So now I have a solar PV system how do I make the most of it???

grahamc2003

thenudeone wrote: »

Which is why it's much better to shift your own consumption (for water heating, for example) to the times when you are generating leccy.
It's much better to save 12-15p (by replacing bought in leccy with self-generated leccy); than to sell spare capacity at 3p.

But do you pay 12-14p to heat your water? You need a new system if you do.

Most people heat water either by gas at around 4p/kwh, or nightime electricity at about 5p/kwh. So, in all probability, you are getting a 4 or 5p value/kwh by heating your water with solar.

This aspect is whetre a lot of the estimates of the value of 'free' solar power go astray. Many times people say they'll use x kwh of their free power (itself often an overestimate imv), then assign a value of 13 times x pence/kwh to that value to get the actual monetry value of that electricity, when some or much of it actually has a value of 4 times x pence/kwh if used for water heating.

In fact, typically,if you only have anything less than 2kw spare generation at any instant, and your 3kw immersion heater is turned on to use it, then you are paying more for your hot water than simply heating with gas (because the 1kw import at daytime electricity prices brings the average price of that heating above the gas price (I.E. you are increasing your bills, not decreasing them, by using solar under those conditions.

free_juice?

jackieblack wrote: »

http://www.ofgem.gov.uk/Sustainability/Environment/fits/Pages/fits.aspx

Hmm. I had been there too and must have failed to get to the bottom of the list, under all that windmill stuff. Thanks.

ChrisJD

grahamc2003 wrote: »

In fact, typically, if you only have anything less than 2kw spare generation at any instant, and your 3kw immersion heater is turned on to use it, then you are paying more for your hot water than simply heating with gas (because the 1kw import at daytime electricity prices brings the average price of that heating above the gas price (I.E. you are increasing your bills, not decreasing them, by using solar under those conditions.

The theoretical solution is a box of tricks which modulates the power drawn by the immersion heater so that it only uses surplus generated electricity. However, it would not cover its cost.

Once you have a smart meter, then you will only be paid for what you actually export, instead of a deemed 50%, which would make it still harder to justify.

Cardew

ChrisJD wrote: »

Actually, you don't really want car batteries, they are more for high current than deep discharge. They also have a relatively short life, so you need to factor in replacement costs.

You also wouldn't be able to claim FIT for this kind of installation.

I didn't consider teachergirl wanted a full technical explanation of battery technology, when the scheme was clearly a non-starter for the OP.

You would be able to claim FIT for this kind of installation when used as a supplementary power supply. It is only when PV panels are used in a 'stand alone'(i.e. no mains supply) that FIT cannot be claimed.

If you look at the title of this thread, you will see that my reply was in that context, as the OP was clearly not considering a stand alone system.

I also stated:

Then of course you don't want them charged from the mains if your panel's output is insufficient!!

ChrisJD

Cardew wrote: »

I didn't consider teachergirl wanted a full technical explanation of battery technology, when the scheme was clearly a non-starter for the OP.

You would be able to claim FIT for this kind of installation when used as a supplementary power supply. It is only when PV panels are used in a 'stand alone'(i.e. no mains supply) that FIT cannot be claimed.:

Fair point on the battery detail.

Yes, I see what you mean about FIT - if you were simply dumping otherwise unused generated power to batteries (as compared with immersion heater elsewhere in the thread). As you say, absolutely not economic.

John_Pierpoint

jackieblack wrote: »

http://www.ofgem.gov.uk/Sustainability/Environment/fits/Pages/fits.aspx

Anybody got the skills to extract the data from the big spreadsheet and turn it into something meaningful?

For example create a dot overlay on a Google map:
My bet is the installations will cluster round Oxford, Cambridge, Brighton & Bristol - but i could be wrong.

teachergirl

Cardew wrote: »

The lights have rechargeable AA or AAA batteries.

It would be very easy for your panels to charge car batteries. Have you got a big well ventilated shed to keep them(health and safety)

Then of course you don't want them charged from the mains if your panel's output is insufficient!!

Then another inverter to change the battery DC voltage back to 240v AC

A couple of thousand pounds should be sufficient.;)

O.K. it's a definite no no for now then;)....surely though someone should be working on it. If we are going to have more solar panals in this country(rightly or wrongly) we should be working on ways to make the most of them.
A poor day today about 5.34kWh...I won't be getting rich on that:rotfl:

Cardew

teachergirl wrote: »

O.K. it's a definite no no for now then;)....surely though someone should be working on it. If we are going to have more solar panals in this country(rightly or wrongly) we should be working on ways to make the most of them.
:rotfl:

The problem is that there is no way of storing the sort of electricity you would need in a house. Conventional rechargeable batteries, say the size of your car battery would be OK for running a few low powered lights. Leave your car headlights on, which are say 100 watts, and see how long it is before your battery goes flat.;)

Many millions of pounds have been spent on research on battery technology. If anyone does ever invent a cheap storage device they will make billions of pounds.

Mcfi5dhc

John_Pierpoint wrote: »

Anybody got the skills to extract the data from the big spreadsheet and turn it into something meaningful?

For example create a dot overlay on a Google map:
My bet is the installations will cluster round Oxford, Cambridge, Brighton & Bristol - but i could be wrong.

Rank Postcode Area Count Percent Postcode Town/City
1 S 1238 6.28% Sheffield (guess who!)
2 PO 659 3.34% Portsmouth
3 EX 550 2.79% Exeter
4 BS 489 2.48% Bristol
5 AL 482 2.44% St Albans
6 RG 389 1.97% Reading
7= DN 385 1.95% Doncaster
7= NG 385 1.95% Nottingham
9 TN 373 1.89% Tonbridge
10 NR 352 1.78% Norwich

Data above is straight from the data - I have not tried to combine the London postcodes into one clump, but I guess they would be quite high in the rankings if I did.

HTH

Darren

PS sorry about the formatting, I did try and tidy it up a bit

thenudeone

grahamc2003 wrote: »

But do you pay 12-14p to heat your water? You need a new system if you do.

Most people heat water either by gas at around 4p/kwh, or nightime electricity at about 5p/kwh.

Around 1 million homes use heating oil as they don't have access to mains gas. I expect that would at least double the gas cost (but haven't done the sums.

Anyway - unless you have a smart meter fitted it doesn't make any difference how much of solar electricity you actually use. The tariff just assumes 50%.