Free solar panel discussion

AquilaJon

BrummyGit wrote: »

Incorrect - I challenge your assertion as to the benefit people will make without detailed analysis. Just as valid as challenges to rent-a-roof suppliers.




I'm not disputing this - invalid claims of excess performance are just as bad as invalid claims about how poor the returns are.

But in sub-optimal conditions you will generate a proportion of the quoted maximum, therefore the more potential you have, the more actual you have - with some caveats. Various panels give differing performance in sub-optimal conditions, and additionally different inverters have different start-up thresholds, operating efficiency and standby power requirements.

In my case I looked at the actual components that would be supplied by HomeSun - Zen CP 220wp panels with a Fronius IG TL inverter. These are at the better end of the market for performance and I expect that I get more electricity in low light conditions (mornings and evenings) than
someone with lower end equipment in identical circumstances.

Until supply outstrips demand in the home, there is a big difference between system capacities and actual performances - just as location and orientation are also important. Therefore consumption patterns are also relevant.



I think that incorrect information or assumption is wrong - in either case. Therefore I would simply prefer to see statements which advise people that there are lots of variables and therefore they should look carefully at their own circumstances.

I would suggest that trying to put people off before they do their own maths is just as irresponsible. I agree that there is a lot of exaggeration
about potential savings, and for many the benefits are minimal. But in some cases it is a viable proposition which can offer savings with no financial outlay.

All MCS approved installers should be working to the same calculations on benefits and savings. If you feel you have been mislead then I would suggest contacting MCS and asking their advice. In my opinion Solar PV is brilliant and if you concentrate on getting the most out of it rather than debating theroratical numbers you can save a lot of money. I would suggest buying an energy monitor as this will help you use the pv system to its best potential. You can get them off the internet for £20-£50 or some energy companies will provide them FOC

digitaltoast

AquilaJon wrote: »

In my opinion Solar PV is brilliant

Solar micro-PV is one of the world's most inefficient methods of generating non-storable electricity at precisely the wrong time to meet demand, which will take no generating capacity offline for which a select rich few with large south-facing roofs are subsidised to the tune of 3x retail price by usually poorer people who don't fit the bill.

http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Demand/demand24.htm
At mid-day, the time of maximum sun, the load is around 50gigawatts. At 6pm, the load is around 53gigawatts.
Of which not one single solitary watt will be provided by solar PV.

Can you explain why, if it's so good, it needs to be subsidised to the tune of ... what, 8* more than standard generation?

Maybe it's to get manufacturing going to lower prices. Oh dear:

The price of solar panels fell steadily for 40 years, until 2004 when high subsidies in Germany drastically increased demand there and greatly increased the price of purified silicon

As for "doing the sums", how about these?

http://lowcarbonkid.blogspot.com/2010/03/does-pv-solar-electricity-work-in-uk.html

Solar panel manufacturers quote figures for the “peak power” and “installed capacity” of their products. According to industry standards these are the amounts of electrical output in watts that they would generate if one kilowatt per square metre of the sun’s energy were to fall on them. But how close is this to the amount of sunshine at your location? These figures can be found out from the same source on insolation given in the section on solar water heating. For most of the latitudes that cover England and Wales, the summer insolation is a fraction of that figure. Even Europe’s sunniest place, Limassol in Cyprus, only gets 325 W per square metre. London gets 198 and Edinburgh 172 in July. In December, the figures are 96, 22 and 13 respectively. So in the winter, it’s a lot less -- and that’s when you need more power because the lights will be on for longer.

On average, Edinburgh receives just 9% of the solar energy required by the panel to generate what it says it will on the box.

Lesson 2: Suppose you installed 30m2 of panels that were quoted by the manufacturer as having a peak power or installed capacity of 5.7kWp. Suppose they were installed in London, which has an average insolation figure over the year of 109W/m2. In that case you wouldn’t get 5.7kW averaged over the year, but 0.109 x 5.7kW = 621W. However that is the average figure.

In darkest December they were generating just 125W, or enough to power 10 low energy light bulbs. In fact it might be even less than this, because of shading, downtime and other system inefficiencies.

Have you read http://www.withouthotair.com/ ? You can read it for free at the website, but buy the book from Amazon. Well worth it.

While you wait for delivery, you might want to read this, too:
http://www.guardian.co.uk/commentisfree/2010/mar/01/solar-panel-feed-in-tariff

Against micro-PV, there's George Monbiot, countless failed studies, the highly acclaimed book "Without Hot Air" and hence physics mathematics and economics,, the experience of my father and his first in engineering from Imperial College and the experience of the German government who have basically given up on the hugely expensive failed experiment.

It's not green, it's not economical, it's not practical in most parts of the UK, so perhaps you can explain more about why you think this is so "brilliant"?

Delerium_2

digitaltoast wrote: »

....stuff.....

