Sunday, May 31, 2009

More work on the Bamboo Grove

May, 2009

It's been raining the last two weekends, so it was hard to get much done outside. But this weekend was nice, so it was back to work!

I've got the cement wall poured from bedrock. The cement wall will all be underground. It took about 15 to 20 bags of Ready-Mix concrete, to pour the wall around the back half of the "Jungle". I dug out about 2 feet around it, down to bedrock. I went straight down from the previous stone edging, which allowed me to use the dirt on the Jungle side as one half of the forms. I used simple (cheap) masonite for the other side, with a 1x4 between them to keep the two sides apart. As I shoveled concrete in, I pulled out the 1x4. Let sit overnight, remove the masonite and it's done.

Now the problem is to put the stones back on top of it. I hired a day laborer with some masonry experience to do that, but, all in all, I think I could do as well. And it seems that the one row that he put on is too low, so I'll put another row on top of them. We were low on rocks, so I went to Custom Stone and got another 30 or so (Blanco chop). These were from Austin Custom Stone 400 pounds for $23.82. I've got those placed, but figure I'll put most of the dirt back in before doing the rest of the masonry.

So this weekend it was digging again. Try to go down to bedrock and get the smaller rocks out, and mix the dirt up with compose and leaves, so that it will be more organic and less rocky wasteland. Remember bedrock is only 9 to 12 inches down, so it's not a lot of digging. But it's rocky and rooty.

Another problem that I had forgotten about was the old sprinkler system. There are still PVC pipes for the old sprinkler system. I've taken out most of it, and will work on getting more, but there is at least one piece that goes from the current working area over to the far corner of the fence. I guess it will have to stay until this whole area is dug up.

There is a trench along the back fence that has telephone, cable and electrical lines in it. But that seems to be quite a ways down. They cut thru the limestone bedrock to trench it down at least 18 inches. I dug (carefully) into the trench at least 10 inches and found nothing. So this area should be clear of anything except roots and rocks and the occasional PVC sprinkler pipe.

I got two wheelbarrows full of rocks today, and a pile of dirt. My approach is effectively to dig a trench and then move it forward, putting the dirt behind me, pulling out the rocks (which go in the wheelbarrow) and the roots (which go into a plastic trash can to be taken to the curb for lawn waste recycling once a week).

At the moment I am digging in the Bamboo Grove itself, mainly because I have the opportunity to clean the dirt that is not yet overrun by the bamboo. This will probably take another 2 to 3 weeks of digging. Then I can do the same on the section that is next to it. This area is separated by the cement wall and stones that are to be at ground level (not an edging), to just contain the bamboo. Since this area is behind the Jungle, it's not visible from the house, so we will move the compost pile to this area when it is done.

Tuesday, May 5, 2009

Replacing a Solar Panel

Our solar system was in the direct path of the hail storm of March 25. Almost every house in our neighborhood is having its roof replaced. The hail was literally golf ball size. We took a direct hit on one of our 24 solar panels. Davis Elementary School, just blocks away, has a much larger solar system, probably twice the size we have. Two of their panels were visibly damaged by the hail. 

Immediately after the hail storm, I tried to contact the company that installed my system to have the panel replaced. Our system was installed in August, 2006, but the company is no longer here in Austin. Of the eight companies that I worked with in getting our solar system, only two are still on the City's directory of participating companies now. Once I was able to find another company (Green City Austin) to work with, we found that the panels I have are no longer being made. The panels are different sizes with different specifications; it's not clear if how they can be mixed. We eventually found a panel in a warehouse somewhere that had been forgotten about and had it shipped here. 

When they brought the panel out to install, they found that it was wired differently, but were able to use parts from the broken panel to re-wire the new panel and install it. 

We have 24 panels, arranged in two rows of 12. Each row is electrically separate, so losing one panel meant that we were generating only 50% of our normal power. Think of it like Christmas lights -- when one goes out, everything in that strand goes out. But replacing the broken panel did not improve our power output. Testing the broken panel, once it was removed, showed that it was working fine. The glass cover was broken, but not the silicon -- it had continued to generate power. (Of course, it was not thought to be working when it was removed, so it's really not functional now). 

But why then were we only generating half power? Since January, the City has been printing how much we generate each month on our utility bill. Those numbers have been consistent, but it turns out, they have been at 50% for months. How long I can't tell. When the system was installed, I carefully monitored it for several months, recording the power generated every day. 

But that proved really boring ... another day, another 14 kilowatts. The system requires no maintenance. I don't need to add gas or check the oil or change the filter or mow it or water it or anything. 

Or so I thought. After a couple hours of investigation, we determined that something -- most likely a squirrel -- had chewed thru one of the power cables. That short circuit was what was causing the problem, not the hail-damaged solar panel. It turned out they had chewed thru not just one cable, not two cables, but three separate cables.

So I have learned several things from this episode: 

1. Solar power is still in its infancy; companies will come and go with great frequency. Any customer needs to be prepared to switch companies as necessary, or take over maintenance and repair themselves. 

2. While solar systems are very hardy, they are not indestructible and they will not last forever. A solar system needs to be designed to be maintained, monitored, and repaired. 

3. The parts that are available now will not be available in the future (not unlike just about anything else in life). So if panels need to be replaced, they will not be compatible in size or appearance (at the least). On a long-lived system (these are supposed to last 20 years or more), expect it to become non-homogeneous -- not all parts will be the same. 

4. Even a system that requires no maintenance will need regular monitoring. 

 5. Squirrels are evil.