Art meets Engineering

I can't stop admiring the Silicon Energy panels! I was so enamored with them that I asked if there was a way to get a demo sample so I could put it in people's hands; it seemed a shame to mount them so far off the ground so no one could actually touch them.

Rebecca made some calls got us a demo panel, hand delivered by the president of Silicon Energy when he was visiting their soon to open production facility in Mountain Iron, Minnesota. In my world, this makes Minnesota one great place to live!

I always thought PV panels had a distinct "industrial vibe" about them. Often framed in metal, all though high as cool, magical inventions, they lacked a certain...panache, a je ne sais quois about them. I imagined we'd have tolerable, but rather "practical" panels. These Silicon Energy panels are incredible: beautiful, solid and elegant.

These are all tempered glass with fused edges:

From what I understand, other all-glass panels are two layers with a sealant bead around the edge. Eventually, as the seal ages, eventually moisture gets in, fogging it up and diminishing the production of the panel. These beautiful creatures, with their fused edges keep moisture out and class in. Look at how beautiful the _undersides_ of the panels are:

There is nothing to hide here! no little wires or ugliness. Beautiful engineering. If all engineering was this beautiful the world would be such a better place. The magical silicon crystals are also mesmerizing on the top.




Of course, what's good engineering without a little science geek humor? Priceless.

 

Remind me again why were are spending so much money and polluting so much  of our one and only Earth with stupid, ugly engineering like tar sands and coal mining? And why do we keep hoping for cold fusion to actually become EROI positive? If anything, these panels are the best argument that the time for solar is now, and it can be beautiful.

Power Up!

Today we went online!

This week, Xcel came an installed the production meter and finalized their end of the arrangement. Today, Rebecca and Dan came and gave us a generous walk through of the system. They spent over and hour and a half answering our questions, explaining the wiring runs and the system. They also gave us a substantial packet of information about our system, detailing the wiring, how to reboot if necessary and pointers on possible issues that might arise.

All that was left was to throw the switch!

Rebecca insisted that we each got to try out starting the system, so that we all know what it feels like and know what to expect if we have to turn it on or off for some reason. We took our turns under Rebecca's watchful eye. As she says, she has a healthy respect for electricity.

Proud owners of a PV system!

And the solar midwives who made it all happen: Powerfully Green!

Our wireless fusion receivers makin' lovely watts:

Nik the electrician was critical in putting it all together. Because we swapped in new breaker boxes, there were a modicum of issues that Nik had to deal with to get the final approval from the city.

Big Snow! How does it cover the modules?

Yesterday we got about 17" of blowy, light snow; one of the top ten snowstorms ever recorded in the Twin Cities. This morning was spent digging out our sidewalks and car and helping our neighbors do the same.

One of the things we wondered about was if we would have to keep the solar modules clear of snow in the winter time. Powerfully Green assured us that it would just slide off with no fuss, and although it would take a while for the roof installation to be cleared, the pergola with it's near 45 degree pitch would shed snow quickly as modules warmed.

Just for show and tell:

Here you can see the massive drifts in the yard. Easily 36+ inches in many places. Some of the neighbors roofs have easily 24" drifts in places. 

About 10am, 0F. Sunny. The roof installation is covered, with about 9-12 inches of drifts.

 About 10am, 0F. Sunny. Very little snow accumulated overnight on the pergola installation. Small melting drips are forming despite the temperature.

At about 230pm, temperatures "warmed" to about 5F, and while the roof installation is still covered for the most part but showing a little progress, the pergola is well on it's way to shedding the snow. It was fun watching the melting snow slide off over the side of the panels in spite of the cold. We're definitely going to want a gutter to catch rain water run off in the spring. That's a lot of surface area catching precipitation.

UPDATE:

A week of very cold and grey has prevented the roof array from clearing. A week later, that array is still mostly covered. We could sweep off the snow, but I'm intrigued to see how long it takes. This is all we've gotten uncovered at this point. The depth of snow has diminished, but we really need a sunny day to help it melt.

Finishing Touches

Yesterday the final inspection was completed. All is a go. Early next week, Xcel installs a production meter and connects the system to the grid. Last Monday, Rebecca and Terry put the finishing touches on the roof system.

Module Installation

The weather has been cold and snowy the last couple weeks, so progress has been a little slower than anticipated. They hope to get the final city inspection tomorrow. It's dark out now and they are still going strong.

Here are a few photos of the progress from the last couple days.

 Pergola modules being installed. I was concerned that the modules would easily be removed, but they are very firmly attached with much hardware. Fat chance they will disappear easily.

