Free solar panel discussion

zeupater

BrummyGit wrote: »

Well I can put one scaremonger to rest - the model of inverter that HomeSun fitted for cradbent is rated at <1w idle consumption.

Electricity would be at the lower rate as it is on top of your normal consumption, and of course you don't consume when you are generating so a budget of 50p per year would be generous.

But then of course we haven't looked at the outrageous costs of running the meter :wall:

Hi

Not scaremongering, just informing. If you notice, I have given a band of known standby power consumption and have requested details on this issue from Krish.

Like many other household items, the power consumed in standby mode varies considerably. The Fronius IG series performs at the lower end of the banding (<1W nominal), others may not. As we do not yet have a full list of installed inverters the known consumption band across all mainstream inverters must stand.

Anyway, not wishing to scaremonger (or not), I do note that you do not dispute the amortisation of the initial £500 over the anticipated lifetime of the system (a very generous 35 years ... I could have used 25 !!) resulting in a reduction of the annual savings of around £15, perhaps it would be better to say £15 - £20 depending on the anticipated system life after the initial lease period.

At the end of the lease period rent-a-roof customers will probably choose to keep the system if their contracts allow this. A few years later their inverter is likely to pack up resulting in a replacement cost of well in excess of £1000 or a removal and scrapping cost of the complete system, probably well in excess of £2000 (current cost basis). Remember, FiTs will have expired by this time, so the saving per year would be purely based on power self generation & an export tariff which could be claimed by the new owner. These considerable costs should really also be amortised over the system life, whatever that would be, but probably somewhere near 35 years is likely, so another £30(ish) to £60(ish) reduction in annual savings.


Informing without commercial interest ....
HTH
Z

BrummyGit

There seems to be much negativity about rent-a-roof schemes on here, however I am pleased to say that I've signed contracts with HomeSun today for the installation of a 3.52KWp system on my home. I am lucky that my roof is big enough to take the full capacity system but slightly off the ideal by 15 degrees orientation and my pitch is only 20 degrees - looking at various information sources this will degrade my output slightly meaning that my home does not meet the criteria for a totally free installation and I will be making a one-off payment.

I would like to write down my own reasoning for going ahead in the hope that it offers some balance on the forum......

• I do not have the spare money to purchase my own system available for 10 years or more until I see a return on my investment.
• I do not want to take the risk that in the next 25 years a radical change of political policy might revoke the current FITs
• I do not want to take the risk that over 25 years a relatively new technology will not fail in some way and cost me more than anticipated
• HomeSun is providing the capital outlay for a system installation on my home - and obviously expects a return on that money. I have a minor financial investment. With a family of 5, I might have spent it on a social event or weekend away - I consider it spent and forgotten.
• I am happy that the aesthetics of the installation will not be detrimental to my home due to not being overlooked to the south, and where all items will be installed. So no impact there
• I have no expectation of needing my roof for any other reason
• HomeSun will monitor the system and maintain it in peak working efficiency - I have no costs associated with any of this. So in 25 years time I know I will still have a system generating nearly the same amount of power as new without any maintenance cost.
• In the next 25 years I expect energy efficiency changes to mean my household demand reduces
• In the next 25 years I expect energy costs to increase
• In the next 25 years I expect Solar PV to improve, but I also expect the FITs to reduce, so this could be a small window of opportunity for a "free" system
• I have no plans to move, but believe that at the moment the system would make my home easier to sell. In any case I can buy it outright should it be a sticking point.

As the technology and industry develops I will be looking at investing my money into equipment like the EMMA which would divert unused generation capacity into heating my water. That would help reduce my gas bill too - mainly in summer, but that's when my central heating isn't required anyway. Currently EMMA is too expensive :sad:

So for negligible outlay I get 25 years of whatever electricity I can use from the output of my system with someone else taking the vast majority of risk. I'll be investing my efforts and money in making the most of that free energy.

I have no big expectations, but the energy savings trust calculator estimates that in my circumstances I could save up to around £198 per year - and that's in 2011, how about in 2031?

Maybe I'll save £10 per month initially, but if nothing else I'll enjoy the experimenting.

