Solar panels with no smart meter?

[ericmark]

I have had a survey done, and a firm is to install solar panels and battery, they should work in three stages, first they supply existing load, then they charge the battery, then they heat the immersion heater, and only if any spare after that should it export the power, so unlikely much power will be exported, however they tell me the supplier will use the reading from the meter being installed by the solar panel installer, to credit me with any export, and they their meters are not calibrated, this seems odd, I had expected to be told my meter must be changed, so it can measure import and export where the existing meter as far as I am aware would log both import and export as import.

Have I got some thing wrong?

 

[Adam_151]

I think they are just a bit of date, The meter they will be installing will be measuring generation, not export (i.e. units are recorded on there even if you use them yourself), back in the days of the feed in tarriff you were payed on generation (you also got a smaller amount on top for exported units- and they used to assume 50% of generated were exported)

These days, there is no feed in tariff (for new installs) and assuming 50% of units generated would be exported would not hold true for battery systems.

I don't know about other suppliers, but I think octopus inisist you have a smart meter for tariffs with payments for exporting, now I suppose as long as a meter had an separate export register, it wouldn't have to be 'smart' to correctly log the export units, but not sure how many of the older meters could do that.

I would expect it would be down to you to sort out tarriff with the supplier, solar people will just do their job and hand it over, and if you have not moved to the right tariff, any exported units will just be gifted to the grid (perhaps the feel good factor of contributing green energy is enough!)

There are probably quite a few old electro-mechical meters without a backstop out there as well, but it would be wrong of you to let it subtract units from the import resgsister and not tell them there was an issue!

 

[JohnW2]

I have had a survey done, and a firm is to install solar panels and battery, ....

Perhaps I'm wrong, but I thought that you were a fairly similar age to me. If that is the case, have you considered (I presume you must have done!) the duration of the 'pay-back time' (i.e. the time to 'break even', with detrimental cash flow situation prior to then) for such an installation?

Kind Regards, John

 

[Murdochcat]

Perhaps I'm wrong, but I thought that you were a fairly similar age to me. If that is the case, have you considered (I presume you must have done!) the duration of the 'pay-back time' (i.e. the time to 'break even', with detrimental cash flow situation prior to then) for such an installation?

Kind Regards, John

Interesting thoughts.

When I installed our panels/ divertor it cost me a total of just over £4k

At the time banks would pay about 1% and our mortgage was costing about 2%

Our savings prior to the energy price hikes were about 8%

Our inverter won’t work with batteries so I need to look at the cost / payback of a new inverter & batteries but suspect the numbers won’t stack up.

 

[ericmark]

Estimated pay back time 6 years, however one of the points with new system is the ability to use battery/solar power when we have a power cut, in the past that was not an option, also it will power the immersion heater, so saving on oil as well.

I is designed to first provide what we are using, then spare to battery, then to immersion, and only after that to export so seems unlikely will export much. However the last thing I want to be doing is paying for power exported, and I really can't see how an energy provider would go by the readings of my meter I would have thought they would only go by what their meter says?

 

[JohnW2]

Interesting thoughts. When I installed our panels/ divertor it cost me a total of just over £4k

That's fairly modest, even for 'just PV', nd is likely to be appreciably higher when one brings batteries (and associated gadgetry into the equation.

At the time banks would pay about 1% and our mortgage was costing about 2% Our savings prior to the energy price hikes were about 8%

Changes in the financial climate over the past couple of years or so have certainly weakened the argument.

However, as I implied, it's not just a matter of real time 'savings' and/or loss of notional investment income on the capital outlay. To say that it will take, say, 6 years, 10 years or whatever to reach the 'break even point' is another way of saying that for the first 6 or 10 years one will be 'worse off' than one would have been without the PV.

Furthermore, one mustn't forget that, even when one has passed the 'break even point' one does not then continue to 'win' for ever. Warranties on the systems are unlikley to be any longer than 10 years, at most, and it wouldn't surprise me if many systems need replacing not long after that. One therefore may end up 'worse off for 6-10 years', then enjoy a year or five of 'benefit' before having another major capital outlay and hence starting the 'X years of being worse off' cycle again.

 

[JohnW2]

Estimated pay back time 6 years, ....

That seems consistent with what most people say - 6-10 years 'pay back time' seems fairly typical. However, as I've just written, one shouldn't make the mistake of thinking that the benefit will persist for ever once one has passed the 'break even point', since one might have to 'start again' only a few years beyond that point.

however one of the points with new system is the ability to use battery/solar power when we have a power cut, in the past that was not an option, also it will power the immersion heater, so saving on oil as well.

