Our microFIT

[Ralph Day]

We started our microFIT project in September of 2009 with application to the OPA just after the program was released. The site chosen was to the west of our domestic pv arrays and north (out of the shading) of our wind turbine. It was covered in thick scrub, red cedars and salvagable firewood.

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A couple of days work cutting and drawing out firewood was needed before major clearing work could begin. After waiting for 6 weeks it was decided to commence operations (that had to be paid for) before getting the letter of offer of contract from the OPA. Should have started sooner. Fast forward to November.

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Clearing was performed by a 45 ton dozer driven by a 79 year old teenager. He could make the machine dance if he wanted to. 10 hours over 2 days cleared about 1 acre...more than needed, but adequate.

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Not knowing whether we would be working in the winter, or in the spring when half load restrictions are put on the municipalities roads a rough driveway was pushed through to the ground mount site. 3+ crushed stone (coarse stuff) was dropped and smoothed out then 3/4 stone was spread out enough to foundation a 75x10 foot concrete pad, 7 3/4 inch thick. The stone was compacted before concrete work commenced. The picture is of my neighbour, Todd. Very helpful, more of him later.

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After begging the local concrete supplier to fit me in on one of the last Saturday's before hard freezing we prepared for concrete pouring. There's Todd again, helping with the forming an hour before the first truck arrives.

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Forms up and truck backs into the open ended form, over the soft patch where the rear wheels squish down the rock about a foot. Scary, but the rock acted like a carpet and kept the truck afloat until it reached solid compacted rock...phew! Sorry, no picture, I ran away. A crane would have been needed to extricate a premix truck with 10 cubic yards of mix in the drum.

Waiting between trucks, me, in the toque (that's a Canadian hat) and sunglasses. Screeding the top seemed like the easiest job for the most senior of the crew...Calvin, the young lad with the rake spent 2 hours shoveling and raking wet concrete...the best money spent on the whole job, he worked the hardest of anyone that day.

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And there's Todd on the other end of the screed board. Kevin doing a quick change of a 2x8 cleat (removed from inside the forms and put outside where it should have been).

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Always order more concrete than you think you'll need! Here the tractor loader is securing the end board of the forms...in from the end of where it was expected to finish...one more yard of concrete would have been just fine. 2 helpers finishing the edge of the pad.


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Once the concrete set for 5-6 hours 2 large bales of straw were distributed over the top and tarped down as protection against freezing.

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A few short weeks later and mother nature has covered all the mud and work so far. This represents the state of things until April 2010.

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April. Holes were drilled in the concrete for 3/4 inch rods to be sunk in A10 adhesive anchor from Redhead. Great stuff to work with, sorry, no pictures as the photographer (spouse) was away on a work related course. But it was loud and dusty.

[Ralph Day]

Trenching for cabling well before racking was ready. Here's the engineer wondering where the heck Ralph wants the line to go!

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The main support posts are in place and secured prior to the installation and welding of the racking.

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With temporary bracing in place we're ready for the pre-fabricated racks.

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Welding on site of back braces to plates, the tractor ready to place another rack piece.

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[Ralph Day]

A good perspective of the entire array. This is well engineered stuff, 100mph wind before failure (if then).

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Panels were applied in mid May, Enphase inverters too.

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This is the latest, you'll notice 2 meters. We decided to have a load service re-installed after 6 years off grid, thinking of the future. To just have the revenue meter, without any load service means the customer has to buy the transformer...$3K to $5K.

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And how many of us see a meter at 0000, or at least for long (that's the load service meter).?

[Rob Beckers]

Holy Cow Ralph!
That is some serious racking! Wow! :hail:

How deep is the gravel foundation for the pad? I didn't notice any rebar or mesh. You're not worried about cracks? Usually a pad this size needs control joints, to direct the cracking. I assume you made it 7 3/4" thick so it doesn't need the joints? By the way, my concrete pad in the warehouse is just 5" thick; that was the thickness needed to carry my 8000 lbs fork lift...

Well, nobody will tell you that racking is under-engineered. That's way beyond any home-made racking I've ever seen.

So, did you get your first cheque yet from the OPA? :)

-RoB-

[Ralph Day]

Rob,
The gravel foundation is about 6-8 inches thick compacted with a plate compacter. The gravel was laid over almost solid rock, shale over bedrock anyways. The concrete has the nylon fibres in it, no metal reinforcment. The total volume 19cu yards, stress relief cuts are between each 12 panel array and in the middle of the 20 panel array.

We're getting the microFIT hooked up Tuesday, so the first cheque will probably be in October (if payment is quarterly). Looking forward to that. We've been paying interest on the loan since November!

Ralph

[Joe Blake]

Makes a guy feel kinda inadequate seein' all that.
:cheesy:
Looks great.

