Rent-a-roof - questions on contracts people have signed.

rogerblack

As I understand the scheme, you get someone to come along, fit solar panels, which they own, as well as the rights to site them on your roof for 25 years.
They get the FIT and export payments, you get the 'free' electricity, when you can use it.

A few thoughts arise.

Is there any clause stopping you adding equipment to use more of the generated power, for example an immersion heater to heat a very large, well insulated tank for hot water, or batteries to store the 'free' electricity. (I'm aware that with current batteries this is hard to make breakeven, but in 5 years time...) Ideally the export meter wouldn't turn.

Do they bear all servicing costs - if for example the inverter dies in 11 years?

After the 25 years are up, do the panels revert to my ownership, or in principle can they come and take them.
(why they'd do this is another question, I'm wondering about the legality)

Thanks!

Cardew

There is nothing to stop you using as much of the generated electricity as you can. The company can presently elect for an assumed 50% to be exported(and sold at 3.1p/kWh) regardless of zero or 100% being exported. Even if that were to change, at 3.1p/kWh it is not a big deal compared to FIT.

As discussed in other threads, it is much more difficult than people imagine to use greater amounts of generated electricity in-house. Most people heat water with gas, oil or Economy 7 electricity and the use of an immersion heater to 'use up' generated electricity can actually cost the householder money!

energysavingexp

you can use all of the generated leccy as you want as most installs dont have an export meter anyway. as cardew says at 3.1p its nothing.
yes they will bear all servicing costs and insurance costs
after 25 years most will transfer ownership of the system to you at no cost or very little as it will cost them more to remove them and they will be of no use to then anyway.

rogerblack

Cardew wrote: »

and the use of an immersion heater to 'use up' generated electricity can actually cost the householder money!

Slightly confused - how does this work?
Or are you meaning for the case of purchased panels, where you get the export payment, and gas is under 3.1p/kWh?

For rent-a-roof - is there any incentive at all to not use it all?
I do understand that I'm unlikely to be able to use it all.

I'm assuming that there is a generation meter, which measures the generation, to keep track of the FITs.
How is this connected to the normal meter?

Is it simply connected downstream of the normal meter, and the normal meter swapped for one that does not go backwards?

Thanks!

noncom_2

OK, let's suppose you put a 3kW immersion heater in your water tank and plan to run it from the free electricity.

Given that the output from a PV system can go from peak production (let's assume 4kWp) to very little in the course of only a few minutes (a heavy storm cloud passing overhead for example), how do you plan to tell the immersion when to switch on and off? Are you going to sit there all day watching the generation meter, and when the output of the system is below 3kW run upstairs and turn it off?

What is more likely is that you will try and assume that the system will produce enough energy to run the immersion heater between certain times of the day, and set a clock to switch the immersion on at this time. But when that storm cloud passes overhead, the immersion is still switched on and you are heating your water at the cost of your standard daytime electricity.

This is why, as Cardew points out, it may end up costing you more than not trying to do it in the first place.

There are electronic gizmos available which can monitor the generation/export/import of your house, and divert power to a selected circuit only when excess power is being generated. However the cost of buying and installing these devices (as of a year ago when I investigated the same question) makes them uneconomical for domestic systems.

noncom_2

rogerblack wrote: »

I'm assuming that there is a generation meter, which measures the generation, to keep track of the FITs.
How is this connected to the normal meter?

Is it simply connected downstream of the normal meter, and the normal meter swapped for one that does not go backwards?

Thanks!

In my system at least, the Generation meter is connected "inside" the house wiring with respect to the Standard Energy Co meter (not sure whether you refer to that as down- or up-stream, as it depends whether you are looking at the imported or the exported electricity, surely?).

If you have an old meter which is capable of spinning backwards when you export, the Energy company may want to come and change it. But anecdotal evidence on this forum suggests that they may not be in a huge hurry to do so.

zeupater

noncom wrote: »

.... If you have an old meter which is capable of spinning backwards when you export, the Energy company may want to come and change it. But anecdotal evidence on this forum suggests that they may not be in a huge hurry to do so.

... especially so as you will owe them for the energy which they estimate you have benefited from anyway, so there's no real incentive for them to hurry anyway !

Z

Cardew

rogerblack wrote: »

Slightly confused - how does this work?
Or are you meaning for the case of purchased panels, where you get the export payment, and gas is under 3.1p/kWh?

For rent-a-roof - is there any incentive at all to not use it all?
I/QUOTE]

If you have gas you will be paying around 3p to 4p/kWh(after taking into account boiler efficiency). Electricity will be around 10p/kWh

As Noncom states for much of the year - even at midday, you might have, say, 'only' 1kW of excess generated electricity.(or even less)

So, assuming 1kW excess generated electricity, heating water with a 3kW immersion heater means it will be using 2kW from the mains. That will cost you 20p an hour on your electricity bill, to save 6p to 8p an hour* off your gas bill.

This is not just 'theory' it will happen - to a greater or lesser extent for the majority of PV systems if you try to heat water with an immersion heater.

* kWh

bris

You can't run an immersion heater with these panels, there is just not enough power generated for it, yes the figures say it's possible but the reality is that you would be taking from the grid for most of the time. Gas will always work out cheaper.
The best use of the system is for the dishwasher, washing machine and smaller stuff. Staggered through the day. The rent a roof scheme is a poor deal for the house holder, you will save £100 while they get £1500. There is also the hassle of the readings every quarter.

Cardew

bris wrote: »

The rent a roof scheme is a poor deal for the house holder, you will save £100 while they get £1500. There is also the hassle of the readings every quarter.

£100 if you are very lucky - £70 a year is average!

For that you sign away rights of access to your roof for 25 years - binding on the next owner as well.

rogerblack

bris wrote: »

You can't run an immersion heater with these panels, there is just not enough power generated for it

Ah - I see where this comes from now, I omitted important stuff for simplicity.

Specifically, I'd be using a device which is basically a dimmer, with a clip-on sensor to the meter.
If there is any inflow of power, it turns down the 'dimmer' essentially instantly.

So it never uses any extra power from the mains.