Thursday, May 14, 2009

1.21 Gigawatts!

OK, so maybe I'm not harnessing the power of the lighting bolt, but the sun works well too. I've been patiently waiting as Acro Electric has been installing the solar system for the house, and more importantly the power to charge the car as well!

I kept climbing up on the roof when I'd get home from work to see what they had accomplished.

Here is a picture of some of the anchor bolts installed for one of the two groups of panels.

Here is a close-up of one. You see all the black caulking that goes into the drilled hole. Additionally the black piece of flashing will be over the bolt and hole with the higher shingle laid over this as well see later. This flashing allows most, if not all, of the water never even get near the hole.

Here is the south facing group of rails installed. You can now see how each anchor is covered by the flashing and slide under the higher shingle.
Here is a picture of the west facing group. I didn't have much south facing roof space so half of the panels went here.
The panels and inverters are brought in for installation. The panels are from SunPower model SPR-225-BLK-U. They are small and rated for 225 watts a piece, which is quite a bit especially for their size. There are two inverters SPR-3000m and SPR-4000m. As you've probably guessed they are rated for 3k watts and 4k watts respectively. There are 28 panels total for a DC/STC rating of 6.3kW. This is fancy rating they give to "lab conditions" and you won't see these numbers in the real world. Therefore another rating is given (CEC/CSI) which is a "real world" rating of 5.56kW. The physical roof footprint is 393 sq.ft.
Here is the south roof again with the panels installed. They are a nice solid black color, you can't see the PV cells like you can with the other panels.
The west facing group.
Here is the west facing group again with some perspective of how little roof space was needed for half (3.15kW) of panels. I could really add a lot more if I need to.
Day 4 and 5:
The last couple days was doing all the wiring and finishing touches on the system.
Here are the two inverters mounted in my garage. You can also see the new 220v plug I had them install while they were at it for the car charger. I was running a long, and rather big, cable across my garage before.
Today was the first day they got to fully operate over the entire time frame of sun light and they produced 40kW. I'm pretty sure as summer really kicks in we'll get even more out of them.


Chris said...

Really cool! I love your car, and you're PV setup as well. Are you charging batteries with the solar panels, or are you selling your excess back to the utility company?

Brian said...

Both. The system is large enough to provide 100% of my home usage as well as charge the car.

Technically with PG&E you don't really sell the power. They keep track of how much extra you generate and they give you credit in a monetary sense. I'm doing a time of day usage, so I get more money (again credit) during peak usage times, then later in the evening when I'm home and using the power I get to buy it back at a cheaper rate than I sold to them at earlier in the day. This system allows me to only provide about 75% of my power and still cover 100% of my usage.

Jim and Elizabeth Karamalis said...

This is great Brian. You have made a major step forward in reducing your carbon footprint....

The incentives you folks get makes investing in such systems very attractive. Many people have to remember that before trying to get off the grid or become 100% self sufficient, they really need to look at their energy consumption and find all the ways possible to cut back. We all generally consume too much.

Your setup is very impressive and inspiring. My dream has been to build a home that is so efficient it needs very liitle energy to heat and cool while harnessing nature's gifts like sunlight and the wind.


Simon said...

Funny how one gets up on the roof and photo logs it all... I did just the same...

nice looking panels, too. Enjoy.

Dumb question maybe, where does the 1.21GW come from?

Brian said...

Dang I figured everybody would know that one. It's from the movie "Back to the Future". There were three total, they were great.

Anonymous said...

Hi! I love your work. I'm have been following your progress here from Finland. This may be a silly question but are the solar panels directly connected to the grid via the inverter? Or do you store the electricity first in batteries and then via the inverter use it for lightning in your house and charging your car?

Please give an insight into how your solar system works ;o) In Finland the electricity companies do not allow households to sell back electricity to the grid. That sucks big time.

All the best!

LeftLibertarian said...

Wow, I'm amazed you did the conversion of the Honda 200 but didn't install the PV system yourself. Those PV systems are very simple to install in comparison to your Honda 2000 conversion!

Brian said...

I would love to have installed it and saved some cash. I think I mentioned earlier that my power company will not allow me to be tied to the grid unless a licensed installer does the job.

LeftLibertarian said...

Ah . . . they tricked you. PG&E does allow self installs. You do need to get it inspected & approved though. A lot of installers will tell you otherwise though . . . they want the business and are not above misleading people.

LeftLibertarian said...

Info on PG&E self-install:
"Can I install a solar PV system myself?
While uncommon, self installations are allowed so long as proper building permits are obtained and local codes are followed."

And see section 2.1.4 of the California Solar Initiative handbook.

Yes, I have done a self-install at a previous house (though that was not PG&E) and plan to do one at my current house which is PG&E.

Sorry to be the bearer of bad news. :-(

Brian said...

Figures, oh well it's done now :)

Anonymous said...

the panels were not mounted square to each other.
They took way too long to do the install. This should have been done in 2 days tops. Unless only one person did it all.
There are missing brackets between rows to tie the panels together on both sides. That is safer in case of heavy winds.
I have a 4.05KW sunpower similar system using the 4KW inverter and it is producing at similar efficiency in MD, which is great given that in CA you must get a lot more sun shine at lower temps than we get in the summer.
You could have saved 10K or more doing it yourself, but then again the time it would have taken would be the equivalent to more tha 5K for most of us who can afford this thing.
With all the Federal, state and local incentives plus REC credits one can sell my 4KW system will be paid off in 6 years or less . After that it is free energy.
It is nice to see the meter run backwards. Someday in spring and fall the bill will have a negative power comsumption.
Someone had a good comment about reduction in energy waste being a good start. Not only I generate 600 KWH/month now, but I also have reduced the total house energy consumption by 30%. So my bill instead of being for 1500 KWH for july was only 450KWH.
It is amazing how much you can save by setting computers to hibernate in 1 hour instead of staying on all the time (i.e. 200W x 24 hours = 4.8 KWH). setting thermostat to 78F instead of 72F, running more fans to make 78 feel like 72. opening windows at night to cool the house instead of using the AC to do that, etc. Improving the roof insulation does not pay back as much for cooling as it does for heating, but is also a good area to look at.

click said...

Really cool post!