PV Efficiency Survey ..... « Alternative Technology Assn Forums

Alternative Technology Assn Forums » Energy

PV Efficiency Survey .....

(21 posts) (10 voices)

Started 12 years ago by GJOESQ
Latest reply from bluesky

Tags:

GJOESQ
Member

I had a 2 kW PV system installed on February 19, 2010 and I'm checking weekly how much electricity they're exporting to the grid. My Smart Meter and Gross FiT Meter were installed on April 29. I have Off Peak 1 boosting for my solar HWS which I usually turn off. My electricity supplier is Origin from whom I purchase 100% Green Wind Energy. I am located in Phillip Bay, Sydney, and face 10 degrees west of north. The panel angle is 17.5 degrees.

Here are my average daily monthly electricity generation for each month (number of days in brackets) as well as the best generation days:

February (10): 8.0 kWh. Best day 27 @ 12.5 kWh.
March (31): 8.3 kWh. Best days 3, 4, 9, 7, 16 and 17 @ 11.0 kWh.
April (30): 7.4 kWh. Best days 1 and 2 @ 10.5 kWh.
May (31): 5.2 kWh. Best days 2 and 6 @ 8.9 kWh.
June (19): 5.4 kWh. Best day 10 @ 7.5 kWh.

I'd appreciate it if any of you could publish your stats here so that we can get an idea of how our PVs are performing. Thanx.

Posted Sunday 20 Jun 2010 @ 9:59:53 am from IP #
Gruen
Member

GJOESQ, can't give you any feedback on the usage because I don't yet have the PVs in (waiting to order from Origin, in Victoria). So, that means that you kept your existing meter for a couple of months prior to receiving the smart meter. That means you did not benefit from the FiTs during that period... is that right? Was that your decision or just an installation lag. Thanks for mentioning that you are buying what I assume are your additional power needs via 100% Green Wind Energy... I'll look into that.

Hope someone else can answer your question on PV performance

Posted Monday 21 Jun 2010 @ 9:33:45 am from IP #
Inspector
Member

My 2.2kw system has been installed (with gross metering) for just over 1 month, so I would not be able to give you any output history but only a daily average for the previous month, which was 178.4/30days = 5.94kwh/day. My panel tilt angle is higher than yours and therefore slightly better suited to winter output (not entirely sure of my roof angle - it's probably typical for a Sydney home) and the extra 0.2kw also would've contributed. My highest output was 8.4kwh on the same date as you - 10th June, and I've had two 8.1 and three 8.0 days since then, and alot of very poor days before it (the lowest in the last 2 weeks was only 1.7kwh, but I haven't calculated the first two weeks, which were very overcast and possibly even less output)...

I'm near Bankstown (and tend to get Liverpool temperatures), but this time of the year I could have colder temperatures than you right on the coast, even with your sea-breezes.

Posted Monday 21 Jun 2010 @ 11:00:12 am from IP #
lillypilly
Member

It sounds like your system is doing really well.

I entered your details in to the PVWatts Calculator using Sydney for Latitude,Tilt 17.5, Azimuth 350 and Derate Factor 0.77 (default) :

January 9.2
February 8.0
March 7.5
April 6.2
May 4.7
June 4.1
July 4.9
August 6.4
September 7.6
October 8.6
November 8.6
December 8.9
Annual 2570 kWh

Our system is fairly close to the PVWatts calculations, monthly averages only +/- about 0.2 kWh per day. We have a 1 kW system connected in May last year, in Melbourne, the tilt is 27 degrees and azimuth is 285 degrees. PVWatts says it should generate 1125 kWh pa and we got 1177 kWh in the first 12 months. We exported just over 616 kWh last year and we imported 1991 kWh (100% green electricity).

Inspector - just curious, assuming the cloud cover and haze are the same on both locations (and I've no idea if they are or not) do you think the hotter summer temperatures might have a bigger impact on efficiency than the cooler winter temperatures you experience compared with a coastal location?

Posted Monday 21 Jun 2010 @ 1:38:19 pm from IP #
GJOESQ
Member

Gruen, I had one of the old disk meters which ran backwards when my PVs were exporting more than I was using. Very nice touch that!! So yes, I just got a one for one credit until the gross meter was installed.

I haven't received a bill as yet but what happens, believe, is that all the standard electricity I use will be billed @ 22.66c/hWh and off peak @ 12.87c/kWh while I'll get credit for all the electricity I export to the grid @ 66c/kWh. However, I have a funny feeling that there will be a hiccup on the billing. We'll just have to wait and see ....

