With pv solar panels it makes sense to heat the water by electric when the sun is shining. Easy enough to switch on the immersion heater when you're about but that's not always the case. Is there a cost effective way of automatically switching on the immersion heater when the solar panels are producing enough electricity?
Yes.
Don't you feel you have expropriated enough cash from the general public already with the outrageous FIT payments you are already receiving?
"producing enough electricity' hahahahaha
Certainly not if there is scope for more.
Does teh FIT give you more money for electricity consumed by yourself than for electricity fed into the system?
As I understand it, the FIT tariff is an additional payment based on 50% of the system theoretical capacity. If so, it takes no account of electricity generated or consumed.
There are separate prices for energy bought and sold. It costs more to buy electricity than to forego the sale of your own.
In article , The Other Mike writes
Wouldn't the theft be most effective if the PV power was sold to the network at markup and the water heated with real electricity during shade time (or gas, if available, at a third the cost of that)?
Yes; you need a Crookes radiometer, a potato, duct tape, and some bell wire.
system theoretical capacity. If so, it takes no account of electricity generated or consumed.
electricity than to forego the sale of your own.
Partly right. You can find all the details on line
I will give figures for my installation. Current ones will be different.
The FIT pays £0.454 per kWh generated. It doesn't matter what you do with it.
In addition, you are paid for exported units, which are deemed to be 50% of what you generate (unless you have a smart meter), at £0.032.
Using this same assumption, you consume half of what you generate, saving your daytime rate of £0.096.
So, the big money is from the FIT, it is also to your advantage if you can maximise your use and minimise export. As these numbers are a lot smaller, it is not worth spending much on clever kit to achieve this.
When smart meters are fitted, it is anticipated that export payment will then be for actual metered exported power.
Chris
No because the real electricity costs about 12p unit and the supplier only pays about 3p for exported units.
mark
Does the word 'deemed' mean payment is independent of what you actually generate.
Run a water tube behind the solar panels and you'll get rather more heat that way
NT
No. Read again what you have snipped:
It directly depends on what you generate.
Again, this amount depends upon what you generate, not what you actually export.
So, following my meter reading in June, I had generated 1136 kWh in that quarter.
For this I was paid 1136 x £0.454 = £515.74 for the FIT.
Additionally I received 1136 x 0.5 x £0.032 = £18.18 for the amount of power I was deemed (ie considered) to have exported.
Assuming this 50 % export, then I would have saved 1136 x 0.5 x £0.096 = £108.59 by not having to pay for peak rate electricity which I actually used.
So, If I obtained a theoretically ideal piece of electrical control equipment which was able to ensure that, when generating, I always used exactly that amount, with no wastage and no additional consumption, then I would be using 100%, and not exporting at all.
This would mean that, in the example above, I would have been making use of power worth £108.59.
However, if you are using it to, say, heat water instead of using gas, then your saving is only what the much cheaper gas would have cost you. Additionally, the real-life situation is such that the ideal is not achieved.
Chris
Thanks for the clear explanation. I previously read exported electricity wasn't metered. I somehow ended up thinking payment was based on installed capacity.
Now you've explained payments calculated from generated electricity, I presume the meter has to be tamper-proof. Is that true?
metered. I somehow ended up thinking payment was based on installed capacity.
You might have been confused by other discussions about solar thermal, which is soon to have a payment scheme of that nature.
the meter has to be tamper-proof. Is that true?
Naturally.
As a householder, you have to use an installer on the MCS list
Chris
Just Google solar immersion heater switch.
You will probably find the device uneconomic. The savings are not great as you can store only a limited amount of hot water.
The FIT pays for all electricity generated. It doesn't matter whether it is "self consumed " or not. It is still fossil fuel saved.
In this case deemed means guessed at.
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