Storage Of Electricity From PV Cells

[R500POP]

We are batting ideas around about the build of our next house.

One thought is that we'd like to live "off grid" as far as our energy usage is concerned.

We are looking at to possibility of storing electricty generated from wind & solar PV in a bank of batteries. Has anybody seen it done well in a domestic application?

[cjs]

You can do it for low voltage, 12v, usage. Not much help in a domestic house, you would need a huge battery bank to give you any reasonable usage at 230v, totally uneconomical when you take into account battery costs/maintenance, space for them etc etc.

[R500POP]

Perhaps use the excess electricity during the day to spin up a large flywheel (ala flywheel hybrid).

(This is a joke BTW)

[rsv gone!]

It's actually quite hard to store electricity in large quantities.

Best you can do is use the feed-in tariffs to minimise bills.



On a huge scale, they use this method;

http://en.wikipedia.org/wiki/Pumped-storage_hydroe...

(I'm not suggesting you buy your own reservoir)

[R500POP]

rsv gone! said:

It's actually quite hard to store electricity in large quantities.

Best you can do is use the feed-in tariffs to minimise bills.

I suspect that by the time we find the land & save the finances to build that the FIT will not be available any more.

[rsv gone!]

It has been guaranteed for close on 25 years

[R500POP]

rsv gone! said:

It has been guaranteed for close on 25 years

I know that they will pay it for 25years on new installations, but I assume at some point in the near futur there will be a point where they will not pay on new installs, just continue paying on existing ones until the 25 years is up.

[freecar]

I've looked into this and the best way is a water wheel.

There is a company that makes water wheels in the shape of an inclined archimedes screw, setup is £100,000 and annual electricity is something like £48,000 at normal non subsidised rates!

I can't remember their name but remember seeing them on TV a while back, they were a touch pissed as they weren't getting any green subsidy as it wasn't solar or wind!

[dickymint]

I,ve often wondered if it was possible/viable to secretly tap into the water main to run a turbine. relying on users downline to feed it.

[Tuna]

dickymint said:

I,ve often wondered if it was possible/viable to secretly tap into the water main to run a turbine. relying on users downline to feed it.

Possible - yes
Legal - no
Practical - not even slightly

You actually need a surprising amount of water to generate power - and in the process you take out all of the pressure/flow, so you'd need to work out how to tap into a large water main without anyone noticing, and how to explain to half your town why the water isn't really coming out of their taps any more.

On the other hand, if you can find the location, water power is probably the most cost-efficient and reliable way to generate your own electricity. The first 'industrial machines' were water powered for a reason.

It's all about scale though - a little stream with a cute waterfall won't do the job. Think in terms of converting a water mill, and you're on the right track. Would be a wonderful project too.

[dickymint]

Spoilsport

How about using free day time PV electrickery to pump water up-hill then releasing said water down-hill to a turbine.

[Sam_68]

rsv gone! said:

It's actually quite hard to store electricity in large quantities.

Best you can do is use the feed-in tariffs to minimise bills.

This is the practical solution.

Effectively, you're getting the National Grid to store your electricity for you; in the periods when you're generataing more electricty than you need, it's fed into the grid for other people to use, and offset on your bill against the electricity you draw from the grid in periods when you're not generating enough to meet your own needs.

[thinfourth2]

If you want to live offgrid then talk to someone who lives offgird

http://lifeattheendoftheroad.wordpress.com/categor...

This guy has no mains electricity/gas/water/sewage/phone and not through choice

Folk can't belive folk in the UK have houses without mains everything. We only have electricy and a phoneline everything else we have to do ourselves

[anonymous-user]

Buy 2 Electric cars?
1 on charge during the day. 1 to use.

[zaphod42]

There was a woodsman on grand designs that I remember. He was using wind and solar going to 2v submarine batts (a lot of them) feeding a 12v system for led lights, laptop, phone. He had no other services. Water was a huge tank and long drop for sewerage.

[Mr GrimNasty]

rsv gone! said:

It has been guaranteed for close on 25 years

It could be withdrawn at any time for new installations.

Large schemes were cut on a 3 tier scale as of 1st August.

And even the existing installations that think they have a 25 year guarantee will have a shock a few years down the line, that I will guarantee.

It's also immoral taking advantage of the FIT because of the way it is funded and the complete futility/hypocrisy of the supposed 'green' credentials anyway - not that that bothers most people these days when they think they've discovered a free lunch.

[dickymint]

Mr GrimNasty said:

rsv gone! said:

It has been guaranteed for close on 25 years

It could be withdrawn at any time for new installations.

Large schemes were cut on a 3 tier scale as of 1st August.

And even the existing installations that think they have a 25 year guarantee will have a shock a few years down the line, that I will guarantee.

It's also immoral taking advantage of the FIT because of the way it is funded and the complete futility/hypocrisy of the supposed 'green' credentials anyway - not that that bothers most people these days when they think they've discovered a free lunch.

+1

[netherfield]

Household appliances are AC,batteries store in DC.

[Tuna]

netherfield said:

Household appliances are AC,batteries store in DC.

...and you can buy a relatively efficient Inverter to power household stuff off your batteries from many suppliers now. It's not a trivial task (the legislation is incredibly strict on isolating your private power source from the grid), but you can do so.

It makes a lot of sense to use an inverter, as a low voltage DC circuit has to carry a LOT of amps to transfer the same power. Firstly that means that you need very thick cables (this is why overhead power lines are at an even higher voltage - it avoids needing thick wire), and secondly it's a serious fire risk - amps mean big, chunky sparks.

The power loss in a 12v circuit is big enough that you can't really consider wiring your house for it. The few off-grid homes that use 12v tend to be small, and have all their appliances in one place.

[R500POP]

netherfield said:

Household appliances are AC,batteries store in DC.

Solar PV cells are DC output too.