Solar Panel Guide Discussion

digitaltoast wrote: »

I just got an email from the selfbuilder.tv mailing list.

Perhaps I'm getting the wrong end of the stick, but isn't the following just total BS, especially the last para? (My bolding)

No I don't think so.

For a 4kW system the UK average anual output would be in the region of 3,400kWh per year(850kWh per kWp)

If it were possible to increase that output by 10% that would be an extra 340kWh pa which at 43.3p/kWh would be £147.

Mind you I have no idea how they increase output by 10% - unless they move the house and PV system to Cornwall;)

Don't particularly want to get involved with the bashers of the scheme in general. However:

Here are some key points that stand out for me:
On the rent-your-roof-out-for-25-years scheme, the best you can hope for is £70 a year in savings. You could easily save triple that just by using off-peak electricity. Greener, more reliable, doesn't steal from little old ladies to fund a massive con.

Absolute rubbish. I've got my own system (which is like-for-like with what a rent a roof company offered me) and my energy bill was down £300 in 3 months earlier this year! No idea where figures like that come from, I think 30% is very achievable for the majority of UK households, and if the average electricity bill is only £233 in this climate I would be stunned.



Having said that, that wasn't the purpose of my reply, although it has affected what I am going to write. I had my own system installed by tesco in january (now doing 20% off, grrrr) but was largely very impressed with the way they handled everything. My first payment was much more than expected, because the SAP calculation is so conservative (not saying that's a bad thing). My real ROI for the life of the system will be >15%, and might even reach 20%.

I was so impressed I had some panels put on a rental property for which I am the landlord, but shopped around a lot more aggressively, came across some very crooked companies, and also some very good ones - got the install done on the second place about 15% cheaper (although in 6 months, prices have come down a bit), and very impressed with it so far (2 months in). Again vastly exceeding the SAP calculations.

I live in a "visible" house on the corner of a road through a suburban estate, and since having my own panels I have had 15-20 people knock on the door to ask questions, have told them everything I can about the systems, and what to do vis-a-vis rent a roof, or borrowing to finance their own systems, and the pros and cons. I'm very pleased I've had it done - I appreciate the points about NPV etc (although measuring over 25 years is a bit stupid and nonsensical, just because that's when the FITs run out - my grandfather's house has had solar thermal for over 50 years and still gets a great result in terms of bill savings from his old system, so I would expect the solar PV systems to provide good output (and also be a lot cheaper to maintain) for a lot longer than that. If we took the attitude that some do in this thread, there would never be any renewable incentives - of course its more expensive to start with; no business would ever start up if they didn't have to spend money to get a foothold in the market - but why let anything other than beer-mat economics blind you? Everyone knows that the market clearing economic solution is always the best allocation of resources - oh wait......

Even so, given that the status quo is as it is, the rational economic decision is to get your own system and get as many people as you know to get their own systems, rather than moaning about some inaccurate figures regarding the issue. IMO.

Underscore wrote: »

Don't particularly want to get involved with the bashers of the scheme in general. However:

Here are some key points that stand out for me:
On the rent-your-roof-out-for-25-years scheme, the best you can hope for is £70 a year in savings. You could easily save triple that just by using off-peak electricity. Greener, more reliable, doesn't steal from little old ladies to fund a massive con.

Absolute rubbish. I've got my own system (which is like-for-like with what a rent a roof company offered me) and my energy bill was down £300 in 3 months earlier this year! No idea where figures like that come from, I think 30% is very achievable for the majority of UK households, and if the average electricity bill is only £233 in this climate I would be stunned.



Having said that, that wasn't the purpose of my reply, although it has affected what I am going to write. I had my own system installed by tesco in january (now doing 20% off, grrrr) but was largely very impressed with the way they handled everything. My first payment was much more than expected, because the SAP calculation is so conservative (not saying that's a bad thing). My real ROI for the life of the system will be >15%, and might even reach 20%.

I was so impressed I had some panels put on a rental property for which I am the landlord, but shopped around a lot more aggressively, came across some very crooked companies, and also some very good ones - got the install done on the second place about 15% cheaper (although in 6 months, prices have come down a bit), and very impressed with it so far (2 months in). Again vastly exceeding the SAP calculations.

I live in a "visible" house on the corner of a road through a suburban estate, and since having my own panels I have had 15-20 people knock on the door to ask questions, have told them everything I can about the systems, and what to do vis-a-vis rent a roof, or borrowing to finance their own systems, and the pros and cons. I'm very pleased I've had it done - I appreciate the points about NPV etc (although measuring over 25 years is a bit stupid and nonsensical, just because that's when the FITs run out - my grandfather's house has had solar thermal for over 50 years and still gets a great result in terms of bill savings from his old system, so I would expect the solar PV systems to provide good output (and also be a lot cheaper to maintain) for a lot longer than that. If we took the attitude that some do in this thread, there would never be any renewable incentives - of course its more expensive to start with; no business would ever start up if they didn't have to spend money to get a foothold in the market - but why let anything other than beer-mat economics blind you? Everyone knows that the market clearing economic solution is always the best allocation of resources - oh wait......

