Grid Tied PV in Ireland

[cye]

I am hoping to document a few interesting, inexpensive, very easy-to-do, and non-technical grid tied PV installations over the coming months, and post the details here on the forum.

I was absolutely gob-smacked last weekend when visiting a guy to buy some secondhand solar hot water gear for our workshops, to discover that he'd set up his own Grid Tied PV, and that it was all so simple. Much much simpler than I had expected from reading the various solar forums. This is something anyone can do, and no technical expertise is required provided someone sets out a few case studies covering what you need and how you rig it up.

Just fit your panels, plg them into a grid-tie inverter, and plug into the nearest wall socket. That's it, no messing around with your meter box (consumer unit). You don't need to export electric to NIE / ESB you just end up using less from the utility suppliers.

Here's a link to a guy who's currently installing 700W pv with a soladin 600 grid tie inverter. He'll be updating this page shortly with full details of what he's done..

www.richardcollins.net/gridtie_intro.html

[cye]

At last some progress. I will have a small (micro) 100w-300w grid tie PV setup in place in the next few weeks.

I've been doing the sums, and micro grid tie will provide a financial return greater than an ISA account even in the setup costs as much as £3 per peak watt. Now the micro grid tie I am installing will come in at under £2 per peak watt.

Will provide more info with figures and sums over the next few weeks.

[campbeji]

Hi Cye,

This is really interesting, I had a read through the Richard Collins website and it seems to be pretty good, not that I understood everything in there

I just did a quick costing exercise on ebay with the following results;

Mastervolt Soladin 600 Inverter - £355
7off 12v 100w PV Panels at £150 to £300 each - £1050 to £2100
mcb - forgot to check this price but probably about £30.00

Total cost about £1450

My problem is that I don't know how to work out how much this would save in electricity costs, and so this makes it hard for me to figure out the pay back time.

The major drawback with this system is the fact that if there is a powercut then the Mastervolt shuts down and will not allow any power to feed into the system. It is a sensible safety measure but it almost defeats the purpose of the system.

It will be really interesting to see how your set up works Cye. Do you have your micro system yet?

Jim

[cye]

hi jim,

grid tie i'm using is micro grid tie, smaller scale than richards. it's never intended to be able to power everything in the house, whereas it is intended to be just about the easiest way someone to do some very small-scale pv without getting too technical.

GT inverter (up to 360w) <£100, plus pv panels at under £1.50 per watt peak.

To compute the saving (return on investment), 100w peak of pv saves you 80kwh, or 80 units of electric per year. I pay 17p per unit. By my reckoning, a setup such as this (keeping it under 300w peak) will give me a return of over 5% pa provided the whole system comes in at under £3/watt (including inverter).

Installation on a roof requires effort, but as a temporary measure, you could simply put your panels in the garden, plug into the GT inverter, plug the latter into a domestic socket, and off you go.

I'm doing this as an experiment, a micro scale case study, to prove the simplicity and viability of such an arrangement. unlike richard collins, i'm not trying to supply most of my electricity needs myself.


the issue you raised about the inverter cutting off is called islanding and is a safety feature to protect the utility firm employees when they are working on a supply line. there are alternative arrangements whereby, in the event of power failure, the system could safely switch pv DC output to a separate 'internal only' power line, such as for charging batteries directly.

my system will be operational next week, albeit only 80w to start with, and I will post more details then.

[campbeji]

So a GT Inverter would cost say £100 and 3 100w panels would cost £150+ each, so a total cost of £550. Is this right?

This sort of setup would generate about 240kWh, or 240 units of electricity at 17p each per year, so total saving per year of £40.80.

This will give a payback period of about 13.5 years.

Now if we were to be able to get the cost of this down, maybe with a bulk buy from China or something , we could probably get the payback period to under 10 years.

Where did you get your inverter from, do you have a link?
Will your inverter take an input from a wind turbine?

Jim

[cye]

hi jim,

i'm sure your payback sums are 100% correct, but I'm guessing the underlying assumption is that energy costs remain static? I genuinely believe energy costs will rise significantly above inflation and the financial return will therefore end up higher and the payback period shorter.

Anyway, generally folks try and do the things they think are right, provided they're cost neutral, rather than focus too much on savings. I just thought it would be informative to show that folks would be financially better off running a small grid tie (and feeling slightly empowered into the bargain) than lending their spare cash to a bank for next to nothing! I'm hoping to show with this experiment that it's slightly better than cost neutral, very easy-to-do, and good too from an education and feelgood point of view!

The 360W GT wouldn't be fit for most turbines, other than perhaps a small rutland/marlec. i will post up pics of the inverter once it arrives. i have the panels now, just waiting on the inverter.

Hoping also shortly to experiment with homemade pv panels, using manufactured cells but inside homemade frames and glass. this might bring the cost of pv down to 50-75 per watt peak, we'll see.

[campbeji]

Hi Cye,

Don't get me wrong I personally think that a payback period of about 10 years is ok, in fact better than I expected, and of course I didn't take price rises into consideration.

I talk to a lot of people about eco power and sustainable living, it's one of my soapbox things , but I have noticed that people fall into 3 or 4 broad categories,
1/ A majority of people who aren't really interested and think if any thing needs to be done it should be the government or maybe other people.
2/ A large minority of people who agree with me and think that it's an important thing but haven't done anything and don't really know what to do, apart from maybe seperating their rubbish for recycling
3/ A small minority of people who don't think we should bother doing anything because there isn't a problem.
4/ A small minority of people who have actually done something, like yourself.

I'd consider myself as moving from group 2 to group 4.

In my opinion to get people from groups 1 and 2 to actually do something like install a PV system or a Solar heating system, or any of the other options they will need to have a sound reason to convince them, and in most cases that'll be a good financial argument.

