Photovoltaic info.

papac

Anybody know of an online source for info on photovoltaic performance in Irish conditions.

Not looking for usual introductory stuff with unsubstantiated payback times etc.Theres lots of that around.

Good concrete performance figures from independant source. Anybody??

Cheers

Papa.

P.S Sorry for mentioning concrete in the green forum

quentingargan

This probably belongs in the renewable energy forum. Solar PV output is almost directly proportional to the level of light, so if you have a panel that is 20% efficient, you can pretty much take 20% of solar radiation in your area from NASA and apply this, less 6% or so for inverter losses.

Payback time is abysmal. I have 100Kw of panels on a roof in Spain where we get 45c per KwHr for the output. That makes sense. But at 16c per Kwhr in Ireland, it is about 30 years payback time or more.

The only case I could make for PV is someone with a fairly apocalyptic world view, or to meet Part L requirements in a holiday home, where solar water heating is going to be a waste.

Q

papac

you can pretty much take 20% of solar radiation in your area from NASA and apply this, less 6% or so for inverter losses.

Thanks. This is what I needed.-I think.

it is about 30 years payback time or more.

Monetary payback.
I am in a peculiar situation vis a vis electricity usage.(i have to use a lot). Wind is not an option. I am one of those loonies who will pay to reduce carbon footprint.
With careful design and diy installation I feel I could maybe reduce costs a bit.
PV is just one consideration in my overall plan.

The only case I could make for PV is someone with a fairly apocalyptic world view

Have you seen the news this century.? Is there another world view that makes any sense.??:):)

Thanks for reply. I am thinking of doing one of your courses. Might be in touch in the coming week.
Papa.

Capt'n Midnight

http://www.met.ie/climate/sunshine.asp

December is the dullest month with an average daily sunshine ranging from about 1 hour in the north to almost 2 hours in the extreme southeast.
...
Irish skies are completely covered by cloud for well over fifty percent of the time. This is due to our geographical position off the northwest of Europe, close to the path of Atlantic low pressure systems which tend to keep us in humid, cloudy airflows for much of the time

1 hour, that means you need 23 hours of storage !


and that's average , if there is a storm or bad weather you could be several days without power so you would need several days storage.


closer to the equator you could could on 8 hours a day worst case, so you are talking about 10 times the installed capacity and tens of times the storage capacity that you could get away with there.


only good news is that wind power is better in winter

photovoltaic is probably only worth if the ESB standing charge could pay for your system , otherwise go for wind turbine or but green electricity

quentingargan

Hi Capt'n. It isn't quite that bad, - PVs produce power roughly in direct proportion to the light intensity. On a cloudy day with, say 400W per Sq M, your panel will produce about 80w per sq m. On a sunny day with 1000 W per Sq M of sunshine, your panel will produce about 200W per sq m.

But I've lived with batteries on a wind turbine for the last 8 years now, and I wouldn't recommend it. Their efficiency is abysmal, and when you go to step up the voltage using an inverter, you lose another bit.

The only viable option is grid tied - selling the surplus power to the grid. I've worked on projects in Spain where we were getting paid 45c per KwHr for the electricity - in Spain!! That works. But 19c per KwHr in Ireland just doesn't stack.

But if you want to live off the grid, for whatever reason, ideally you need a mix of both wind and solar - they complement each other, and by and large when you don't have one, you have the other.

If you have a good windy site, then at current PV prices, a turbine is the most viable option for electricity.

The only site where I would recommend PVs is if you want to meet Part L compliance on a holiday home. Solar water heating can be a hassle in that situation as it is dumping heat when you're not there.

Q

probe

quentingargan wrote: »

The only site where I would recommend PVs is if you want to meet Part L compliance on a holiday home. Solar water heating can be a hassle in that situation as it is dumping heat when you're not there.

Q

Why not use the solar water heating to keep a holiday home aired? The humidity levels in Ireland are sky high. No point in wasting energy or using carbon based fuel to air a house.

PV solar cells could be used to run a dehumidifier. Solar water could be fed into a radiator perhaps?

