Why PV on a domestic dwelling make sense

fclauson · 22-12-2013 1:13pm #1

There is much talk about renewables but we are really missing a trick with PV on domestic properties.

I am not talking about the vast expanses of PV as in Europe with REFIT numbers of 40c plus / Kwh but about smaller installations such as I have (4.2peek Kwh)

At a marco level PV is not very cost effective but at a local level it is. I have used around 85% of the Kwh produced locally within the house and hence rather than receiving the Irish 9c/Kwh REFIT I have effectively been receiving 19c (my ESB unit price).

Setting the HeatPump, Dishwasher, Washing machine etc to use this day time energy is obviously a good idea too

I typically need my excess produced Kwh at night when the ESB are kind enough to allow me to purchase it back at 8.5c/unit (when they have an excess)

I believe if the government is going to encourage anything then it should be domestic PV - up to a size which make sense for the dwelling its attached to.

Capt'n Midnight · 22-12-2013 10:09pm

My query would be on the payback time.

Prices are constantly falling and the question becomes "will a system save enough this year to match the reduced price of a similar system next year ?"

fclauson · 22-12-2013 11:11pm

Capt'n Midnight wrote: »

My query would be on the payback time.

Prices are constantly falling and the question becomes "will a system save enough this year to match the reduced price of a similar system next year ?"

good question - see http://www.pv-magazine.com/investors/module-price-index/
Part of the price is the system but then there is the fitting etc which probably will go up

But to answer your Q - I don't know - but I do know that all my hot water and heating was paid for via the PV Kwh (as mentioned using the Grid as an inter-seasonal store)
and it will pay for it self in around 10 years (assuming a 5% inflation on electricity and no cost attached to the money)

So I am happy

quentingargan · 23-12-2013 9:43am

I wouldn't expect prices to fall much further than they have already. EU has claimed that China was indulging in below cost selling, and introduced a levy which has caused a lot of confusion. But it is possible that the prices we saw earlier this year were below cost, which means that the market has reached its equilibrium. So I don't think you need to factor in cost reduction in terms of ROI.

freddyuk · 23-12-2013 10:14am

There is now a minimum price per watt for Chinese exported panels to the EU. Production is either being used for the increasing domestic market or being re routed via Malaysia into the EU. Penalty costs for importing non approved Chinese panels are around 67% so most importers will not take the chance. There are 96 approved Chinese manufacturers so no shortage at the minimum price.
India is fast becoming a big player as they have unlimited cheap labour. South America is also getting involved so the cycle will continue. The EU for all it's interference will not stop free market global trade. The price without manipulation will be dictated by quality and supply and demand.

fclauson · 23-12-2013 10:26am

just so people can compare
16 x 250pw QPeak Monocrystalline (=4Kwp)

PV + Inverter + cables = €5200
Roof Rails + Fitting etc = €1500 (roughly)
total = €6700
plus vat @ 13.5 (done as part of build of house)

installed Dec 2012

and in the 12 months to 6th Dec 2013 delivered 4213Kwh
exported 1608Kwp and used rest on site

and as an aside - my Heatpump ran for both h/w and heating using (roughly) 4188Kwh so basically zero carbon - zero cost

Why PV on a domestic dwelling make sense

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