Even so, given that the status quo is as it is, the rational economic decision is to get your own system and get as many people as you know to get their own systems, rather than moaning about some inaccurate figures regarding the issue. IMO.

I really do find it quite extraordinary that someone can write well, yet demonstrate they obviously have little knowledge of the subject.

1. Nobody has said 'the best you can hope for is £70 a year savings'
The Energy Saving Trust have carried out tests and stated that is an average figure. So £100 pa is possible - as is £20pa.

2. Your 'energy bill is down £300 in three months earlier this year' That could be possible, but it sure isn't due to Solar PV if that is what you are trying to imply.

Even in the unlikely event you used all your generated power, £300 saving would mean you had generated 3,000kWh in 3 months. Just nonsense!

3. Of course 30% savings on electricity bills are possible. The UK average annual consumption is 3,300kWh(don't forget the majority of houses don't heat with electricity). So 30% = 990kWh or around £100 savings. Higher than average but obviously possible.

4. Like it or not, the FIT system is funded by lots of people who cannot, for a variety of reasons, benefit from the subsidies available which are paid for by all electricity consumers. Those reasons are:

They live in flats.

They live in rented accomodation

They have an unsuitable roof, wrong size - wrong orientation - wrong construction - shaded etc

They can't afford the costs.

Nobody is criticising those who take advantage of the system, but for the Government to allow 'Rent a Roof' firms to collect these subsidies is a disgrace IMO.

5. If you are in favour of 'renewable incentives' and use that as the justification for just about the most inefficient way to generate electricity known, then shouldn't we have huge solar farms of factory roofs, supermarkets, scrubland in SW England rather tha thousands of tiny systems dotted about all over UK?

6. As for 'beer mat economics' - well you have given the perfect reason why they should not be trusted. How about giving some real figures?

Studlea_Phatt_Katt wrote: »

Okay, these are my thoughts for what they’re worth.

Roof Letting scheme or Buy panels?

My view is:

If you are generally at home during the day, and have the cash sitting around, buy for FIT and personal savings on electricity.

If you are generally out during the day, but have the cash sitting around, buy to obtain FIT.

If you are generally out during the day, but don’t have the cash sitting around, consider a rent scheme, benefit at weekends, and use timers for dishwashers etc to come on whilst you’re out. The system is not really worth going into debt for.

If you are generally at home during the day, and don’t have the cash sitting around, the rent scheme is almost a no brainer.

All of the above assume the roof is generally south facing and not too steeply raked.

We fall into this last category, working from home as we do, and so are considering a 3.51kw system from one of the roof rent scheme providers. Our view is that we use most of our electrical energy during the day, with ovens, washing machine, dishwasher, ironing, computers, phone TV etc and not least the regular boiling of the kettle. The office / working area of the house is also heated electrically.

We have read through the lease, arranged alterations to ensure our peace of mind, and met with the installer. (A sub contractor, national firm, usual work is fitting satellite dishes etc.)

If it saves us £100 per annum, we’re quids in, but I estimate that on average, our grid electrical consumption will reduce by around 35%, saving us around £225 per annum for no investment on our part.

As to the morality or otherwise of the FIT scheme, right or wrong, it is in place and will be far more effective at improving the environment than the criminally and morally corrupt car scrappage scheme.

As to the poor subsiding the middle classes, we are poor, so does this mean we are now subsiding ourselves, ergo, a good thing?

Hi

Unless you have an atypical baseload I would think that the £225pa saving is a little optimistic on a 3.51kWp system and as you estimate your electricity bill as being ~£650 it looks a little high but doesn't seem to be atypical at all, possibly around 5700kWh.y if you're on a decent tariff, less if you're not.

If you have an unshaded South facing system you would reasonably expect around 3000kWh.y from a 3.51kWp system which has a tier 2 purchase value of approximately £300, so effectively you would need to self-consume 75% of generation in order to save £225. Many (/most?) with larger systems sized at around 4kWp and who are at home during the day would expect to self-consume around 1/2 of your expectation, which is the basis of the £100pa savings which many post is likely. The EST reckon on a typical saving being £70pa, my system, for what it's worth, saves slightly over £100/year.

HTH
Z

Studlea_Phatt_Katt wrote: »

If it saves us £100 per annum, we’re quids in, but I estimate that on average, our grid electrical consumption will reduce by around 35%, saving us around £225 per annum for no investment on our part.

QUOTE]

Just a bit of a reality check - I too work from home and cook with electric. We generate loads of electricity - just too much to use through the summer, we've reduced our summer quarter by 18% which would have been a huge disappointment had we been dependent on electricity savings.

We use an average of 5000 kwh/year. You won't be able to use the heating in the part of the house that uses electrical heating because it would be ludicrous to put the heating on on a summer's day when the sun is shining.

We've had our system just over 10 months and are delighted with the generation but would be devastated if we'd rented out roof for the savings we had achieved.