Regarding 100% Green Wind Power, I felt that was essential to remain consistent with my principles. I was NOT going to buy coal fired energy ever again!!!

Posted Monday 21 Jun 2010 @ 3:24:38 pm from IP #
GJOESQ
Member

Inspector, it seems our systems are performing fairly equally as I had two 7kWh days after my best June day as well. It seems 7 kWh is the best I can expect at winter solstice time!

I decided not to adjust the panel angle to an 'average' angle because I reckoned that I'd lose more generation in summer than I would gain in winter and, since I was taking a yearly perspective in respect of payback, I felt that I'd generate more electricity pa if I maxed out on summer production.

Posted Monday 21 Jun 2010 @ 3:32:52 pm from IP #
GJOESQ
Member

lillypilly, I got more generous numbers after getting BOM stats and working it out myself at 85% panel efficiency instead of the default 77% the PV Watts calculator uses: http://pvwatts.org/ I didn't allow for the angle either. Interesting! Here are my figures:

Jan 11.6
Feb 10.3
Mar 8.9
Apr 7.0
May 5.1
Jun 4.4
Jul 4.8
Aug 6.6
Sep 8.4
Oct 10.1
Nov 10.9
Dec 11.8

My panels are doing about what I hoped, a little better in winter though.

I ran the PV Watts calculator for my angle, the latitude angle, the +15 degrees winter angle and the -15 degrees summer angle my theory that using a summer angle all year rather than the winter angle has been proved correct!! It gives a 4% increase in power generation. However, the latitude angle does appear to have the advantage, only just at 0.85% improvement over the summer angle.

So I'm glad my roof is 17.5 degrees and not 49 degrees!! My angle does lose only 0.41% but I'm not too bothered about that. I suppose the message is to set to latitude if you can but if not, well you'll only lose between 1% and 5%. So I suppose one shouldn't lose sleep over it although I must admit that I spent many hours considering this matter because I didn't have the use of the PV Watts calculator!! Why didn't someone tell me about it a year ago!! Perhaps it wasn't around then.

I realised I left out .09 in my PV size. It's actually 2.09 kW. You see, size DOES matter!!

Posted Monday 21 Jun 2010 @ 4:24:06 pm from IP #
GJOESQ
Member

Oh, I just discovered that if one adjusts the angle of their panels at the end of March to the winter angle and then at the end of September to the summer angle you can get a further 4% improvement over the latitude angle.

I've also discovered that having PVs pointing a little west is better than pointing a little east. An azimuth of -15 degrees (15 degrees west of north, which is my siting) is equivalent to one of +10 degrees (10 degrees east of north). Interesting!! And all this from the PV Watts calculator. What an amazing tool!!!!

Posted Monday 21 Jun 2010 @ 4:28:39 pm from IP #
rockabye
Member

My 1kWp NW facing system has produced 1485kWh in 12 months as of June 16 at Lat 23:23 S. On a perfect sunny Sunday 20 June it produced 4.48kWh. So double for a 2KWp system.

Posted Monday 21 Jun 2010 @ 9:49:50 pm from IP #
Russell Moore
Member

Take a look at the Whirlpool forums, and check the solar output thread. People are entering daily solar outputs from around Australia, myself included.

Posted Monday 21 Jun 2010 @ 10:28:32 pm from IP #
Inspector
Member

lillypilly - I would expect my hotter summer temperatures to be detrimental to solar generation - I regularly see over 40 degrees whereas coastal areas (even Sydney CBD) tend to be around 8-10 degrees cooler on a regular basis throughout summer. I'd have to do some calculations, but Joe might even find his system - even though only slightly less "system power" than mine, might produce the same or even more than mine during summer - and he also has the possible advantage of his panels facing more horizontal, meaning they are more perpendicular to the sun than mine. Panel temperature co-efficient will also likely be different between his panels and my panels, which is going to be the most significant factor. I guess time will tell, and we can update this thread as time progresses. There's a good possility someone else might have had their system installed longer than me that would be able to provide summer output results sooner than me waiting for summer to roll around...

Posted Tuesday 22 Jun 2010 @ 3:11:11 am from IP #
lillypilly
Member

Okay, I was wondering if they might average out but as you are probably not 10 degrees cooler on an average winter day then probably not. The figure I have seen quoted in a few places is 0.5% decrease in efficiency per degree.