Protracted power cuts are extremely rare. Provided one has gas or oil heating, all one needs is some lighting and the enough electricity to run the CH/DHW system, and, in my case, that is more than adequately served by my £150 Lidl genny! Those reliant on heat pumps (or other electrical heating) presumably have a problem - even with your proposed system, no credible/affordable battery-based system would be able to support that.

I is designed to first provide what we are using, then spare to battery, then to immersion, and only after that to export so seems unlikely will export much. However the last thing I want to be doing is paying for power exported, and I really can't see how an energy provider would go by the readings of my meter I would have thought they would only go by what their meter says?

As you have implied, with the system you are proposing at your PV generation exceeded your total energy requirements - so the questions about metering etc. (to which I don't know the answer) may be rather moot?

Kind Regards, John

 

[SpecialK]

Does your current "dumb" meter show an export figure? I doubt the electric company will take the reading from the installed meter. Can you get a smart meter installed? If so you can go on agile or flux tariffs with octopus were the electric and export rates change depending on the time of day.

You may get some export depending on which way the array faces and how many panels you have. I have charged my battery, ran the house and heated my 210L water tank today with 19kWh of solar. I don't export as I have no MCS cert but I was predicted to make 30kWh today so would have exported around 10kWh for about £1.50 in return at 0.15/kWh

 

[JohnW2]

You may get some export depending on which way the array faces and how many panels you have. I have charged my battery, ran the house and heated my 210L water tank today with 19kWh of solar. I don't export as I have no MCS cert but I was predicted to make 30kWh today ...

How big a solar array do you have, and which direction does it face?

Kind Regards, John

 

[Murdochcat]

That's fairly modest, even for 'just PV', nd is likely to be appreciably higher when one brings batteries (and associated gadgetry into the equation.

Changes in the financial climate over the past couple of years or so have certainly weakened the argument.

However, as I implied, it's not just a matter of real time 'savings' and/or loss of notional investment income on the capital outlay. To say that it will take, say, 6 years, 10 years or whatever to reach the 'break even point' is another way of saying that for the first 6 or 10 years one will be 'worse off' than one would have been without the PV.

Furthermore, one mustn't forget that, even when one has passed the 'break even point' one does not then continue to 'win' for ever. Warranties on the systems are unlikley to be any longer than 10 years, at most, and it wouldn't surprise me if many systems need replacing not long after that. One therefore may end up 'worse off for 6-10 years', then enjoy a year or five of 'benefit' before having another major capital outlay and hence starting the 'X years of being worse off' cycle again.

My motivation for solar wasn’t just about saving money

 

[SpecialK]

How big a solar array do you have, and which direction does it face?

Kind Regards, John

5.7kWp, South facing. Roof is about 22 degrees so not ideal for winter unfortunately

 

[JohnW2]

My motivation for solar wasn’t just about saving money

I didn't suggest that it was. I was merely pointing out that 'financial benefits' are not necessarily as simple or attractive as many people seem to think.

I fear that a lot of people are being persuaded/misled into thinking only about real-time reduction in 'energy bills', without giving enough consideration to the 'big picture'

 

[SpecialK]

I didn't suggest that it was. I was merely pointing out that 'financial benefits' are not necessarily as simple or attractive as many people seem to think.

I fear that a lot of people are being persuaded/misled into thinking only about real-time reduction in 'energy bills', without giving enough consideration to the 'big picture'

It needs working out properly before investing as some systems are £14k+!. Some people are low users so the payback time is not worth it and as you say doesn't account for equipment failures down the line. The price of equipment has dropped considerably since last year and hopefully it will continue to get cheaper. It would be nice if the export got subsidised 1:1 so batteries are not required as they are an expensive part of the system.

 

[JohnW2]

It needs working out properly before investing as some systems are £14k+!.

Exactly, and, as I said, I fear that many people are being led down a path of just focussing on 'immediate reductions in energy bills', with far too little consideration, let alone 'proper working out' of the 'big picture'.

Some people are low users so the payback time is not worth it and as you say doesn't account for equipment failures down the line.

Quite - and those 'equipment failures' are probably an eventual inevitability at some point in time, so certainly need to be taken into consideration.

The price of equipment has dropped considerably since last year and hopefully it will continue to get cheaper.

Maybe but, even if that transpires in the future, it doesn't help the person considering purchasing a system today.

Kind Regards, John

 

[StephenStephen]

I'd suggest you get a couple more quotes.

Apart from anything else, from a financial point of view, you can heat water with gas for about 5 or 6p/kWh (accounting for inefficiency), and sell your excess solar for between 20p and 32p/kWh.
It also would make more sense to use a time of use tariff (Flux, for example) to charge the battery on a low rate and then export at peak time - if they're not mentioning this, I'd be concerned.
It DOES make more environmental sense to heat water from home solar than to export, but given that many people will be looking to save money by installing solar and batteries, I would be concerned that they're not mentioning this.