I cant agree with most of what you've put here. There's no doubt that its not the most efficient piece of tech in the world as we dont live in a country near the equator where solar radiation is much higher but saying its worthless isnt true either as its still generating electricity from nothing.

I have an solar array and based on industry standard radiation calculations from actual readings, I still stand to generate and make substantial money from my investment (sorry going into the whole paid installation here).

But fact remains, if its so inefficient, why are there companies such as british gas that are fitting them for free/near free to claim income - surley they will have done their sums right?

Del

digitaltoast

Delerium wrote: »

I cant agree with most of what you've put here.

There's nothing to "agree" or "disagree" with here. There's numbers and statistics, and there are salesmen.

Delerium wrote: »

its still generating electricity from nothing.

It's generating electricity from a photo-electric reaction in a complex piece of expensive equipment running at a few percent efficiency using increasingly scarce materials like silicon.

Delerium wrote: »

I have an solar array and based on industry standard radiation calculations from actual readings, I still stand to generate and make substantial money from my investment

On a FiT? I'd LOVE to see your readings. Not at the FiT rate, but at the standard unit price, taking into account all eventualities including degradation and replacement of the costly inverter.

Delerium wrote: »

But fact remains, if its so inefficient, why are there companies such as british gas that are fitting them for free/near free to claim income - surley they will have done their sums right?

Oh, they've done their sums right. And it works out because the FiT is MASSIVELY subsidised for those with large houses, by those in retirement houses, poor people, people in smaller houses.

Our electricity has just gone up 9%. That's where your income is coming from.

Fact is, without me subsidising you, it would never work out for you, or anyone.

Doesn't it make you feel good to know that British Gas and people with mansions are doing so very nicely out of poor people with small houses?

Gizmosmum_2

AquilaJon wrote: »

All MCS approved installers should be working to the same calculations on benefits and savings. If you feel you have been mislead then I would suggest contacting MCS and asking their advice. In my opinion Solar PV is brilliant and if you concentrate on getting the most out of it rather than debating theroratical numbers you can save a lot of money. I would suggest buying an energy monitor as this will help you use the pv system to its best potential. You can get them off the internet for £20-£50 or some energy companies will provide them FOC

Current cheap energy monitors aren't really up to much because they don't monitor generation against use. There's a newish monitor out that does this - not sure how effective it is - I'll let you know when I've tried it http://www.diykyoto.com/uk/wattson/about - mind you on the rent a roof's it'll cost about a year's worth of savings.

Unfortunately all installers aren't using the same calculations, many are prematurely using SAP 2009 to calculate the savings where MCS clearly requires SAP 2005. Conveniently 2009 figures are higher.

Out of interest, many of the installers I work with don't advise their customers that they can save 50% off their electric on systems over 2.5kwp because it's extremely unlikely they'll be able to do that.
There's only so many meals you can cook and clothes you can wash ....

Delerium_2

digitaltoast wrote: »

There's nothing to "agree" or "disagree" with here. There's numbers and statistics, and there are salesmen.

Getting numbers from government statistics is not getting numbers from a salesman. You seem to be very bitter about this.

digitaltoast wrote: »

On a FiT? I'd LOVE to see your readings. Not at the FiT rate, but at the standard unit price, taking into account all eventualities including degradation and replacement of the costly inverter.

Oh, they've done their sums right. And it works out because the FiT is MASSIVELY subsidised for those with large houses, by those in retirement houses, poor people, people in smaller houses.

Our electricity has just gone up 9%. That's where your income is coming from.

Fact is, without me subsidising you, it would never work out for you, or anyone.

Doesn't it make you feel good to know that British Gas and people with mansions are doing so very nicely out of poor people with small houses?

I'm confused, are you saying that solar PV is not worth it because installing it would be beneficial to you but other people would get price increases? In all honesty mate, thats not my problem. This thread is talking about how much the individual can make, not how much it costs others.

Also just to let you know, i dont live in a mansion, i live in a semi-detached house with a garage and my array stands to tripple my investment over 25 years. The figures are verified based on industry averages and calculated by me (im an accountant). So no, its not just the rich that benefit.

Now what you might have meant is that smaller arrays dont warrant the outlay - well this, of course, is true but if british gas are paying for it, what does it matter?

Del

Delerium_2

Gizmosmum wrote: »

Unfortunately all installers aren't using the same calculations, many are prematurely using SAP 2009 to calculate the savings where MCS clearly requires SAP 2005. Conveniently 2009 figures are higher.

Wouldn't it be more accurate to use 2009 figures given global warming means solar radiation is on the increase?

Gizmosmum wrote: »

Out of interest, many of the installers I work with don't advise their customers that they can save 50% off their electric on systems over 2.5kwp because it's extremely unlikely they'll be able to do that.
There's only so many meals you can cook and clothes you can wash ....

