Free solar panel discussion

mark61120

Can anyone, who has solar panels, please state the sort of things that may be powered on a normal winters day. Like a convection heater for instance (or two, or three, etc).

Many thanks,
Mark

Doc_N

mark61120 wrote: »

Can anyone, who has solar panels, please state the sort of things that may be powered on a normal winters day. Like a convection heater for instance (or two, or three, etc).

Many thanks,
Mark

Sorry to disappoint, but from November to January you're likely to get, on average, just over 3 kWh a day in total, and that's for a 4 kWp system.

Forget the convection heater, I think, unless it's a very small one.

digitaltoast

mark61120 wrote: »

Can anyone, who has solar panels, please state the sort of things that may be powered on a normal winters day. Like a convection heater for instance (or two, or three, etc).

Many thanks,
Mark

This is from a pro-renewables site, so figures will be optimistic:

Suppose you installed 30m2 of panels that were quoted by the manufacturer as having a peak power or installed capacity of 5.7kWp. Suppose they were installed in London, which has an average insolation figure over the year of 109W/m2. In that case you wouldn’t get 5.7kW averaged over the year, but 0.109 x 5.7kW = 621W. However that is the average figure.

In darkest December they were generating just 125W, or enough to power 10 low energy light bulbs. In fact it might be even less than this, because of shading, downtime and other system inefficiencies.

Searching Argos, almost all convection heaters are about 2Kw, that's 2000w, meaning that with THIRTY SQUARE METRES* of solar panels, in the winter in the middle of the day, you would be lucky to be able to run 1/16th of one heater.

According to http://www.solarguide.co.uk, the industry's independent calculation site, 30m2 would cost you £18,034.40 to install.

So, nearly £18k and 30 square metres of roof to power 1/16th of heater when you need it most.

What a fantastic technology. No wonder we're subsidising it to the tune of £billions.

Edit: oops, I see someone else has replied since I pressed "reply" then got distracted. Anyway, hope the extra figures help.

ronlizpatsimon

Ditgital Toast,
Your calculations and conclusions, even if correct, are misleading, in that they only apply during the worst period of the year

digitaltoast

mark61120 wrote: »

Can anyone, who has solar panels, please state the sort of things that may be powered on a normal winters day. Like a convection heater for instance (or two, or three, etc).

digitaltoast wrote: »

In darkest December they were generating just 125W

ronlizpatsimon wrote: »

Ditgital Toast,
Your calculations and conclusions, even if correct, are misleading, in that they only apply during the worst period of the year

OK, he asked for winter figures, I gave him winter figures.
What is misleading about posting figures which you admit are correct?
I've posted links to industry sites and used DECC-approved industry figures for the calculations.

Perhaps you'd like to provide YOUR calculations for a winter period. Don't forget the links and methodology, now....

ronlizpatsimon

It is true that the original question concerned winter usage. However your conclusions will leave many readers with the impression that you are of the opinion that solar panels are not generally financially viable. Of course you are fully entitled to hold this view. Personally I believe that they are a good financial investment.

Cardew

ronlizpatsimon wrote: »

It is true that the original question concerned winter usage. However your conclusions will leave many readers with the impression that you are of the opinion that solar panels are not generally financially viable. Of course you are fully entitled to hold this view. Personally I believe that they are a good financial investment.

They are financially viable for the subsidies paid for all electricity generated.

However using that power in the house - no matter how much you 'work at it' is unlikely to save more than £100 a year, and apart from very prief periods in Summer you won't run appliances like an immersion heater.

In fact if you try and use the generated electricity to power high consumption items(if you have gas) you can lose money.

ronlizpatsimon

You may not think that £100 is worth having. In that case; sent that sum to me. Thats 62 of Mcdonalds finest milk shakes!

grahamc2003

ronlizpatsimon wrote: »

You may not think that £100 is worth having. In that case; sent that sum to me. Thats 62 of Mcdonalds finest milk shakes!

The evidence is that £100 is the max saving, 'for those who work at it'. Beacuse 'workjing at it' generally means heating water to use the electricity mid summer (occasionally), then I think the £100 itself is an overestimation, because the value to heat water is typically about 3p/kwh, instead of the usual 10p/kwh typically ued for the value of generated electricity.

(edt - and did you notice the little reference to bills possibly increasing when trying to use all the solar panel's output by turning on the immersion heater - most renters favorite solution to using up the generated eletricity)?

Anyhow, let's make a reasonable speculation that panels in 20 years time put buyers of buying your house (e.g. since they will then be old technology yet still come with a 5 year obligation). (You may not agree that wll happen, but we are just speculating that it may). Say to sell your house you have to knock 5% off its true value without the roof lease burden (or sitting tenant panels), and say your house in 20 years has a market value of £1m, so the loss is £50,000.

Well that's 31,000 McD finest milkshakes in your value metric.

I'd just make sure you have a reasonable buyout clause written into your contract if you go ahead, to guard against the above possible scenario. Unortunately, posts on here seem to suggest the buyout clauses are currently being re-written.

Jon_Tiffany

digitaltoast wrote: »

So, nearly £18k and 30 square metres of roof to power 1/16th of heater when you need it most.

Speaking for myself, I use gas heating in the winter and you may be surprised to hear that I need electric just as much in the summer as well!

I'm not saying that running electric heaters with solar pv is viable, but I had a quite a few days in December where we were generating around 900w (my system is only small) and could have powered a 1200w halogen heater on the first or second setting - available from Argos.