Maximum kW?

New to renewable energy? Have questions? Here's a great place to ask them and view information about wind and solar power basics.

Re: Maximum kW?

Postby Cherokee Solar » Wed Jul 30, 2014 8:02 am

Hi Gordon,

Thanks for the reply. That sounds correct to me. The electrician who installed the mains wiring here (from the inverter into the house) was always a bit freaked out by how stable the voltage was. I got the impression that the mains voltage fluctuates quite a lot up in this part of the world. There are SWER mains lines here all over the place.

offgridQLD wrote:He thinks that if you go of grid your starting a generator every day :lol:


What a joke. The batteries here didn't get below 70% full (state of charge) on the worst day this winter - despite it being cloudier than I can recall. Plus, I've now added an extra 2 x 190W panels to the system over the past week. Panels are cheap...

offgridQLD wrote:He also thinks that your PV's out is down to 1/2 output after a few years.


My oldest panel is about 8 years old now and it performs just as well today as it did when I purchased it. If its output is down, I really can't tell.
Off grid solar + hot water. Heavily insulated + owner built flamezone house BAL-FZ. 300 mixed fruit trees + herbs + flowers + vegetables. Bees + heritage chickens. High up in the mountains north of Melbourne. http://ferngladefarm.blogspot.com.au/
Cherokee Solar
Solar Crusader
Solar Crusader
 
Posts: 824
Joined: Tue Jan 05, 2010 9:11 pm
Location: Cherokee, Victoria

Re: Maximum kW?

Postby offgridQLD » Wed Jul 30, 2014 9:12 am

It's good to be positive about the results of living offgrid and while I think that some people perhaps misinformed or just having a negative attitude really do have the wrong idea of what to expect from a off grid system .

I do often think though the reality of offgrid systems in the suburbs could be challenging. Just finding the real estate for enough north or close to north facing PV that isn't shaded and often you have little say or choice in creating shade free space. Given the homes are getting closer and closer together. Roof eaves almost touching the house next door. Blocks are getting smaller and smaller. If there is no shade fee space on your block then you have little choice.

I could probably make it happen generator free at our house in the suburbs of Brisbane (keeping consumption modest during low sun) with perhaps 3kw of PV and some lithium. But it would take multiple rows of tilt frames at a big incline on the southern roof facing north (big wind sock) and some very careful planing to squeeze them all in. (small two story homes don't have a big roof space) Plenty of other people on the street would have no hope due to trees, house orientation or other homes and structures shading there block. In the country with some land around you it's easy. If the roof isn't a good option just find a spot in the paddock and build a frame.

So I think some people in the suburbs could go completely off grid 100% generator free though not everyone could there limited ability to gather the kwrs from PV. Unless they were willing to really scrimp on consumption and watch every whr in bad weather.

Kurt
offgridQLD
Solar Crusader
Solar Crusader
 
Posts: 2117
Joined: Thu Jan 26, 2012 11:50 am
Location: South Australia, Fleurieu Peninsula

Re: Maximum kW?

Postby Whitespeed » Wed Jul 30, 2014 9:33 am

Sometimes even in the country it's not easy. People assume having 10 acres we have tons of space, but it's not always great for solar. We also have enough vacant roof at 45 degrees on the house for 20+kw of panels but not in the right direction. Also enough on the shed at 22 degrees for the same, but then there is the shade problem :)

We are a little stunted by having a bush block with a native vegetation overlay in place, meaning during winter the array on the shed still gets shade outside of 10.30am-3.00pm.

We have a perfect spot for a ground mount set with virtually no shade at any time of the year, unfortunately it's on the opposite side of the house and would need excessively long extension leads to run heating/hot water.

Lots of space but not a lot of economical solutions :)
Whitespeed
Solar Crusader
Solar Crusader
 
Posts: 172
Joined: Sat Apr 05, 2014 9:16 pm
Location: Central Vic

Re: Maximum kW?

Postby offgridQLD » Wed Jul 30, 2014 9:57 am

You must have big - tall trees very- very close to you house - shed?

We have 8 acres down a old logging trail and probably only 1 acre is flat cleared land the other 7 all thick tall trees with very big gums and the like but as long as their is 50 - 60m space between you home and the big trees in East - North - West then I don't see how it could be a issue.

The building rules - bush fire rules in our area and I'm sure they are not as tough as down south. Require the trees to be cleared a good distance from the house.

kurt
offgridQLD
Solar Crusader
Solar Crusader
 
Posts: 2117
Joined: Thu Jan 26, 2012 11:50 am
Location: South Australia, Fleurieu Peninsula

Re: Maximum kW?

Postby bpratt » Wed Jul 30, 2014 10:26 am

Whitespeed wrote:Sometimes even in the country it's not easy. People assume having 10 acres we have tons of space, but it's not always great for solar.


Our old place was on 20 acres and we had that same problem. Plenty of land but trees not far from the house.

Fortunately having a 'hand held portable lightning machine' i.e. chain saw, I carefully picked off about 12 tall gum trees that were obstructing / shading our solar panels from early morning to mid afternoon.

It's nice to have some grand trees around the place, but you have to look at the grander scheme of things, i.e. solar pv/shw, possible fire hazard even in areas not known for bushfires.

What people forget is that bushfires are a natural and regular event, as they burn off the fuel on the ground, and if it is not done you can eventually get a massive blaze, hence the need for 'hazard reduction burns', even though many greenies hate them.
Kaco 6600
26 x Trina Honey 250w panels. (wish I could work out how to upload to pvoutput.org)

New house build :-
http://bandlnewhomebuild.blogspot.com

My weather station :-
http://jimboombaweather.com
bpratt
Solar Crusader
Solar Crusader
 
Posts: 945
Joined: Wed Oct 14, 2009 11:09 am
Location: Jimboomba, Queensland - Energex and Origin

Re: Maximum kW?

