Solar panel system quote advice.

Brismith1987

Hi Martyn,

I pretty much just want a battery to increase the amount of energy saved, my house will be mostly unoccupied until after 4pm, to benefit without the battery I'd have to time everything to be used during the day while I'm out rather in the evening.

I very likely do need bird protection, my neighbours used to have solar panels and had s terrible problem with pigeons including dead ones underneath the panels.

I'm still awaiting responses from other companies, you've all been very helpful.

Brismith1987

Hi Zarch,

Unfortunately that's something I can't take advantage of as I have a combi boiler.

Zarch

Brismith1987 wrote: »

Hi Martyn,

I pretty much just want a battery to increase the amount of energy saved, my house will be mostly unoccupied until after 4pm, to benefit without the battery I'd have to time everything to be used during the day while I'm out rather in the evening.

I very likely do need bird protection, my neighbours used to have solar panels and had s terrible problem with pigeons including dead ones underneath the panels.

I'm still awaiting responses from other companies, you've all been very helpful.

Lets suggest that your 2.4kWh battery can hold 2.0kWh capacity for ease of numbers.

And your current electricity tariff is 13p per kW. (use your actual figure in the calcs)

These are rudimentary figures and don't include any inflation etc.... but you get the idea.

If you could max fill up the battery from excess solar every day that would save you 2 x £0.13 (£0.26) each day if you then used all of it?

365 x 26p = £94.90 saved per year, so over 10 years you'd save £949 worth of 'bought' electricity.

But the battery is going to cost you £2105?

This is why folk don't think we are quite there yet when it comes to batteries.

Hope this helps.

Martyn1981

Zarch wrote: »

365 x 26p = £94.90 saved per year, so over 10 years you'd save £949 worth of 'bought' electricity.

But the battery is going to cost you £2105?

Love the numbers, though they also make me sad!

Can I run with them, assume 3 months of too low generation for storage and an extra 2.4kWh batt pack.

So we then get 274 x 52p = £142.48 v's approx £2.8k.

So 20yrs = £2.85k and back where you started. And I suspect we are being generous at 9 months full usage pa and ignoring batt capacity drop off and lost interest.

Thinking about batts makes me smile, thinking about the economics makes me sad.

Coastalwatch

Zarch wrote: »

If you could max fill up the battery from excess solar every day that would save you 2 x £0.13 (£0.26) each day if you then used all of it?

365 x 26p = £94.90 saved per year, so over 10 years you'd save £949 worth of 'bought' electricity.

But the battery is going to cost you £2105?
.

Unfortunately that's something I can't take advantage of as I have a combi boiler.

Hi Brian, Not trying to influence you in any way as I appreciate we all have our own thoughts and ideas on the direction we wish to take and long may it continue that way.

However, I would just like to advise that we too have a gas fired combination boiler and full central heating system yet are still planning to install a hot water tank and Iboost as Zarch suggested. I do like the thought of having "free" hot water on tap while at the same time reducing further our dependency on FF's. Given the price of gas I'm not sure that it makes much more economic sense than a battery so prioritising in flavour of one is perhaps more of a lifestyle choice rather than being dictated by any sound financial basis.
Whatever route you eventually decide to follow we wish you a successful and satisfactory outcome. It's quite a journey isn't it?

ASavvyBuyer

Coastalwatch wrote: »

Hi Brian, Not trying to influence you in any way as I appreciate we all have our own thoughts and ideas on the direction we wish to take and long may it continue that way.

However, I would just like to advise that we too have a gas fired combination boiler and full central heating system yet are still planning to install a hot water tank and Iboost as Zarch suggested. I do like the thought of having "free" hot water on tap while at the same time reducing further our dependency on FF's. Given the price of gas I'm not sure that it makes much more economic sense than a battery so prioritising in flavour of one is perhaps more of a lifestyle choice rather than being dictated by any sound financial basis.
Whatever route you eventually decide to follow we wish you a successful and satisfactory outcome. It's quite a journey isn't it?

We also have a combi boiler and hot water tank. The diverter we have keeps us in all the "free" hot water we need from about May till September.
For the rest of the year, we now use the Octopus Go tariff to heat the water overnight at 5p/kWh.

As the combi is only about 50% efficient when heating water, it works out cheaper to heat with 100% efficient electric.

Joy2

Have been reading this thread as we have been given a quote for valo solar panels, and persuaded to part with deposit for them. This includes 14 panels, inverter, optimiser, battery, monitoring (an app),voltage optimiser, and installation. Total price £11,495. We are 30° off south in Essex with no shade, and a 18° pitch to roof as its a town house. Our energy tariff is 16.67p, so they estimate we will save £477.83 by using solar power per annum, making an annual benefit of at least £712.52 including fit and export tariff. Is this a good deal as looking on here it seems over priced now?

EricMears

At first glance, £11,495 sounds at least twice as much as best quote would have been !

A further 'warning bell' is sounded by inclusion of a 'voltage optimiser'. That would be highly unlikely to offer any benefit whatsoever to a private house and its only function would therefore be to maximise installer's profits.

To save £477.83 on electricity you'd need to use 2866 units of own generation. That's around 7.8kWh every day ! Or since there will be over half the days in a year when you wouldn't even generate 7kWh, you'd need to save 15kWh every sunny day. If that's even possible, you wouldn't need solar panels; a mini nuclear power plant would be more suitable

Get some more quotes ! And ask for refund of deposit (which I hope you paid by credit card)

EricMears

I've just run Joy2's figures through pvgis ( http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php#)

"14 panels" isn't really enough to go on unless we're also given the Wp per panel (which could be anywhere between 200 & 350 !) so I've assumed installers were aiming for 4kWp

"30° off south" could mean E of S or W of S. There is a slight difference in annual generation and a rather bigger difference in whether or not peak generation occurs at a useful time.

"In Essex" could be more accurate - I've assumed Colchester.

But, doing the best I can, annual generation comes out at around
3770kWh. Installers are assuming you'd use 75% of own generation but haven't included any devices in the quote that would help to do this (e.g. Immersun or similar). Without such a device very few people would get anywhere near 75% though a large electricity user always at home might just manage that.

Martyn1981

EricMears wrote: »

To save £477.83 on electricity you'd need to use 2866 units of own generation. That's around 7.8kWh every day ! Or since there will be over half the days in a year when you wouldn't even generate 7kWh, you'd need to save 15kWh every sunny day. If that's even possible, you wouldn't need solar panels; a mini nuclear power plant would be more suitable

And like you, with a shallow pitch roof the annual generation is going to be a little bit more concentrated into the summer months, when it'll be coming out of their ears, and less in the winter when they could use it all.