as hot as this soup.

 

[Bam Bam]

DNO stands for Distribution Network Operator and their scope is way more than the last mile of the grid. Easiest to go to the website of your local DNO if you want a deeper understanding:

General information

We power communities to thrive today and create a net zero world for tomorrow while delivering a safe, resilient and responsive network for all our customers.

www.ssen.co.uk

Oops - slip of the fingers there with district.

For the pithy definition I asked my wife who worked on this until recently to summarise DNOs in one sentence and that is what she came up with.

As a rough rule DNOs deal with lower voltage (under 132kv) and transmission is very high voltage (over 132kv).

Distribution and transmission connections- what's the difference? | National Grid ET

The differences between high voltage electricity transmission and distribution connections can be varied and complex. Generally, some limits of capacity and voltage classifications can be applied. But this isn’t always the case. So, what are the differences?

www.nationalgrid.com

 

[Tangoed Man]

About £13,400 was the cost for our solar (16 panels), battery and car charger (plus backup power facility). A lot of money but it will pay back in about 9 years depending where energy prices go. Solar panels last at least 25 years so you'll get the money back.

Would it increase the value of your house to have them?

9-years plus the loss of interest of about £9,300 over that period. Everyone who installs solar omits that element.

 

[Rolfe]

All is going according to plan here. Sun splitting the sky, just a bit of high, broken cirrus cloud. Car has been charging pretty steadily at over 4 kwh since 9.30, when I saw the system beginning to export and plugged it in. 17 kwh delivered already. I was up on the village green all morning manning a charity stall at our gala day, watching developments on my phone with interest.

The car thinks it will be done by 4.30, which of course it won't be, because solar output starts to tail off a bit after three in the afternoon due to the angle of the roof. But if it doesn't get all the way to 100% and balanced today, it can finish in the morning. Then I will have filled the car from sunshine. Very satisfying.

The sun stayed out and the car reached 100% at about five to five, despite the solar output starting to dip about 3.20, and a few clouds coming over just after that. It started to balance, but there was some sort of electrical country-dancing going on between the Zappi, the Eddi and the grid, and the balance charge terminated after only about ten minutes, whereas it usually takes about 35 minutes. I did try to get it to continue balancing on the granny lead, but no dice. Seemed to be a happy car. Worth watching though, because I don't think it went through an entire balance cycle.

I can see it will all be a lot simpler, as well as more profitable, when the G99 comes through and I switch from grabbing all the sunshine I can for my own personal use to exporting as much as possible and charging the car and the home battery overnight at 7.5p. But it's all good education.

 

[Rolfe]

Thinking ahead to that G99 (and indeed winter), can someone confirm whether there is any cap to the amount of mains power one can import during the cheap period? Supposing I set my car to start charging at 11.30, turned on the washing machine and the dishwasher, and the house battery was recharging all at the same time, would I flip something out?

 

[Bam Bam]

Thinking ahead to that G99 (and indeed winter), can someone confirm whether there is any cap to the amount of mains power one can import during the cheap period? Supposing I set my car to start charging at 11.30, turned on the washing machine and the dishwasher, and the house battery was recharging all at the same time, would I flip something out?

I'm not an electrician so others will know much better, but I believe it would be about 22-23kW max for a house IF you've got a 100A fuse.

So if you think:

• battery 4
• EV 7
• Washing machine 4 (very briefly when heating the water?)
• Dishwasher 4 (very briefly when heating the water?)
• Hot water 4 (until water gets to desired temperature)
• Standby/other devices 1

That adds up to about 24 so if you got unlucky and they all did go full guns at the same time you might manage to exceed it.

But those wouldn't all be going on full at the same time so a bit of staggering and I expect you could do all of them in one night.

Plus would you switch to oil-burning for your hot water in the winter?

Also - the thing about the battery is that you can use power during the day and it comes out at night-time rates, so you could still do one of the above (apart from the EV) during the day without needing to use the grid. Particularly so if it is a sunny day.

 

[Rolfe]

Thanks. That's more or less what I was thinking. Obviously, I'd probably try not to put on other heavy-load items if I was charging the car. And it probably makes better sense to use the oil to heat the water in winter too.

I don't know yet how far the battery will go during the day and I won't really know till maybe October. We have very long days here right now. This morning my panels started to wake up at 4.20am, were taking over from the battery by 5am and powering the house completely before six. (Official sunrise is 4.36 and we still have three weeks to go before the solstice.) But the flip side of that is that we have very short days in winter, and these days are often cloudy, so the battery is going to have to shoulder a lot of load during that time. I'll see how it goes before switching on anything with a heavy load during the peak tariff time, unless I have to. Obviously cooking is not going to be happening between 11.30pm and 5.30am though!

 

[Bam Bam]

Thanks. That's more or less what I was thinking. Obviously, I'd probably try not to put on other heavy-load items if I was charging the car. And it probably makes better sense to use the oil to heat the water in winter too.

I don't know yet how far the battery will go during the day and I won't really know till maybe October. We have very long days here right now. This morning my panels started to wake up at 4.20am, were taking over from the battery by 5am and powering the house completely before six. (Official sunrise is 4.36 and we still have three weeks to go before the solstice.) But the flip side of that is that we have very short days in winter, and these days are often cloudy, so the battery is going to have to shoulder a lot of load during that time. I'll see how it goes before switching on anything with a heavy load during the peak tariff time, unless I have to. Obviously cooking is not going to be happening between 11.30pm and 5.30am though!

