Solar panels - or not?

[853]

One way to proceed with micro solar is without any Grid connection, powering a few domestic appliances from a dedicated inverter and cable running from a battery and solar PV. I know of a house which powers the fridges, freezers and washing machine this way, saving £300-£400 a year. Attention should be given to the earthing of the inverter, rather than relying purely on RCDs and SPDs (which may be built in, or added).

This is the direction I was thinking might work for me.

I can't save £300-£400 a year, however, as my predicted electricity bill for 2025, using the latest increase that came in yesterday, is £145-50. It's the £231-45 of standing charge that puts it up to almost £377.

I think it would be a hobby for me rather than a money saver at the moment, although this could all change if a zero standing charge tarrif is allowed again.

[Biospace]

If I power up my router from a 12v battery will my home phone still work. It's an old on pre dect phones. ?

And can you use an inverter plugged into a domestic supply fed from a solar panel or is there a synchronisation issue here to ensure it's in phase. ?

And what's an SPD? I don't mean shoes either.

Our 4kw solar panel array only reduces our consumption annually by approx 400kw so only saves us £100. You can see the savings here.
viewtopic.php?t=148868&start=2040#p1817841

I'd expect the sort of phone which needs no battery as it is might well work if your router supplying the connection is powered. But that's simply a stab in the dark.

The Europeans are widely using the newer 'plug and play' type micro generation inverters and plugging into their household circuits, the electronics sorts out phasing, switches everything off in a power cut and so on. I don't know if they're all pure sine wave outputs, but Ecoflow's certainly are.

400kWh at 25p per unit is indeed £100. A constant 400w feeding your house would represent around 3500kWh in a year although I wouldn't expect quite as much as that with a micro solar generation setup.

[Biospace]

This is the direction I was thinking might work for me.

I can't save £300-£400 a year, however, as my predicted electricity bill for 2025, using the latest increase that came in yesterday, is £145-50. It's the £231-45 of standing charge that puts it up to almost £377.

I think it would be a hobby for me rather than a money saver at the moment, although this could all change if a zero standing charge tarrif is allowed again.

A neat way of protecting computer equipment from power drop-outs if you happen to live where the supply isn't 100% reliable, obviously very handy in prolonged outages and portable to travel.

That's a pretty economical figure, although if cooking and heating without electricity clearly achievable with modern electrics. It must be so galling having the excessive standing charges.

[[XAP]Bob]

This type of setup means you have back up power in the case of a power cut (all landlines will require this soon) as well as a portable power supply for camping or similar.

If I power up my router from a 12v battery will my home phone still work. It's an old on pre dect phones. ?

And can you use an inverter plugged into a domestic supply fed from a solar panel or is there a synchronisation issue here to ensure it's in phase. ?

Yes - a 12V supply will happily keep your kit running.

If you do plug in an inverter than you'll likely blow something up if it isn't specially labelled grid tied.
And you'll certainly blow something up if there is ever a power cut - if you're lucky it will just be your inverter (and hopefully it won't catch fire), but if you're unlucky it will be the line repair engineer...

[rjb]

Thanks Bob, will be knocking up a 12v battery pack soon. And my 12v car inverter is not grid tied so won't be plugging that into the mains either.

[Biospace]

If you do plug in an inverter than you'll likely blow something up if it isn't specially labelled grid tied.
And you'll certainly blow something up if there is ever a power cut - if you're lucky it will just be your inverter (and hopefully it won't catch fire), but if you're unlucky it will be the line repair engineer...

Are there such inverters which come with a plug on their output? I'd be beyond amazed if there are.

[[XAP]Bob]

There are, terrifyingly.

https://www.wallboxdiscounter.com/en/2- ... erter.html

[[XAP]Bob]

Thanks Bob, will be knocking up a 12v battery pack soon. And my 12v car inverter is not grid tied so won't be plugging that into the mains either.

The "right" approach here is to either accept that you're going to lose connectivity then manually plug it in later, or to have a UPS, which can actively warn you when you need to plug in a bigger battery to support the important load.

https://www.youtube.com/watch?v=1q4dUt1yK0g

[[XAP]Bob]

Just to add to my previous information dump about personal usage:

I am a heavy user of electricitly - we have Gas for most heat and hot water, but I do use a storage heater in my office.
Two people at home all day, so no respite in usage, EV (only car), two teenagers...

Last year we used a fraction over 10MWh, of which 3.2 are registered on my EV charger (over ~13k miles that's about 4m/kWh, it's probably a shade under).
So that's 6.8MWh domestic usage for four people compared with the average 2.7 for 2.4 people (i.e. about 50% above average), and it cost just under £635 - compared with the "price cap" of £1700 ish (Last year it was £1928/£1690/£1568/£1717) which converts to £2833 for four people (or £4250 for our actual usage).
Our gas usage was actually just under the 2.4 person average at another 10 MWh - costing £773 (i.e gas is more expensive than electricity for us).
My cost also included transport energy which would have cost me (at an assumed £1.40 average over the year for diesel) well over £2k.
So whilst I do still have finance costs, and of course the motability lease cost on the EV, I'm easily £4k better off per year than I would have been otherwise (more than covering that expense).

For stats: just 1.5% of my grid electricity was imported at peak rate, and a third of that (i.e. .5% of the total) was imported on days which had a DFS session (either NESO or Free Electricity).
I maxed an average of 58A (14.4kW) over a half hour settlement period, which would have been the car, as well as a variety of white goods, and the storage heater...