BrummyGit

I agree that the Fronius IG TL is at the right end of the scale, and I'm waiting to hear what model will be installed in my home. It also helps to show that efficiency is important for rent-a-roof as FiTs make money - this means that you should see optimum price/performance with reliability considered too.

There are a couple of extra points to consider....

• In the next 25 years the cost of electricity is almost certain to increase (my guess is substantially) and therefore the savings year on year should increase.
• In 25+ years time it is likely that I can contract a solar installer to upgrade/replace for a much reduced cost and get the old system stripped at the same time. I could also simply switch it off and leave it there if I choose

zeupater

BrummyGit wrote: »

There seems to be much negativity about rent-a-roof schemes on here, however I am pleased to say that I've signed contracts with HomeSun today for the installation of a 3.52KWp system on my home. I am lucky that my roof is big enough to take the full capacity system but slightly off the ideal by 15 degrees orientation and my pitch is only 20 degrees - looking at various information sources this will degrade my output slightly meaning that my home does not meet the criteria for a totally free installation and I will be making a one-off payment.


I would like to write down my own reasoning for going ahead in the hope that it offers some balance on the forum......

• I do not have the spare money to purchase my own system available for 10 years or more until I see a return on my investment.
• I do not want to take the risk that in the next 25 years a radical change of political policy might revoke the current FITs
• I do not want to take the risk that over 25 years a relatively new technology will not fail in some way and cost me more than anticipated
• HomeSun is providing the capital outlay for a system installation on my home - and obviously expects a return on that money. I have a minor financial investment. With a family of 5, I might have spent it on a social event or weekend away - I consider it spent and forgotten.
• I am happy that the aesthetics of the installation will not be detrimental to my home due to not being overlooked to the south, and where all items will be installed. So no impact there
• I have no expectation of needing my roof for any other reason
• HomeSun will monitor the system and maintain it in peak working efficiency - I have no costs associated with any of this. So in 25 years time I know I will still have a system generating nearly the same amount of power as new without any maintenance cost.
• In the next 25 years I expect energy efficiency changes to mean my household demand reduces
• In the next 25 years I expect energy costs to increase
• In the next 25 years I expect Solar PV to improve, but I also expect the FITs to reduce, so this could be a small window of opportunity for a "free" system
• I have no plans to move, but believe that at the moment the system would make my home easier to sell. In any case I can buy it outright should it be a sticking point.

As the technology and industry develops I will be looking at investing my money into equipment like the EMMA which would divert unused generation capacity into heating my water. That would help reduce my gas bill too - mainly in summer, but that's when my central heating isn't required anyway. Currently EMMA is too expensive :sad:

So for negligible outlay I get 25 years of whatever electricity I can use from the output of my system with someone else taking the vast majority of risk. I'll be investing my efforts and money in making the most of that free energy.

I have no big expectations, but the energy savings trust calculator estimates that in my circumstances I could save up to around £198 per year - and that's in 2011, how about in 2031?

Maybe I'll save £10 per month initially, but if nothing else I'll enjoy the experimenting.

Hi

I really do wish you well with your endeavour ...... as long as you understand the situation, whether you consider posts as being negative is your own view and as such you are completely entitled to hold it.

Now, regarding the EST calculator .... there is a logic problem. I comsume a total of around 2600kWh/year and could install extra panels on my roof up to 10kWp .... the EST site says that 10kWp would save me £500/year on my electricity bills .... the problem is .... I don't use anywhere near half of £500 worth of electricity, so how can I possibly save that amount ??

Please keep us informed on the progress of your system, negative or not, many of us are genuinely interested ....

Z

BrummyGit

zeupater wrote: »

Hi

I really do wish you well with your endeavour ...... as long as you understand the situation, whether you consider posts as being negative is your own view and as such you are completely entitled to hold it.

Now, regarding the EST calculator .... there is a logic problem. I comsume a total of around 2600kWh/year and could install extra panels on my roof up to 10kWp .... the EST site says that 10kWp would save me £500/year on my electricity bills .... the problem is .... I don't use anywhere near half of £500 worth of electricity, so how can I possibly save that amount ??

Please keep us informed on the progress of your system, negative or not, many of us are genuinely interested ....

Z

Thanks - we agree then that both of us are entitled to our opinions.