 The modules are translucent, transmitting something like 20% of light, which means we won't have dark and massive shadows to deal with in our garden. The silicon wafers are embedded between fused pieces of tempered glass. Because of the way they are manufactured, moisture can't sneak in through seams or because of joints. They seem to have about a 40 year life, which is extraordinary. The tempered glass withstands all sorts of thermal or physical shocks. They shouldn't crack if someone decides to pitch a rock at them. Rebecca said they can support something crazy like 600lbs. They are beautiful engineering, elegantly made. It's a shame they will be out of reach!

 Electricians at work. Nik and Charlie (?). All of the Powerfully Green contractors have been wonderful folks and been gentle and gracious with my curious boys.

 A rare photo of Rebbecca not in motion.
 
 Snowstorm last week left 6-8"

 Sebastian, 7yrs: "Dad, do you think they could leave the ropes for us to use?"

 Rails being installed for module brackets.

 Sebastian: "Can we get a truck and trailer like that?"

 Sebastian: "Wow! Look! Even their truck is solar powered!"

Super heroes at work.

Pergola Installation

Here are a few photos of the pergola structure, sans pv panels. Powerfully Green built it out of cedar with massive 6x6 posts. Because we're a duplex we have a 9' setback from the property lines. We could have done an additional 3 panels if we had another four feet. Generally the setback is 6' in St. Paul, MN. We love the pergola idea because we have so little roof space. They will squeeze in 9 panels on the roof, but that will leave no space for solar water or additional panels.

The trench! They dug down about 24." They managed to get it dug and filled before the ground got too frozen. I'm glad I didn't have to dig this trench. The black box under the pergola is a compost bin. We'll move it in the spring; we intend to use the space under the panels for bike and scooter parking.

kWh Consumption and Production

The Metroplex, a 1922 up-down duplex, has two Xcel energy accounts, that is two power lines in, two meters. For a variety of reasons, we're going to tie into the upper unit's feed, but are internally combining the billing since we share in the consumption in both units.

The lower unit uses more electricity because as a whole household we have three compressors running (freezer, fridge, and basement dehumidifier), and often a heater in the chicken coop. The upper unit has only one compressor on its circuits. We have no air conditioning.

We have windows in every room so for a lot of the year our lighting needs are met by the sun. For example, right now, in our unit we have a computer running (this one) and not a whole lot more. It's sunny out and we really don't need additional light anywhere. Upstairs we've been working on eliminating "phantom-load" and have been reluctant to purchase electronic equipment or appliances that rely on standby power.

For the upper unit our last year consumption in kWh was this:
10/24/10 - 169 kWh
9/23/10 - 208 kWh
8/24/10 - 162 kWh
7/26/10 - 160 kWh
6/24/10 - 162 kWh
5/25/10 - 147 kWh
4/26/10 - 136 kWh
3/28/10 - 209 kWh
2/25/10 - 369 kWh
1/27/10 - 479 kWh
12/28/09 - 275 kWh
11/23/09 - 192 kWh

Average: 222 kWh

Lower unit:
10/24/10 - 270 kWh
9/23/10 - 343 kWh
8/24/10 - 547 kWh
7/26/10 - 625 kWh
6/24/10 - 379 kWh
5/25/10 - 427 kWh
4/26/10 - 356 kWh
3/28/10 - 350 kWh
2/25/10 - 310 kWh
1/27/10 - 661 kWh
12/28/09 - 428 kWh
11/23/09 - 317 kWh

 Average: 418 kWh

Total metroplex monthly consumption: 640kWh.

Our system will be 3.24 kW composed of 18 Silicon Energy 180 watt modules with 9 modules flush mounted on house roof and 9 mounted on pergola in yard.

By the estimates from the National Renewable Energy Laboratory (NREL)

Month	Solar Radiation (kWh/m2/day)	AC Energy (kWh)	Energy Value ($)
1	3.85	325	25.68
2	4.72	348	27.49
3	4.97	393	31.05
4	4.90	353	27.89
5	5.73	410	32.39
6	5.91	398	31.44
7	5.88	409	32.31
8	5.64	393	31.05
9	5.21	362	28.60
10	4.28	320	25.28
11	2.95	220	17.38
12	2.85	234	18.49
Year	4.74	4165	329.04

On a monthly average, our system hopefully will produce ~345kWh. Or approximately 54% of our use.

The fanatic in me wonders, so what else can we reduce? I'd love to see the dial spin backwards and have Xcel pay us.