Solar panel supplementary

My Father in Law has had solar panels installed for a couple of years now. (The ins and outs of the sales techniques is a whole other story but we are where we are and he now has them installed for better or worse).

I have seen advertised in today's Sunday papers a product called "Midnight sun" to use your own PV generated electricity at night. The advert was woefully short on detail (costs, storage capacity, technology used (I am assuming some kind of rechargeable battery, equipment life etc) and as usual had a "phone us for more details". That is the one thing I am not going to do, as it will doubtless result in a tirade of high pressure sales Bullsh*t.

The ad claimed that they were very common in Italy now being introduced to UK

The website is equally non forthcoming with any useful info (web site addy not repeated here lest I be accused of spamming) but enough info in this post if anyone wants to find it.

Does anyone have any further knowledge about this type of PV "add on".

Thanks

Reply to
news
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I also saw the advert in a newspaper a week or so ago, and I did some googling on that item.

I can't remember much of what I saw now, but on one site which was a Sheffield based solar panel company, it inferred that that said item was quite costly, but how costly I never really found out.

Reply to
Bob H

news wrote: [snip]

Off grid systems as you describe exist but make no sense if you are on a Feed In Tariff (FIT). The point of FIT is that you get paid more for the electricity that you pump into the grid than the electricity you draw from the grid. Therefore All the electricity you generate must be fed into the grid to get the maximum benefit. At night draw back from the grid and pay the same as everyone else.

Adding off grid storage will just reduce the subsidy that you are getting

*and* you will have to pay for the off grid systems as well. It's a mug deal.

And if they say it is common in Italy they are telling lies. I live there, the son of a neighbour sells solar systems and the solar systems installed are all FIT.

Reply to
Steve Firth

ISTR it was discussed a while ago in sci.electronic.design or thereabouts in unglowing terms. Looks like snake oil, smells like snake oil and is advertised like snake oil - draw your own conclusions.

Reply to
Martin Brown

Don't think that's the case with all UK installations. FI Law gets paid FIT for all power he generates whether he uses it himself or feeds it to the grid. There is a small additional payment for 50% of what he generates that is "Assumed" to be fed back. If he actually feeds nothing back he will still get both these payments (unless I have misunderstood), but if he now has some huge batteries fully charged he wont have to buy any power off the grid overnight. (or at least reduced demand)

At night draw back from the grid and pay

Reply to
news

Was there not something in the regulations for the cheaper leccy this made that said no storage devices were allowed in houses? Brian

Reply to
Brian Gaff

It is almost certainly 100% BS. In Italy there is likely to be much power generated because they have more hours of sunshine that in the UK. In any case the tariff is all about generation and feeding the electricity into the grid. Unless I am mistaken all the power generated is fed to the grid. Snake oil and or barge poles come to mind.

Reply to
Peter Crosland

Peter Crosland wrote: [snip]

It still doesn't make any sense. If generating electricity the best thing to do is to feed it into the grid. Diverting any of it to storage just loses money, about 40p/unit IIRC.

Buying it back from the grid when you need it is cheaper than losing the

40p and having to pay for off grid storage.
Reply to
Steve Firth

The Midnight sun is possibly BS as others have said. You would have to check out the technology. But it's not impossible by a long way. Suspicious that they reveal no technical details.

However you CAN buy equipment to do this.

First buy a Mitsubishi I-miev electric car which can be charged up off the solar panels. Then buy the Mitsubishi "Power Station" which plugs into the charging port and converts the DC to AC. The car battery stores 16Kwh of power.

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Then you have the benefits of a car and the reduced electricity bill.

Reply to
harry

And an empty battery in the morning ... brilliant!

Reply to
Andy Burns

I use less than 2Kwh overnight. The battery is 16Kwh.

This technology that is being considered for when/if electric cars become common. In the brave new world of renewable power electricity will go both in and out of electric cars on charge. Another sort of FIT payment no doubt. I am looking out for it.

Hmm. I reckon my existing grid tie inverter could do this right now, the DC voltages are compatible. Pointless though in my case.

Reply to
harry

Well when first fitted mine was made of some naff plastic and leaked at the join to copper, so had to fit a proper metal one. That was bsp as i recall, but that was some years back.

Brian

Reply to
Brian Gaff

So for the sake of 20p worth of electricity, how much do you spend on solar panels, an electric car, a 'power station' and wear'n'tear on all the above?

It's still 1/8th of your charge gone, 80 mile range anxiety.

Fuck me, is there no end to your greed? You're (over)paid once to generate it, paid a second time on the assumption you've exported it even if you haven't, and now you want to be paid a third time to charge your car with it?

Reply to
Andy Burns

On face value that is sort of correct but in the UK it's not that simple.

Yep, 40 odd p/unit(*) as the meter on the panels reads.

Yep about 3p/unit but that 50% assumption only applies to installations that are not fully metered.

No misunderstanding. 40p/unit(ish) for every unit the panels generate plus 3p/unit(ish) for 50% of the number of units generated.

Correct and with a *not* fully metered system it wouldn't cost anything on the FIT payments. On a fully metered system it would cost 3p/unit.

I don't know what the grid cost per unit is on a FIT tarrif or if you are tied to a company or can choose who you buy from like everyone else. Even so you'd be lucky to get grid power for less than about 9p/unit these days.

As to the system itself unless it has a socking big battery it'll not store anything useful. Lets assume the overnight load is 1 kW for 10 hours and on a reasonable day the panels can recharge the batteries completely, that 10kWHr of energy. 96 V battery pack I = 1000/100 = 10 A over 10 hours, that's 8 x 12v 100 plus AHr batteries. To take into account ineffciencies an not wanting to regulary completely flatten the batteries they'd need to be 120 or maybe 150 AHr.

TBH battery storeage of the nergy is a looser, be better to have intelligent control of an immersion heater and get hot water. If the immersion was part of a thermal store all the better but why bother with the PV? Direct solar thermal would be more effcient, ah you don't get to screw 40 plus p/unit from everyone paying an electricty bill do you?

Reply to
Dave Liquorice

But you can the charge it during the day. Oh you want to *use* the car for transport? Well with it's range you may as well get a push bike.

Reply to
Dave Liquorice

yet more profit for green snake oil salesman, yet more cost for your FIL.

Reply to
The Natural Philosopher

Pretty easy to wind up aren't you? Are you a socialist?

Reply to
harry

I've never been mistaken for one before. You see yourself as "investing" in green technologies to save the planet, as far as all your insulation is concerned, fine that's spend-to-save. But solar panels and electric cars, where's your risk? ... don't try and pull the wool, it's sponging.

Reply to
Andy Burns

On the FIT you are paid something like 4x the real price for the electricit y you generate. So, if you plug a lamp into the mains and shine it on the panels can you use 'normal priced' electricity to make 'FIT electricity' pe rhaps. Maybe you need to plug it in next door...

it must be illegal.

Robert

Reply to
RobertL

you generate. So, if you plug a lamp into the mains and shine it on the panels can you use 'normal priced' electricity to make 'FIT electricity' perhaps. Maybe you need to plug it in next door...

You would need the overall efficiency of the lamp > PV panel > Inverter to be rather high for the maths to work.

Chris

Reply to
Chris J Dixon

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