Solar PV - Grid Connected System

Forums › Home Workshop DIY › Solar PV - Grid Connected System - Anybody got one?

benmurphy66

352 posts

Ultimate Geek
+1 received by user: 32

ID Verified

Trusted

#115958 13-Apr-2013 13:59

I am looking at installing a PV based Solar Power system in my house. it will be grid connected and I am interested to see if anybody has one currently and could share their experience with how well it works or doesn't work.

most interested with how much they find they use vs export etc.

1 | 2

1039 posts

Uber Geek
+1 received by user: 118

#798775 13-Apr-2013 14:04

Take a look at http://www.ecobob.co.nz/Forum/ForumGroups.aspx

Has loads of great information

grant_k

3539 posts

Uber Geek
+1 received by user: 124

Trusted

#798779 13-Apr-2013 14:47

Also, be aware that Meridian has just cut the rate paid for power exported to the grid this week, in line with Genesis:

http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10875682

Stan

929 posts

Ultimate Geek
+1 received by user: 183
Inactive user

#798981 13-Apr-2013 22:57

A good evacuated tube solar hot water system has much faster payback. Where about do you live?

You can get good value stuff if you imported from Australia as it is very popular, in some cases under 1aud per watt+shipping and taxes for the panel.

2Kw system in Christchurch live monitoring here http://nicoll.homeip.net:81/ around 5.7kwh on average cost to install around 9-10k. Cost for an evacuated tube solar system to do 5.3kwh in hot water per day retro fit around 5K, to me solar hot water is more reasonable.

Niel

3267 posts

Uber Geek
+1 received by user: 80

Trusted

#799013 14-Apr-2013 07:26

Agree with above. The sun radiates the earth with 1kW per sqm. Evaluated tubes work very well to capture most of that.

Electric solar cells have a terrible efficiency, they are best suited to remote locations unless you get them at exceptionally good price. Or if you are just into the technology and don't care about the cost.

Note the 1kW per sqm. is fairly constant during the day (ignoring clouds), it is just that the angle changes. This is something we discovered during a recent product development regarding temperature increase of an LCD when used in direct sunlight.

You can never have enough Volvos!

Handle9

11924 posts

Uber Geek
+1 received by user: 9675

Trusted

Lifetime subscriber

#799069 14-Apr-2013 09:59

If you want to retrofit microgeneration of any kind don't expect an economic return. The payback for most systerms , other than home made solutions aren't reasonable.

Doing on a new build is a little better but still nowhere near sub 10 year returtns .

benmurphy66

352 posts

Ultimate Geek
+1 received by user: 32

ID Verified

Trusted

#799155 14-Apr-2013 14:03

Handle9: If you want to retrofit microgeneration of any kind don't expect an economic return. The payback for most systerms , other than home made solutions aren't reasonable.

Doing on a new build is a little better but still nowhere near sub 10 year returtns .

Out of interest what do you base this on? the numbers seem to make sense to me if you intended to live in the house for say 10 years. Just not sure if real world experience is the same as what the sales people are providing.

I am looking at a 5kw system for between $15k-16k, which is a pretty big system but the whole family is home all day and we seem to be using a lot of power. The production model estimates I would generate 6500 kWh a year. Based on Contacts export price of 17 cents a kWh is equals a ~7% return. I figure that is more than I would get in the bank. And clearly I would use some of this power for a much better return.

We are on the Kapiti coast, Wellington.

I am also going to look into a different hot water solution as maybe a mixture of solutions might work better.

Lenovo

Shop now for Lenovo laptops and other devices (affiliate link).

Ham

462 posts

Ultimate Geek
+1 received by user: 13

#799168 14-Apr-2013 14:40

I like the idea of PV Solar. Also remember that if you sell your house the PV system will more than likely add value to the sale price, so it's not lost money once it's invested.

benmurphy66

352 posts

Ultimate Geek
+1 received by user: 32

ID Verified

Trusted

#799169 14-Apr-2013 14:47

Ham: I like the idea of PV Solar. Also remember that if you sell your house the PV system will more than likely add value to the sale price, so it's not lost money once it's invested.

Yeah I had that in the back of my mind too. I wasn't using that in my justification but it will always have some value.

No matter which way I look at it it seems to make sense, my concern is it seems to good to be true hence trying to find somebody with a system themselves.

Beccara

1473 posts

Uber Geek
+1 received by user: 517

ID Verified

#799172 14-Apr-2013 14:56

benmurphy66:
Ham: I like the idea of PV Solar. Also remember that if you sell your house the PV system will more than likely add value to the sale price, so it's not lost money once it's invested.

Yeah I had that in the back of my mind too. I wasn't using that in my justification but it will always have some value.

No matter which way I look at it it seems to make sense, my concern is it seems to good to be true hence trying to find somebody with a system themselves.

Where the wheels come off is people dont budget for faults/repairs, If your somewhere where there is hail like Wellington then you run the risk of having a panel or 3 break over the next 10 years, Likewise for an area with alot of kids + rugby balls = broken panel. Working your way back the controllers aren't cheap, even the top of the line units die sometimes.