Joe

[Rob Beckers]

Ralph, payments should be at the same frequency as meter readings (which is currently every 3 months for Hydro-One here). When the LDC moves to using the new electronic meters and their remote reading capability it should become monthly. Many places have the electronic meters installed (looks like you have one), but they are not used to their full capabilities just yet.

When you have a chance, please post a few pictures of the finished array. Looks like you can seasonally change the tilt on it, is that right?

Somehow thought you were hooked up already, since you applied so early. It'll be a great sight to see that production meter finally spin!

-RoB-

[Ralph Day]

Hi Rob
If the meter spins that means a tornado has picked up my garage and taken it away!:D

The wooden bars holding the racks up were just for convenience of panel and inverter addition. The steel adjustment bars are in. The balance is easy to work, one person can do it easily.

More pics soon, now that I know how.

Ralph

[Ralph Day]

The latest...
Hydro One's meter tech came by on Tuesday the 29th and installed the bi-directional revenue meter for the system. After the 5 minute wait by the inverters production commenced.

From 13:00 hrs until night 29kwhrs accumulated. The next day had clouds covering the sky for the peak available hours 11-14:00, only 45kwhrs (better than a poke in the eye with a sharp stick). This morning I checked the Enphase Envoy (monitoring module) and power was being produced at 5:45am, panels with no direct sun on them, the sun being ''behind" the array for another 2 hours anyway.

Once the system is on line with the Enphase website I'll provide the link that will take you to my system's public page.

I'm trying not to become too meter sensetive...always running to look at just how much is being produced every minute of the day, but it's just such fun! :love:

Ralph

[Ralph Day]

A collective scream heard all over Ontario! The OPA has screwed the RE community yet again...first the content requirements, now the ground mounting aspect (great for those without appropriate facing roofs and land available) has been gouged out to $58.8 per kwh. Must be putting the brakes on the program.

July 2, 2010 -
The OPA has created a proposed new price category for ground-mounted solar PV projects 10 kilowatts or less in size. There will be a 30-day comment period on the proposed price of 58.8 cents per kWh for the new category.

link:

http://microfit.powerauthority.on.ca/Program-updates/ground-mount.php

Sorry folks.:eek:
Ralph

[Ralph Day]

Some changes since July 2. Apps prior to then can still recieve 80,2 cents and have until May 2011 to utilize the 40% ontario content rule. That's for ground mounting. More info elsewhere.

A year since application, on line June 29th, revenue stream to commence at the end of September 2010. Hydro One pays quarterly for now. The first payment will be for about 4 megawatts. Bills for the system have been paid out since Nov 2009. Not a great business plan, sure glad we weren't financing a 10Mw system!

Ralph

[Ralph Day]

We actually received a payment from Hydro One at the end of September. Looking forward to monthly revenue to offset our load use.

Load test: The house was put on inverter standby for 24 hours (domestic system, used only utility power) and the total usage was 7.5kwhrs. That's not much creep up from our off-grid baseline of 6.5-7 from 6 years ago. And we made toast and did a little ironing!

Ralph

[Rob Beckers]

This was the first payment Ralph? Have they told you anything when they expect to start using a monthly payment cycle?

With 7.5 kWh a day that works out to 228 kWh a month. That's very good! I'm ashamed to admit using just about 4x that much over here :embarrassedt: (and that's 1/3 down from when we bought this house, after replacing all the light bulbs with CFLs and getting a new fridge). Running a handful of computers 24x7, which serve up this forum amongst other things, doesn't help either. Though I've been slowly replacing them with less power hungry types.

-RoB-

[Ralph Day]

Monthly payments have started...as of last month. The end of each month will be payday.

I've heard so many people complain that their bills and consumption have gone up since smart meters had been installed. My load meter is at 139 kwhrs. I'm confident it's not reading high, and when there are no loads, there's no incrementing (conspiracy theories not withstanding).

Ralph

[Dave Schwartz]

Not quite the case with Waterloo North Hydro. They just instituted a policy where the microFIT payment (including HST) will be applied, on a monthly basis, to the associated load account and that they will review the accounts quarterly and refund any amount over $500. They said they might be convinced to do better than quarterly for projects closer to the 10kW max but they're still going to be holding on to a $500 float of your money.

[Ralph Day]

It's no wonder people feel they are looking down the barrell of a gun. Having electricity is like being mugged, repeatedly and slowly.

With Hydro One you had to set up a separate account, with costs of course. The account carries for about $7.50 per month, which you have to pay, it's not deducted from your payment.

