Solar Panels -how much less electricity are you using ?

Cardew

Energetic wrote: »

We're finding that 40% consumption of your pv generation is acheivable without 'too much' effort, with an intelligent immersion controller that can push you into 60-80% consumption, if you have a high enough HW demand you could be exporting very little.

However it depends on how big your system, and how much you are generating.

With a small system generating, say, 1,500kWh pa, I suspect it would be fairly easy to use 40%.

However with a larger system generating, say, 4,000kWh pa it would be more difficult for many people to use 40%.

Energetic_2

Cardew wrote: »

However it depends on how big your system, and how much you are generating.

With a small system generating, say, 1,500kWh pa, I suspect it would be fairly easy to use 40%.

However with a larger system generating, say, 4,000kWh pa it would be more difficult for many people to use 40%.

You are right, there are a lot of variables to consider. It's virtually impossible to get to that kind of self consumption without clever power management. If you wish to use more of what you generate and have a DHW tank with an immersion element you could have an intelligent immersion controller fitted, this will monitor what you are generating and also what you're consuming and send any excess to the tank rather than exporting it to the grid. They only use what is spare and won't import.

Particularly effective payback when replacing oil or LPG. We've been installing two, they are both very efficient and work in a similar way:

Immersun
S&G Wooldridge Solar PV Switch

You'll have to goggle them if you're interested, i cant post links yet. We've had great feedback for both but one is a little cleverer that the other.

davebrik

BirnamBear wrote: »

January 2011 to January 2012 we used 10862kwh.

We had solar panels installed at the end of February this year.

Just had a bill from EON and they say we used 7758kwh in the last twelve months till now.

Quite happy with that :j

Wow! This is 40%! I also thinking of installing solar system. Now I'm using solar water heater, that saves me a lot I think. But this is a different system from that of generating electricity. I want to build my own solar panels, but I think they won't last so long as manufactured but less expensive.

zeupater

davebrik wrote: »

Wow! This is 40%! I also thinking of installing solar system. Now I'm using solar water heater, that saves me a lot I think. But this is a different system from that of generating electricity. I want to build my own solar panels, but I think they won't last so long as manufactured but less expensive.

:rotfl:.... :rotfl: ..... :think: .... :doh:.... :wall:

:wall:
Z

dm827430

zeupater wrote: »

:rotfl:.... :rotfl: ..... :think: .... :doh:.... :wall:

:wall:
Z

not sure about the rofl and head banging????????
its fairly easy to buy broken cells and solder them together cheaper than buying full pv units. equally solar water heating can be done fairly cheaply with diy instrutions off the net.
and tin cans and perspex provide a nice heat source for greenhouses.

zeupater

dm827430 wrote: »

not sure about the rofl and head banging????????
its fairly easy to buy broken cells and solder them together cheaper than buying full pv units. equally solar water heating can be done fairly cheaply with diy instrutions off the net.
and tin cans and perspex provide a nice heat source for greenhouses.

Hi

I understand what you are saying, however, taking the massive reductions in panel prices over the past couple of years, have you looked at the economics of doing this recently ? ... toughened glass, supporting frame (aluminium ?), cells, backing, connectors, cables, mounting frame, fixings ... test equipment, solder, tools, scrap allowance .... and after all this you'll still need a grid-certified inverter (or a shedload of deepcycle batteries) and a considerable amount of time to achieve anywhere near the energy generation required to achieve a significant import reduction -

Additionally, did you not notice that "Wow! This is 40%!" related to a reduction in billed electricity from 10862kWh to 7758kWh is actually a little out .. .. 28.6% is a little more realistic - then there's the issue that the import reduction of 3104kWh (10862-7758), if applied to the average UK household electricity consumption would represent 94% (3104/3300) of the total, therefore the high reduction in imported electricity in the referenced case is likely directly related to an abnormally high rate of consumption which results in an abnormally high rate of self-consumption, the usual rate being accepted as being somewhere around 1000kWh/year by the majority who have panels.

On the water heating .... the poster stated that he 'thinks' that the current system saves 'a lot' .. it might save something, but it would also cost something and should therefore be subjected to a cost/benefit analysis .... even the DIY solutions mentioned have an investment cost, both in time and monetary terms ...

We ourselves have domestic scale pv and thermal. I built my first DIY pv circuits in the early '70s, well before consumer items such as solar calculators etc, and have had a number of off-grid systems over the intervening years, therefore I fully support 'playing' with small DIY systems within a learning context. Also, our family has had significant DIY solar thermal provision since the mid/late '70s .... however, considering all of this past experience, what we have in place now is not DIY, the driving factors simply being scale, performance, reliability, legislation, risk, maintenance & cost.

"not sure about the rofl and head banging????????" ... :think::wall::whistle: ... :D

HTH
Z

mardycow

not sure if am using less but it sure is costing me less, don't ask me for figures and stats, but after receiving over £200 electric rebate and paying less per month to me that signifies paying less . For this first full year i have earnt over £1700 from FIT payments on a 4 kw system.:T

rogerblack

davebrik wrote: »

Wow! This is 40%! I also thinking of installing solar system. Now I'm using solar water heater, that saves me a lot I think. But this is a different system from that of generating electricity. I want to build my own solar panels, but I think they won't last so long as manufactured but less expensive.

I was pondering this - and it's hard.
The cells may be somewhat cheaper, but the glass, ... remains the same cost.
I note someone on ebay selling off 'lightly used' solar panels at 50p/watt.
That is a really good bargain.
However, the economics are problematic.
Without the appropriate blessing from the priests of MCS, you cannot export to the grid legally.
Even if your meter permits it.

This makes the return of panels that are much more than about twice your baseload questionable.
(always on loads).
And means you need additional hardware to avoid exporting to the grid, in the case you have a meter which will detect 'tampering'.

Martyn1981

Looking at some of the on-line shops, you can get some mono panels, such as YingLi's for about 60p/watt. I've even spotted some Jetion poly panels for 50p/watt. All prices including VAT @20%.

Hard to imagine you could do better DIY or second hand given they are new warranted panels.

Mart.

Dave_Fowler

It's interesting to look at the graphs produced on Gridwatch http://www.gridwatch.templar.co.uk/ for the last two days. There's very little sign of the evening peak at around 6pm. I wonder if this, to some extent, is because people with solar PV are still generating a significant amount at 6pm now that the clocks have gone forwards by 1 hour.

It can't be anything to do with varying un-metered wind generation as metered wind generation has been very low for the past few days.

Dave F