MSE News: EST cuts solar panels' bill savings estimate

akarobin

The claim by the EST that Solar PV will save 50% of your Electricity use was always flawed when you consider the facts. i.e.

• Most people use most of their electricity in the evening when the PV system is generating little or no power. So you still import most of your evening demand from the grid.
• Generally the PV system generates a modest amount of power BUT for a long period of time. There is not an appliance in your house that matches the Production curve of the PV system, domestic Demand tends to be a high peak of power for a short period - PV Production tends to be a low peak of power for a long period.

Be sceptical of PV Installers claiming you can make significant savings from your electicity bill as they misunderstand the systems they are selling. Make your purchasing decision on the FIT payment in isolation and consider any electricity cost savings as a bonus - I'm trying very hard and the best I can save is 30% based on 18months data - this is important because at this time of the year with a long Production time it appears you are saving a lot but believe me Nov/Dec/Jan/Feb the savings are minimal.

enakn

I can't find article referred to on the EST website (was hoping to read more about survey size etc). Does anybody know where it is?
All the sites I've seen seem to consider 50% as gospel (except Solar Guide which lets you choose). Its nice to see some research coming out!

Cardew

http://www.telegraph.co.uk/finance/personalfinance/consumertips/household-bills/8620325/Solar-panels-save-just-70-a-year.html

GardenersDelight

It appears that one of the potential problems with Solar PV is that the current life of the inverters used to convert the electricity from DC to AC is only about 10 years and that the replacement cost could wipe out any savings you have made in the meantime.

I bought Solar panels to heat water some 5 years ago. Yes, they work, but a seal went after 3 years - not that costly to replace, but. And we did pay way over the odds - our fault noone elses.

davidanddeirdre

Having had panels since march, paid for, I am happy with them, I would say the report is about right. The big money is always in the FIT though. Having said that, I have 1.75kW nominal (c. 13sq. metres) due to size of roof, and I would say that is about the minimum anyone should consider. Ideally 3kW + .

For newbies to PV, watch out that you must personally get your FIT application in early, preferably before you start. I didn't know and am having a big argument with Southern Electric about it. I may lose £150 if I lose, but am preparing to go to Ofgem.

enakn

GardenersDelight wrote: »

It appears that one of the potential problems with Solar PV is that the current life of the inverters used to convert the electricity from DC to AC is only about 10 years and that the replacement cost could wipe out any savings you have made in the meantime.

Definitely would wipe a bit of electricity saving, but not the gains for the feed in tariff because looking at Wire Free Direct I think we're talking about a roughly £1500 part here.
Seems to be quite some debate on lifetime from what I've read. Solar Guide let you put inverter life into their calculator although I'm not so sure how certain they can be of the price or efficiency of inverters in 10years time.

furndire

I (maybe naively) thought that if a smaller invertor is used, it will be having to work more at its full capacity, especially with the summer we are having, to gain a few KWhs by starting up at a lower pont - plus could this shorten its working life?? I was pleased when Evo Energy suggested the Fronius IG40 as I personally believe that this will maybe gain on the life of the invertor - only time will tell - plus we also gain on the readings at the top end - the highest reading we have had on our daily monitor was 4410 & it has frequently been around the high 3900/4000 during the day.

raider

So, any guesses to whether the export tariff will change from 50% to 75%?

Wishful thinking.......:)

susieQ_2

We had our solar PV panels installed in November 2010, a 3.85 Kw display to qualify for the domestic export tariff of 41.3p per Kwh.

We were fortunate in having savings in the bank and decided that with interest rates at an all-time low, we could get a better return from our money with PV. Just over 8 months into the first year our interest is running at over 6%. Last week we produced 135 Kw earning almost £60 and for the first 6 months our FIT payments were £416.:T
This does not take into account the fact that we are using and paying for far less electricity during the day.

Obviously you have to be canny and we now put the dishwasher on in the morning, do the washing during daylight hours, and put one machine on at a time using timers if necessary. Our electricity consumption according to the E-on website has dropped by 50% on last summer! Best of all we can watch the meter running backwards!! :j

If you can afford it I say 'go for it' - if only we could do the same for gas............

Cardew

susieQ wrote: »

This does not take into account the fact that we are using and paying for far less electricity during the day.

Obviously you have to be canny and we now put the dishwasher on in the morning, do the washing during daylight hours, and put one machine on at a time using timers if necessary. Our electricity consumption according to the E-on website has dropped by 50% on last summer! Best of all we can watch the meter running backwards!! :j

............

If your meter is running backwards, then it doesnt matter about using electricity in the house. Only the very old meters run backwards.

e.g. If you are generating, say 3,000kWh pa and using 500kWh in the house - your meter winds back 2,500kWh. If you are using 1,000kWh in the house it winds back 2,000kWh.

Either way you are reducing the amount of electricity for which you pay by 3,000kWh.

Without passing any moral judgement, you are aware, I take it, that technically you are committing fraud/theft and that you should notify your supplier and get the meter changed - it is perfectly possible that the Company could estimate and bill you for the amount the meter has run backwards?

As EON have some record of previous consumption, which has dropped 50%, it shouldn't be difficult for them to estimate!!!

Seriously I would at least write to the company to cover yourself, if they ignore it - it is their problem.