Ralph

[Peter Mistel]

HI Ralph

I joined the forum to ask you a few questions. I install PV in Ontario and we have installed several Enphase systems. My question is in regards to module and inverter matching. Enphase says you can match up to a 230 watt module with a 190 watt inverter. My concern was that there would be some wasted watts if the inverter could not keep up with the module. I am also concerned that if the inverter is maxxed out it would cause more wear and tear on the inverter, especially the caps. When I designed a system for my roof I used a 185 watt module into a 190 watt Enphase inverter.

I did a little more research, saw some systems with 230 watt panels an started to think it was ok, then I saw your system. Yours seem to be really clipping power. I thought a 230 watt panel might be ok in our climate as we usually have poor insolation in the winter.

So my question is, could you please describe your system? What make and wattage panels do you have? I assume you have M190 inverters?

Regards

Peter

[Ralph Day]

Welcome Peter

As you can see from the power curves there's clipping at 10.3kw now. In the summer we would have a longer solar day, but were lucky if the power peak reached 10kw, definitely no clipping.

When the panels are hot their performance degrades/derates considerably, that's the reason for driving the M190's with more pv. In our case 12 kw pv for 10kw inverters. The clipping loses a bit of power no doubt, but the over pv amount allows for more harvest throughout the year. If you were to have 190 and 190 then the overall yield would be less due to the heat performance degradation.

My panels are 230 watt NESL polycrystalline from China. They've been manufacturing for over 20 years, not a flash in the pan Chinese company. My installer actually went to China to view the facility before ordering enough for several systems. He has engineering experience in the electronics manufacturing sector so knew what to look for in factory processes. He was happy with what he saw, and the price was good.

I'm hoping the Enphase inverters are all they are hyped up to be. No problems yet, except mine are running in the extended range mode. We both missed the electrician's ''undersizing'' the feed line from panels to meter. It met minimum voltage drop requirements (one of his first solar installs), but the voltage drop induced higher voltages and subsequent inverter drops. Enphase fixed this by resetting the inverters to the extended voltage range performance. I still think there's a performance penalty in doing this instead of pulling a larger feed cable. There are 2 identical systems by the same installer close by that out perform mine by about 1% total yield per day. Not much on a daily but over 20 years... some appreciable dollars...but enough to warrant scrapping the 6/3 for heavier cable? Not clear on that yet.

I don't think I'd put Enphase under panels over a roof. If you have an inverter fail in the middle of an array the logistics of removal and replacement are formidable. The rental of a portable boom device can't be cheap! It's not like an original install working from bottom to top, it's trying to get at the middle that would be problematic. (unless you could put the inverters in an accesible attic...hmm).

I look forward to the longer solar days, cold temperatures and snow reflection gain in February and March. Hoping for 85kwhr days then. Had an 83 in July:nuts:, in the heat, and a 741watt hr day last week in the gloom. :cry:

Ralph

[Peter Mistel]

Thanks for the reply

I had looked at this system

https://enlighten.enphaseenergy.com/public/systems/xpWw4801

230 watt panels into an M190. It showed some clipping but a few things made me think that wouldn't happen here. It is in Arizona so they have cold clear winters with very little humidity in the air, and they are on a ground mount with a good winter angle. Then I saw your system here in Ontario and you have even worse clipping. Not sure what the answer is. What angle are your panels at? Is the rack tilt adjustable?

I am not sure why you had to reset your inverters. The voltage range seems to be quite large. " 240V/211V-264V"

It just seems like you Modules are working really well! Maybe too well?

[Rob Beckers]

Hi Peter,

Very much in general, you should be able to oversize the PV array by 15% (ie. 115% of rated inverter capacity) without running into significant clipping. As Ralph mentioned, during the times of real energy production (late spring - early fall) the panel temperatures cause enough output derating to stay within the limit. For example, a typical derating percentage for regular silicon modules is -0.45% per degree C. Rated is 25C, we've seen typical cell temperatures of 55C for ground mount, more like 60C for roof (and it doesn't seem to matter too much what ambient is, it gets up there really quick). That's a 13% loss right there. Add at least 3% for inverter losses (for the best of them), and there you have it.

At 15% oversize the array will still occasionally clip, but it won't have a serious effect of energy production potential. Beyond that you'll get into the diminishing returns area. It also depends on the modules, for example Sanyo doesn't derate nearly as much with temperature, and consequently you would want to be more careful in oversizing.

Enphase inverters sell on their monitoring solution. The vast, vast majority of PV installs see no benefit in using micro inverters, but people want the monitoring. Personally, I only prescribe Enphase for installs that have complex shading issues, where I need more than two MPPT inputs to mitigate shading. Normally we stick Power-One inverters on the wall, which lets me deal with simple shading (depending on array size we often use two inverters, so that's 4 independent inputs). No matter what Enphase states in their marketing claims, and despite their 20-year warranty, the odds of a micro inverter failing are many times larger than for a string inverter to fail. It's simply a matter of part count (the MTBF of micro inverters can't be made all that much better than that of a string inverter). The thought of having to pull panels off a roof just to get to that failed inverter makes me shudder, and Murphy will make sure it's always the one in the middle. It doesn't help that Enphase will replace it free of charge.