You can't just pay for it and forget it and trying to get a ROI on it without budgeting atleast 25% of the purchase cost for repais

Most problems are the result of previous solutions...

All comment's I make are my own personal opinion and do not in any way, shape or form reflect the views of current or former employers unless specifically stated

grant_k

3539 posts

Uber Geek
+1 received by user: 124

Trusted

#799176 14-Apr-2013 15:09

Inverters can also be killed by lightning strikes, and a decent-sized one usually costs upwards of $2k to replace, sometimes more like $5k.

The elephant in the room so far as Off-Grid systems are concerned is eventual battery replacement. The most expensive batteries available will last 10 years if well looked after, or 12 years if you are extremely lucky. If not well looked after due to frequent deep discharges, the life will be shortened drastically. Unlike PV panels, the price of batteries has not plunged, but remained fairly constant AFAIK. A decent-sized battery bank providing sufficient capacity for a few days without sun is likely to cost upwards of $10k, therefore must be allowed for when working out the total cost of ownership.

Fortunately, this doesn't apply to Grid-Tie systems, which effectively use the grid as a giant battery. Interesting to hear that Contact pay 17c per kWh for exported power. That strikes me as not too bad.

benmurphy66

352 posts

Ultimate Geek
+1 received by user: 32

ID Verified

Trusted

#799187 14-Apr-2013 15:47

grant_k: Inverters can also be killed by lightning strikes, and a decent-sized one usually costs upwards of $2k to replace, sometimes more like $5k.

The elephant in the room so far as Off-Grid systems are concerned is eventual battery replacement. The most expensive batteries available will last 10 years if well looked after, or 12 years if you are extremely lucky. If not well looked after due to frequent deep discharges, the life will be shortened drastically. Unlike PV panels, the price of batteries has not plunged, but remained fairly constant AFAIK. A decent-sized battery bank providing sufficient capacity for a few days without sun is likely to cost upwards of $10k, therefore must be allowed for when working out the total cost of ownership.

Fortunately, this doesn't apply to Grid-Tie systems, which effectively use the grid as a giant battery. Interesting to hear that Contact pay 17c per kWh for exported power. That strikes me as not too bad.

Yep that is the advice I was given too. a non-gird connected system isn't worth it if the grid is available to you.

Lego

Shop now for Lego sets and other gifts (affiliate link).

benmurphy66

352 posts

Ultimate Geek
+1 received by user: 32

ID Verified

Trusted

#799189 14-Apr-2013 15:56

Beccara:
benmurphy66:
Ham: I like the idea of PV Solar. Also remember that if you sell your house the PV system will more than likely add value to the sale price, so it's not lost money once it's invested.

Yeah I had that in the back of my mind too. I wasn't using that in my justification but it will always have some value.

No matter which way I look at it it seems to make sense, my concern is it seems to good to be true hence trying to find somebody with a system themselves.

Where the wheels come off is people dont budget for faults/repairs, If your somewhere where there is hail like Wellington then you run the risk of having a panel or 3 break over the next 10 years, Likewise for an area with alot of kids + rugby balls = broken panel. Working your way back the controllers aren't cheap, even the top of the line units die sometimes.

You can't just pay for it and forget it and trying to get a ROI on it without budgeting atleast 25% of the purchase cost for repais

Good point regarding these costs and these should be considered. The full cost model provided by one supplier works on the basis that the value of the PV reduces over time & it's performance overtime reduces. but also the cost of over increases. Basically they work out that over 25 years life time we would pay 12 cents for each kWh generated by the system. That is capital, plus maintenance budget / power created.

myfullflavour

896 posts

Ultimate Geek
+1 received by user: 382

Trusted

Full Flavour

#799190 14-Apr-2013 16:05

Stan: 2Kw system in Christchurch live monitoring here http://nicoll.homeip.net:81/ around 5.7kwh on average cost to install around 9-10k.

Out of curiosity, has anyone else got their monitoring system public on the net?

Your location & link would be appreciated !

richms

29098 posts

Uber Geek
+1 received by user: 10208

Trusted

Lifetime subscriber

#799288 14-Apr-2013 19:21

With the number of science articles about breakthru nano tech stuff boosting efficiency happening all the time, I wouldnt think it would be too wise to buy right now.

Also the only reason that payback works at the moment is that there are so few of them. Once everyhouse has one on the roof trying to push 6+ kW back into the grid in the middle of the day with nowhere to go the price per unit will plummet. Already there are people in aussie reporting high mains voltage in the day time and concents for new ones being withheld.

If the price of panels and kit keeps coming down, then the price of power during the daytime on sunny days will have to come down since there will be an oversupply of it. The current payback at so close to the sell price of power will not be long term sustainable for the power companies.

Richard rich.ms

Skolink

1081 posts

Uber Geek
+1 received by user: 32

#799441 15-Apr-2013 09:59

NIWA have quite a useful tool here.

1 | 2