solar energy can you store it and use later?

[kika]

Can anyone help me with some information about solar energy. As I've understood it as you produce energy through the panels and can either consume it or sell it to enel,(who pay a lot less per kw than what they charge when you buy from them) can you store it in anyway and use later for example in the evening? If so what is this storage unit called? Where can you buy one? How much does it cost?

Thanks for any infomation

[alan h]

I think its called a battery.


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[deborahandricky]

Originally Posted by alan h

I think its called a battery.


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You Techheads really understand these things......but can you keep it simple for the rest of us..................................:laugh s:

[alan h]

Originally Posted by deborahandricky

You Techheads really understand these things......but can you keep it simple for the rest of us..................................:laugh s:

As I understand it - you use the solar power to charge a battery [say a normal car battery - although you could go hi-tech and get something fancy/expensive like a lithium thingummy battery]

You then use a DC/AC Power Inverter to convert the 12 volts back to 220-240 volts AC.

You can get a DC/AC Power Inverter that gives 300W at 230V from a 12 volt car batter for about £35, which could provide a fair amount of low energy lighting in a house at night, and I suppose you could ramp up the system to give more power - but you need to wait for the techies to answer properly later on [when they've stopped caressing their diodes - or whatever they do in their spare time]


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[kika]

Originally Posted by alan h

I think its called a battery.


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Hi alan
Don't want to seem dimmer than dim, but I did say that to said sales person but he was adamant that you can not store but sell it to enel. Seeing as we're in Italy and not Germany you can never be to sure of anything really! I've also been told that you need permission from the comune!

[kika]

Has anyone successfully fitted solar panels d.i.y. style?

[NickZ]

1) Batteries tend to be expensive.

2) Need to be maintained.

3) require a battery charger a bit more money

The older Italian program didn't really alllow batteries. At least they didn't provide any money for it. Under the current system with no upfront money from the government I guess you could install the batteries. But I wouldn't. It's wasted money for a grid connect system.

On DIY grid connect systems are connected to the grid. If you screw up you put Enel's grid at risk. They will make sure anything you do is done by fully licensed people. Could you offer to do some of the grunt work? I guess if you find the right installer.

[elliven]

Yes Kika I would like to know about DIY installations. I know my son in Spain only really got good results by jettisonong the fancy control equipment and feeding straight in to the battery.
I reckon the feeding back in to the grid concept sounds expensive and not really worth it.
Lead acid batteries not hugely expensive but they do have a limited life and need replacing every so often

[Noddy]

The best episode of Grand Designs (IMHO) was where a bloke who worked as a forest ranger in a Sussex forest was granted permission to build an eco home that was to be his home whilst he held that job, and if he went the construction had to go too. Anway, he had pv with batteries, and it worked well enough. There was no mains supply of anything.
I was an Eco Homes assessor and environmentalist in the UK and I found most of the information I required on the Energy for Sustainable Development (Camco Global - creating value in the sustainable energy and low carbon markets) and the Energy Savings Trust (Energy Saving Trust - Energy Efficiency & Energy Conservation to combat Climate Change - Energy Saving Trust) websites.
There's a case study of 'stand alone pv' on the EST site that might help understand the process in simple terms. Very positive results.
Sorry I can't help with how to do it over here. I'd be very interested in your progress. Good luck.

[AllanMason]

Originally Posted by kika

...you produce energy through the panels and can either consume it or sell it to enel,(who pay a lot less per kw than what they charge when you buy from them)

Not true.

It seems to me that ENEL tries as much as UK electricity producers to obscure how much exactly you're paying per kWh by using standing charges, sliding scales, apparently random discounts and so on, but as far as I can make out, we're currently paying something less than €0.20 per kWh for ENEL's finest vintage juice. A leaflet I picked up today in OBI says that ENEL will pay between €0.38 and €0.49 for electricity produced by solar panels. The exact amount depends on the size of the installation (bigger ones earn less) and whether the panels are integrated (top surface of panels level with roof tiles - the highest rate), partially integrated (on top of roof tiles - a middle rate) or non-integrated (not on roof at all - the lowest rate).

As far as going the non-grid integrated path is concerned, it is of course entirely possible to have a few solar panels connected to a battery bank and perhaps an inverter to supply 240 VAC and so be totally independent of ENEL. However, this approach does get very expensive and full of hassles if you're looking to do anything more than run a couple of lights at night. By the way, it is definitely not a good idea to use a car battery for this sort of purpose since they are designed to be slightly discharged and then immediately charged up again. After only a few cycles of running a car battery close to flat and then recharging (what you basically want to do with an independent solar system), the battery will be ruined and unable to hold any sort of charge. Instead, what you need for this purpose are "deep discharge" batteries like those used in forklifts, golf carts and caravans. These things are not cheap, and even with careful handling they have a lifespan of perhaps five years or so.

If a house is in a very rural position, has no mains supply and the owner (for whatever reasons) decides that's not wanted, then one could install a 12VDC system and use lighting and appliances designed for caravans. I looked into this a couple of years and discovered there's actually quite a wide range of stuff available to run off 12VDC, but you can forget about things like washing machines and other major appliances. I know it's possible to get refrigerators that run off gas (and even parafin, if memory servers) in the USA, but I don't know about their availability in Europe. What I do know is that 12VDC fridges were pretty pathetic the last time I looked.

Bottom line is that it is a lot more convenient for us non-ultra green types to plug a photovoltaic panel system into the grid, export the electricity produced on the roof on sunny days when we're not using much and buy electricity from ENEL when the panels aren't producing.

A friend in the village here has had a 3kW PV panel installation for over a year now and he's completely convinced that it was a good buy. He told me recently that the money he's getting back from ENEL is enough to pay for the wood he needs to heat the house over the winter and he figures the payback for the investment in the panels is something like 20% per annum at ENEL's current rates.

Al