The EST calculator I used considers my likely export ratio, and being a family of 5 with me working from home a lot of the time I think that I am in a good position to benefit as we are heavy electricity users.

It will be an interesting experiment - I have no unrealistic expectations and look forward to seeing the outcome.

Cardew

BrummyGit wrote: »

Maybe I'll save £10 per month initially, but if nothing else I'll enjoy the experimenting.

This really illustrates the way these systems are marketed.

You believe £120pa is a realistic estimate of your savings for a 3.52kWp system in a slightly less than ideal position. Whilst I think that would be at the top end, it is in the same ballpark and you have obviously researched the subject.

However Cradbent with a much smaller system(2.4 or 2.6kWp) (presumably sited not as well as yours) has, like you, paid £500 and on top of this he pays HomeSun £5 a month. Yet he posts:

I expect to save £250 a year, but I'll try to save more.

Someone else a few weeks ago with a Homesun system posted even more outrageous claims.

On the Homesun website there are eight 'featured homes'. Seven give no indication of their estimated savings.(I wonder why?)

However one of their featured homes had identical system which was was paid for(no £500 or £5 a month) by a council for a 74 year old(presumably home all day). For this lady:

The results so far have been even better than expected, saving her £26.41 on her Feb to May bill and £26 between May and August.

Anyone familiar with PV output statistics will tell you that if a system saves £52.41 in the 6 month period February to August, you would estimate an annual saving of £75 to £80 a year(and that was better than expected!!)

Had she paid the £500 and £5 a month(it was a 2.6kWp system) she would just about have broke even.

So I wonder how Cradment and others get their estimate of saving - surely it is discussed with the Homesun salesman??

Any comment Krish - you state you are sanctioned to post as the official HomeSun rep on MSE, so surely we could have the company's position on potential savings? or do you view this thread merely as an opportunity for free publicity?

cradbent

Cardew wrote: »

I take it this is your deal?



A 2.4kWp or 2.6kWp system - which is fitted because your house is not ideal - will be lucky to get a generated output above 2,000kWh pa.

If you can use 1,000kWh pa in the house(50%) you will have done well. So that is a saving of approx £100 a year.

You pay £60 a year to Homesun plus lost interest of about £15 a year on the £500 you paid them.

So I suspect your savings might be around £25 a year.

A valid, but pessimistic estimate. I hadn't included the cost of ownership in my "expected savings" but even with Zeupater's amortisation of my £500 I'm not out of pocket (I'm not in it to make a profit, but hope I will). How about some more optimistic estimates, based on an annual cost of ownership of £100.

I've got an unshaded, 3.6 kW system, in a SE orientation in East Anglia. Not close enough for HomeSun's free install but not the worst case. I'm on a green electricity tariff - 12p a unit - a shocking admission to moneysavingexperts!

I've found data from half a dozen people around the UK. Using their figures on what they've generated, I should get between 2500 to 5000 kW per annum. Say I can use 50% of that at 12p a unit, I could save £150 to £300 a year. That’s £50 to £200 saved per annum.

How about basing it on average daily insolation levels (energy from the sun) at my rough location courtesy of NASA. Assuming 20% efficiency of my system, and 50% use, that gives me £275 a year and £175 saved.

I’ve only had my panels for 1 week (and what a grey week that has been). 15.6 kWh generated and nearly all used by me. That would give me £97 worth of electricity a year, so nothing saved. I’m confident I will generate, use and hence save more than that.

All in all I hope this shows how imprecise all this estimating is. There’s a risk that my real savings will be nothing, if you allow for cost of ownership, but I will reduce my carbon footprint. For a one off outlay of £500 and £5 a month, that’s a risk I’m prepared to take.

I have the best intentions to keep posting as I get more real data. And apologies for any mistakes in my maths.

BrummyGit

Hi Cardew

I can only speak for myself, but I've tried to research my own situation. Of course there are many assumptions too.

We are a family of 5 with a washing machine that usually runs at least once a day, we run a full dishwasher every day and often tumble dry our washing too. I work from home 3 or 4 days per week and my wife only works part time 4 days a week too.

For the reasons above we are heavy users of electricity and certainly would not match the usage profile of a typical 74 year old lady living on her own who was probably brought up in more austere times.