With the records against the national grid's carbon intensity... My low carbon electrical imports added to my solar generation came to just 3% shy of my usage - a very small amount indeed. That does of course assume that all of my exports were offset against fossil fuel power sources, which is *probably* valid. HA doesn't record the product of exports with carbon intensity.
Of course "low carbon" in this context probably includes Drax
And half of my energy consumption was actually direct gas

If I look at my gas usage and assume a 90% efficiency on the boiler (ambitious, it's manual only claims 88%) and an ASHP scop of 3.5 (should be easily achievable - heatgeek average install is 4.4) then I'd need another 3.2MWh of electricity, much of which would be at off peak rates - my modelling (pretty detailed) suggests that the cold snap over the last seven days would have cost me ~£1.70 more than I've spent on gas, but even December would have been about 66p cheaper, and last year as a whole £133 cheaper.
That's not a huge cost saving, but given that I probably need to replace the boiler next year anyway... I am going to move to a heat pump. It's far cleaner than gas, and will get cleaner and cleaner over the next decade. If we finally disentangle electricity pricing from gas then it will become significantly cheaper in an instant. Of course I also hope to achieve a scop well above 4 (which would have been £463 in 2023 and £213 in 2024)

[PDQ Mobile]

^^
Hmm.
At the moment just under 6% wind.
Zero solar.

But lots of gas, biomass, and nuclear.
Demand is high.

[[XAP]Bob]

^^
Hmm.
At the moment just under 6% wind.
Zero solar.

But lots of gas, biomass, and nuclear.
Demand is high.

Yep - and my contribution to that demand is zero.

Your point is what? That a low capacity system can't keep up with full demand? Of course it can't, in the same way you can't ride a bike without wheels... but you still start building it by building up the frame.

[PDQ Mobile]

^^
Hmm.
At the moment just under 6% wind.
Zero solar.

But lots of gas, biomass, and nuclear.
Demand is high.

Yep - and my contribution to that demand is zero.

Your point is what? That a low capacity system can't keep up with full demand? Of course it can't, in the same way you can't ride a bike without wheels... but you still start building it by building up the frame.

I don't accept your contribution is zero if you use offpeak leccy is, I guess, my point.
Your consumption is simply too high to allow that.

And on top of it you are a quite a hefty gas user.

Sorry, I understand your heart is in the really right place but...

............

I see low consumption as a better way forward.
Though I did fall on black ice on the bike today!
Nothing broken!!

[[XAP]Bob]

My contribution at times of peak demand, and peak fossil use are generally zero, or negative…
Since you were picking an individual spot in time I looked at that same spot in time as well.

My contribution to the daily load is absolutely not zero, particularly not over winter (though it gets pretty close in summer).
I’d not say I was a heavy gas user, between four people we use less than the (ofgem defined) typical “medium” household of 2.4 (and this house is permanently occupied, we aren’t out at work all day, with the obvious savings that could bring).

Absolutely low consumption is the way forward (that’s why I want to move to a heat pump for heating) but a good chunk of my power is running office infrastructure, which is obviously in addition to “normal” usage - and a car, which is far less energy than would be used by an ICE vehicle, it just all shows on the one meter.

Our heating is zoned, and has custom timings through the day, so the kids bedrooms aren’t kept hot all day long - the flow temperature is under 50 degrees (as cold as this combo can be set), and I have anti short cycling systems set up,

There is only so much energy reduction that is possible whilst still living in this world, I work in IT, and have various disabilities which drive much of my “bat cave”. Only run the one home server (I used to have a farm of 17 running at full chat 24/7 on the SETI@Home project).

[PDQ Mobile]

My contribution at times of peak demand, and peak fossil use are generally zero, or negative…
Since you were picking an individual spot in time I looked at that same spot in time as well.

My contribution to the daily load is absolutely not zero, particularly not over winter (though it gets pretty close in summer).
I’d not say I was a heavy gas user, between four people we use less than the (ofgem defined) typical “medium” household of 2.4 (and this house is permanently occupied, we aren’t out at work all day, with the obvious savings that could bring).

Absolutely low consumption is the way forward (that’s why I want to move to a heat pump for heating) but a good chunk of my power is running office infrastructure, which is obviously in addition to “normal” usage - and a car, which is far less energy than would be used by an ICE vehicle, it just all shows on the one meter.

Our heating is zoned, and has custom timings through the day, so the kids bedrooms aren’t kept hot all day long - the flow temperature is under 50 degrees (as cold as this combo can be set), and I have anti short cycling systems set up,

There is only so much energy reduction that is possible whilst still living in this world, I work in IT, and have various disabilities which drive much of my “bat cave”. Only run the one home server (I used to have a farm of 17 running at full chat 24/7 on the SETI@Home project).

I only took a screen shot to show how dependent the country still is on non carbon neutral (and nuclear) energy.
Overall is the important, indeed only relevant, thing IMV.

We are on the same page here though, or perhaps two sides of the same coin.

I am a techno-phobe though, and ever more so; in that we do differ.
The levels of fraud, the ever growing pressure to "update" stuff, the increasing level of "influencers" putting their views out to millions at the press of a button, make me sometimes want to throw my phone in a lake!
I fail to see the advantages over older paper based stuff.

And another difference between us is that I love cycling in shorts.
Not today though.

Best wishes.

[Biospace]

I fail to see the advantages over older paper based stuff.

That in itself is a whole thread of interesting discussion!

Parking, for one, used to be so easy before everything was connected to the internet. It's not always possible for me to dump a car on the outskirts of a city and cycle in.