Simple solar PV question

huzzer84

Hi,

I'm considering getting solar PV but just want to make sure I've got my head around something.

I've got a south facing roof, free from shade, ability to pay upfront, plan to stay in my property for a long time, ie many of the factors that make solar PV a decent investment. However, on the downside at the moment at least (may change in a couple of years if children come along) neither my wife nor I are typically at home during the day when the sun shines the brightest.

Of course we can time appliances to run during the day, etc, but I want to make sure I understand why this is beneficial.

As I understand it, I would receive FIT currently at 14.9p/kWh, which is based on the amount generated by the system, and is not affected by how much energy I use, or when I use it.

I would save ~13p/kWh (whatever my supplier charges me) on everything up to the point (at any instant) at which the panels generate the same as my usage.

I would then save 0p/kWh for everything where generation exceeds usage.

The export tariff of 4.64p/kWh would be paid at a rate of 50% of the total amount generated, ie as with the FIT it is irrespective of how much energy I use.

Therefore, I want to have appliances on during the day to save myself from the 0p/kWh situation and get as much of the ~13p/kWh situation as I can?

Is that correct?

Thanks!

(once I've got my head around this I may start thinking about actually getting some quotes!)

Martyn1981

mhurren wrote: »

Hi,

I'm considering getting solar PV but just want to make sure I've got my head around something.

Is that correct?

Thanks!

(once I've got my head around this I may start thinking about actually getting some quotes!)

Yes.

Mart.

huzzer84

Excellent, thanks!

EricMears

mhurren wrote: »

Therefore, I want to have appliances on during the day to save myself from the 0p/kWh situation and get as much of the ~13p/kWh situation as I can?

Is that correct?

One small caveat. Running your appliances during the day will only be beneficial if you are generating enough 'free' electricity to operate them. i.e. set up your washing machine (perhaps 2kW when heating), dishwasher (also approx. 2kW) & oven (perhaps 3kW) all to run from 11 till 3 and you'll be using twice as much as you're generating on a day like today (or 7 times as much in December !). Run just one of them each day & it might be free.

There are various devices available (e.g. 'Optiplug' ) that could be used to make sure that (say) your oven only runs when free power is available.

Ectophile

If you're willing to fork out extra money, you can buy a gadget that monitors your power generation and consumption. When it sees an excess of generation, it diverts any spare power to your immersion heater.

Of course this is only useful if you have a hot water tank with an immersion heater.

albyota

Or....on the application form, tick the box that lets you opt for metered export by having an export meter fitted, that way you will get nearer to 90% what you generate per year rather than the 50% deemed.

AL

RobT85

albyota wrote: »

Or....on the application form, tick the box that lets you opt for metered export by having an export meter fitted, that way you will get nearer to 90% what you generate per year rather than the 50% deemed.

AL

Except for the fact that most energy suppliers will not do this for you without charging.

Furthermore, unless you have a large system most family homes will use more than their system produces at any one time, except for midday in the summer. Therefore an assumed export of 50% is great!

EricMears

RobT85 wrote: »

Except for the fact that most energy suppliers will not do this for you without charging.

Agree with that.

RobT85 wrote: »

Furthermore, unless you have a large system most family homes will use more than their system produces at any one time, except for midday in the summer. Therefore an assumed export of 50% is great!

Guess it depends on what you call 'large'. Most of us here have aimed for 4kWp - the biggest system that will earn the max FIT tariff - and this week I've been generating more than 0.5kW (my 'background usage' ) for approx. 12h/day and still exporting something even when running one major appliance between 10am & 4pm. Afraid I'm a bit short on accurate export figures but I would expect it to be around 50% and anyone out all day has no chance of using much more than a quarter of their generation.

Wh05apk

Sometimes, I think too much effort is put into trying to save a few pennies, the OP is presumably using appliances at the moment and paying for the power use, the main gains really are from the FIT, for most people, I think it unlikely during the summer months, they will use more than 25% of what is produced, and so overall savings will be minimal.

Ultimately we made the choice based on the FIT, I estimate for July as an example we will earn about £100, but save about £30, we might save £30 a month for 4-5 months, but I suspect outside of the peak months it will only be about £10pm.

I work from home, so normally 1 load in the dishwasher a day, and probably 4-5 in the washing machine, as Ericmears says, try to use around midday, and use timers if you will be out, sometimes the sun goes in, and generation is not enough, but it will still be a contribution to lessening the power bought in.