GJOESQ - that's interesting about facing slightly west better than slightly east - I wondered if might be due to efficiency in the winter being reduced by fog but (in Melbourne at least) it is the summer figures that are lower not winter.

Posted Tuesday 22 Jun 2010 @ 1:18:14 pm from IP #
lillypilly
Member

And at 31 degrees tilt and N facing PVWatts says annual output should be 1274 kWh/kW and 18 degrees tilt and 18 degrees W of N the output should be 1257 kWh/kW so that isn't a huge loss.

Posted Friday 25 Jun 2010 @ 6:38:31 am from IP #
lillypilly
Member

Oops, the post above was meant for another thread. Sorry, for any confusion.

Posted Friday 25 Jun 2010 @ 8:02:47 am from IP #
GJOESQ
Member

Yes, that Whirlpool site is great: http://forums.whirlpool.net.au/forum-replies.cfm?t=1459336

Posted Friday 25 Jun 2010 @ 3:15:51 pm from IP #
Anonymous
Unregistered

A solar cell is a device that converts the energy of sunlight directly into electricity by the photovoltaic effect. Sometimes the term solar cell is reserved for devices intended specifically to capture energy from sunlight such as solar panels and solar cells, while the term photovoltaic cell is used when the light source is unspecified. Assemblies of cells are used to make solar panels, solar modules, or photovoltaic arrays. Photovoltaic is the field of technology and research related to the application of solar cells in producing electricity for practical use. for PV efficiency survey visit us.............

Posted Wednesday 30 Jun 2010 @ 4:37:38 am from IP #
bluesky
Member

Hhas anyone been measuring their output from their pv system over the course of a day? I'm a student doing research into grid-connected solar and struggling to find any real output curves (ie measuring time of day against kWh).

There is a lot of theoretical info and papers but v.little in the way of real measurements. I know each system is dependent on many factors, but I'm more interested in shape of graphed curves, how long peak generation occurs. Mainly to counter ongoing arguments about how solar only good at midday, when you can realistically get good generation at even early and late hours for a well positioned system.

Posted Tuesday 20 Jul 2010 @ 1:29:24 am from IP #
ghostgum
Member

I've got data for 4 months at 15 minute intervals. Some of the data is affected by partial shading for 3 months of the year.

You can get some data at hourly intervals by looking at the publicly available plants at
http://www.sunnyportal.com/
If you can display a system output histogram, then you can also download the hourly data that is displayed.

You can also use PVWatts v1 to give you energy vs time of day.

Posted Tuesday 20 Jul 2010 @ 1:41:19 am from IP #
Russell Moore
Member

Some of the posters on the whirlpool site have links to daily graphs that show output minute by minute.

Posted Tuesday 20 Jul 2010 @ 4:44:26 am from IP #
bluesky
Member

Thanks ghostgum and Russell, I hadnt seen the sunnyportal site b4 - excellent. Will try the whirlpool site as well! ghostgum, have you got that data online?

Posted Thursday 22 Jul 2010 @ 4:48:28 am from IP #
Anonymous
Unregistered

Dear sir
i am glad to contact your with e-mail, we are interesting in your pv solar business , cause we are solar panel manufacturer .
Here are some of our company informations
1. my company name :
Znshine PV-Tech Co., Ltd
2.Company website: http://www.znshinesolar.com/
3.Capacity :Annual capacity :300MW planned annual capacity:500MW.
4.Certification : TUV IEC MCS UL VDE ISO CE PV CYCLE
5.Solar modules effeciency 16-18%
6.Guarantee : Bankable and 25 years life span.
Very glad to inform you that at present our solar Module (solar panel ) is very good selling.
Also we can support you MOQ Order (56-100pcs) as trial order to support you test market.
If you can place order right now, we can support you very competitive price 0.87Euro per watt /1.24USD Per watt
The price including Package shipping (by sea ) cost and insurance fee.
For this product, it is with 5 functions as follow :
1.High cell efficiency 16-17%
2.Pass TUV IEC VED UL MCS CEC ISO CE certification
3.PTC test same with STC test .power generation is high ,we have Pothon test to prove it
4.Delivey time :Fast,Cauese We have warehouse
Payment advantage :10% deposit ,rest should be pay after delivery (if you are reliable)

Posted Friday 19 Aug 2011 @ 6:26:04 am from IP #

RSS feed for this topic