A south facing conservatory open to the rest of the house would also be very effective.

quentingargan

Hi Probe,

You're only worried about Part L on a new house, and to meet part L other aspects of the house would be well enough constructed that damp shouldn't be a problem in summer. In winter, the solar won't do much.

But you are right in your thinking otherwise. Q

probe

quentingargan wrote: »

Hi Probe,

You're only worried about Part L on a new house, and to meet part L other aspects of the house would be well enough constructed that damp shouldn't be a problem in summer. In winter, the solar won't do much.

Quite frankly I don't wake up with shivers in the morning about my compliance with "Part L" or any other part of whatever you are talking about.

Sustainability has nothing to do with bureaucracy. It is common sense basically.

quentingargan

probe wrote: »

Quite frankly I don't wake up with shivers in the morning about my compliance with "Part L" or any other part of whatever you are talking about.

Sustainability has nothing to do with bureaucracy. It is common sense basically.

My point about PVs is that at present I would regard them as too expensive to justify their purchase in most situations. However, when building a new house, you have to comply with a new Part L of the building regs which requires the house to fitted with renewable energy systems that produce specific amounts of energy from renewables. In a holiday home, PVs may be the most cost-effective way to do this.

Other people may opt for PVs because they are willing to pay well over the odds for renewable energy - I agree with that and have done it myself, but the sad truth is that most people want to know what the payback time is for any renewable energy system, and if they are told thirdy-odd, years, thats the end of the conversation. Of course if you had to cost in the hidden costs of carbon emissions, then different payback times would prevail. Q

kyote00

here is an excellent and cost effective source of PVs

http://www.koekraf.eu/


I have a small 500watt PV installation in operation for the last two years. I use it to run a small DC immersion heater (150watt) in my hot water tank and some LED outside lighting.

Overall, my experience is that in Ireland, you would need to couple wind, pv (power) and thermal (water heating) to have a reasonable system.

I also use this manual - its excellent, technical oriented, without any hype....
http://www.earthscan.co.uk/?tabid=317

Capt'n Midnight

Forgot to mention earlier , if you are considering PV in Ireland ,the first step would be to make sure you have the lowerst energy rated devices you can have, and set them on aggressive power saving settings. The cost of providing PV+storage may outweigh the cost of replacing many applicances with better ones.

You can get fridges that run off gas, so maybe there is one that could run off stored heat / solar. And look at convetiing a fridge freezer into a fridge, ( so no cold air is lost when you open the door)

kyote00

I would also mention that it is nearly impossible to run Ac devices in an efficient way as the DC to AC process is very inefficient (via inverters) . In ireland, you can basically forget about running domestic applicances that need AC from your PV solar array as your will need massive battery bank to run AC loads....

The trick,IMHO, is to start with a small but scabale system and slowly add capacity when it has proven itself.

As Captain M mentions, the storage is power from PV system is in batteries - not your commoner garden type - but deep cycle batteries which are expensive and need intelligent controller to ensure the lifespan of the battery is maximised by not running "too deep" a deep cycle ....

The main advanatge is that once charged the power will stay in the batteries not reasonably long period of time (at least compared to hot water in your hot water tank ....)

Overall, again IMHO, you will not save any money in first 10-15years using PV (or solar thermal) in Ireland.

Again, I think the combo of all technologies is probably the way to go in ireland

here is an article on how to build your own turbine...http://www.mdpub.com/Wind_Turbine/index.html (next summers project ! )

Capt'n Midnight wrote: »

Forgot to mention earlier , if you are considering PV in Ireland ,the first step would be to make sure you have the lowerst energy rated devices you can have, and set them on aggressive power saving settings. The cost of providing PV+storage may outweigh the cost of replacing many applicances with better ones.

You can get fridges that run off gas, so maybe there is one that could run off stored heat / solar. And look at convetiing a fridge freezer into a fridge, ( so no cold air is lost when you open the door)

quentingargan

kyote00 wrote: »

here is an article on how to build your own turbine...http://www.mdpub.com/Wind_Turbine/index.html (next summers project ! )

Try Hugh Piggotts book as well. Very comprehensive. I've a friend who did this about four years ago and its still going strong.