Some people do have slow cookers but I've not got into that myself.

Have been using an old bread machine more since we got solar + battery though!

 

[Rolfe]

Cooking doesn't take very long when I do it. At least not routinely. I would imagine the battery will cope most of the time.

 

[johnb80]

Thinking ahead to that G99 (and indeed winter), can someone confirm whether there is any cap to the amount of mains power one can import during the cheap period? Supposing I set my car to start charging at 11.30, turned on the washing machine and the dishwasher, and the house battery was recharging all at the same time, would I flip something out?

You have nothing to worry about. The main incoming fuse is likely to be rated at 100 amps, assuming you have a nominal 238v so highly likely 23.8 kW is you maximum load. What most people dont realise is how long a fuse takes to blow. The service head fuses will take a considerable current for quite a long time before they blow. a 100 amp fuse with 200 amps passing through it takes 8.3 minutes to blow, 150 amps takes 91.6 minutes. Whilst I wouldn't recommend relying on this my system regularly goes over 33 kW for a few minutes.
You will find using IOG that Octopus will regularly set your charge to start after 01:00 to avoid the huge 23:30 grid surge. If you want to protect your system more, set the Zappi Max Grid Power to 23 kW. If the load approaches this value it reduces the Zappi output to keep under the limit youve set.

In terms of appliances, we hit peak by:
i3 Charging 7.2kW
MG5 Charging 7kW
Dishwaher 2kW - Short Time
Washing Machine 2kW - Short Time
House Battery 1 3 kW
House Battery 2 5 kW
Heatpump 1 4 kW - Around 40 minutes at this rate if cold weather
Immersion Heater 3 kW - 2 hours

Thanks. That's more or less what I was thinking. Obviously, I'd probably try not to put on other heavy-load items if I was charging the car. And it probably makes better sense to use the oil to heat the water in winter too.

I doubt oil will be cheaper than 7.5p kWh into the immersion and electricity is greener.

I don't know yet how far the battery will go during the day and I won't really know till maybe October. We have very long days here right now. This morning my panels started to wake up at 4.20am, were taking over from the battery by 5am and powering the house completely before six. (Official sunrise is 4.36 and we still have three weeks to go before the solstice.) But the flip side of that is that we have very short days in winter, and these days are often cloudy, so the battery is going to have to shoulder a lot of load during that time. I'll see how it goes before switching on anything with a heavy load during the peak tariff time, unless I have to. Obviously cooking is not going to be happening between 11.30pm and 5.30am though!

Air fryers are very good for use with battery, very efficient, effectively mini fan ovens.

Cooking doesn't take very long when I do it. At least not routinely. I would imagine the battery will cope most of the time.

Christmas day with the whole family over, heatpump providing the heating , two ovens and hob running for traditional Christmas fayre, 21kWh of battery storage just and only just made it.

 

[T1 Terry]

It goes like this.

1. I really should get a home charger.
2. If I get a home charger, I need a variable electricity tariff.
3. A variable electricity tariff will make my daytime usage more expensive.
4. The answer is to get a home battery and fill it with cheap electricity overnight.
5. Look at your roof, if you have a home battery it would be criminal not to install solar.
6. That will be £13,700 altogether.
7. But I could buy a hell of a lot of electricity for that. Um.
8. But I really should get a home charger.

How do you get out of this loop?

Move to Australia, plenty of solar power, buy a battery from a damaged EV and charge that as the power storage for your EV ..... the major sticking point might be the first part :lol:

T1 Terry

 

[Bam Bam]

Move to Australia, plenty of solar power, buy a battery from a damaged EV and charge that as the power storage for your EV ..... the major sticking point might be the first part :lol:

T1 Terry

Yeah its a no brainer in Australia from what I gather!

 

[Rolfe]

I imagine it will be fine on that front. Time will tell how I'll get on with the 9.5 kWh battery in the short winter days with lights on (yes I have bought a bunch of low-energy bulbs and I'm retiring the incandescent ones) and probably more cooking, but looking at it sensibly the solar is running the house for just 12 hours at the moment and the battery never goes below 50%. In winter the battery will have to run the house for just 18 hours, so it should work.

Yeah its a no brainer in Australia from what I gather!

I encountered an Aussie on one of these ghastly anti-EV YouTube channels who had a solar system that had already paid for itself and who announced there was no way he could run a car on it, he needed all the generation for the house.

 

[T1 Terry]

Yeah its a no brainer in Australia from what I gather!

Unfortunately, we have more than our fair share of them Off shore wind turbines is the latest "anti" craze, the sound will disturb the marine life they harvest, they can't pull the "visual pollution" card because they would be well over the horizon.
Vertical wind turbines have not been explored much over here, they could be a great generation period extension and a decorative item at the same time, no "ultrasound" BS and they can be installed at home as well as areas with disturbed wind, I mean around building etc, not the gasbagging from politicians and professional protesters ....
Besides the houses of parliament, is there enough wind over your side for vertical turbines around the house or property?

Our plan, when we get home from our travels, is to increase the solar on our motorhome and make it the off grid power supply so we can disconnect from the grid and store the energy in the 260Ah 24v LFP cells we have on board. Maybe later we will add a house battery pack and solar/wind to supplement it for recharging the future electric Kombi and (hopefully) another EV with a better than 400km range so we can do the trips to the big smoke and back without needing to recharge ... it isn't that far, around 200km round trip, just some real big hills involved and motorway speeds so we don't get run over by the trucks, they are fast and big buggers over here.

T1 Terry