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

EricMears

sly_dog_jonah wrote: »

EDIT: found their pricing info 'From £250' http://www.engensa.com/blog/solar-power-news/engensa-launches-solar24/ I've updated my previous posting as well. At that price it's quite competitive with the Rudge Renewables device.

Indeed, in which case your import savings will be higher than average. However your overall consumption of kWh in the kettle example above is the same, you're just skewing it in favour of using generated instead of imported power. Replacing appliances/bulbs/etc with more efficient versions or reducing usage will deliver consumption savings which will again improve your import:export ratio (as more of your electricity consumption will be covered by the panel's output, even on a poor day).

Beware the 'weasel word' FROM !

It doesn't mean 'will be' , 'could be' , 'approximately' or even 'might be'. Alas, it usually means "under very special circumstances (that won't apply to your order) it's just about possible that we might quote one of our customers this price; everyone else will pay more (maybe a lot more)". OTOH, it can sometimes mean that your quote won't be a lot more than the 'from price' so probably worth investigating. I believe I showed earlier that it could (again only in special circumstances) be possible to save up to £250 p.a. if you make 'real' use of your otherwise exported electricity so a price that offered the chance of a one year payback would be a 'nobrainer' and even a 3 or 4 year payback is potentially attractive. Of course, calling immersion heating a 'real' use is arguable - only if you would always heat water that way can you do the calculation of savings at 'electricity prices'; otherwise you'd have to cost the energy at (say) gas prices or if you've also got thermal solar panels then running the immersion heater is unlikely to offer any cash saving.

I do of course realise that a 500w kettle for 12 mins is using exactly the same as a 3kw one for 2 mins. As I wrote that, my Wattson meter was telling me I had a 500w excess so the little kettle cost absolutely nothing to run, the bigger one would have been working at '17% off'. Afraid nearly all of the usage reduction methods you suggested are already in place here (but of course other readers may not be so fortunate).

EricMears

sly_dog_jonah wrote: »

EDIT: found their pricing info 'From £250' http://www.engensa.com/blog/solar-power-news/engensa-launches-solar24/

I've just been reading their webpage. They do at least calculate the savings they might get you by using 'gas prices' rather than using 'electricity prices'. However, (as SDJ noted earlier) their assumption that the average panel owner exports 50% isn't necessarily true: many people might well export more like 75% (which would make their product more desirable) but the people most likely to consider an extra investment in kit such as theirs are more likely to have taken other measures already so wouldn't have that level of 'spare' electricity to use up.


Their faqs are a bit coy about whether or not they're offering 'supply only' terms.

Can I install it myself?
As it is a permanently mounted mains installation an Electrician should install it. Engensa is happy to offer this service and offers FREE installation if you get a solar installation with Engensa at the same time.

I don't think their assertion that it has to be installed by 'an electrician' is strictly true. Part P of the Building Regs does indeed expect new circuits to be installed by a registered contractor but I think that's sufficiently ambiguous for a competent DIYer to assume that he can amend his existing immersion heater circuit. It would definitely be perfectly legal to buy the kit and get a local electrician of your choice rather than one of theirs to install it.

sly_dog_jonah

EricMears wrote: »

Beware the 'weasel word' FROM !

It doesn't mean 'will be' , 'could be' , 'approximately' or even 'might be'. Alas, it usually means "under very special circumstances (that won't apply to your order) it's just about possible that we might quote one of our customers this price; everyone else will pay more (maybe a lot more)". OTOH, it can sometimes mean that your quote won't be a lot more than the 'from price' so probably worth investigating.

A warning worth making indeed. I guess it will depend on the amount of electrical work needed to make it usable, and whether its a retro-fit or can be done at the same time as a new installation. They may also be willing to sell the kit with instructions for a local electrician to fit.

I believe I showed earlier that it could (again only in special circumstances) be possible to save up to £250 p.a. if you make 'real' use of your otherwise exported electricity so a price that offered the chance of a one year payback would be a 'nobrainer' and even a 3 or 4 year payback is potentially attractive. Of course, calling immersion heating a 'real' use is arguable - only if you would always heat water that way can you do the calculation of savings at 'electricity prices'; otherwise you'd have to cost the energy at (say) gas prices or if you've also got thermal solar panels then running the immersion heater is unlikely to offer any cash saving.