My background consumption during a normal daytime is between 700w and 1kw. Using rough averages this costs me around £400 per year. If I can save one quarter of that then I'll be happy, but the bigger savings are to make use of the excess generation which is where we need to make some effort to fully benefit from our system - we will change the time we run our dishwasher, washing machine and tumble dryer; and try to modify our consumption profile by maybe using a lower heat setting for longer at times when our generation can support the load; and staggering the use of our appliances using their built-in timers. I plan to learn during the first year and if possible fit an internet connected monitor which will track and graph my generation constantly. This will allow me to see clearly where my opportunities are to use "spare" electricity.

I would like to defend HomeSun a little and state that they never made wild claims of huge savings in my case. I just re-read the leaflet they left and it tells me that they can't be certain how much I am likely to save because so many factors are involved.

I'm going into this with my eyes wide open and an expectation that my initial payment is already spent - therefore I can only save money for 25 years, and no matter how much that is or isn't, I will be better off and have a little fun improving my energy consumption habits along the way.

Despite all of the best research, there is always the unexpected - we could have a big volcano erupt and spew ash into our atmosphere wiping out much of the sunlight. I guess my solar output would be the least of anyone's worries then.

Cardew

cradbent wrote: »

A valid, but pessimistic estimate. I hadn't included the cost of ownership in my "expected savings" but even with Zeupater's amortisation of my £500 I'm not out of pocket (I'm not in it to make a profit, but hope I will). How about some more optimistic estimates, based on an annual cost of ownership of £100.

I've got an unshaded, 3.6 kW system, in a SE orientation in East Anglia. Not close enough for HomeSun's free install but not the worst case. I'm on a green electricity tariff - 12p a unit - a shocking admission to moneysavingexperts!

I've found data from half a dozen people around the UK. Using their figures on what they've generated, I should get between 2500 to 5000 kW per annum. Say I can use 50% of that at 12p a unit, I could save £150 to £300 a year. That’s £50 to £200 saved per annum.

How about basing it on average daily insolation levels (energy from the sun) at my rough location courtesy of NASA. Assuming 20% efficiency of my system, and 50% use, that gives me £275 a year and £175 saved.

I’ve only had my panels for 1 week (and what a grey week that has been). 15.6 kWh generated and nearly all used by me. That would give me £97 worth of electricity a year, so nothing saved. I’m confident I will generate, use and hence save more than that.

All in all I hope this shows how imprecise all this estimating is. There’s a risk that my real savings will be nothing, if you allow for cost of ownership, but I will reduce my carbon footprint. For a one off outlay of £500 and £5 a month, that’s a risk I’m prepared to take.

I have the best intentions to keep posting as I get more real data. And apologies for any mistakes in my maths.

My point in commenting on your earlier input was that you posted on a Money Saving Website - where people come for information - that you expect to save £250 pa - but hope to save more - on your HomeSun system.

Now when challenged you conceed you may save nothing each year.

Surely that correction is important information for potential customers?

If you want I will discuss the other assumptions for your other system. However suffice to say that anyone who believes a 3.6kWp system with a SE orientation in East Anglia might generate up to 5,000kWh pa is living in cloud cuckoo land.

What has NASA's input got to do with your system. You surely must have been given an estimate for your output there are loads of tables. - I suspect around 2,600kWh???

Anyway we are not talking about other systems but the HomeSun product and if you are happy to pay them £500 and give them rights over your house for 25 years, to possibly break even, I suspect many Money Savers will not be thrilled at that prospect.!

grahamc2003

cradbent wrote: »

All in all I hope this shows how imprecise all this estimating is. There’s a risk that my real savings will be nothing, if you allow for cost of ownership, but I will reduce my carbon footprint. For a one off outlay of £500 and £5 a month, that’s a risk I’m prepared to take.

.

I think all it proves is how imprecise your estimating is. Others use more realistic estimates based on all the available evidence and theory, and at least some are trained and experienced in estimating.

Estimates should be neither optimistic nor pessimistic. They should be realistic.

Do you have an export meter fitted? That would mean that your usage wouldn't have to be estimated (for example, by the very unreliable method of comparing past years' usage with the current year's).

As to your aim to cut your carbon footprint, I'd say there are far better and cheaper by orders of magnitude methods than installing solar panels.