[Greenbuilding] PV tracking...

[RT]

Gordon Howell wrote:

> It appears that typically no solar PV tracking system is economically 
> worthwhile.  This arises because you can install additionalfixed-tilt  
> solar PV modules to equal the same amount of annual energyas the  
> tracking system provides, yet the additional modules cost less
> than the tracking system's costs.

> This has been apparent for several years, and with the significantdrop  
> in PV module pricing the difference is even greater today.

> There may be applications where a single-axis tracker is indeed 
> worthwhile, if it is designed and constructed in a very simplemanner,  
> such as in an off-grid system.

For those who may not know of Gordon, years ago (10 ? 15 ? ) when some
architects, engineers etc from Mongolia were brought to North America to
be given a tour of strawbale buildings here in Canada and the US, Rob Joly
(who had been an early entrant in the SB revival and who had built a
strawbale home near Edson Alberta (not far from Edmonton Alberta) offered
up Gordon as being an expert in matters of solar and
energy-efficient building and Gordon graciously consented to being a tour
guide while the Mongolians were in Alberta.

I might also mention that the Mongolians' reaction to our solar
initiatives was sort of "Ho hum. Been there, done that." according to Rob
Joly. Apparently the Mongolians had long been using PV for power
generation... out of necessity, there being little electrical supply
infrastructure over there.

That is to say, I have no doubt that Gordon's comments above are accurate.

And that being said, the following excerpt from one of my email exchanges
with my neighbour:
=================copied material =================================
Wed, 11 May 2011 16:34:51

> I hit 10 K very soon after the sun comes up. Actually for most of the  
> day it is doing 10.2 K or a little more. The panels have a potential of  
> 11.4 K

>> On Tue, 10 May 2011 22:53:30
>>
>>
>>> On a daily basis I can compare our results with Enphase Energy which  
>>> is near Dunrobin Village so has similar sun conditions as our system  
>>> and shows their results on line.
>>
>>> Today we did 108.3 Kwhs, Enphase did 75,1, a difference of over 44%


>> It'd be interesting to compare the two sets of output (ie to see at what
>> point in the daily cycle the output from your system attains the 10kW
>> level and for how long that peak is maintained.
>>
>> If you are beating the Enphase results by 30% or more on a daily basis
>> (say, ballpark avg of 15 kWh daily x 365 days/yr = over $4,000  
>> incremental income per year x 20 year contract = $80k, roughly the cost  
>> of a whole
>> additional 10kW system) then it would seem to be a pretty good argument  
>> in favour of tracking systems like yours, over fixed.
=========== end of copied material ===========

... point being that if the addition of a tracking mechanism (at a cost of  
$ #,000 can increase production to such a degree that the incremental  
production will pay for a whole another 10 kW array within the 20 year  
contract period, in addition to the array's production paying for itself  
100% (including borrowing costs for 100% financing of the system ) while  
also generating annual profits in excess of $3,000 annually for the full  
20 year term of the contract, there would seem to be little downside to  
choosing the tracked system.

... which is sort of a long-roundabout answer to the Derelict's comment:

--- In SB-r-us at yahoogroups.com, Derek Roff <derek at ...> wrote:

> but the pricing doesn't make sense.  This would seem to be saying that  
> they are paid $.845 per kilowatt hour.

Many of the detractors (mostly Progressive Conservative party politicians
and their supporters) to the MicroFIT program (which was created by the
current Liberal (provincial) govt here in Ontario) make the same
argument... that the very generous rate paid to Green energy producers
under the MicroFIT program doesn't make sense.

Consumers in Ontario currently pay ~ $0.11 per kiloWatt-hour (kWh) for
their electricity.

Under the MicroFIT program, producers of electricity from renewable
sources are paid 80-something cents per kWh if they use a ground-mounted
PV array and 50-something cents per kWh for roof-mounted arrays ... for
systems up to 10 kW in capacity and only for systems with the required
"Made in Ontario" content.

That rate is guaranteed for 20 years by contract.

Another party that does not like the MicroFIT program is Japanese
producers of PV solar cells and they've taken the Provincial govt to court
over it, arguing that the required "Made in Ontario" content requirement
illegally (in the Japanese PV manufacturers' opinion) shuts them out of  
the market.


-- 
=== * ===
Rob Tom
Kanata, Ontario, Canada
< A r c h i L o g i c  at  Y a h o o  dot  C A >
(manually winnow the chaff from my edress if you hit REPLY)