[Greenbuilding] PV Tracking

[Frank Tettemer]

Hi All, Here's some more fun data to add to the mix!

I mentioned our non-tracker/over-loaded-panels before, briefly.  I'll 
describe it again.
We've mounted 13,000 watts DC panels, in agreement with the Ontario 
Power Authority to sell, at max., 10 Kw per hour.
Our thinking is to be able to produce (and sell) 10 Kw per hour from 9AM 
to 4 PM,
with variously smaller hourly productions before and after those times 
of day.

These sunny summer days, we vary from 75 to 92 Kw per day sold to the 
power authority.  We, of course produce more than that, from 9 until 4, 
but the inverters cut off the over-production, sending only the allowed 
10Kw per hour to the grid.

This corresponds to the tracker claims, mentioned by others on the 
list.  And as expected, the trackers generate their 35% more, on these 
summer sunny days.  However, for over half the year, our seasonally 
adjusted array produces only 15% less than other local trackers. And in 
Winter, our array produces almost the same amount as other local 
trackers with 11,000 watts DC on them.

We change the angle to 45 degrees around Late August/Early September.
We change again to about 65-70 degrees to horizontal in October/Early 
November.
We change again, back to 45 degrees, in Late February/Early March.
And we change to Summer Mode, at 25 degrees, in Late April/Early May.

Please Note that we definitely Do Not change angles on the Solstice nor 
the Equinox.
That timing would be exactly the Wrong Time to change angles!!!

Some background to the Ontario microFIT program:
They pay 81 cents per Kw produced, up to a maximum of 10 Kw per hour, 
for ground mounted arrays, for the early adapters of last years 
applications..
A common installation has about 11,000 watts DC of panels.  We have 
added about $6,000.00 more in panels, or 2,000 more watts DC.

This means we produce more full 10Kw each hour than the standard 11,000 
watts arrays, because we have invested more in panels but not in 
tracking devices.
A common fixed, seasonally adjustable array with 11,000 of PV's is 
averaging a little over $10,000 income from production in this area.
And like John Staube has mentioned about his area of Southern Ontario, 
there are over 100 microFIT installations now in production in our local 
County of Renfrew, all within a 45 minute drive of us, any direction,

and 95% of these people are small family farms.

So if an installation varies from $65,000 in cost to $95,000 in cost, or 
with trackers, $120,000 in cost, you can see how an annual gross income 
of about $10,000 would take close to half of the 20 year contract to pay 
off the investment.

Our over-paneled-array will hopefully average us over $13,000 per year. 
As we did our own design, purchasing and installation, with about $3,000 
paid input from a local electrician, our initial investment of time and 
cash will pay off in a bit under six years.
We won't get rich, after that, but we won't be concerned about tracker 
maintenance, either.

Frank Tettemer
Living Sol ~ Building and Design
www.livingsol.com
613 756 3884



================= More Forwarded material ==================

WatJohn and I have a mutual friend (Don Fugler) here in Ottawa , now 
retired, who used to pedal to and from work every day, year round.

In winter, those bike trips both ways would be in the dark ... the sun 
not yet having risen in the mornings (7-ish) and already long gone in 
the evenings (4:30-ish).

OTOH in summer the northeastern sky will often be a spectacular blazing 
red in the hour before 6 am and I remember many June nights working 
outside until almost 10 pm without having to use artificial light.

The Unbelieving Heathens on this List were having trouble swallowing the 
production figures for my neighbour's 10 KW single-axis tracking array. 
Well, those UHs are probably going to gag on the following which came 
from a person whose company has just brought their dual-axis tracking 
system out of R&D and put it on-line.
(I don't know him personally (but I did meet his partner when he was out 
pitching their single-axis system and my SlipperySalesDevil hackles were 
activated) so I can't vouch for the veracity of his claims as I would 
for those of my llama-rancher neighbour.

================= Forwarded material ==================

Sent: Wednesday, June 22, 2011 7:10 PM
Subject: Weekly update...

This is an excellent day for [partner] and me because our first 
dual-axis has been tracking perfectly for 1 week
<snip>
  As my wife transcribed for me last week, we have no idea how effective 
our system is going to be, but for an astonishing figure, our first 
dual-axis has produced an average of 134 Kw per day over the last 3 days 
and even 38 Kw today as of 4pm in all this cloud cover and rain. These 
are amazing figures that NO COMPETITOR can touch.
<snip>

=============== End of forwarded material ===============
(Presumably those are "kWh" not "kW" and yes, I too am having a bit of 
trouble swallowing some of the above ...the bit about the competition, 
in particular)

On those June days, my llamaRancher neighbour's single-axis array was 
producing in the neighbourhood of 100 kWh per day, roughly 40% better 
the the nearby Enphase fixed array.


On Thu, 04 Aug 2011 08:09:25 -0400, jfstraube <jfstraube at gmail.com> wrote:

> PVwatts.org is a wonderful website calculator for PV output that I use 
> all the time.
<snip>
> In Ottawa, it predicts a full 2-axis tracker will produce 36% more 
> electricity than ideally sloped fixed system. I beleive it.
>
> On 2011-08-04, at 7:05 AM, Haudy Kazemi wrote:
>
>> When most people use the power output calculators/estimators,
>> they look at the annual production figures not the daily figures.

>>  A tracker in a high latitude may make larger differencein the summer 
>> than in the winter because the arc of the sun is longer,

>>  A fixed array in those conditions will self-shade in the early and 
>> late parts of the day.  This may the root of the daily difference 
>> between the reported performance difference between the tracked and 
>> non-tracked array.

>> During summer, tracked array may outproduce the non-tracked array by 
>> the ~40% reported in this discussion thread.
>> During spring/fall, tracked array may outproduce non-tracked array by 
>> 20%.
>> During winter, with a short arc, tracked array may outproduce 
>> non-tracked array by 5%.
>> On an annual basis the tracked array may only exceed the non-tracked 
>> array by ~20%, even it does better than that in the summer.
>>
>> Perhaps someone can check this in a calculator?
>
>> On 8/3/2011 8:00 PM, Nick Pyner wrote:
>>>
>>> I just think nobody is taking the geography in to account.
>>>
>>> There are plenty of PV installations around here , but I have never 
>>> seen or heard of a tracking one. This is probably because there is 
>>> no point in them. The situation could  be quite different in the 
>>> more frigid parts of the world for two reasons.
>>>
>>> 1. Even in what is laughably called the banana belt of Canada, the 
>>> insolation is not that great, and the skies are not so clear, so you 
>>> would need to chase every watt you can find.
>>>
>>> 2. In the summer, the days are longer. Hence the practical window of 
>>> opportunity may be as much as an hour wider, but the hourly march of 
>>> the sun is the same.
>>>
>>> A tracking system helps in both cases, and this heathen would 
>>> imagine the more polar you get the more sense a tracker will make.
>>>
>>> Nick Pyner
>>>
>>> Dee Why   NSW (Australia)
>>>
>>> -----Original Message-----
>>> From: greenbuilding-bounces at lists.bioenergylists.org 
>>> [mailto:greenbuilding-bounces at lists.bioenergylists.org]On Behalf Of RT
>>> Sent: Wednesday, 3 August 2011 2:59 PM
>>>
>>> I told him that I had been telling people (this List) that his 
>>> single-axis tracking array had produced 40 and sometimes 44% more 
>>> than the Enphase fixed array and that you (the Listmembers) were 
>>> telling me that I was full of $#!+.
>>>
>>> We both just shrugged our shoulders (as if to say "Nyeh! What can 
>>> you do about  unbelieving heathens ?")


-- 
=== * ===
Rob Tom

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