Postby offgridQLD » Wed Jul 30, 2014 10:44 am

What I was getting at was if you draw a straight line from the house roof to the sun at say 9am and again at 3pm the trees would have to be 100m tall or very close to your home. For trees to be shading the house dropping leaves all over it - fire risk or perhaps storm risk to be a issue.

That said I have seen a few homes in the dry hot areas on farms that have 300 Acres of clear land and then all around the house they have planted trees so they have shade. My fathers farm is like that several hundred acres of mixed clear land and bush but putting PV on his house or shed roof would be useless as 35 years ago about 200 trees were planted around the house yard (though fit the trencher on the tractor and a frame in the front paddock would solve that issue) While I can understand that in the southern states where its a dry heat the tree shade works well. In QLD your better off without the tree's to close to your home and allow more of a breeze through the home. With no shade on your house and a few more PV on there and a Aircon can run all day for free to keep cool.

Kurt
offgridQLD
Solar Crusader
Solar Crusader
 
Posts: 2117
Joined: Thu Jan 26, 2012 11:50 am
Location: South Australia, Fleurieu Peninsula

Re: Maximum kW?

Postby r0bs » Wed Jul 30, 2014 1:42 pm

Gordon-Loomberah wrote:
the new trend is to ban energy exports to the grid!


Yes, unfortunately we have a wonderfully progressive government up here. The instability issue is a minor one compared to the oversupply of electricity we have in Queensland.

Spot prices (mainly due to solar) are down to 2.2 cents/kWh during the day ($22.00/MWh):
http://www.wattclarity.com.au/2014/07/spot-prices-back-to-yesteryear
This would be making the Generators sweat!.

I too want to increase both my properties to more than the 6.5kW I currently have on both (I'm allowed to export 5kW, but I have 6.5kW of panels on both properties - 26 x 250W REC panels and a 5kW inverter on each system)

Guessing I could store it and keep exporting 5kw constantly, night and day... I didn't read anything in the contract that prevents me from doing that... I just can't export more than 5kW at any instance.....

I guess I could also use my off-peak to charge that storage at $0.20299/kWh and recoup $0.52/kWh....

If they want to play stupid games of not exporting more than 5kW to the grid I can play that game....

Might just need to work out what the sums are to recoup my investment in storage.

Anyone want to do the sums? I have an unlimited area for ground mounted panels (5 Acres) and three-phase to each property... Just need the battery and some way of limiting the feed to the grid to 5kW.

Rob
r0bs
Solar Supporter
Solar Supporter
 
Posts: 1
Joined: Tue Dec 18, 2012 7:37 pm

Re: Maximum kW?

Postby offgridQLD » Wed Jul 30, 2014 2:00 pm

Why would we want to help you do the sums to install that. We all ready pay enough tax as it is without needing to pay anymore to cover peoples 24/7 - 5kw $0.52 kw feed in tariff scam.

The retailers are not paying you that. The Government is paying it.

You have been playing by the rules. Max 5kw inverter at each property and rewarded with a very - very generous feed in tarrif for your early uptake of renewable energy.

I too want to increase both my properties to more than the 6.5kW

The issue now is you want to make your system bigger! I take it you want to make more money from this. Now you want to not play by the rules.

If they want to play stupid games of not exporting more than 5kW to the grid I can play that game


I think saying you can not export more than 5kw isn't playing stupid games. The feed in tariff to encourage early uptake of PV at a private homes was the idea wasn't it?

Kurt
offgridQLD
Solar Crusader
Solar Crusader
 
Posts: 2117
Joined: Thu Jan 26, 2012 11:50 am
Location: South Australia, Fleurieu Peninsula

Re: Maximum kW?

Postby Gordon-Loomberah » Wed Jul 30, 2014 2:13 pm

I think the rules specifically say that you can only export from renewable energy sources, solar, wind, hydro, biomass (well, some of it is renewable), so exporting from batteries, particularly ones charged at off-peak rates would be a definite no go!
http://gunagulla.com Loomberah weather and astronomy including live solar radiation intensity and UV + Gunagulla aquaponics, organic eggs and cherries
User avatar
Gordon-Loomberah
Community Moderator
 
Posts: 5763
Joined: Thu Sep 24, 2009 9:41 pm
Location: Loomberah NSW Australia

Re: Maximum kW?

Postby Cherokee Solar » Wed Jul 30, 2014 6:04 pm

Lots of interesting comments.

I'm only 2/3rds of the way up the ridge which is to the north of me. At this time of the year the sun peeks above the trees at about 10.45am. Lots of panels helps a great deal.

As to clearing and forest fuels management. Yeah, down south, if you don't reduce the fuel loads on the forest floor and increase the spacing between the existing mature trees, nature will do it for you. You may not like that freebie wildfire job though!

Generally very little is spent on forest management around these parts, because it is hard work and no one wants to pay for it. I keep a very tidy ship within 100m of the house though. The funny thing is that is where most of the native animals here like to eat.
Off grid solar + hot water. Heavily insulated + owner built flamezone house BAL-FZ. 300 mixed fruit trees + herbs + flowers + vegetables. Bees + heritage chickens. High up in the mountains north of Melbourne. http://ferngladefarm.blogspot.com.au/
Cherokee Solar
Solar Crusader
Solar Crusader
 
Posts: 824
Joined: Tue Jan 05, 2010 9:11 pm
Location: Cherokee, Victoria

PreviousNext

Return to Q&A - wind and solar power basics

Who is online

Users browsing this forum: Majestic-12 [Bot] and 3 guests

new solar power specials