Thats just an additional benefit surley, you're generating the electricity so its a use it or lose it scenario. With clever use, you can use a fair chunk of what you generate. Sure there's the obvious things like timing washing, dishes, dryers etc but im sure there's other things that you can time during the day too. Whether you can use all that you generate though is definitley up for argument

Del

zeupater

Hi All

Looks like we're back to the 'oh yes it is .... oh no it isn't' debate.

It's quite simple really ....

According to BG the typical UK household uses 3300kWh of electricity per year ... therefore at a typical decent buy price the maximum typical saving at 100% solar pv usage and no import at all would be £330.

What's a typical pv system ? .... well if you follow the logic on the development of the FiT scheme it's around 2kWp, and on this typical system there is evidence to support exporting 50% of production. My roof is pretty typical being 'off south' and a 2kWp system would typically produce 1500kWh/year therefore typical in house 50% usage would be worth about £75.

'Ahhhh but, my system is larger than 2kWp' you may say .... well so is mine, however, no matter what my array is capable of producing, I still have the same electricity baseload. As long as the baseload is covered it is only peakloading which makes any difference to the power consumed and as peakload is variable the majority of extra generation provided by larger arrays is simply exported, thus reducing the percentage of total generation which can be used in house.

With a 4kWp system it would be very rare to fully cover the demand from high draw systems such as washing machines, dishwashers etc without having to import some electricity. It is a given that, unless you start to consider that the electricity is 'free' and therefore increase usage proportional to generation (however you manage that), the larger the system you install the higher the percentage you will export and considering that 'rent-a-roof' scheme export does not benfit the householder it doesn't really count towards any savings.

For households without mains gas supply etc which rely on off peak energy for heating it would generally still be cheaper to run high load appliances overnight which removes the any associated savings from the calculation, or conversely, additional costs from using the appliances during the day should logically be subtracted fron the calculated savings.

If I had a 'rent-a-roof' system which covered the size of a football field I would only be able to save the value of the electricity which I use during daylight hours, which in my case is around £100/year, a figure which seems to be considered as being 'typical' by most with purchased system who post on this forum.

HTH
Z

BrummyGit

Hi beedydad - the product I signed for with HomeSun is called "Free Solar" on their website, also referred to as "Free SolarShare". Therefore my definition is correct, but I was attempting to use the common terms in use on the board for general clarity.

I didn't pay anything like £500 for my system - in fact my Solar PV system was technically free as contractually I made a one-off pre-payment towards electricity received. I agreed not to disclose the specific details of my final agreement with HomeSun, however due to a number of factors affecting my installation we agreed a single payment to cover increased installation costs compared to a typical home which otherwise rendered my home ineligible for their "Free SolarShare" product. I also received offers from other suppliers for a totally free system, however I selected HomeSun based on criteria I considered more important than a small one-off payment.

Whether you wish to call it rent or not, I receive a benefit in return for leasing my roof to the installer. I have the opportunity to consume all of the electricity generated by the system - a system which the installer is obliged to insure and maintain in good working order for a period of 25 years 3 months. It was therefore my responsibility to decide whether the returns justified the commitment I was making.

I am all in favour of pointing out potential negatives to people on the board, but there seem to be many posters who wish to shout about all the potential negatives with "rent-a-roof" or "free solar" schemes without acknowledging any potential positives. My single intent is that people should not quote low-end (or high-end) estimates of returns without a clear disclaimer that circumstances vary so widely that everyone should perform the calculations for themselves.

Hi AquilaJon - I think you misunderstand my intentions. I love my Solar PV system, and in my case I am happy that I decided to take the "free" route as it ticks the boxes I wanted ticked based on an informed decision. I already have multiple monitors on my system (1 monitoring the system output, and 1 more problematic one monitoring my grid connection that can't differentiate between import and export, but that's for another thread especially if you can offer some advice), and I take as much pleasure from watching the output and trying to maximise my use of the generation as I do from the potential savings. I have no gripe with my installer, and am pleased with the system configuration and performance.

My gripe is that on this thread there are a number of contributors who simply want to bash "free solar" offerings and put others off. I prefer a balanced approach which encourages people to make an assessment of their own circumstances. They cannot simply tell someone that they will only save £80-£100 per year in electricity without analysis behind. There are so many variables involved that it MUST be an individual decision. I'm happy to go into my own reasons for choosing the option I did, but really my point is that "free solar" does work for some people, solar funded by other means works for others, but Solar just doesn't work for some people at all - it needs analysis in each case and an informed decision.

BrummyGit

zeupater wrote: »

If I had a 'rent-a-roof' system which covered the size of a football field I would only be able to save the value of the electricity which I use during daylight hours, which in my case is around £100/year, a figure which seems to be considered as being 'typical' by most with purchased system who post on this forum.

And this is the key point I've been trying to make - for some it works, for others it doesn't. It's down to many factors (consumption profile, system output, willingness to modify your habits, location, orientation etc etc etc). There are too many factors for a "one size fits all" set of answers to people considering their options.