If you could say that if you were to spend £500 (for example) and get a payback period of 5 to 7 years then lots of people would be more willing to look at it. Whereas if you are asking people to invest £3000+ with a payback period of 15 to 20 years they will think nice idea but I'll wait till it's cheaper.

Imagine if some non-profit organisation (like Bryson house) managed to get a scheme going where they were to install this sort of system at cost price in lots of houses around the country, and they were able to drive the cost price down by buying in bulk. What sort of a difference would that make?

I just did a quick calculation, and I'm sure it's not accurate, but it'll give you the idea of what I'm thinking;

Ballylumford power station cost about £200mill and produces up to 600Mwatts, and after transmission losses thats about 540Mwatts delivered (I think). £200 mill would buy 400,000 pv installations at £500 each, if each installation were to produce say 1500watts that would give a total amount produced of 600Mwatt.

Maybe 1500 watt would be more than could be managed on the £500 per house (who can tell how the costs would work out at these levels) but if the householder was to put in £200 to £500 each then it should be easily possible.

OK thats a bit more than I meant to put into this post but like I said when I get on my soapbox....

I'm really looking forward to hearing more of your experiments and results, can you let us know where you sourced everything? I'd love to do a few experiments myself.

Jim

[campbeji]

Check out this cool tool

info.cat.org.uk/solarcalculator

Jim

[cye]

hi jim,

i like your taxonomy, and unfortunately i think you are right.

i also love your idea about getting a charitable organisation like bryson house involved, but fear they are not in quite that space yet. collecting waste for recycling is one thing, but electricity and heights would be perceived to be in another, more risky, category.

pv costs will come down substantially in the next few years as the new 'paint on pv' technology comes into production. in the meantime i still feel it is useful for folks with an interest in solar pv to experiment on a very small scale, familiarise themselves with what's involved, get the subject into conversation with the neighbours, etc..

i will provide details of what i've purchased later - i want to make sure it works first, but i can't guarantee that anything i'm using is quality product until i have experience of it under my belt. i have bought budget components from reputable eBay suppliers to keep the costs down. The equipment is extremely straightforward - I'm using initially 2X 40w X 12v moncrystalline panels wired in parallel (to provide 80w peak @ 12v). Initially, and on a temporary basis, these will plug directly into a 360W grid tie inverter, which will plug directly into a socket. I will insert a small plug-in power meter between the GT and the socket to monitor output. As the system expands and I acquire more pv, I will make the necessary adapations for building control compliance, e.g., lockable DC disconnect switch, separate connection to the consumer unit, etc.

more info next week

[campbeji]

Hi Cye,

I know it's not the 'paint on pv' tech you mentioned but I thought this was pretty interesting, found it on ebay. www.ebay.co.uk/itm/SOLAR-Flexible-Roof-Panel-124-watt-UniSolar?item=280722002063&ih=018&cmd=ViewItem

Its described as 'SOLAR Flexible Roof Panel 124 watt UniSolar', basically a sticky back pv panel.

here are the specs that are listed;

PVL-124 Specs.

16 ft. 5⅛ in. length x 15½ in. width x 0.16 in. thick Weight 15.5 lb.

Electrical Specification: PVL-124
Rated Power
Pmax 124 Watts
Nominal Operating Voltage 24 Volts
Operating Voltage (Volts)Vmp 30.0 Volts
Operating Current (Amps)
Imp 4.13 Amps
Open-Circuit Voltage (Volts)
Voc 42.0 Volts
Short-Circuit Current (Amps)
Isc 5.1 Amps
Series Fuse Rating (Amps) 8 Amps
Min. Blocking Diode 8 Amps

I have no idea if they are any goo, but I thought it was interesting.

Jim

[cye]

hi jim. this is an interesting product thanks for posting details.

it's only 6% efficient however - i worked the area out to be 2 sq metre, an area which would receive peak radiation of 2kw. Compared with 14-17% efficiency of monocrystalline inflexible panels, it's not a great use of space. Having said that, maybe the flexibility means that it can be used in odd places where a normal panel cannot? Not too dear either at £1.40 per watt including P&P to UK.

i have a small amorphous silicon panel and it's at least 3 times the size of a comparable (powerwise) mono panel.

i'd say this would be good for all sorts of temporary applications where the flexibility is paramount.

[cye]

panels loosely set on carport roof, temporary trial.

2X40w mono panels, 12v

(oh and that's my thermal panels in the background on the tile roof). the pv panels are not inclined anywhere near correctly and are only sitting at about 10 degrees, i.e., pointing very nearly directly upwards)

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[cye]

and another pic of panels on roof..

this time from underneath the carport. just threw them up there for a few hours today.

the sun, already behind the clouds all afternoon, had already gone down behind the school at this time (7pm), so the panels were picking up only weak ambient light. still generating 10w into the mains though - better than i had thought for this time on a dull april evening!

if you follow the cabling for about a foot down from the panels you will see 4 mc4 connectors. easy to connect and disconnect, and waterproof too. 1 used 4mm sq wire (hence the 4 in mc4)

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[cye]

and here's the inverter. fit for up to 360w of pv. so far i've only got 80w peak

the red and black wires are cables carrying the dc power in from the panels.

out the back of the gti is a black lead which is a kettle type lead with a 3pin plug on the other end. just plug into the nearest mains socket and off you go!!!! couldn't be easier

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[cye]

and another pic of the gti..

£75 for gti on ebay, and about £55 per 40wp panel, though i've since found a supplier of a similar panel for less than £50 apiece.

other costs: mc4 connectors (£5) and i resused some old 4mm2 cable i'd salvaged from tidying the wiring in the house.

at 3pm, cloudy, raining but fairly brightish i was getting 20w on one panel at times, and at 7ish, very dull, i was getting 10w on 2 panels...

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