-RoB-

[Ralph Day]

Hi Rob
Yeah, Enphase will replace, but that doesn't include removal!

Peter, our racking is adjustable seasonally with 5 selection points. The angle for December was not worth drilling in the support arm. The inverters were having high voltage/over voltage events. About 15% -20% of them would be dropping out and trying to re-synch with the grid power. The result was 5 hours of 75% production. The extended voltage range available (reset by Enphase in California) allowed the inverters to stay synch-ed at up to 260 volts ac, and I[ve measured the line voltage at 255vac on a sunny day. There is seldom if ever any load on the transformer and line when it's sunny out. My neighbour's line voltage will be 240 when mine is 255, but they have a full house load and teenagers. The loading of the service must have something to do with the high line voltage, not just the undersized feed line:idea:. That's my story and I'm sticking with it!:laugh:

Ralph

[Peter Mistel]

Hi Bob

Yes I undestand "negative temperature co-efficent". I know there is a bit of a gold rush here in Ontario. We regularly see roofers who want to install solar, even a roofing company in Missisauga that opened a showroom for solar next to thier roofing showroom. Hopefully they will get proper training, but I know there will be hundreds of poorly installed systems that will need repair in the future. We actually installed a few grid-tied systems before the Green Energy Act!

We have had the "inverter in the middle" give us problems, turns out one of the mc4's was not completely plugged in. I probably was responsible for that! It was not a hard fix.

Ralph, now I understand about the voltage, your line voltage was to high. I guess that is more of a problem out in the country.

I think what is going on with Ralphs system and the other system I posted is that they are both ground mount with good winter angles, so the panels can produce at thier maximun. My concern is that some of the systems we are installing will clip, but I still don't think it will happen because most of ours are roof mount and the angles would not be optimum when it is cold.

I personally don't think that clipping is good, it means the inverter is working at maximum, putting more strain on the components. Kind of like driveing your car full out for several hours.

[Rob Beckers]

We too have had a couple places where we had to up the voltage setting for the inverters. The issue we see is poor line impedance, and you're right Peter, it's mostly 'out in the country' where a residence may be at the end of a long line. So even though the nominal voltage is 245V (for some reason it's often on the high side to start with, probably because the power company knows it'll nose-dive when people put a serious load on), when the inverters try to backfeed they have to raise the voltage to 260V or so to pump a full 10kW back.

As to running full-load for extended time periods: I know the Power-One's are designed for it (and would expect any inverter to be able to handle that). No problem at all. The exact same hardware is used for their wind Aurora inverters (just different firmware). We actually program those to run up to 6.2kW (for a 6kW inverter) with Power-One's blessing, and they'll run full power for many hours on end. One of my customers uses a 6kW wind inverter with a diesel engine to backfeed the grid, like a genset, and I know they've been running this at full-power for over a year 24x7. Just keeps humming along. Pretty sturdy stuff...

-RoB-

[Ralph Day]

Hi Rob
Is that diesel/inverter install in Ontario? Net metering or some kind of FIT? It can't be cheap to drive 6kw with a diesel engine and still make money. That would require probably 1.5 - 2 litres per hour...75cents per litre...etc etc.

Ralph

[Rob Beckers]

Nope, it's not in Ontario. I can't talk much about it, due to an NDA. It doesn't just produce electricity though.

-RoB-

[Peter Mistel]

HI Ralph

One more question. It seems like you have a good location for a string inverter. Why did you choose Enphase?

[Ralph Day]

Like most people...the monitoring. I've had one underproducing panel found so far (within the first week of installation). Plus the high voltage events were easy to see, perhaps not so with a single or double string inverter.

Ralph

[Peter Klaassen]

Hi Ralph,
I see the graphs on the Enphase site now. Very handy to monitor the panels for problems and to follow the production over the long term.

Is there concern about lightening strikes affecting the computer link etc.?

Pete

[Ralph Day]

Is there concern about lightening strikes affecting the computer link etc.?


Well thanks Peter, no concerns until now!!!

Just joking, the wind turbine either has never been hit or has shed any problems so far. The EMP from that close a strike would be a problem, although the main wire is buried reducing it's antenna potential.

I think when you looked before the internet was down, hence nothing visible. Someone emailed me before when that happened. It requires a re-boot of the Roger's router to kick things back into play.

I'm thinking it's time to change the panel angle. The snow as reflective surface is mostly gone now so it might be best to optimize the angle of the panels.

Ralph