I posted previously about my guestimated savings for toggling a 1kW immersion on and off depending on a current-controlle switch: http://forums.moneysavingexpert.com/showpost.php?p=51193263&postcount=1603 Based on an installed price of around £400 I estimated around 7year payback. This Solar24 product on the face of it should yield a better return as the initial outlay appears lower, and the regulation (instead of toggling) of the immersion should result in better savings. We don't have solar thermal and heat water twice a day using gas usually. We're hoping to reduce this as much as possible in future though, by minimising export where possible. We don't have sufficient roof space left on the house for solar thermal and the garage is probably too far from the cylinder for it to be worth doing.

I do of course realise that a 500w kettle for 12 mins is using exactly the same as a 3kw one for 2 mins. As I wrote that, my Wattson meter was telling me I had a 500w excess so the little kettle cost absolutely nothing to run, the bigger one would have been working at '17% off'. Afraid nearly all of the usage reduction methods you suggested are already in place here (but of course other readers may not be so fortunate).

Then you're doing a good job of minimising consumption and import, well done :beer:

grahamc2003

seagull09 wrote: »

Following on from yesterday's observation about an impressive 80% peak from my far-from-optimum SE/SW split (single tracker) system, today at 12.50 I was registering a consistent (between clouds) output of 2.08 kWh from a 2.28 kW system - that's 91%! I am mildly astonished.

The mpp for both panels is likely to be similar around midday for your se/sw systems - they are both off the same angle at that time, so you'd expect a similar output at midday whether you have a single or dual tracker system (assuming there are no other differences apart from the angle). At all other times of course, a dual tracker will give better performance.

EricMears

seagull09 wrote: »

That's a very interesting point by EricMears about the kettle - it makes sense to try and decrease the number of high consumption but quick appliances and increase low consumption but slower appliances, for those with solar, particularly like me with a smaller system.

We have a spare low wattage kettle which I'd never thought of using - I shall now start using that one instead, except for when I have to start work at silly o'clock and don't want to wait!

Pleased to have been able to help. That is of course the sort of thing that the thread title seems to be expecting rather than the "why didn't I build my house 200 miles away" or "should I reconstruct my roof" ideas that seem to be creeping in

orrery

seagull09 wrote: »

That's a very interesting point by EricMears about the kettle - it makes sense to try and decrease the number of high consumption but quick appliances and increase low consumption but slower appliances, for those with solar, particularly like me with a smaller system.

True - we need all appliances to have 'solar friendly' features such as reduced instantaneous consumption and timers.

The kettle is one of the best moves you can make. I've found that switching to a small 500W Kenwood travel kettle (less than £15 if I remember correctly) means that, not only do I have more chance of covering the consumption from solar but, I now only boil about as much water as I need. I'd previously have boiled x2 or x3 the amount I actually required. Win-win!

larkim

But can you actually put up with the frustration that is a low powered kettle?!? Personally, I don't drink many hot drinks but they drive me nuts when I'm in a hotel and it takes 10+ minutes for the damned thing to boil!!!



Matt

EricMears

larkim wrote: »

But can you actually put up with the frustration that is a low powered kettle?!? Personally, I don't drink many hot drinks but they drive me nuts when I'm in a hotel and it takes 10+ minutes for the damned thing to boil
Matt

If you fill it to minimum level for need (probably just enough to cover element for one cupful) it shouldn't take anywhere near ten mins to boil (though I appreciate it might feel that way). In the comfort of your own home, it's unlikely anyone really needs a hot drink quite that quickly and you can always pass the time by watching your generation meter tick over and calculating your earnings.

Or of course with a 4kw system running flat out you can use a more powerful kettle than mine. We have our low power one for use in caravan where a standard hookup trips out under the modest load of a normal kettle.

sly_dog_jonah

seagull09 wrote: »

That's a very interesting point by EricMears about the kettle - it makes sense to try and decrease the number of high consumption but quick appliances and increase low consumption but slower appliances, for those with solar, particularly like me with a smaller system.

I tried heating my lunch in the microwave at a lower wattage than the normal 750W. However our microwave simply duty cycles the magnatron to create the effective power requested (ie on for 15sec, off for 30sec, average power 250W). Fortunately the PV was making in excess of 2kW so it didn't matter, but something to watch out for with 'low power' settings on devices and appliances.

As I write this, we've just broken through our record generation at 3:15pm. 15.8kWh and still going strong at 1.05kW currently, despite quite a lot of clouds marring the blue sky this afternoon. Our previous best days were 15.7kWh on the 11th Feb and 22nd October. :j

larkim

YEs, I've noticed that about microwaves before; a bit of a con really, where you think turning it down will have a similar effect to cooking something more slowly on a hob / in an oven. All it does is blast it with microwaves for a few seconds, then nothing other than a bit of spinning around, then blast again.

Do more expensive makes actually modulate the power outputs?

Matt