Energy Saving Trust(EST) Bulletin on solar

Cardew

I have just received the latest Energy Saving Trust Bulletin(Energywire) which this month concentrates on Solar PV.
It states:

How much can you save?
A typical PV system is 4kWp, at an average cost of £7,560 for the unit and installation. This will vary depending on the product and installer you choose.

That figure is based on analysis of RECC insurance data.

That average figure of £7,560 seems at odds with the quotes many are posting on MSE - £5k to £6k for a 4kWp system seems to be achievable??

I suspect that some installers will use that higher figure to justify their quotes for a system.

The EST have also revised their estimate for the percentage of generated electricity used in the house down to 25% and a saving of £125 pa.

Based on a south-facing roof, at 35 degrees using SW1A 0AA annual average solar irradiation data; assuming 25% of electricity generated is used on site and an average electricity price of 13.52p/kWh,

I suspect that not many installers will use the 25% figure in their estimates.

They also state:

Energy Saving Trust assumes that a PV system’s generating capacity will degrade by 20 per cent over a 25 year lifetime.

There are also readers who share their experiences of solar PV

You can sign up and receive the EST Bulletin here:

http://www.energysavingtrust.org.uk/Energy-Saving-Trust/Contact-us/Sign-up-for-Energywire

Martyn1981

Cardew wrote: »

That average figure of £7,560 seems at odds with the quotes many are posting on MSE - £5k to £6k for a 4kWp system seems to be achievable??

I suspect that some installers will use that higher figure to justify their quotes for a system.

I spoke to them a couple of weeks ago about their website and the mistakes on it, especially their solar calculator (some have since been rectified).

They state that the average cost is £6k to £7.4k:

The average domestic solar PV system is 4kWp and on average costs between £6,000 and £7,400 (including VAT at 5%).Costs have fallen significantly over the last year.

I pointed out that they appear to be (and always have been in my opinion) about 12 months behind. They explained that those figures are based on install costs from Aug 13 to Jul 14 (after removing the highest and lowest 5%). So accepted that they may lag the reductions seen during the year, especially the price drops since Spring.

Mart.

nigelpm

Pretty clear to me that the knowledge on here is beyond what they have - perhaps an opportunity arises?

theboylard

MSE Solar & Renewables, the energy saving experts.
A gazillion years experience of real users, with a bazillion views on everything!

Don't think Martin will let us have the above?!

Martyn1981

nigelpm wrote: »

Pretty clear to me that the knowledge on here is beyond what they have - perhaps an opportunity arises?

TBH they've been annoying me for years.

Back when I first began shopping in the summer of 2011 they were saying that 4kWp systems cost £14k, when prices were £12k. By the end of the year they'd revised it to £12k when prices were £10k. And after the subsidy had been revised in Mch 12 and prices were around £8k, they were saying £10k.

I'm very glad to see they are now displaying a range of prices (£6k to £7.4k) as people will hopefully aim towards the lower, but their use of average prices over a year will mean they are always behind the curve until prices stabilise.

Perhaps the statisticians can explain, but why remove the bottom 5% from the average? I understand the idea of removing the top and bottom slices when comparing 'things' to remove extreme outlyers, but whilst installers could charge silly high prices ....... can they charge silly low prices?

Quick review of my other comments when I rang (all relate to their solar calculator):

1. They were still in mid Sept stating that the tariff rate was only available till the end of Sept. Their 'hasn't been confirmed yet' Oct to Dec rate showed a 3.5% degression, despite confirmation back in July that there wouldn't be one till 1/1/15. I pointed out that this may cause people to rush, and rushing is not usually a good idea. Result: they amended it for the last week of Sept.

2. They have a leccy savings figure which is based on generation * 25% * 13.52p. It works for a 1kWp test (and 2kWp) but not for a 3 or 4kWp test, where their results (this morning for me on a 4kWp facing ESE) came out as 3,081kWh and a leccy saving of [STRIKE]£104.14[/STRIKE] £79!!!!!!! Result: still broken at 7am this morning.

3. They use this same calculation for all system sizes, so their 1kWp example (for my location ESE 770kWh) is £26. So the maths works, but when I pointed out that a 1kWp or 4kWp (or 40kWp) would still meet most of baseload when operating, so hopefully saving £50 to £80+ (depending on baseload and tariff) as a minimum, with no effort, and no daytime/weekend consumption. They agreed, but pointed out that this was just too complicated to explain on the website - which I kind of agree with. Result: tricky, they may look at this but I doubt it.

Mart.

Cardew

Martyn,


We are in clear agreement about the inaccuracies on the EST website - not just Solar.


As I stated in the first post, their bulletin published yesterday states the average cost for a 4kWp system is £7,560 - not the prices you quote from their website - another discrepancy.


Some years ago I had a run-in with them about the savings from silver foil placed behind radiators. They used results from a study and applied the savings to all radiators. To cut a long story short, had they read the report properly, the saving figure EST used was only for a radiator against an single skin(i.e. non cavity) outside wall. In practice the savings for most people are negligible(pence per year) but of course at least one firm quoted the EST saving figure for every radiator.


