12kW MicroFIT DIY MicroFIT Solar

[Rob Beckers]

A friend of mine recently completed his DIY solar system. He purchased the modules, and of course the inverters, then built the mounting hardware himself out of Ontario-grown cedar, and Ontario-made 4" well-casing (to comply with the domestic content rules).

The entire array consists of 42 Suntech modules, of 280 Watt each, for a total of 11,760 Watt. These are very large modules! To comply with the 10kW maximum for MicroFIT, the inverters are Power-One Auroras, 5kW each, with two of those for 10kW total. The rational is that PV modules will rarely produce their rated power, and you can oversize by 15% to better utilize the inverter power.

The structure was made by having a well-driller auger 6" holes. The 4" well-casing had square plates welded to the ends, with a hole drilled into the middle for drainage, and those were put in the holes. Tops were lined up so they were level. This meant that 4' of pipe is underground, about 2' above ground. The tops of the pipe have T-brackets welded to them, and the wood bolts to that. The frames that hold the panels were constructed indoors, and he simply raised them in place one-by-one, the cross-braces were added, and 1x stock was bolted to the top to hold the modules. It's very, very sturdy (and cheap to make). By using cedar he solved the problem of Ontario-made and weather resistance. Still, he put wood-preserver on it to play it safe.

The economics worked out to be somewhere between 1/2 and 2/3 of the price of a similar sized array, if it was installed by a business. Conversely, the payback time is somewhere around 6 years, with the rest of the 20-year contract pure profit! That is nothing to sneeze at; an array this size will conservatively produce around 13,400 kWh per year. With the feed-in-tariff here that translates to $10,750 per year!

I was amazed how fast he constructed all this, and how well made it is. Hopefully it helps give people that are considering a ground-mounted array some ideas. It was inspected and approved last week, and switched on. Works like a charm!:cool:

-RoB-

[Joe Blake]

Wow.:eek:

Power Crazy!!;)

Like. :D

Joe

[Rob Beckers]

The 'crazy' part is that a solar array this size just about offsets what the average Canadian household uses in electricity. Amazing how much RE hardware it takes to generate one's own electricity! (the owner falls far below the Canadian average though, they use relatively little).

The way people see it here is as an investment. That is also pretty well the main (if not only) reason for most to put money into renewable energy. While there is concern for the environment this mostly runs a distant second. The numbers are quite good though, this case is around 6 years payback, most cases where it is installed by pros gets around 9 or 10 years payback time.

-RoB-

[Rob Stephens]

Sweet!

Pretend this message is longer.

[William Qian]

This is a very brilliant idea and a neat built! Rob, do you know who is the supplier of the Suntech panels?

[Rob Beckers]

Hi William,

Nope, I do not know. The owner bought those directly from the States. He mentioned a friend of his arranged for them. If you're interested, I can get a price for you for Suntech modules, the same ones or other sizes. Not sure what my supplier is asking these days, but it should be close to the US prices, and since they are in Canada there won't be customs/brokerage. Contact me offline in interested.

-RoB-

[Rob Stephens]

Hi William,

Nope, I do not know. The owner bought those directly from the States. He mentioned a friend of his arranged for them. If you're interested, I can get a price for you for Suntech modules, the same ones or other sizes. Not sure what my supplier is asking these days, but it should be close to the US prices, and since they are in Canada there won't be customs/brokerage. Contact me offline in interested.

-RoB-


Brokerage charges. That is what UPS charges to break them right?

[Rob Beckers]

Brokerage charges. That is what UPS charges to break them right?

:D
You're a customer too I see...

-RoB-

[Michel de Breyne]

My issue with this install is that I'd be concerned the cedar mount won't last 20 years. Our cedar fence is looking pretty shabby after 5 and it's not supporting any weight other than itself ... That said, I'm certainly not an expert.

[Rob Beckers]

I hear you Michel; cedar these days is not the same stuff as was sold 20+ years ago. It's all sapwood now, from much younger trees. The cedar decking used now in these parts lasts just 7 to 10 years before it rots out.

The owner did take care to put wood preservative on all wood, and dip the end-grain in preservative. Much of the structure consists of very substantial structural members, not 1-by planking, and even the planking used is rough lumber (so it's much thicker than finished lumber). It's a pretty beefy structure.

Time will have to tell. The owner figures that he'll be OK for 20 years (at least). If it was me, I wouldn't mind the cedar structure for the main parts, but would have used aluminum extrusion on top of it as mounting rails for the PV modules (just regular L- or U-channel, there's plenty available that is Ontario made).

-RoB-

[William Qian]

RoB, I've send you a PM.

Another thought. How about a 1-axis or 2-axis tracking system? Will it worth the cost and trouble for the more harvest?

[Wilco Vercoelen]

If the home owner is doing the maintenance for twenty years I do not see a problem with choosing wood, however I myself have very serious doubts that it will hold twenty years.
The location itself can reduce the stress on the system such as wind load if it enough widely surrounded not interfering with the sun exposure of the array. My other concern would be that wood under the influence of temperature changes and outdoor exposure minor cracks appear where moisture will penetrate. I have seen bending as well creating additional mechanical stresses on the modules and the array.
It all comes down to the actual design and proper maintenance.

I see more and more wooden support structures in the field that are installed by dealers, and I do not like one bit!

[Rob Beckers]

William, a 1-axis tracker adds a maximum of 25% vs. fixed (for the Ottawa latitude). A 2-axis tracker adds 33% vs. fixed. So, your returns would increase by the same amount. However, the trackers I've seen also add about 25% to the installation price. The net-result is that your payback time does not change, it's about the same for fixed vs. tracking. Your simple profit at the end of the 20-year contract does increase though, since the array produces more energy. Keep in mind that trackers require maintenance, you radically depart from the simplicity of no moving parts that a fixed PV array represents. I do not know of any trackers that will work for 20 years without breaking, so reserve some money for maintenance/repairs and there will be some downtime. Because of all that I do not install trackers. In my view the gain is too little to warrant the additional issues.

I agree with Wilco that commercial installers should not be using wood. While I believe it can work for home owners if done right, and makes for an economical way to install PV, it is not durable enough to guarantee 20 years of maintenance-free production. When someone is paying big bucks to a company to install solar they have a right to get durable materials.

-RoB-

[Rob Beckers]

I should qualify the tracker vs. fixed a bit more: I do believe trackers have their place, just not for MicroFIT. They are great for off-grid installations where there is more of a need to get every last kWh out of an array, and where the PV arrays tend to be much smaller than 10kW.

-RoB-

[Wilco Vercoelen]

Trackers for the microFIT offer the highest annual dollar return (not necessarily ROI), but are also higher risk as it is a mechanical device that moves, therefore additionally comprimise the up-time and risk down-time.
I see a limited place for it in the microFIT, but would personally never install one.
Do not rely on referrals and sales pitches alone, these are just as reliable as the one that claims them.
Go with independent actual facts that can be shown and proven.