In the days of tier1/tier2 prices for electricity, they quoted the average unit electricity price taking both tiers into account.(i.e. a composite figure) So with average electricity consumption 3,300kWh pa, if 900kWh were tier 1 at, say, 25p/kWh and 2,400 tier 2 at 11p/kWh the EST figure was 14.8p/kWh.


However the true saving for any device - including solar in the house - would be at the tier 2 rate(11p) for the vast majority of users. However the EST 14.8p/kWh figure was seized upon by virtually all installers in their savings estimates.

EricMears

Martyn1981 wrote: »

Perhaps the statisticians can explain, but why remove the bottom 5% from the average? I understand the idea of removing the top and bottom slices when comparing 'things' to remove extreme outlyers, but whilst installers could charge silly high prices ....... can they charge silly low prices ?

I'm not claiming to be a 'real' statistician but I think I know enough to answer the question.

If you removed outliers from one end only you'd get a skewed result.

And yes, you can have "silly low prices". How about the case where a supplier offers a huge backhander in return for customer recommending them to neighbours. Or indeed where the scaffolding was excluded because the roof was being refurbished anyway and the SP company simply used the same scaffolding . I expect others could come up with even more creative examples.

But I'm not really convinced that either set of outliers need to be excluded - if there were real transactions at those prices then they ought to be included.

Smiley_Dan

I guess it depends on the distribution of the outliers. Salaries vary wildly, but PV installation prices? Maybe, you'd need the figures at hand.

Maybe it also deals with data errors, bad typing etc. and is considered general "best practice" because with this volume of data you never know what you're going to get.

Martyn1981

EricMears wrote: »

I'm not claiming to be a 'real' statistician but I think I know enough to answer the question.

If you removed outliers from one end only you'd get a skewed result.

And yes, you can have "silly low prices". How about the case where a supplier offers a huge backhander in return for customer recommending them to neighbours. Or indeed where the scaffolding was excluded because the roof was being refurbished anyway and the SP company simply used the same scaffolding . I expect others could come up with even more creative examples.

But I'm not really convinced that either set of outliers need to be excluded - if there were real transactions at those prices then they ought to be included.

Cheers Eric, good examples that could lead to lower prices, but I don't think they'd be 'silly low' prices, just low, balanced against slightly poorer deals, or more complex installs.

However, some salesmen, if they can get away with it are still trying 'silly high' prices. On another thread, one poster is fighting back after paying £7,659 for a 1.5kWp system. The manager (knowing he's be caught IMO) has offered £2k refund and 6 or 7 extra panels.

Other discussions on MSE and elsewhere show people mentioning quotes of £10k or so!

As to leaving all prices in, that's fine if you simply want to report the average price, but surely the EST want people to get a good deal today, not an historicaly average deal, particularly when the market is still seeing price reductions. Think about it, if you were shopping round, would you have much/any interest in what some naive people at the upper end had paid a year ago.

But, I've no idea how you go about explaining this fairly on the EST site. At least they now have an average range, so hopefully folk will aim for the lower ..... don't know?

[Edit: Eric, just had a thought, What Car used to show target prices (next to list prices) for cars. I know that would be a nightmare for PV, but my point being that they were trying to convey a good price, rather than an average price. M.]

Mart.

Cardew

Martyn1981 wrote: »

However, some salesmen, if they can get away with it are still trying 'silly high' prices. On another thread, one poster is fighting back after paying £7,659 for a 1.5kWp system. The manager (knowing he's be caught IMO) has offered £2k refund and 6 or 7 extra panels.

This case (My Solar UK) raises IMO an even more important issue than the high installation cost; namely the inflated estimated savings. This was the main reason for the poster purchasing the system.


They used an inflation rate of 8.79% pa for electricity prices for 20 years, and still their savings figures were £thousands more than even that high rate.


The other ploy was to supply LED bulbs as part of the installation. These were estimated to save the customer over £5,400!! and that figure was included in the overall estimated savings.


What has LED lighting, which is generally switched on when PV is not generating, to do with a quote for a PV installation. They might as well throw in a water saving device and include the savings from that in the estimate!


Initially we were told that MCS registration would ensure that firms would not use the sales techniques employed by double-glazing salesmen of yesteryear. It seems to me some PV firms have refined those double-glazing sales techniques.

The_Green_Hornet

Cardew wrote: »

Initially we were told that MCS registration would ensure that firms would not use the sales techniques employed by double-glazing salesmen of yesteryear. It seems to me some PV firms have refined those double-glazing sales techniques.

Cowboys will enter any industry if there is a quick buck to be made from duping gullible people, and Solar PV is no different. The only defence for the consumer is to do plenty of research by visiting forums such as this, and sites such as EST (albeit they do appear to have some inaccuracies) and Which?, before committing pen to paper, and to report any transgressors to the relevant bodies.